b0684bf084
The new defaults that came in with 644400054c5769a397ded4f569e2ac0600d65305 are nice, however, it is still possible that someone knows their inputs are always small and wants to use the simpler implementations. We keep the default to make the choice at runtime, but expose the linear functions in the public interface of std.mem. Also improved the doc comments.
2367 lines
79 KiB
Zig
2367 lines
79 KiB
Zig
// SPDX-License-Identifier: MIT
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// Copyright (c) 2015-2020 Zig Contributors
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// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
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// The MIT license requires this copyright notice to be included in all copies
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// and substantial portions of the software.
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const std = @import("std.zig");
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const debug = std.debug;
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const assert = debug.assert;
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const math = std.math;
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const builtin = @import("builtin");
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const mem = @This();
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const meta = std.meta;
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const trait = meta.trait;
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const testing = std.testing;
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/// https://github.com/ziglang/zig/issues/2564
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pub const page_size = switch (builtin.arch) {
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.wasm32, .wasm64 => 64 * 1024,
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else => 4 * 1024,
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};
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pub const Allocator = @import("mem/Allocator.zig");
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/// Detects and asserts if the std.mem.Allocator interface is violated by the caller
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/// or the allocator.
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pub fn ValidationAllocator(comptime T: type) type {
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return struct {
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const Self = @This();
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allocator: Allocator,
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underlying_allocator: T,
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pub fn init(allocator: T) @This() {
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return .{
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.allocator = .{
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.allocFn = alloc,
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.resizeFn = resize,
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},
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.underlying_allocator = allocator,
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};
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}
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fn getUnderlyingAllocatorPtr(self: *@This()) *Allocator {
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if (T == *Allocator) return self.underlying_allocator;
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if (*T == *Allocator) return &self.underlying_allocator;
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return &self.underlying_allocator.allocator;
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}
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pub fn alloc(
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allocator: *Allocator,
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n: usize,
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ptr_align: u29,
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len_align: u29,
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ret_addr: usize,
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) Allocator.Error![]u8 {
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assert(n > 0);
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assert(mem.isValidAlign(ptr_align));
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if (len_align != 0) {
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assert(mem.isAlignedAnyAlign(n, len_align));
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assert(n >= len_align);
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}
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const self = @fieldParentPtr(@This(), "allocator", allocator);
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const underlying = self.getUnderlyingAllocatorPtr();
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const result = try underlying.allocFn(underlying, n, ptr_align, len_align, ret_addr);
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assert(mem.isAligned(@ptrToInt(result.ptr), ptr_align));
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if (len_align == 0) {
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assert(result.len == n);
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} else {
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assert(result.len >= n);
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assert(mem.isAlignedAnyAlign(result.len, len_align));
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}
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return result;
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}
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pub fn resize(
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allocator: *Allocator,
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buf: []u8,
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buf_align: u29,
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new_len: usize,
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len_align: u29,
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ret_addr: usize,
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) Allocator.Error!usize {
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assert(buf.len > 0);
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if (len_align != 0) {
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assert(mem.isAlignedAnyAlign(new_len, len_align));
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assert(new_len >= len_align);
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}
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const self = @fieldParentPtr(@This(), "allocator", allocator);
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const underlying = self.getUnderlyingAllocatorPtr();
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const result = try underlying.resizeFn(underlying, buf, buf_align, new_len, len_align, ret_addr);
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if (len_align == 0) {
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assert(result == new_len);
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} else {
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assert(result >= new_len);
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assert(mem.isAlignedAnyAlign(result, len_align));
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}
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return result;
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}
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pub usingnamespace if (T == *Allocator or !@hasDecl(T, "reset")) struct {} else struct {
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pub fn reset(self: *Self) void {
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self.underlying_allocator.reset();
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}
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};
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};
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}
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pub fn validationWrap(allocator: anytype) ValidationAllocator(@TypeOf(allocator)) {
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return ValidationAllocator(@TypeOf(allocator)).init(allocator);
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}
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/// An allocator helper function. Adjusts an allocation length satisfy `len_align`.
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/// `full_len` should be the full capacity of the allocation which may be greater
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/// than the `len` that was requsted. This function should only be used by allocators
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/// that are unaffected by `len_align`.
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pub fn alignAllocLen(full_len: usize, alloc_len: usize, len_align: u29) usize {
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assert(alloc_len > 0);
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assert(alloc_len >= len_align);
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assert(full_len >= alloc_len);
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if (len_align == 0)
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return alloc_len;
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const adjusted = alignBackwardAnyAlign(full_len, len_align);
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assert(adjusted >= alloc_len);
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return adjusted;
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}
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var failAllocator = Allocator{
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.allocFn = failAllocatorAlloc,
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.resizeFn = Allocator.noResize,
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};
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fn failAllocatorAlloc(self: *Allocator, n: usize, alignment: u29, len_align: u29, ra: usize) Allocator.Error![]u8 {
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return error.OutOfMemory;
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}
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test "mem.Allocator basics" {
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testing.expectError(error.OutOfMemory, failAllocator.alloc(u8, 1));
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testing.expectError(error.OutOfMemory, failAllocator.allocSentinel(u8, 1, 0));
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}
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/// Copy all of source into dest at position 0.
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/// dest.len must be >= source.len.
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/// dest.ptr must be <= src.ptr.
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pub fn copy(comptime T: type, dest: []T, source: []const T) void {
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// TODO instead of manually doing this check for the whole array
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// and turning off runtime safety, the compiler should detect loops like
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// this and automatically omit safety checks for loops
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@setRuntimeSafety(false);
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assert(dest.len >= source.len);
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for (source) |s, i|
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dest[i] = s;
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}
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/// Copy all of source into dest at position 0.
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/// dest.len must be >= source.len.
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/// dest.ptr must be >= src.ptr.
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pub fn copyBackwards(comptime T: type, dest: []T, source: []const T) void {
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// TODO instead of manually doing this check for the whole array
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// and turning off runtime safety, the compiler should detect loops like
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// this and automatically omit safety checks for loops
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@setRuntimeSafety(false);
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assert(dest.len >= source.len);
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var i = source.len;
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while (i > 0) {
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i -= 1;
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dest[i] = source[i];
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}
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}
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/// Sets all elements of `dest` to `value`.
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pub fn set(comptime T: type, dest: []T, value: T) void {
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for (dest) |*d|
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d.* = value;
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}
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/// Generally, Zig users are encouraged to explicitly initialize all fields of a struct explicitly rather than using this function.
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/// However, it is recognized that there are sometimes use cases for initializing all fields to a "zero" value. For example, when
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/// interfacing with a C API where this practice is more common and relied upon. If you are performing code review and see this
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/// function used, examine closely - it may be a code smell.
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/// Zero initializes the type.
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/// This can be used to zero initialize a any type for which it makes sense. Structs will be initialized recursively.
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pub fn zeroes(comptime T: type) T {
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switch (@typeInfo(T)) {
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.ComptimeInt, .Int, .ComptimeFloat, .Float => {
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return @as(T, 0);
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},
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.Enum, .EnumLiteral => {
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return @intToEnum(T, 0);
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},
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.Void => {
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return {};
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},
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.Bool => {
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return false;
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},
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.Optional, .Null => {
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return null;
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},
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.Struct => |struct_info| {
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if (@sizeOf(T) == 0) return T{};
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if (comptime meta.containerLayout(T) == .Extern) {
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var item: T = undefined;
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set(u8, asBytes(&item), 0);
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return item;
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} else {
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var structure: T = undefined;
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inline for (struct_info.fields) |field| {
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@field(structure, field.name) = zeroes(@TypeOf(@field(structure, field.name)));
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}
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return structure;
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}
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},
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.Pointer => |ptr_info| {
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switch (ptr_info.size) {
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.Slice => {
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return &[_]ptr_info.child{};
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},
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.C => {
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return null;
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},
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.One, .Many => {
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@compileError("Can't set a non nullable pointer to zero.");
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},
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}
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},
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.Array => |info| {
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if (info.sentinel) |sentinel| {
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return [_:sentinel]info.child{zeroes(info.child)} ** info.len;
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}
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return [_]info.child{zeroes(info.child)} ** info.len;
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},
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.Vector => |info| {
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return @splat(info.len, zeroes(info.child));
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},
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.Union => |info| {
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if (comptime meta.containerLayout(T) == .Extern) {
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// The C language specification states that (global) unions
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// should be zero initialized to the first named member.
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var item: T = undefined;
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@field(item, info.fields[0].name) = zeroes(@TypeOf(@field(item, info.fields[0].name)));
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return item;
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}
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@compileError("Can't set a " ++ @typeName(T) ++ " to zero.");
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},
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.ErrorUnion,
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.ErrorSet,
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.Fn,
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.BoundFn,
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.Type,
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.NoReturn,
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.Undefined,
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.Opaque,
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.Frame,
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.AnyFrame,
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=> {
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@compileError("Can't set a " ++ @typeName(T) ++ " to zero.");
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},
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}
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}
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test "mem.zeroes" {
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const C_struct = extern struct {
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x: u32,
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y: u32,
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};
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var a = zeroes(C_struct);
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a.y += 10;
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testing.expect(a.x == 0);
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testing.expect(a.y == 10);
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const ZigStruct = struct {
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integral_types: struct {
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integer_0: i0,
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integer_8: i8,
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integer_16: i16,
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integer_32: i32,
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integer_64: i64,
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integer_128: i128,
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unsigned_0: u0,
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unsigned_8: u8,
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unsigned_16: u16,
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unsigned_32: u32,
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unsigned_64: u64,
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unsigned_128: u128,
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float_32: f32,
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float_64: f64,
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},
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pointers: struct {
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optional: ?*u8,
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c_pointer: [*c]u8,
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slice: []u8,
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},
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array: [2]u32,
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vector_u32: meta.Vector(2, u32),
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vector_f32: meta.Vector(2, f32),
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vector_bool: meta.Vector(2, bool),
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optional_int: ?u8,
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empty: void,
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sentinel: [3:0]u8,
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};
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const b = zeroes(ZigStruct);
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testing.expectEqual(@as(i8, 0), b.integral_types.integer_0);
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testing.expectEqual(@as(i8, 0), b.integral_types.integer_8);
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testing.expectEqual(@as(i16, 0), b.integral_types.integer_16);
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testing.expectEqual(@as(i32, 0), b.integral_types.integer_32);
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testing.expectEqual(@as(i64, 0), b.integral_types.integer_64);
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testing.expectEqual(@as(i128, 0), b.integral_types.integer_128);
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testing.expectEqual(@as(u8, 0), b.integral_types.unsigned_0);
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testing.expectEqual(@as(u8, 0), b.integral_types.unsigned_8);
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testing.expectEqual(@as(u16, 0), b.integral_types.unsigned_16);
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testing.expectEqual(@as(u32, 0), b.integral_types.unsigned_32);
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testing.expectEqual(@as(u64, 0), b.integral_types.unsigned_64);
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testing.expectEqual(@as(u128, 0), b.integral_types.unsigned_128);
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testing.expectEqual(@as(f32, 0), b.integral_types.float_32);
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testing.expectEqual(@as(f64, 0), b.integral_types.float_64);
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testing.expectEqual(@as(?*u8, null), b.pointers.optional);
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testing.expectEqual(@as([*c]u8, null), b.pointers.c_pointer);
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testing.expectEqual(@as([]u8, &[_]u8{}), b.pointers.slice);
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for (b.array) |e| {
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testing.expectEqual(@as(u32, 0), e);
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}
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testing.expectEqual(@splat(2, @as(u32, 0)), b.vector_u32);
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testing.expectEqual(@splat(2, @as(f32, 0.0)), b.vector_f32);
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testing.expectEqual(@splat(2, @as(bool, false)), b.vector_bool);
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testing.expectEqual(@as(?u8, null), b.optional_int);
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for (b.sentinel) |e| {
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testing.expectEqual(@as(u8, 0), e);
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}
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const C_union = extern union {
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a: u8,
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b: u32,
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};
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var c = zeroes(C_union);
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testing.expectEqual(@as(u8, 0), c.a);
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}
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/// Sets a slice to zeroes.
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/// Prevents the store from being optimized out.
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pub fn secureZero(comptime T: type, s: []T) void {
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// NOTE: We do not use a volatile slice cast here since LLVM cannot
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// see that it can be replaced by a memset.
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const ptr = @ptrCast([*]volatile u8, s.ptr);
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const length = s.len * @sizeOf(T);
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@memset(ptr, 0, length);
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}
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test "mem.secureZero" {
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var a = [_]u8{0xfe} ** 8;
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var b = [_]u8{0xfe} ** 8;
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set(u8, a[0..], 0);
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secureZero(u8, b[0..]);
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testing.expectEqualSlices(u8, a[0..], b[0..]);
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}
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/// Initializes all fields of the struct with their default value, or zero values if no default value is present.
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/// If the field is present in the provided initial values, it will have that value instead.
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/// Structs are initialized recursively.
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pub fn zeroInit(comptime T: type, init: anytype) T {
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comptime const Init = @TypeOf(init);
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switch (@typeInfo(T)) {
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.Struct => |struct_info| {
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switch (@typeInfo(Init)) {
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.Struct => |init_info| {
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var value = std.mem.zeroes(T);
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if (init_info.is_tuple) {
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inline for (init_info.fields) |field, i| {
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@field(value, struct_info.fields[i].name) = @field(init, field.name);
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}
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return value;
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}
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inline for (init_info.fields) |field| {
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if (!@hasField(T, field.name)) {
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@compileError("Encountered an initializer for `" ++ field.name ++ "`, but it is not a field of " ++ @typeName(T));
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}
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}
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inline for (struct_info.fields) |field| {
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if (@hasField(Init, field.name)) {
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switch (@typeInfo(field.field_type)) {
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.Struct => {
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@field(value, field.name) = zeroInit(field.field_type, @field(init, field.name));
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},
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else => {
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@field(value, field.name) = @field(init, field.name);
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},
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}
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} else if (field.default_value) |default_value| {
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@field(value, field.name) = default_value;
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}
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}
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return value;
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},
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else => {
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@compileError("The initializer must be a struct");
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},
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}
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},
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else => {
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@compileError("Can't default init a " ++ @typeName(T));
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},
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}
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}
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test "zeroInit" {
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const I = struct {
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d: f64,
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};
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const S = struct {
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a: u32,
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b: ?bool,
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c: I,
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e: [3]u8,
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f: i64 = -1,
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};
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const s = zeroInit(S, .{
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.a = 42,
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});
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testing.expectEqual(S{
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.a = 42,
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.b = null,
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.c = .{
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.d = 0,
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},
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.e = [3]u8{ 0, 0, 0 },
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.f = -1,
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}, s);
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const Color = struct {
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r: u8,
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g: u8,
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b: u8,
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a: u8,
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};
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const c = zeroInit(Color, .{ 255, 255 });
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testing.expectEqual(Color{
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.r = 255,
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.g = 255,
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.b = 0,
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.a = 0,
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}, c);
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}
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/// Compares two slices of numbers lexicographically. O(n).
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pub fn order(comptime T: type, lhs: []const T, rhs: []const T) math.Order {
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const n = math.min(lhs.len, rhs.len);
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var i: usize = 0;
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while (i < n) : (i += 1) {
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switch (math.order(lhs[i], rhs[i])) {
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.eq => continue,
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.lt => return .lt,
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.gt => return .gt,
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}
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}
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return math.order(lhs.len, rhs.len);
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}
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test "order" {
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testing.expect(order(u8, "abcd", "bee") == .lt);
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testing.expect(order(u8, "abc", "abc") == .eq);
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testing.expect(order(u8, "abc", "abc0") == .lt);
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testing.expect(order(u8, "", "") == .eq);
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testing.expect(order(u8, "", "a") == .lt);
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}
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/// Returns true if lhs < rhs, false otherwise
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pub fn lessThan(comptime T: type, lhs: []const T, rhs: []const T) bool {
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return order(T, lhs, rhs) == .lt;
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}
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test "mem.lessThan" {
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testing.expect(lessThan(u8, "abcd", "bee"));
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testing.expect(!lessThan(u8, "abc", "abc"));
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testing.expect(lessThan(u8, "abc", "abc0"));
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testing.expect(!lessThan(u8, "", ""));
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testing.expect(lessThan(u8, "", "a"));
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}
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/// Compares two slices and returns whether they are equal.
|
|
pub fn eql(comptime T: type, a: []const T, b: []const T) bool {
|
|
if (a.len != b.len) return false;
|
|
if (a.ptr == b.ptr) return true;
|
|
for (a) |item, index| {
|
|
if (b[index] != item) return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// Compares two slices and returns the index of the first inequality.
|
|
/// Returns null if the slices are equal.
|
|
pub fn indexOfDiff(comptime T: type, a: []const T, b: []const T) ?usize {
|
|
const shortest = math.min(a.len, b.len);
|
|
if (a.ptr == b.ptr)
|
|
return if (a.len == b.len) null else shortest;
|
|
var index: usize = 0;
|
|
while (index < shortest) : (index += 1) if (a[index] != b[index]) return index;
|
|
return if (a.len == b.len) null else shortest;
|
|
}
|
|
|
|
test "indexOfDiff" {
|
|
testing.expectEqual(indexOfDiff(u8, "one", "one"), null);
|
|
testing.expectEqual(indexOfDiff(u8, "one two", "one"), 3);
|
|
testing.expectEqual(indexOfDiff(u8, "one", "one two"), 3);
|
|
testing.expectEqual(indexOfDiff(u8, "one twx", "one two"), 6);
|
|
testing.expectEqual(indexOfDiff(u8, "xne", "one"), 0);
|
|
}
|
|
|
|
pub const toSliceConst = @compileError("deprecated; use std.mem.spanZ");
|
|
pub const toSlice = @compileError("deprecated; use std.mem.spanZ");
|
|
|
|
/// Takes a pointer to an array, a sentinel-terminated pointer, or a slice, and
|
|
/// returns a slice. If there is a sentinel on the input type, there will be a
|
|
/// sentinel on the output type. The constness of the output type matches
|
|
/// the constness of the input type. `[*c]` pointers are assumed to be 0-terminated,
|
|
/// and assumed to not allow null.
|
|
pub fn Span(comptime T: type) type {
|
|
switch (@typeInfo(T)) {
|
|
.Optional => |optional_info| {
|
|
return ?Span(optional_info.child);
|
|
},
|
|
.Pointer => |ptr_info| {
|
|
var new_ptr_info = ptr_info;
|
|
switch (ptr_info.size) {
|
|
.One => switch (@typeInfo(ptr_info.child)) {
|
|
.Array => |info| {
|
|
new_ptr_info.child = info.child;
|
|
new_ptr_info.sentinel = info.sentinel;
|
|
},
|
|
else => @compileError("invalid type given to std.mem.Span"),
|
|
},
|
|
.C => {
|
|
new_ptr_info.sentinel = 0;
|
|
new_ptr_info.is_allowzero = false;
|
|
},
|
|
.Many, .Slice => {},
|
|
}
|
|
new_ptr_info.size = .Slice;
|
|
return @Type(std.builtin.TypeInfo{ .Pointer = new_ptr_info });
|
|
},
|
|
else => @compileError("invalid type given to std.mem.Span"),
|
|
}
|
|
}
|
|
|
|
test "Span" {
|
|
testing.expect(Span(*[5]u16) == []u16);
|
|
testing.expect(Span(?*[5]u16) == ?[]u16);
|
|
testing.expect(Span(*const [5]u16) == []const u16);
|
|
testing.expect(Span(?*const [5]u16) == ?[]const u16);
|
|
testing.expect(Span([]u16) == []u16);
|
|
testing.expect(Span(?[]u16) == ?[]u16);
|
|
testing.expect(Span([]const u8) == []const u8);
|
|
testing.expect(Span(?[]const u8) == ?[]const u8);
|
|
testing.expect(Span([:1]u16) == [:1]u16);
|
|
testing.expect(Span(?[:1]u16) == ?[:1]u16);
|
|
testing.expect(Span([:1]const u8) == [:1]const u8);
|
|
testing.expect(Span(?[:1]const u8) == ?[:1]const u8);
|
|
testing.expect(Span([*:1]u16) == [:1]u16);
|
|
testing.expect(Span(?[*:1]u16) == ?[:1]u16);
|
|
testing.expect(Span([*:1]const u8) == [:1]const u8);
|
|
testing.expect(Span(?[*:1]const u8) == ?[:1]const u8);
|
|
testing.expect(Span([*c]u16) == [:0]u16);
|
|
testing.expect(Span(?[*c]u16) == ?[:0]u16);
|
|
testing.expect(Span([*c]const u8) == [:0]const u8);
|
|
testing.expect(Span(?[*c]const u8) == ?[:0]const u8);
|
|
}
|
|
|
|
/// Takes a pointer to an array, a sentinel-terminated pointer, or a slice, and
|
|
/// returns a slice. If there is a sentinel on the input type, there will be a
|
|
/// sentinel on the output type. The constness of the output type matches
|
|
/// the constness of the input type.
|
|
///
|
|
/// When there is both a sentinel and an array length or slice length, the
|
|
/// length value is used instead of the sentinel.
|
|
pub fn span(ptr: anytype) Span(@TypeOf(ptr)) {
|
|
if (@typeInfo(@TypeOf(ptr)) == .Optional) {
|
|
if (ptr) |non_null| {
|
|
return span(non_null);
|
|
} else {
|
|
return null;
|
|
}
|
|
}
|
|
const Result = Span(@TypeOf(ptr));
|
|
const l = len(ptr);
|
|
if (@typeInfo(Result).Pointer.sentinel) |s| {
|
|
return ptr[0..l :s];
|
|
} else {
|
|
return ptr[0..l];
|
|
}
|
|
}
|
|
|
|
test "span" {
|
|
var array: [5]u16 = [_]u16{ 1, 2, 3, 4, 5 };
|
|
const ptr = @as([*:3]u16, array[0..2 :3]);
|
|
testing.expect(eql(u16, span(ptr), &[_]u16{ 1, 2 }));
|
|
testing.expect(eql(u16, span(&array), &[_]u16{ 1, 2, 3, 4, 5 }));
|
|
testing.expectEqual(@as(?[:0]u16, null), span(@as(?[*:0]u16, null)));
|
|
}
|
|
|
|
/// Same as `span`, except when there is both a sentinel and an array
|
|
/// length or slice length, scans the memory for the sentinel value
|
|
/// rather than using the length.
|
|
pub fn spanZ(ptr: anytype) Span(@TypeOf(ptr)) {
|
|
if (@typeInfo(@TypeOf(ptr)) == .Optional) {
|
|
if (ptr) |non_null| {
|
|
return spanZ(non_null);
|
|
} else {
|
|
return null;
|
|
}
|
|
}
|
|
const Result = Span(@TypeOf(ptr));
|
|
const l = lenZ(ptr);
|
|
if (@typeInfo(Result).Pointer.sentinel) |s| {
|
|
return ptr[0..l :s];
|
|
} else {
|
|
return ptr[0..l];
|
|
}
|
|
}
|
|
|
|
test "spanZ" {
|
|
var array: [5]u16 = [_]u16{ 1, 2, 3, 4, 5 };
|
|
const ptr = @as([*:3]u16, array[0..2 :3]);
|
|
testing.expect(eql(u16, spanZ(ptr), &[_]u16{ 1, 2 }));
|
|
testing.expect(eql(u16, spanZ(&array), &[_]u16{ 1, 2, 3, 4, 5 }));
|
|
testing.expectEqual(@as(?[:0]u16, null), spanZ(@as(?[*:0]u16, null)));
|
|
}
|
|
|
|
/// Takes a pointer to an array, an array, a vector, a sentinel-terminated pointer,
|
|
/// a slice or a tuple, and returns the length.
|
|
/// In the case of a sentinel-terminated array, it uses the array length.
|
|
/// For C pointers it assumes it is a pointer-to-many with a 0 sentinel.
|
|
pub fn len(value: anytype) usize {
|
|
return switch (@typeInfo(@TypeOf(value))) {
|
|
.Array => |info| info.len,
|
|
.Vector => |info| info.len,
|
|
.Pointer => |info| switch (info.size) {
|
|
.One => switch (@typeInfo(info.child)) {
|
|
.Array => value.len,
|
|
else => @compileError("invalid type given to std.mem.len"),
|
|
},
|
|
.Many => if (info.sentinel) |sentinel|
|
|
indexOfSentinel(info.child, sentinel, value)
|
|
else
|
|
@compileError("length of pointer with no sentinel"),
|
|
.C => indexOfSentinel(info.child, 0, value),
|
|
.Slice => value.len,
|
|
},
|
|
.Struct => |info| if (info.is_tuple) {
|
|
return info.fields.len;
|
|
} else @compileError("invalid type given to std.mem.len"),
|
|
else => @compileError("invalid type given to std.mem.len"),
|
|
};
|
|
}
|
|
|
|
test "len" {
|
|
testing.expect(len("aoeu") == 4);
|
|
|
|
{
|
|
var array: [5]u16 = [_]u16{ 1, 2, 3, 4, 5 };
|
|
testing.expect(len(&array) == 5);
|
|
testing.expect(len(array[0..3]) == 3);
|
|
array[2] = 0;
|
|
const ptr = @as([*:0]u16, array[0..2 :0]);
|
|
testing.expect(len(ptr) == 2);
|
|
}
|
|
{
|
|
var array: [5:0]u16 = [_:0]u16{ 1, 2, 3, 4, 5 };
|
|
testing.expect(len(&array) == 5);
|
|
array[2] = 0;
|
|
testing.expect(len(&array) == 5);
|
|
}
|
|
{
|
|
const vector: meta.Vector(2, u32) = [2]u32{ 1, 2 };
|
|
testing.expect(len(vector) == 2);
|
|
}
|
|
{
|
|
const tuple = .{ 1, 2 };
|
|
testing.expect(len(tuple) == 2);
|
|
testing.expect(tuple[0] == 1);
|
|
}
|
|
}
|
|
|
|
/// Takes a pointer to an array, an array, a sentinel-terminated pointer,
|
|
/// or a slice, and returns the length.
|
|
/// In the case of a sentinel-terminated array, it scans the array
|
|
/// for a sentinel and uses that for the length, rather than using the array length.
|
|
/// For C pointers it assumes it is a pointer-to-many with a 0 sentinel.
|
|
pub fn lenZ(ptr: anytype) usize {
|
|
return switch (@typeInfo(@TypeOf(ptr))) {
|
|
.Array => |info| if (info.sentinel) |sentinel|
|
|
indexOfSentinel(info.child, sentinel, &ptr)
|
|
else
|
|
info.len,
|
|
.Pointer => |info| switch (info.size) {
|
|
.One => switch (@typeInfo(info.child)) {
|
|
.Array => |x| if (x.sentinel) |sentinel|
|
|
indexOfSentinel(x.child, sentinel, ptr)
|
|
else
|
|
ptr.len,
|
|
else => @compileError("invalid type given to std.mem.lenZ"),
|
|
},
|
|
.Many => if (info.sentinel) |sentinel|
|
|
indexOfSentinel(info.child, sentinel, ptr)
|
|
else
|
|
@compileError("length of pointer with no sentinel"),
|
|
.C => indexOfSentinel(info.child, 0, ptr),
|
|
.Slice => if (info.sentinel) |sentinel|
|
|
indexOfSentinel(info.child, sentinel, ptr.ptr)
|
|
else
|
|
ptr.len,
|
|
},
|
|
else => @compileError("invalid type given to std.mem.lenZ"),
|
|
};
|
|
}
|
|
|
|
test "lenZ" {
|
|
testing.expect(lenZ("aoeu") == 4);
|
|
|
|
{
|
|
var array: [5]u16 = [_]u16{ 1, 2, 3, 4, 5 };
|
|
testing.expect(lenZ(&array) == 5);
|
|
testing.expect(lenZ(array[0..3]) == 3);
|
|
array[2] = 0;
|
|
const ptr = @as([*:0]u16, array[0..2 :0]);
|
|
testing.expect(lenZ(ptr) == 2);
|
|
}
|
|
{
|
|
var array: [5:0]u16 = [_:0]u16{ 1, 2, 3, 4, 5 };
|
|
testing.expect(lenZ(&array) == 5);
|
|
array[2] = 0;
|
|
testing.expect(lenZ(&array) == 2);
|
|
}
|
|
}
|
|
|
|
pub fn indexOfSentinel(comptime Elem: type, comptime sentinel: Elem, ptr: [*:sentinel]const Elem) usize {
|
|
var i: usize = 0;
|
|
while (ptr[i] != sentinel) {
|
|
i += 1;
|
|
}
|
|
return i;
|
|
}
|
|
|
|
/// Returns true if all elements in a slice are equal to the scalar value provided
|
|
pub fn allEqual(comptime T: type, slice: []const T, scalar: T) bool {
|
|
for (slice) |item| {
|
|
if (item != scalar) return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// Deprecated, use `Allocator.dupe`.
|
|
pub fn dupe(allocator: *Allocator, comptime T: type, m: []const T) ![]T {
|
|
return allocator.dupe(T, m);
|
|
}
|
|
|
|
/// Deprecated, use `Allocator.dupeZ`.
|
|
pub fn dupeZ(allocator: *Allocator, comptime T: type, m: []const T) ![:0]T {
|
|
return allocator.dupeZ(T, m);
|
|
}
|
|
|
|
/// Remove values from the beginning of a slice.
|
|
pub fn trimLeft(comptime T: type, slice: []const T, values_to_strip: []const T) []const T {
|
|
var begin: usize = 0;
|
|
while (begin < slice.len and indexOfScalar(T, values_to_strip, slice[begin]) != null) : (begin += 1) {}
|
|
return slice[begin..];
|
|
}
|
|
|
|
/// Remove values from the end of a slice.
|
|
pub fn trimRight(comptime T: type, slice: []const T, values_to_strip: []const T) []const T {
|
|
var end: usize = slice.len;
|
|
while (end > 0 and indexOfScalar(T, values_to_strip, slice[end - 1]) != null) : (end -= 1) {}
|
|
return slice[0..end];
|
|
}
|
|
|
|
/// Remove values from the beginning and end of a slice.
|
|
pub fn trim(comptime T: type, slice: []const T, values_to_strip: []const T) []const T {
|
|
var begin: usize = 0;
|
|
var end: usize = slice.len;
|
|
while (begin < end and indexOfScalar(T, values_to_strip, slice[begin]) != null) : (begin += 1) {}
|
|
while (end > begin and indexOfScalar(T, values_to_strip, slice[end - 1]) != null) : (end -= 1) {}
|
|
return slice[begin..end];
|
|
}
|
|
|
|
test "mem.trim" {
|
|
testing.expectEqualSlices(u8, "foo\n ", trimLeft(u8, " foo\n ", " \n"));
|
|
testing.expectEqualSlices(u8, " foo", trimRight(u8, " foo\n ", " \n"));
|
|
testing.expectEqualSlices(u8, "foo", trim(u8, " foo\n ", " \n"));
|
|
testing.expectEqualSlices(u8, "foo", trim(u8, "foo", " \n"));
|
|
}
|
|
|
|
/// Linear search for the index of a scalar value inside a slice.
|
|
pub fn indexOfScalar(comptime T: type, slice: []const T, value: T) ?usize {
|
|
return indexOfScalarPos(T, slice, 0, value);
|
|
}
|
|
|
|
/// Linear search for the last index of a scalar value inside a slice.
|
|
pub fn lastIndexOfScalar(comptime T: type, slice: []const T, value: T) ?usize {
|
|
var i: usize = slice.len;
|
|
while (i != 0) {
|
|
i -= 1;
|
|
if (slice[i] == value) return i;
|
|
}
|
|
return null;
|
|
}
|
|
|
|
pub fn indexOfScalarPos(comptime T: type, slice: []const T, start_index: usize, value: T) ?usize {
|
|
var i: usize = start_index;
|
|
while (i < slice.len) : (i += 1) {
|
|
if (slice[i] == value) return i;
|
|
}
|
|
return null;
|
|
}
|
|
|
|
pub fn indexOfAny(comptime T: type, slice: []const T, values: []const T) ?usize {
|
|
return indexOfAnyPos(T, slice, 0, values);
|
|
}
|
|
|
|
pub fn lastIndexOfAny(comptime T: type, slice: []const T, values: []const T) ?usize {
|
|
var i: usize = slice.len;
|
|
while (i != 0) {
|
|
i -= 1;
|
|
for (values) |value| {
|
|
if (slice[i] == value) return i;
|
|
}
|
|
}
|
|
return null;
|
|
}
|
|
|
|
pub fn indexOfAnyPos(comptime T: type, slice: []const T, start_index: usize, values: []const T) ?usize {
|
|
var i: usize = start_index;
|
|
while (i < slice.len) : (i += 1) {
|
|
for (values) |value| {
|
|
if (slice[i] == value) return i;
|
|
}
|
|
}
|
|
return null;
|
|
}
|
|
|
|
pub fn indexOf(comptime T: type, haystack: []const T, needle: []const T) ?usize {
|
|
return indexOfPos(T, haystack, 0, needle);
|
|
}
|
|
|
|
/// Find the index in a slice of a sub-slice, searching from the end backwards.
|
|
/// To start looking at a different index, slice the haystack first.
|
|
/// Consider using `lastIndexOf` instead of this, which will automatically use a
|
|
/// more sophisticated algorithm on larger inputs.
|
|
pub fn lastIndexOfLinear(comptime T: type, haystack: []const T, needle: []const T) ?usize {
|
|
var i: usize = haystack.len - needle.len;
|
|
while (true) : (i -= 1) {
|
|
if (mem.eql(T, haystack[i .. i + needle.len], needle)) return i;
|
|
if (i == 0) return null;
|
|
}
|
|
}
|
|
|
|
/// Consider using `indexOfPos` instead of this, which will automatically use a
|
|
/// more sophisticated algorithm on larger inputs.
|
|
pub fn indexOfPosLinear(comptime T: type, haystack: []const T, start_index: usize, needle: []const T) ?usize {
|
|
var i: usize = start_index;
|
|
const end = haystack.len - needle.len;
|
|
while (i <= end) : (i += 1) {
|
|
if (eql(T, haystack[i .. i + needle.len], needle)) return i;
|
|
}
|
|
return null;
|
|
}
|
|
|
|
fn boyerMooreHorspoolPreprocessReverse(pattern: []const u8, table: *[256]usize) void {
|
|
for (table) |*c| {
|
|
c.* = pattern.len;
|
|
}
|
|
|
|
var i: usize = pattern.len - 1;
|
|
// The first item is intentionally ignored and the skip size will be pattern.len.
|
|
// This is the standard way boyer-moore-horspool is implemented.
|
|
while (i > 0) : (i -= 1) {
|
|
table[pattern[i]] = i;
|
|
}
|
|
}
|
|
|
|
fn boyerMooreHorspoolPreprocess(pattern: []const u8, table: *[256]usize) void {
|
|
for (table) |*c| {
|
|
c.* = pattern.len;
|
|
}
|
|
|
|
var i: usize = 0;
|
|
// The last item is intentionally ignored and the skip size will be pattern.len.
|
|
// This is the standard way boyer-moore-horspool is implemented.
|
|
while (i < pattern.len - 1) : (i += 1) {
|
|
table[pattern[i]] = pattern.len - 1 - i;
|
|
}
|
|
}
|
|
/// Find the index in a slice of a sub-slice, searching from the end backwards.
|
|
/// To start looking at a different index, slice the haystack first.
|
|
/// Uses the Reverse boyer-moore-horspool algorithm on large inputs;
|
|
/// `lastIndexOfLinear` on small inputs.
|
|
pub fn lastIndexOf(comptime T: type, haystack: []const T, needle: []const T) ?usize {
|
|
if (needle.len > haystack.len) return null;
|
|
if (needle.len == 0) return haystack.len;
|
|
|
|
if (!meta.trait.hasUniqueRepresentation(T) or haystack.len < 32 or needle.len <= 2)
|
|
return lastIndexOfLinear(T, haystack, needle);
|
|
|
|
const haystack_bytes = sliceAsBytes(haystack);
|
|
const needle_bytes = sliceAsBytes(needle);
|
|
|
|
var skip_table: [256]usize = undefined;
|
|
boyerMooreHorspoolPreprocessReverse(needle_bytes, skip_table[0..]);
|
|
|
|
var i: usize = haystack_bytes.len - needle_bytes.len;
|
|
while (true) {
|
|
if (mem.eql(u8, haystack_bytes[i .. i + needle_bytes.len], needle_bytes)) return i;
|
|
const skip = skip_table[haystack_bytes[i]];
|
|
if (skip > i) break;
|
|
i -= skip;
|
|
}
|
|
|
|
return null;
|
|
}
|
|
|
|
/// Uses Boyer-moore-horspool algorithm on large inputs; `indexOfPosLinear` on small inputs.
|
|
pub fn indexOfPos(comptime T: type, haystack: []const T, start_index: usize, needle: []const T) ?usize {
|
|
if (needle.len > haystack.len) return null;
|
|
if (needle.len == 0) return 0;
|
|
|
|
if (!meta.trait.hasUniqueRepresentation(T) or haystack.len < 52 or needle.len <= 4)
|
|
return indexOfPosLinear(T, haystack, start_index, needle);
|
|
|
|
const haystack_bytes = sliceAsBytes(haystack);
|
|
const needle_bytes = sliceAsBytes(needle);
|
|
|
|
var skip_table: [256]usize = undefined;
|
|
boyerMooreHorspoolPreprocess(needle_bytes, skip_table[0..]);
|
|
|
|
var i: usize = start_index * @sizeOf(T);
|
|
while (i <= haystack_bytes.len - needle_bytes.len) {
|
|
if (mem.eql(u8, haystack_bytes[i .. i + needle_bytes.len], needle_bytes)) return i;
|
|
i += skip_table[haystack_bytes[i + needle_bytes.len - 1]];
|
|
}
|
|
|
|
return null;
|
|
}
|
|
|
|
test "mem.indexOf" {
|
|
testing.expect(indexOf(u8, "one two three four five six seven eight nine ten", "three four").? == 8);
|
|
testing.expect(lastIndexOf(u8, "one two three four five six seven eight nine ten", "three four").? == 8);
|
|
testing.expect(indexOf(u8, "one two three four five six seven eight nine ten", "two two") == null);
|
|
testing.expect(lastIndexOf(u8, "one two three four five six seven eight nine ten", "two two") == null);
|
|
|
|
testing.expect(indexOf(u8, "one two three four five six seven eight nine ten", "").? == 0);
|
|
testing.expect(lastIndexOf(u8, "one two three four five six seven eight nine ten", "").? == 48);
|
|
|
|
testing.expect(indexOf(u8, "one two three four", "four").? == 14);
|
|
testing.expect(lastIndexOf(u8, "one two three two four", "two").? == 14);
|
|
testing.expect(indexOf(u8, "one two three four", "gour") == null);
|
|
testing.expect(lastIndexOf(u8, "one two three four", "gour") == null);
|
|
testing.expect(indexOf(u8, "foo", "foo").? == 0);
|
|
testing.expect(lastIndexOf(u8, "foo", "foo").? == 0);
|
|
testing.expect(indexOf(u8, "foo", "fool") == null);
|
|
testing.expect(lastIndexOf(u8, "foo", "lfoo") == null);
|
|
testing.expect(lastIndexOf(u8, "foo", "fool") == null);
|
|
|
|
testing.expect(indexOf(u8, "foo foo", "foo").? == 0);
|
|
testing.expect(lastIndexOf(u8, "foo foo", "foo").? == 4);
|
|
testing.expect(lastIndexOfAny(u8, "boo, cat", "abo").? == 6);
|
|
testing.expect(lastIndexOfScalar(u8, "boo", 'o').? == 2);
|
|
}
|
|
|
|
/// Returns the number of needles inside the haystack
|
|
/// needle.len must be > 0
|
|
/// does not count overlapping needles
|
|
pub fn count(comptime T: type, haystack: []const T, needle: []const T) usize {
|
|
assert(needle.len > 0);
|
|
var i: usize = 0;
|
|
var found: usize = 0;
|
|
|
|
while (indexOfPos(T, haystack, i, needle)) |idx| {
|
|
i = idx + needle.len;
|
|
found += 1;
|
|
}
|
|
|
|
return found;
|
|
}
|
|
|
|
test "mem.count" {
|
|
testing.expect(count(u8, "", "h") == 0);
|
|
testing.expect(count(u8, "h", "h") == 1);
|
|
testing.expect(count(u8, "hh", "h") == 2);
|
|
testing.expect(count(u8, "world!", "hello") == 0);
|
|
testing.expect(count(u8, "hello world!", "hello") == 1);
|
|
testing.expect(count(u8, " abcabc abc", "abc") == 3);
|
|
testing.expect(count(u8, "udexdcbvbruhasdrw", "bruh") == 1);
|
|
testing.expect(count(u8, "foo bar", "o bar") == 1);
|
|
testing.expect(count(u8, "foofoofoo", "foo") == 3);
|
|
testing.expect(count(u8, "fffffff", "ff") == 3);
|
|
testing.expect(count(u8, "owowowu", "owowu") == 1);
|
|
}
|
|
|
|
/// Reads an integer from memory with size equal to bytes.len.
|
|
/// T specifies the return type, which must be large enough to store
|
|
/// the result.
|
|
pub fn readVarInt(comptime ReturnType: type, bytes: []const u8, endian: builtin.Endian) ReturnType {
|
|
var result: ReturnType = 0;
|
|
switch (endian) {
|
|
.Big => {
|
|
for (bytes) |b| {
|
|
result = (result << 8) | b;
|
|
}
|
|
},
|
|
.Little => {
|
|
const ShiftType = math.Log2Int(ReturnType);
|
|
for (bytes) |b, index| {
|
|
result = result | (@as(ReturnType, b) << @intCast(ShiftType, index * 8));
|
|
}
|
|
},
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/// Reads an integer from memory with bit count specified by T.
|
|
/// The bit count of T must be evenly divisible by 8.
|
|
/// This function cannot fail and cannot cause undefined behavior.
|
|
/// Assumes the endianness of memory is native. This means the function can
|
|
/// simply pointer cast memory.
|
|
pub fn readIntNative(comptime T: type, bytes: *const [@divExact(@typeInfo(T).Int.bits, 8)]u8) T {
|
|
return @ptrCast(*align(1) const T, bytes).*;
|
|
}
|
|
|
|
/// Reads an integer from memory with bit count specified by T.
|
|
/// The bit count of T must be evenly divisible by 8.
|
|
/// This function cannot fail and cannot cause undefined behavior.
|
|
/// Assumes the endianness of memory is foreign, so it must byte-swap.
|
|
pub fn readIntForeign(comptime T: type, bytes: *const [@divExact(@typeInfo(T).Int.bits, 8)]u8) T {
|
|
return @byteSwap(T, readIntNative(T, bytes));
|
|
}
|
|
|
|
pub const readIntLittle = switch (builtin.endian) {
|
|
.Little => readIntNative,
|
|
.Big => readIntForeign,
|
|
};
|
|
|
|
pub const readIntBig = switch (builtin.endian) {
|
|
.Little => readIntForeign,
|
|
.Big => readIntNative,
|
|
};
|
|
|
|
/// Asserts that bytes.len >= @typeInfo(T).Int.bits / 8. Reads the integer starting from index 0
|
|
/// and ignores extra bytes.
|
|
/// The bit count of T must be evenly divisible by 8.
|
|
/// Assumes the endianness of memory is native. This means the function can
|
|
/// simply pointer cast memory.
|
|
pub fn readIntSliceNative(comptime T: type, bytes: []const u8) T {
|
|
const n = @divExact(@typeInfo(T).Int.bits, 8);
|
|
assert(bytes.len >= n);
|
|
return readIntNative(T, bytes[0..n]);
|
|
}
|
|
|
|
/// Asserts that bytes.len >= @typeInfo(T).Int.bits / 8. Reads the integer starting from index 0
|
|
/// and ignores extra bytes.
|
|
/// The bit count of T must be evenly divisible by 8.
|
|
/// Assumes the endianness of memory is foreign, so it must byte-swap.
|
|
pub fn readIntSliceForeign(comptime T: type, bytes: []const u8) T {
|
|
return @byteSwap(T, readIntSliceNative(T, bytes));
|
|
}
|
|
|
|
pub const readIntSliceLittle = switch (builtin.endian) {
|
|
.Little => readIntSliceNative,
|
|
.Big => readIntSliceForeign,
|
|
};
|
|
|
|
pub const readIntSliceBig = switch (builtin.endian) {
|
|
.Little => readIntSliceForeign,
|
|
.Big => readIntSliceNative,
|
|
};
|
|
|
|
/// Reads an integer from memory with bit count specified by T.
|
|
/// The bit count of T must be evenly divisible by 8.
|
|
/// This function cannot fail and cannot cause undefined behavior.
|
|
pub fn readInt(comptime T: type, bytes: *const [@divExact(@typeInfo(T).Int.bits, 8)]u8, endian: builtin.Endian) T {
|
|
if (endian == builtin.endian) {
|
|
return readIntNative(T, bytes);
|
|
} else {
|
|
return readIntForeign(T, bytes);
|
|
}
|
|
}
|
|
|
|
/// Asserts that bytes.len >= @typeInfo(T).Int.bits / 8. Reads the integer starting from index 0
|
|
/// and ignores extra bytes.
|
|
/// The bit count of T must be evenly divisible by 8.
|
|
pub fn readIntSlice(comptime T: type, bytes: []const u8, endian: builtin.Endian) T {
|
|
const n = @divExact(@typeInfo(T).Int.bits, 8);
|
|
assert(bytes.len >= n);
|
|
return readInt(T, bytes[0..n], endian);
|
|
}
|
|
|
|
test "comptime read/write int" {
|
|
comptime {
|
|
var bytes: [2]u8 = undefined;
|
|
writeIntLittle(u16, &bytes, 0x1234);
|
|
const result = readIntBig(u16, &bytes);
|
|
testing.expect(result == 0x3412);
|
|
}
|
|
comptime {
|
|
var bytes: [2]u8 = undefined;
|
|
writeIntBig(u16, &bytes, 0x1234);
|
|
const result = readIntLittle(u16, &bytes);
|
|
testing.expect(result == 0x3412);
|
|
}
|
|
}
|
|
|
|
test "readIntBig and readIntLittle" {
|
|
testing.expect(readIntSliceBig(u0, &[_]u8{}) == 0x0);
|
|
testing.expect(readIntSliceLittle(u0, &[_]u8{}) == 0x0);
|
|
|
|
testing.expect(readIntSliceBig(u8, &[_]u8{0x32}) == 0x32);
|
|
testing.expect(readIntSliceLittle(u8, &[_]u8{0x12}) == 0x12);
|
|
|
|
testing.expect(readIntSliceBig(u16, &[_]u8{ 0x12, 0x34 }) == 0x1234);
|
|
testing.expect(readIntSliceLittle(u16, &[_]u8{ 0x12, 0x34 }) == 0x3412);
|
|
|
|
testing.expect(readIntSliceBig(u72, &[_]u8{ 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x24 }) == 0x123456789abcdef024);
|
|
testing.expect(readIntSliceLittle(u72, &[_]u8{ 0xec, 0x10, 0x32, 0x54, 0x76, 0x98, 0xba, 0xdc, 0xfe }) == 0xfedcba9876543210ec);
|
|
|
|
testing.expect(readIntSliceBig(i8, &[_]u8{0xff}) == -1);
|
|
testing.expect(readIntSliceLittle(i8, &[_]u8{0xfe}) == -2);
|
|
|
|
testing.expect(readIntSliceBig(i16, &[_]u8{ 0xff, 0xfd }) == -3);
|
|
testing.expect(readIntSliceLittle(i16, &[_]u8{ 0xfc, 0xff }) == -4);
|
|
}
|
|
|
|
/// Writes an integer to memory, storing it in twos-complement.
|
|
/// This function always succeeds, has defined behavior for all inputs, and
|
|
/// accepts any integer bit width.
|
|
/// This function stores in native endian, which means it is implemented as a simple
|
|
/// memory store.
|
|
pub fn writeIntNative(comptime T: type, buf: *[(@typeInfo(T).Int.bits + 7) / 8]u8, value: T) void {
|
|
@ptrCast(*align(1) T, buf).* = value;
|
|
}
|
|
|
|
/// Writes an integer to memory, storing it in twos-complement.
|
|
/// This function always succeeds, has defined behavior for all inputs, but
|
|
/// the integer bit width must be divisible by 8.
|
|
/// This function stores in foreign endian, which means it does a @byteSwap first.
|
|
pub fn writeIntForeign(comptime T: type, buf: *[@divExact(@typeInfo(T).Int.bits, 8)]u8, value: T) void {
|
|
writeIntNative(T, buf, @byteSwap(T, value));
|
|
}
|
|
|
|
pub const writeIntLittle = switch (builtin.endian) {
|
|
.Little => writeIntNative,
|
|
.Big => writeIntForeign,
|
|
};
|
|
|
|
pub const writeIntBig = switch (builtin.endian) {
|
|
.Little => writeIntForeign,
|
|
.Big => writeIntNative,
|
|
};
|
|
|
|
/// Writes an integer to memory, storing it in twos-complement.
|
|
/// This function always succeeds, has defined behavior for all inputs, but
|
|
/// the integer bit width must be divisible by 8.
|
|
pub fn writeInt(comptime T: type, buffer: *[@divExact(@typeInfo(T).Int.bits, 8)]u8, value: T, endian: builtin.Endian) void {
|
|
if (endian == builtin.endian) {
|
|
return writeIntNative(T, buffer, value);
|
|
} else {
|
|
return writeIntForeign(T, buffer, value);
|
|
}
|
|
}
|
|
|
|
/// Writes a twos-complement little-endian integer to memory.
|
|
/// Asserts that buf.len >= @typeInfo(T).Int.bits / 8.
|
|
/// The bit count of T must be divisible by 8.
|
|
/// Any extra bytes in buffer after writing the integer are set to zero. To
|
|
/// avoid the branch to check for extra buffer bytes, use writeIntLittle
|
|
/// instead.
|
|
pub fn writeIntSliceLittle(comptime T: type, buffer: []u8, value: T) void {
|
|
assert(buffer.len >= @divExact(@typeInfo(T).Int.bits, 8));
|
|
|
|
if (@typeInfo(T).Int.bits == 0)
|
|
return set(u8, buffer, 0);
|
|
|
|
// TODO I want to call writeIntLittle here but comptime eval facilities aren't good enough
|
|
const uint = std.meta.Int(.unsigned, @typeInfo(T).Int.bits);
|
|
var bits = @truncate(uint, value);
|
|
for (buffer) |*b| {
|
|
b.* = @truncate(u8, bits);
|
|
bits >>= 8;
|
|
}
|
|
}
|
|
|
|
/// Writes a twos-complement big-endian integer to memory.
|
|
/// Asserts that buffer.len >= @typeInfo(T).Int.bits / 8.
|
|
/// The bit count of T must be divisible by 8.
|
|
/// Any extra bytes in buffer before writing the integer are set to zero. To
|
|
/// avoid the branch to check for extra buffer bytes, use writeIntBig instead.
|
|
pub fn writeIntSliceBig(comptime T: type, buffer: []u8, value: T) void {
|
|
assert(buffer.len >= @divExact(@typeInfo(T).Int.bits, 8));
|
|
|
|
if (@typeInfo(T).Int.bits == 0)
|
|
return set(u8, buffer, 0);
|
|
|
|
// TODO I want to call writeIntBig here but comptime eval facilities aren't good enough
|
|
const uint = std.meta.Int(.unsigned, @typeInfo(T).Int.bits);
|
|
var bits = @truncate(uint, value);
|
|
var index: usize = buffer.len;
|
|
while (index != 0) {
|
|
index -= 1;
|
|
buffer[index] = @truncate(u8, bits);
|
|
bits >>= 8;
|
|
}
|
|
}
|
|
|
|
pub const writeIntSliceNative = switch (builtin.endian) {
|
|
.Little => writeIntSliceLittle,
|
|
.Big => writeIntSliceBig,
|
|
};
|
|
|
|
pub const writeIntSliceForeign = switch (builtin.endian) {
|
|
.Little => writeIntSliceBig,
|
|
.Big => writeIntSliceLittle,
|
|
};
|
|
|
|
/// Writes a twos-complement integer to memory, with the specified endianness.
|
|
/// Asserts that buf.len >= @typeInfo(T).Int.bits / 8.
|
|
/// The bit count of T must be evenly divisible by 8.
|
|
/// Any extra bytes in buffer not part of the integer are set to zero, with
|
|
/// respect to endianness. To avoid the branch to check for extra buffer bytes,
|
|
/// use writeInt instead.
|
|
pub fn writeIntSlice(comptime T: type, buffer: []u8, value: T, endian: builtin.Endian) void {
|
|
comptime assert(@typeInfo(T).Int.bits % 8 == 0);
|
|
return switch (endian) {
|
|
.Little => writeIntSliceLittle(T, buffer, value),
|
|
.Big => writeIntSliceBig(T, buffer, value),
|
|
};
|
|
}
|
|
|
|
test "writeIntBig and writeIntLittle" {
|
|
var buf0: [0]u8 = undefined;
|
|
var buf1: [1]u8 = undefined;
|
|
var buf2: [2]u8 = undefined;
|
|
var buf9: [9]u8 = undefined;
|
|
|
|
writeIntBig(u0, &buf0, 0x0);
|
|
testing.expect(eql(u8, buf0[0..], &[_]u8{}));
|
|
writeIntLittle(u0, &buf0, 0x0);
|
|
testing.expect(eql(u8, buf0[0..], &[_]u8{}));
|
|
|
|
writeIntBig(u8, &buf1, 0x12);
|
|
testing.expect(eql(u8, buf1[0..], &[_]u8{0x12}));
|
|
writeIntLittle(u8, &buf1, 0x34);
|
|
testing.expect(eql(u8, buf1[0..], &[_]u8{0x34}));
|
|
|
|
writeIntBig(u16, &buf2, 0x1234);
|
|
testing.expect(eql(u8, buf2[0..], &[_]u8{ 0x12, 0x34 }));
|
|
writeIntLittle(u16, &buf2, 0x5678);
|
|
testing.expect(eql(u8, buf2[0..], &[_]u8{ 0x78, 0x56 }));
|
|
|
|
writeIntBig(u72, &buf9, 0x123456789abcdef024);
|
|
testing.expect(eql(u8, buf9[0..], &[_]u8{ 0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x24 }));
|
|
writeIntLittle(u72, &buf9, 0xfedcba9876543210ec);
|
|
testing.expect(eql(u8, buf9[0..], &[_]u8{ 0xec, 0x10, 0x32, 0x54, 0x76, 0x98, 0xba, 0xdc, 0xfe }));
|
|
|
|
writeIntBig(i8, &buf1, -1);
|
|
testing.expect(eql(u8, buf1[0..], &[_]u8{0xff}));
|
|
writeIntLittle(i8, &buf1, -2);
|
|
testing.expect(eql(u8, buf1[0..], &[_]u8{0xfe}));
|
|
|
|
writeIntBig(i16, &buf2, -3);
|
|
testing.expect(eql(u8, buf2[0..], &[_]u8{ 0xff, 0xfd }));
|
|
writeIntLittle(i16, &buf2, -4);
|
|
testing.expect(eql(u8, buf2[0..], &[_]u8{ 0xfc, 0xff }));
|
|
}
|
|
|
|
/// Returns an iterator that iterates over the slices of `buffer` that are not
|
|
/// any of the bytes in `delimiter_bytes`.
|
|
/// tokenize(" abc def ghi ", " ")
|
|
/// Will return slices for "abc", "def", "ghi", null, in that order.
|
|
/// If `buffer` is empty, the iterator will return null.
|
|
/// If `delimiter_bytes` does not exist in buffer,
|
|
/// the iterator will return `buffer`, null, in that order.
|
|
/// See also the related function `split`.
|
|
pub fn tokenize(buffer: []const u8, delimiter_bytes: []const u8) TokenIterator {
|
|
return TokenIterator{
|
|
.index = 0,
|
|
.buffer = buffer,
|
|
.delimiter_bytes = delimiter_bytes,
|
|
};
|
|
}
|
|
|
|
test "mem.tokenize" {
|
|
var it = tokenize(" abc def ghi ", " ");
|
|
testing.expect(eql(u8, it.next().?, "abc"));
|
|
testing.expect(eql(u8, it.next().?, "def"));
|
|
testing.expect(eql(u8, it.next().?, "ghi"));
|
|
testing.expect(it.next() == null);
|
|
|
|
it = tokenize("..\\bob", "\\");
|
|
testing.expect(eql(u8, it.next().?, ".."));
|
|
testing.expect(eql(u8, "..", "..\\bob"[0..it.index]));
|
|
testing.expect(eql(u8, it.next().?, "bob"));
|
|
testing.expect(it.next() == null);
|
|
|
|
it = tokenize("//a/b", "/");
|
|
testing.expect(eql(u8, it.next().?, "a"));
|
|
testing.expect(eql(u8, it.next().?, "b"));
|
|
testing.expect(eql(u8, "//a/b", "//a/b"[0..it.index]));
|
|
testing.expect(it.next() == null);
|
|
|
|
it = tokenize("|", "|");
|
|
testing.expect(it.next() == null);
|
|
|
|
it = tokenize("", "|");
|
|
testing.expect(it.next() == null);
|
|
|
|
it = tokenize("hello", "");
|
|
testing.expect(eql(u8, it.next().?, "hello"));
|
|
testing.expect(it.next() == null);
|
|
|
|
it = tokenize("hello", " ");
|
|
testing.expect(eql(u8, it.next().?, "hello"));
|
|
testing.expect(it.next() == null);
|
|
}
|
|
|
|
test "mem.tokenize (multibyte)" {
|
|
var it = tokenize("a|b,c/d e", " /,|");
|
|
testing.expect(eql(u8, it.next().?, "a"));
|
|
testing.expect(eql(u8, it.next().?, "b"));
|
|
testing.expect(eql(u8, it.next().?, "c"));
|
|
testing.expect(eql(u8, it.next().?, "d"));
|
|
testing.expect(eql(u8, it.next().?, "e"));
|
|
testing.expect(it.next() == null);
|
|
}
|
|
|
|
/// Returns an iterator that iterates over the slices of `buffer` that
|
|
/// are separated by bytes in `delimiter`.
|
|
/// split("abc|def||ghi", "|")
|
|
/// will return slices for "abc", "def", "", "ghi", null, in that order.
|
|
/// If `delimiter` does not exist in buffer,
|
|
/// the iterator will return `buffer`, null, in that order.
|
|
/// The delimiter length must not be zero.
|
|
/// See also the related function `tokenize`.
|
|
pub fn split(buffer: []const u8, delimiter: []const u8) SplitIterator {
|
|
assert(delimiter.len != 0);
|
|
return SplitIterator{
|
|
.index = 0,
|
|
.buffer = buffer,
|
|
.delimiter = delimiter,
|
|
};
|
|
}
|
|
|
|
pub const separate = @compileError("deprecated: renamed to split (behavior remains unchanged)");
|
|
|
|
test "mem.split" {
|
|
var it = split("abc|def||ghi", "|");
|
|
testing.expect(eql(u8, it.next().?, "abc"));
|
|
testing.expect(eql(u8, it.next().?, "def"));
|
|
testing.expect(eql(u8, it.next().?, ""));
|
|
testing.expect(eql(u8, it.next().?, "ghi"));
|
|
testing.expect(it.next() == null);
|
|
|
|
it = split("", "|");
|
|
testing.expect(eql(u8, it.next().?, ""));
|
|
testing.expect(it.next() == null);
|
|
|
|
it = split("|", "|");
|
|
testing.expect(eql(u8, it.next().?, ""));
|
|
testing.expect(eql(u8, it.next().?, ""));
|
|
testing.expect(it.next() == null);
|
|
|
|
it = split("hello", " ");
|
|
testing.expect(eql(u8, it.next().?, "hello"));
|
|
testing.expect(it.next() == null);
|
|
}
|
|
|
|
test "mem.split (multibyte)" {
|
|
var it = split("a, b ,, c, d, e", ", ");
|
|
testing.expect(eql(u8, it.next().?, "a"));
|
|
testing.expect(eql(u8, it.next().?, "b ,"));
|
|
testing.expect(eql(u8, it.next().?, "c"));
|
|
testing.expect(eql(u8, it.next().?, "d"));
|
|
testing.expect(eql(u8, it.next().?, "e"));
|
|
testing.expect(it.next() == null);
|
|
}
|
|
|
|
pub fn startsWith(comptime T: type, haystack: []const T, needle: []const T) bool {
|
|
return if (needle.len > haystack.len) false else eql(T, haystack[0..needle.len], needle);
|
|
}
|
|
|
|
test "mem.startsWith" {
|
|
testing.expect(startsWith(u8, "Bob", "Bo"));
|
|
testing.expect(!startsWith(u8, "Needle in haystack", "haystack"));
|
|
}
|
|
|
|
pub fn endsWith(comptime T: type, haystack: []const T, needle: []const T) bool {
|
|
return if (needle.len > haystack.len) false else eql(T, haystack[haystack.len - needle.len ..], needle);
|
|
}
|
|
|
|
test "mem.endsWith" {
|
|
testing.expect(endsWith(u8, "Needle in haystack", "haystack"));
|
|
testing.expect(!endsWith(u8, "Bob", "Bo"));
|
|
}
|
|
|
|
pub const TokenIterator = struct {
|
|
buffer: []const u8,
|
|
delimiter_bytes: []const u8,
|
|
index: usize,
|
|
|
|
/// Returns a slice of the next token, or null if tokenization is complete.
|
|
pub fn next(self: *TokenIterator) ?[]const u8 {
|
|
// move to beginning of token
|
|
while (self.index < self.buffer.len and self.isSplitByte(self.buffer[self.index])) : (self.index += 1) {}
|
|
const start = self.index;
|
|
if (start == self.buffer.len) {
|
|
return null;
|
|
}
|
|
|
|
// move to end of token
|
|
while (self.index < self.buffer.len and !self.isSplitByte(self.buffer[self.index])) : (self.index += 1) {}
|
|
const end = self.index;
|
|
|
|
return self.buffer[start..end];
|
|
}
|
|
|
|
/// Returns a slice of the remaining bytes. Does not affect iterator state.
|
|
pub fn rest(self: TokenIterator) []const u8 {
|
|
// move to beginning of token
|
|
var index: usize = self.index;
|
|
while (index < self.buffer.len and self.isSplitByte(self.buffer[index])) : (index += 1) {}
|
|
return self.buffer[index..];
|
|
}
|
|
|
|
fn isSplitByte(self: TokenIterator, byte: u8) bool {
|
|
for (self.delimiter_bytes) |delimiter_byte| {
|
|
if (byte == delimiter_byte) {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
};
|
|
|
|
pub const SplitIterator = struct {
|
|
buffer: []const u8,
|
|
index: ?usize,
|
|
delimiter: []const u8,
|
|
|
|
/// Returns a slice of the next field, or null if splitting is complete.
|
|
pub fn next(self: *SplitIterator) ?[]const u8 {
|
|
const start = self.index orelse return null;
|
|
const end = if (indexOfPos(u8, self.buffer, start, self.delimiter)) |delim_start| blk: {
|
|
self.index = delim_start + self.delimiter.len;
|
|
break :blk delim_start;
|
|
} else blk: {
|
|
self.index = null;
|
|
break :blk self.buffer.len;
|
|
};
|
|
return self.buffer[start..end];
|
|
}
|
|
|
|
/// Returns a slice of the remaining bytes. Does not affect iterator state.
|
|
pub fn rest(self: SplitIterator) []const u8 {
|
|
const end = self.buffer.len;
|
|
const start = self.index orelse end;
|
|
return self.buffer[start..end];
|
|
}
|
|
};
|
|
|
|
/// Naively combines a series of slices with a separator.
|
|
/// Allocates memory for the result, which must be freed by the caller.
|
|
pub fn join(allocator: *Allocator, separator: []const u8, slices: []const []const u8) ![]u8 {
|
|
return joinMaybeZ(allocator, separator, slices, false);
|
|
}
|
|
|
|
/// Naively combines a series of slices with a separator and null terminator.
|
|
/// Allocates memory for the result, which must be freed by the caller.
|
|
pub fn joinZ(allocator: *Allocator, separator: []const u8, slices: []const []const u8) ![:0]u8 {
|
|
const out = try joinMaybeZ(allocator, separator, slices, true);
|
|
return out[0 .. out.len - 1 :0];
|
|
}
|
|
|
|
fn joinMaybeZ(allocator: *Allocator, separator: []const u8, slices: []const []const u8, zero: bool) ![]u8 {
|
|
if (slices.len == 0) return &[0]u8{};
|
|
|
|
const total_len = blk: {
|
|
var sum: usize = separator.len * (slices.len - 1);
|
|
for (slices) |slice| sum += slice.len;
|
|
if (zero) sum += 1;
|
|
break :blk sum;
|
|
};
|
|
|
|
const buf = try allocator.alloc(u8, total_len);
|
|
errdefer allocator.free(buf);
|
|
|
|
copy(u8, buf, slices[0]);
|
|
var buf_index: usize = slices[0].len;
|
|
for (slices[1..]) |slice| {
|
|
copy(u8, buf[buf_index..], separator);
|
|
buf_index += separator.len;
|
|
copy(u8, buf[buf_index..], slice);
|
|
buf_index += slice.len;
|
|
}
|
|
|
|
if (zero) buf[buf.len - 1] = 0;
|
|
|
|
// No need for shrink since buf is exactly the correct size.
|
|
return buf;
|
|
}
|
|
|
|
test "mem.join" {
|
|
{
|
|
const str = try join(testing.allocator, ",", &[_][]const u8{ "a", "b", "c" });
|
|
defer testing.allocator.free(str);
|
|
testing.expect(eql(u8, str, "a,b,c"));
|
|
}
|
|
{
|
|
const str = try join(testing.allocator, ",", &[_][]const u8{"a"});
|
|
defer testing.allocator.free(str);
|
|
testing.expect(eql(u8, str, "a"));
|
|
}
|
|
{
|
|
const str = try join(testing.allocator, ",", &[_][]const u8{ "a", "", "b", "", "c" });
|
|
defer testing.allocator.free(str);
|
|
testing.expect(eql(u8, str, "a,,b,,c"));
|
|
}
|
|
}
|
|
|
|
test "mem.joinZ" {
|
|
{
|
|
const str = try joinZ(testing.allocator, ",", &[_][]const u8{ "a", "b", "c" });
|
|
defer testing.allocator.free(str);
|
|
testing.expect(eql(u8, str, "a,b,c"));
|
|
testing.expectEqual(str[str.len], 0);
|
|
}
|
|
{
|
|
const str = try joinZ(testing.allocator, ",", &[_][]const u8{"a"});
|
|
defer testing.allocator.free(str);
|
|
testing.expect(eql(u8, str, "a"));
|
|
testing.expectEqual(str[str.len], 0);
|
|
}
|
|
{
|
|
const str = try joinZ(testing.allocator, ",", &[_][]const u8{ "a", "", "b", "", "c" });
|
|
defer testing.allocator.free(str);
|
|
testing.expect(eql(u8, str, "a,,b,,c"));
|
|
testing.expectEqual(str[str.len], 0);
|
|
}
|
|
}
|
|
|
|
/// Copies each T from slices into a new slice that exactly holds all the elements.
|
|
pub fn concat(allocator: *Allocator, comptime T: type, slices: []const []const T) ![]T {
|
|
if (slices.len == 0) return &[0]T{};
|
|
|
|
const total_len = blk: {
|
|
var sum: usize = 0;
|
|
for (slices) |slice| {
|
|
sum += slice.len;
|
|
}
|
|
break :blk sum;
|
|
};
|
|
|
|
const buf = try allocator.alloc(T, total_len);
|
|
errdefer allocator.free(buf);
|
|
|
|
var buf_index: usize = 0;
|
|
for (slices) |slice| {
|
|
copy(T, buf[buf_index..], slice);
|
|
buf_index += slice.len;
|
|
}
|
|
|
|
// No need for shrink since buf is exactly the correct size.
|
|
return buf;
|
|
}
|
|
|
|
test "concat" {
|
|
{
|
|
const str = try concat(testing.allocator, u8, &[_][]const u8{ "abc", "def", "ghi" });
|
|
defer testing.allocator.free(str);
|
|
testing.expect(eql(u8, str, "abcdefghi"));
|
|
}
|
|
{
|
|
const str = try concat(testing.allocator, u32, &[_][]const u32{
|
|
&[_]u32{ 0, 1 },
|
|
&[_]u32{ 2, 3, 4 },
|
|
&[_]u32{},
|
|
&[_]u32{5},
|
|
});
|
|
defer testing.allocator.free(str);
|
|
testing.expect(eql(u32, str, &[_]u32{ 0, 1, 2, 3, 4, 5 }));
|
|
}
|
|
}
|
|
|
|
test "testStringEquality" {
|
|
testing.expect(eql(u8, "abcd", "abcd"));
|
|
testing.expect(!eql(u8, "abcdef", "abZdef"));
|
|
testing.expect(!eql(u8, "abcdefg", "abcdef"));
|
|
}
|
|
|
|
test "testReadInt" {
|
|
testReadIntImpl();
|
|
comptime testReadIntImpl();
|
|
}
|
|
fn testReadIntImpl() void {
|
|
{
|
|
const bytes = [_]u8{
|
|
0x12,
|
|
0x34,
|
|
0x56,
|
|
0x78,
|
|
};
|
|
testing.expect(readInt(u32, &bytes, builtin.Endian.Big) == 0x12345678);
|
|
testing.expect(readIntBig(u32, &bytes) == 0x12345678);
|
|
testing.expect(readIntBig(i32, &bytes) == 0x12345678);
|
|
testing.expect(readInt(u32, &bytes, builtin.Endian.Little) == 0x78563412);
|
|
testing.expect(readIntLittle(u32, &bytes) == 0x78563412);
|
|
testing.expect(readIntLittle(i32, &bytes) == 0x78563412);
|
|
}
|
|
{
|
|
const buf = [_]u8{
|
|
0x00,
|
|
0x00,
|
|
0x12,
|
|
0x34,
|
|
};
|
|
const answer = readInt(u32, &buf, builtin.Endian.Big);
|
|
testing.expect(answer == 0x00001234);
|
|
}
|
|
{
|
|
const buf = [_]u8{
|
|
0x12,
|
|
0x34,
|
|
0x00,
|
|
0x00,
|
|
};
|
|
const answer = readInt(u32, &buf, builtin.Endian.Little);
|
|
testing.expect(answer == 0x00003412);
|
|
}
|
|
{
|
|
const bytes = [_]u8{
|
|
0xff,
|
|
0xfe,
|
|
};
|
|
testing.expect(readIntBig(u16, &bytes) == 0xfffe);
|
|
testing.expect(readIntBig(i16, &bytes) == -0x0002);
|
|
testing.expect(readIntLittle(u16, &bytes) == 0xfeff);
|
|
testing.expect(readIntLittle(i16, &bytes) == -0x0101);
|
|
}
|
|
}
|
|
|
|
test "writeIntSlice" {
|
|
testWriteIntImpl();
|
|
comptime testWriteIntImpl();
|
|
}
|
|
fn testWriteIntImpl() void {
|
|
var bytes: [8]u8 = undefined;
|
|
|
|
writeIntSlice(u0, bytes[0..], 0, builtin.Endian.Big);
|
|
testing.expect(eql(u8, &bytes, &[_]u8{
|
|
0x00, 0x00, 0x00, 0x00,
|
|
0x00, 0x00, 0x00, 0x00,
|
|
}));
|
|
|
|
writeIntSlice(u0, bytes[0..], 0, builtin.Endian.Little);
|
|
testing.expect(eql(u8, &bytes, &[_]u8{
|
|
0x00, 0x00, 0x00, 0x00,
|
|
0x00, 0x00, 0x00, 0x00,
|
|
}));
|
|
|
|
writeIntSlice(u64, bytes[0..], 0x12345678CAFEBABE, builtin.Endian.Big);
|
|
testing.expect(eql(u8, &bytes, &[_]u8{
|
|
0x12,
|
|
0x34,
|
|
0x56,
|
|
0x78,
|
|
0xCA,
|
|
0xFE,
|
|
0xBA,
|
|
0xBE,
|
|
}));
|
|
|
|
writeIntSlice(u64, bytes[0..], 0xBEBAFECA78563412, builtin.Endian.Little);
|
|
testing.expect(eql(u8, &bytes, &[_]u8{
|
|
0x12,
|
|
0x34,
|
|
0x56,
|
|
0x78,
|
|
0xCA,
|
|
0xFE,
|
|
0xBA,
|
|
0xBE,
|
|
}));
|
|
|
|
writeIntSlice(u32, bytes[0..], 0x12345678, builtin.Endian.Big);
|
|
testing.expect(eql(u8, &bytes, &[_]u8{
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
0x12,
|
|
0x34,
|
|
0x56,
|
|
0x78,
|
|
}));
|
|
|
|
writeIntSlice(u32, bytes[0..], 0x78563412, builtin.Endian.Little);
|
|
testing.expect(eql(u8, &bytes, &[_]u8{
|
|
0x12,
|
|
0x34,
|
|
0x56,
|
|
0x78,
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
}));
|
|
|
|
writeIntSlice(u16, bytes[0..], 0x1234, builtin.Endian.Big);
|
|
testing.expect(eql(u8, &bytes, &[_]u8{
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
0x12,
|
|
0x34,
|
|
}));
|
|
|
|
writeIntSlice(u16, bytes[0..], 0x1234, builtin.Endian.Little);
|
|
testing.expect(eql(u8, &bytes, &[_]u8{
|
|
0x34,
|
|
0x12,
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
0x00,
|
|
}));
|
|
}
|
|
|
|
/// Returns the smallest number in a slice. O(n).
|
|
/// `slice` must not be empty.
|
|
pub fn min(comptime T: type, slice: []const T) T {
|
|
var best = slice[0];
|
|
for (slice[1..]) |item| {
|
|
best = math.min(best, item);
|
|
}
|
|
return best;
|
|
}
|
|
|
|
test "mem.min" {
|
|
testing.expect(min(u8, "abcdefg") == 'a');
|
|
}
|
|
|
|
/// Returns the largest number in a slice. O(n).
|
|
/// `slice` must not be empty.
|
|
pub fn max(comptime T: type, slice: []const T) T {
|
|
var best = slice[0];
|
|
for (slice[1..]) |item| {
|
|
best = math.max(best, item);
|
|
}
|
|
return best;
|
|
}
|
|
|
|
test "mem.max" {
|
|
testing.expect(max(u8, "abcdefg") == 'g');
|
|
}
|
|
|
|
pub fn swap(comptime T: type, a: *T, b: *T) void {
|
|
const tmp = a.*;
|
|
a.* = b.*;
|
|
b.* = tmp;
|
|
}
|
|
|
|
/// In-place order reversal of a slice
|
|
pub fn reverse(comptime T: type, items: []T) void {
|
|
var i: usize = 0;
|
|
const end = items.len / 2;
|
|
while (i < end) : (i += 1) {
|
|
swap(T, &items[i], &items[items.len - i - 1]);
|
|
}
|
|
}
|
|
|
|
test "reverse" {
|
|
var arr = [_]i32{ 5, 3, 1, 2, 4 };
|
|
reverse(i32, arr[0..]);
|
|
|
|
testing.expect(eql(i32, &arr, &[_]i32{ 4, 2, 1, 3, 5 }));
|
|
}
|
|
|
|
/// In-place rotation of the values in an array ([0 1 2 3] becomes [1 2 3 0] if we rotate by 1)
|
|
/// Assumes 0 <= amount <= items.len
|
|
pub fn rotate(comptime T: type, items: []T, amount: usize) void {
|
|
reverse(T, items[0..amount]);
|
|
reverse(T, items[amount..]);
|
|
reverse(T, items);
|
|
}
|
|
|
|
test "rotate" {
|
|
var arr = [_]i32{ 5, 3, 1, 2, 4 };
|
|
rotate(i32, arr[0..], 2);
|
|
|
|
testing.expect(eql(i32, &arr, &[_]i32{ 1, 2, 4, 5, 3 }));
|
|
}
|
|
|
|
/// Replace needle with replacement as many times as possible, writing to an output buffer which is assumed to be of
|
|
/// appropriate size. Use replacementSize to calculate an appropriate buffer size.
|
|
pub fn replace(comptime T: type, input: []const T, needle: []const T, replacement: []const T, output: []T) usize {
|
|
var i: usize = 0;
|
|
var slide: usize = 0;
|
|
var replacements: usize = 0;
|
|
while (slide < input.len) {
|
|
if (mem.indexOf(T, input[slide..], needle) == @as(usize, 0)) {
|
|
mem.copy(T, output[i .. i + replacement.len], replacement);
|
|
i += replacement.len;
|
|
slide += needle.len;
|
|
replacements += 1;
|
|
} else {
|
|
output[i] = input[slide];
|
|
i += 1;
|
|
slide += 1;
|
|
}
|
|
}
|
|
|
|
return replacements;
|
|
}
|
|
|
|
test "replace" {
|
|
var output: [29]u8 = undefined;
|
|
var replacements = replace(u8, "All your base are belong to us", "base", "Zig", output[0..]);
|
|
testing.expect(replacements == 1);
|
|
testing.expect(eql(u8, output[0..], "All your Zig are belong to us"));
|
|
|
|
replacements = replace(u8, "Favor reading code over writing code.", "code", "", output[0..]);
|
|
testing.expect(replacements == 2);
|
|
testing.expect(eql(u8, output[0..], "Favor reading over writing ."));
|
|
}
|
|
|
|
/// Calculate the size needed in an output buffer to perform a replacement.
|
|
pub fn replacementSize(comptime T: type, input: []const T, needle: []const T, replacement: []const T) usize {
|
|
var i: usize = 0;
|
|
var size: usize = input.len;
|
|
while (i < input.len) : (i += 1) {
|
|
if (mem.indexOf(T, input[i..], needle) == @as(usize, 0)) {
|
|
size = size - needle.len + replacement.len;
|
|
i += needle.len;
|
|
}
|
|
}
|
|
|
|
return size;
|
|
}
|
|
|
|
test "replacementSize" {
|
|
testing.expect(replacementSize(u8, "All your base are belong to us", "base", "Zig") == 29);
|
|
testing.expect(replacementSize(u8, "", "", "") == 0);
|
|
testing.expect(replacementSize(u8, "Favor reading code over writing code.", "code", "") == 29);
|
|
testing.expect(replacementSize(u8, "Only one obvious way to do things.", "things.", "things in Zig.") == 41);
|
|
}
|
|
|
|
/// Perform a replacement on an allocated buffer of pre-determined size. Caller must free returned memory.
|
|
pub fn replaceOwned(comptime T: type, allocator: *Allocator, input: []const T, needle: []const T, replacement: []const T) Allocator.Error![]T {
|
|
var output = try allocator.alloc(T, replacementSize(T, input, needle, replacement));
|
|
_ = replace(T, input, needle, replacement, output);
|
|
return output;
|
|
}
|
|
|
|
test "replaceOwned" {
|
|
const allocator = std.heap.page_allocator;
|
|
|
|
const base_replace = replaceOwned(u8, allocator, "All your base are belong to us", "base", "Zig") catch unreachable;
|
|
defer allocator.free(base_replace);
|
|
testing.expect(eql(u8, base_replace, "All your Zig are belong to us"));
|
|
|
|
const zen_replace = replaceOwned(u8, allocator, "Favor reading code over writing code.", " code", "") catch unreachable;
|
|
defer allocator.free(zen_replace);
|
|
testing.expect(eql(u8, zen_replace, "Favor reading over writing."));
|
|
}
|
|
|
|
/// Converts a little-endian integer to host endianness.
|
|
pub fn littleToNative(comptime T: type, x: T) T {
|
|
return switch (builtin.endian) {
|
|
.Little => x,
|
|
.Big => @byteSwap(T, x),
|
|
};
|
|
}
|
|
|
|
/// Converts a big-endian integer to host endianness.
|
|
pub fn bigToNative(comptime T: type, x: T) T {
|
|
return switch (builtin.endian) {
|
|
.Little => @byteSwap(T, x),
|
|
.Big => x,
|
|
};
|
|
}
|
|
|
|
/// Converts an integer from specified endianness to host endianness.
|
|
pub fn toNative(comptime T: type, x: T, endianness_of_x: builtin.Endian) T {
|
|
return switch (endianness_of_x) {
|
|
.Little => littleToNative(T, x),
|
|
.Big => bigToNative(T, x),
|
|
};
|
|
}
|
|
|
|
/// Converts an integer which has host endianness to the desired endianness.
|
|
pub fn nativeTo(comptime T: type, x: T, desired_endianness: builtin.Endian) T {
|
|
return switch (desired_endianness) {
|
|
.Little => nativeToLittle(T, x),
|
|
.Big => nativeToBig(T, x),
|
|
};
|
|
}
|
|
|
|
/// Converts an integer which has host endianness to little endian.
|
|
pub fn nativeToLittle(comptime T: type, x: T) T {
|
|
return switch (builtin.endian) {
|
|
.Little => x,
|
|
.Big => @byteSwap(T, x),
|
|
};
|
|
}
|
|
|
|
/// Converts an integer which has host endianness to big endian.
|
|
pub fn nativeToBig(comptime T: type, x: T) T {
|
|
return switch (builtin.endian) {
|
|
.Little => @byteSwap(T, x),
|
|
.Big => x,
|
|
};
|
|
}
|
|
|
|
fn AsBytesReturnType(comptime P: type) type {
|
|
if (!trait.isSingleItemPtr(P))
|
|
@compileError("expected single item pointer, passed " ++ @typeName(P));
|
|
|
|
const size = @sizeOf(meta.Child(P));
|
|
const alignment = meta.alignment(P);
|
|
|
|
if (alignment == 0) {
|
|
if (trait.isConstPtr(P))
|
|
return *const [size]u8;
|
|
return *[size]u8;
|
|
}
|
|
|
|
if (trait.isConstPtr(P))
|
|
return *align(alignment) const [size]u8;
|
|
return *align(alignment) [size]u8;
|
|
}
|
|
|
|
/// Given a pointer to a single item, returns a slice of the underlying bytes, preserving constness.
|
|
pub fn asBytes(ptr: anytype) AsBytesReturnType(@TypeOf(ptr)) {
|
|
const P = @TypeOf(ptr);
|
|
return @ptrCast(AsBytesReturnType(P), ptr);
|
|
}
|
|
|
|
test "asBytes" {
|
|
const deadbeef = @as(u32, 0xDEADBEEF);
|
|
const deadbeef_bytes = switch (builtin.endian) {
|
|
.Big => "\xDE\xAD\xBE\xEF",
|
|
.Little => "\xEF\xBE\xAD\xDE",
|
|
};
|
|
|
|
testing.expect(eql(u8, asBytes(&deadbeef), deadbeef_bytes));
|
|
|
|
var codeface = @as(u32, 0xC0DEFACE);
|
|
for (asBytes(&codeface).*) |*b|
|
|
b.* = 0;
|
|
testing.expect(codeface == 0);
|
|
|
|
const S = packed struct {
|
|
a: u8,
|
|
b: u8,
|
|
c: u8,
|
|
d: u8,
|
|
};
|
|
|
|
const inst = S{
|
|
.a = 0xBE,
|
|
.b = 0xEF,
|
|
.c = 0xDE,
|
|
.d = 0xA1,
|
|
};
|
|
testing.expect(eql(u8, asBytes(&inst), "\xBE\xEF\xDE\xA1"));
|
|
|
|
const ZST = struct {};
|
|
const zero = ZST{};
|
|
testing.expect(eql(u8, asBytes(&zero), ""));
|
|
}
|
|
|
|
/// Given any value, returns a copy of its bytes in an array.
|
|
pub fn toBytes(value: anytype) [@sizeOf(@TypeOf(value))]u8 {
|
|
return asBytes(&value).*;
|
|
}
|
|
|
|
test "toBytes" {
|
|
var my_bytes = toBytes(@as(u32, 0x12345678));
|
|
switch (builtin.endian) {
|
|
.Big => testing.expect(eql(u8, &my_bytes, "\x12\x34\x56\x78")),
|
|
.Little => testing.expect(eql(u8, &my_bytes, "\x78\x56\x34\x12")),
|
|
}
|
|
|
|
my_bytes[0] = '\x99';
|
|
switch (builtin.endian) {
|
|
.Big => testing.expect(eql(u8, &my_bytes, "\x99\x34\x56\x78")),
|
|
.Little => testing.expect(eql(u8, &my_bytes, "\x99\x56\x34\x12")),
|
|
}
|
|
}
|
|
|
|
fn BytesAsValueReturnType(comptime T: type, comptime B: type) type {
|
|
const size = @as(usize, @sizeOf(T));
|
|
|
|
if (comptime !trait.is(.Pointer)(B) or
|
|
(meta.Child(B) != [size]u8 and meta.Child(B) != [size:0]u8))
|
|
{
|
|
comptime var buf: [100]u8 = undefined;
|
|
@compileError(std.fmt.bufPrint(&buf, "expected *[{}]u8, passed " ++ @typeName(B), .{size}) catch unreachable);
|
|
}
|
|
|
|
const alignment = comptime meta.alignment(B);
|
|
|
|
return if (comptime trait.isConstPtr(B)) *align(alignment) const T else *align(alignment) T;
|
|
}
|
|
|
|
/// Given a pointer to an array of bytes, returns a pointer to a value of the specified type
|
|
/// backed by those bytes, preserving constness.
|
|
pub fn bytesAsValue(comptime T: type, bytes: anytype) BytesAsValueReturnType(T, @TypeOf(bytes)) {
|
|
return @ptrCast(BytesAsValueReturnType(T, @TypeOf(bytes)), bytes);
|
|
}
|
|
|
|
test "bytesAsValue" {
|
|
const deadbeef = @as(u32, 0xDEADBEEF);
|
|
const deadbeef_bytes = switch (builtin.endian) {
|
|
.Big => "\xDE\xAD\xBE\xEF",
|
|
.Little => "\xEF\xBE\xAD\xDE",
|
|
};
|
|
|
|
testing.expect(deadbeef == bytesAsValue(u32, deadbeef_bytes).*);
|
|
|
|
var codeface_bytes: [4]u8 = switch (builtin.endian) {
|
|
.Big => "\xC0\xDE\xFA\xCE",
|
|
.Little => "\xCE\xFA\xDE\xC0",
|
|
}.*;
|
|
var codeface = bytesAsValue(u32, &codeface_bytes);
|
|
testing.expect(codeface.* == 0xC0DEFACE);
|
|
codeface.* = 0;
|
|
for (codeface_bytes) |b|
|
|
testing.expect(b == 0);
|
|
|
|
const S = packed struct {
|
|
a: u8,
|
|
b: u8,
|
|
c: u8,
|
|
d: u8,
|
|
};
|
|
|
|
const inst = S{
|
|
.a = 0xBE,
|
|
.b = 0xEF,
|
|
.c = 0xDE,
|
|
.d = 0xA1,
|
|
};
|
|
const inst_bytes = "\xBE\xEF\xDE\xA1";
|
|
const inst2 = bytesAsValue(S, inst_bytes);
|
|
testing.expect(meta.eql(inst, inst2.*));
|
|
}
|
|
|
|
/// Given a pointer to an array of bytes, returns a value of the specified type backed by a
|
|
/// copy of those bytes.
|
|
pub fn bytesToValue(comptime T: type, bytes: anytype) T {
|
|
return bytesAsValue(T, bytes).*;
|
|
}
|
|
test "bytesToValue" {
|
|
const deadbeef_bytes = switch (builtin.endian) {
|
|
.Big => "\xDE\xAD\xBE\xEF",
|
|
.Little => "\xEF\xBE\xAD\xDE",
|
|
};
|
|
|
|
const deadbeef = bytesToValue(u32, deadbeef_bytes);
|
|
testing.expect(deadbeef == @as(u32, 0xDEADBEEF));
|
|
}
|
|
|
|
//TODO copy also is_volatile, etc. I tried to use @typeInfo, modify child type, use @Type, but ran into issues.
|
|
fn BytesAsSliceReturnType(comptime T: type, comptime bytesType: type) type {
|
|
if (!(trait.isSlice(bytesType) and meta.Child(bytesType) == u8) and !(trait.isPtrTo(.Array)(bytesType) and meta.Child(meta.Child(bytesType)) == u8)) {
|
|
@compileError("expected []u8 or *[_]u8, passed " ++ @typeName(bytesType));
|
|
}
|
|
|
|
if (trait.isPtrTo(.Array)(bytesType) and @typeInfo(meta.Child(bytesType)).Array.len % @sizeOf(T) != 0) {
|
|
@compileError("number of bytes in " ++ @typeName(bytesType) ++ " is not divisible by size of " ++ @typeName(T));
|
|
}
|
|
|
|
const alignment = meta.alignment(bytesType);
|
|
|
|
return if (trait.isConstPtr(bytesType)) []align(alignment) const T else []align(alignment) T;
|
|
}
|
|
|
|
pub fn bytesAsSlice(comptime T: type, bytes: anytype) BytesAsSliceReturnType(T, @TypeOf(bytes)) {
|
|
// let's not give an undefined pointer to @ptrCast
|
|
// it may be equal to zero and fail a null check
|
|
if (bytes.len == 0) {
|
|
return &[0]T{};
|
|
}
|
|
|
|
const Bytes = @TypeOf(bytes);
|
|
const alignment = comptime meta.alignment(Bytes);
|
|
|
|
const cast_target = if (comptime trait.isConstPtr(Bytes)) [*]align(alignment) const T else [*]align(alignment) T;
|
|
|
|
return @ptrCast(cast_target, bytes)[0..@divExact(bytes.len, @sizeOf(T))];
|
|
}
|
|
|
|
test "bytesAsSlice" {
|
|
{
|
|
const bytes = [_]u8{ 0xDE, 0xAD, 0xBE, 0xEF };
|
|
const slice = bytesAsSlice(u16, bytes[0..]);
|
|
testing.expect(slice.len == 2);
|
|
testing.expect(bigToNative(u16, slice[0]) == 0xDEAD);
|
|
testing.expect(bigToNative(u16, slice[1]) == 0xBEEF);
|
|
}
|
|
{
|
|
const bytes = [_]u8{ 0xDE, 0xAD, 0xBE, 0xEF };
|
|
var runtime_zero: usize = 0;
|
|
const slice = bytesAsSlice(u16, bytes[runtime_zero..]);
|
|
testing.expect(slice.len == 2);
|
|
testing.expect(bigToNative(u16, slice[0]) == 0xDEAD);
|
|
testing.expect(bigToNative(u16, slice[1]) == 0xBEEF);
|
|
}
|
|
}
|
|
|
|
test "bytesAsSlice keeps pointer alignment" {
|
|
{
|
|
var bytes = [_]u8{ 0x01, 0x02, 0x03, 0x04 };
|
|
const numbers = bytesAsSlice(u32, bytes[0..]);
|
|
comptime testing.expect(@TypeOf(numbers) == []align(@alignOf(@TypeOf(bytes))) u32);
|
|
}
|
|
{
|
|
var bytes = [_]u8{ 0x01, 0x02, 0x03, 0x04 };
|
|
var runtime_zero: usize = 0;
|
|
const numbers = bytesAsSlice(u32, bytes[runtime_zero..]);
|
|
comptime testing.expect(@TypeOf(numbers) == []align(@alignOf(@TypeOf(bytes))) u32);
|
|
}
|
|
}
|
|
|
|
test "bytesAsSlice on a packed struct" {
|
|
const F = packed struct {
|
|
a: u8,
|
|
};
|
|
|
|
var b = [1]u8{9};
|
|
var f = bytesAsSlice(F, &b);
|
|
testing.expect(f[0].a == 9);
|
|
}
|
|
|
|
test "bytesAsSlice with specified alignment" {
|
|
var bytes align(4) = [_]u8{
|
|
0x33,
|
|
0x33,
|
|
0x33,
|
|
0x33,
|
|
};
|
|
const slice: []u32 = std.mem.bytesAsSlice(u32, bytes[0..]);
|
|
testing.expect(slice[0] == 0x33333333);
|
|
}
|
|
|
|
//TODO copy also is_volatile, etc. I tried to use @typeInfo, modify child type, use @Type, but ran into issues.
|
|
fn SliceAsBytesReturnType(comptime sliceType: type) type {
|
|
if (!trait.isSlice(sliceType) and !trait.isPtrTo(.Array)(sliceType)) {
|
|
@compileError("expected []T or *[_]T, passed " ++ @typeName(sliceType));
|
|
}
|
|
|
|
const alignment = meta.alignment(sliceType);
|
|
|
|
return if (trait.isConstPtr(sliceType)) []align(alignment) const u8 else []align(alignment) u8;
|
|
}
|
|
|
|
pub fn sliceAsBytes(slice: anytype) SliceAsBytesReturnType(@TypeOf(slice)) {
|
|
const Slice = @TypeOf(slice);
|
|
|
|
// let's not give an undefined pointer to @ptrCast
|
|
// it may be equal to zero and fail a null check
|
|
if (slice.len == 0 and comptime meta.sentinel(Slice) == null) {
|
|
return &[0]u8{};
|
|
}
|
|
|
|
const alignment = comptime meta.alignment(Slice);
|
|
|
|
const cast_target = if (comptime trait.isConstPtr(Slice)) [*]align(alignment) const u8 else [*]align(alignment) u8;
|
|
|
|
return @ptrCast(cast_target, slice)[0 .. slice.len * @sizeOf(meta.Elem(Slice))];
|
|
}
|
|
|
|
test "sliceAsBytes" {
|
|
const bytes = [_]u16{ 0xDEAD, 0xBEEF };
|
|
const slice = sliceAsBytes(bytes[0..]);
|
|
testing.expect(slice.len == 4);
|
|
testing.expect(eql(u8, slice, switch (builtin.endian) {
|
|
.Big => "\xDE\xAD\xBE\xEF",
|
|
.Little => "\xAD\xDE\xEF\xBE",
|
|
}));
|
|
}
|
|
|
|
test "sliceAsBytes with sentinel slice" {
|
|
const empty_string: [:0]const u8 = "";
|
|
const bytes = sliceAsBytes(empty_string);
|
|
testing.expect(bytes.len == 0);
|
|
}
|
|
|
|
test "sliceAsBytes packed struct at runtime and comptime" {
|
|
const Foo = packed struct {
|
|
a: u4,
|
|
b: u4,
|
|
};
|
|
const S = struct {
|
|
fn doTheTest() void {
|
|
var foo: Foo = undefined;
|
|
var slice = sliceAsBytes(@as(*[1]Foo, &foo)[0..1]);
|
|
slice[0] = 0x13;
|
|
switch (builtin.endian) {
|
|
.Big => {
|
|
testing.expect(foo.a == 0x1);
|
|
testing.expect(foo.b == 0x3);
|
|
},
|
|
.Little => {
|
|
testing.expect(foo.a == 0x3);
|
|
testing.expect(foo.b == 0x1);
|
|
},
|
|
}
|
|
}
|
|
};
|
|
S.doTheTest();
|
|
comptime S.doTheTest();
|
|
}
|
|
|
|
test "sliceAsBytes and bytesAsSlice back" {
|
|
testing.expect(@sizeOf(i32) == 4);
|
|
|
|
var big_thing_array = [_]i32{ 1, 2, 3, 4 };
|
|
const big_thing_slice: []i32 = big_thing_array[0..];
|
|
|
|
const bytes = sliceAsBytes(big_thing_slice);
|
|
testing.expect(bytes.len == 4 * 4);
|
|
|
|
bytes[4] = 0;
|
|
bytes[5] = 0;
|
|
bytes[6] = 0;
|
|
bytes[7] = 0;
|
|
testing.expect(big_thing_slice[1] == 0);
|
|
|
|
const big_thing_again = bytesAsSlice(i32, bytes);
|
|
testing.expect(big_thing_again[2] == 3);
|
|
|
|
big_thing_again[2] = -1;
|
|
testing.expect(bytes[8] == math.maxInt(u8));
|
|
testing.expect(bytes[9] == math.maxInt(u8));
|
|
testing.expect(bytes[10] == math.maxInt(u8));
|
|
testing.expect(bytes[11] == math.maxInt(u8));
|
|
}
|
|
|
|
/// Round an address up to the nearest aligned address
|
|
/// The alignment must be a power of 2 and greater than 0.
|
|
pub fn alignForward(addr: usize, alignment: usize) usize {
|
|
return alignForwardGeneric(usize, addr, alignment);
|
|
}
|
|
|
|
/// Round an address up to the nearest aligned address
|
|
/// The alignment must be a power of 2 and greater than 0.
|
|
pub fn alignForwardGeneric(comptime T: type, addr: T, alignment: T) T {
|
|
return alignBackwardGeneric(T, addr + (alignment - 1), alignment);
|
|
}
|
|
|
|
/// Force an evaluation of the expression; this tries to prevent
|
|
/// the compiler from optimizing the computation away even if the
|
|
/// result eventually gets discarded.
|
|
pub fn doNotOptimizeAway(val: anytype) void {
|
|
asm volatile (""
|
|
:
|
|
: [val] "rm" (val)
|
|
: "memory"
|
|
);
|
|
}
|
|
|
|
test "alignForward" {
|
|
testing.expect(alignForward(1, 1) == 1);
|
|
testing.expect(alignForward(2, 1) == 2);
|
|
testing.expect(alignForward(1, 2) == 2);
|
|
testing.expect(alignForward(2, 2) == 2);
|
|
testing.expect(alignForward(3, 2) == 4);
|
|
testing.expect(alignForward(4, 2) == 4);
|
|
testing.expect(alignForward(7, 8) == 8);
|
|
testing.expect(alignForward(8, 8) == 8);
|
|
testing.expect(alignForward(9, 8) == 16);
|
|
testing.expect(alignForward(15, 8) == 16);
|
|
testing.expect(alignForward(16, 8) == 16);
|
|
testing.expect(alignForward(17, 8) == 24);
|
|
}
|
|
|
|
/// Round an address up to the previous aligned address
|
|
/// Unlike `alignBackward`, `alignment` can be any positive number, not just a power of 2.
|
|
pub fn alignBackwardAnyAlign(i: usize, alignment: usize) usize {
|
|
if (@popCount(usize, alignment) == 1)
|
|
return alignBackward(i, alignment);
|
|
assert(alignment != 0);
|
|
return i - @mod(i, alignment);
|
|
}
|
|
|
|
/// Round an address up to the previous aligned address
|
|
/// The alignment must be a power of 2 and greater than 0.
|
|
pub fn alignBackward(addr: usize, alignment: usize) usize {
|
|
return alignBackwardGeneric(usize, addr, alignment);
|
|
}
|
|
|
|
/// Round an address up to the previous aligned address
|
|
/// The alignment must be a power of 2 and greater than 0.
|
|
pub fn alignBackwardGeneric(comptime T: type, addr: T, alignment: T) T {
|
|
assert(@popCount(T, alignment) == 1);
|
|
// 000010000 // example alignment
|
|
// 000001111 // subtract 1
|
|
// 111110000 // binary not
|
|
return addr & ~(alignment - 1);
|
|
}
|
|
|
|
/// Returns whether `alignment` is a valid alignment, meaning it is
|
|
/// a positive power of 2.
|
|
pub fn isValidAlign(alignment: u29) bool {
|
|
return @popCount(u29, alignment) == 1;
|
|
}
|
|
|
|
pub fn isAlignedAnyAlign(i: usize, alignment: usize) bool {
|
|
if (@popCount(usize, alignment) == 1)
|
|
return isAligned(i, alignment);
|
|
assert(alignment != 0);
|
|
return 0 == @mod(i, alignment);
|
|
}
|
|
|
|
/// Given an address and an alignment, return true if the address is a multiple of the alignment
|
|
/// The alignment must be a power of 2 and greater than 0.
|
|
pub fn isAligned(addr: usize, alignment: usize) bool {
|
|
return isAlignedGeneric(u64, addr, alignment);
|
|
}
|
|
|
|
pub fn isAlignedGeneric(comptime T: type, addr: T, alignment: T) bool {
|
|
return alignBackwardGeneric(T, addr, alignment) == addr;
|
|
}
|
|
|
|
test "isAligned" {
|
|
testing.expect(isAligned(0, 4));
|
|
testing.expect(isAligned(1, 1));
|
|
testing.expect(isAligned(2, 1));
|
|
testing.expect(isAligned(2, 2));
|
|
testing.expect(!isAligned(2, 4));
|
|
testing.expect(isAligned(3, 1));
|
|
testing.expect(!isAligned(3, 2));
|
|
testing.expect(!isAligned(3, 4));
|
|
testing.expect(isAligned(4, 4));
|
|
testing.expect(isAligned(4, 2));
|
|
testing.expect(isAligned(4, 1));
|
|
testing.expect(!isAligned(4, 8));
|
|
testing.expect(!isAligned(4, 16));
|
|
}
|
|
|
|
test "freeing empty string with null-terminated sentinel" {
|
|
const empty_string = try dupeZ(testing.allocator, u8, "");
|
|
testing.allocator.free(empty_string);
|
|
}
|