zig/std/buffer.zig

164 lines
4.9 KiB
Zig

const debug = @import("debug.zig");
const mem = @import("mem.zig");
const Allocator = mem.Allocator;
const assert = debug.assert;
const ArrayList = @import("array_list.zig").ArrayList;
const fmt = @import("fmt/index.zig");
/// A buffer that allocates memory and maintains a null byte at the end.
pub const Buffer = struct {
list: ArrayList(u8),
/// Must deinitialize with deinit.
pub fn init(allocator: &Allocator, m: []const u8) -> %Buffer {
var self = %return initSize(allocator, m.len);
mem.copy(u8, self.list.items, m);
return self;
}
/// Must deinitialize with deinit.
pub fn initSize(allocator: &Allocator, size: usize) -> %Buffer {
var self = initNull(allocator);
%return self.resize(size);
return self;
}
/// Must deinitialize with deinit.
/// None of the other operations are valid until you do one of these:
/// * ::replaceContents
/// * ::replaceContentsBuffer
/// * ::resize
pub fn initNull(allocator: &Allocator) -> Buffer {
Buffer {
.list = ArrayList(u8).init(allocator),
}
}
/// Must deinitialize with deinit.
pub fn initFromBuffer(buffer: &const Buffer) -> %Buffer {
return Buffer.init(buffer.list.allocator, buffer.toSliceConst());
}
/// Buffer takes ownership of the passed in slice. The slice must have been
/// allocated with `allocator`.
/// Must deinitialize with deinit.
pub fn fromOwnedSlice(allocator: &Allocator, slice: []u8) -> Buffer {
var self = Buffer {
.list = ArrayList(u8).fromOwnedSlice(allocator, slice),
};
self.list.append(0);
return self;
}
/// The caller owns the returned memory. The Buffer becomes null and
/// is safe to `deinit`.
pub fn toOwnedSlice(self: &Buffer) -> []u8 {
const allocator = self.list.allocator;
const result = allocator.shrink(u8, self.list.items, self.len());
*self = initNull(allocator);
return result;
}
pub fn deinit(self: &Buffer) {
self.list.deinit();
}
pub fn toSlice(self: &Buffer) -> []u8 {
return self.list.toSlice()[0..self.len()];
}
pub fn toSliceConst(self: &const Buffer) -> []const u8 {
return self.list.toSliceConst()[0..self.len()];
}
pub fn shrink(self: &Buffer, new_len: usize) {
assert(new_len <= self.len());
self.list.shrink(new_len + 1);
self.list.items[self.len()] = 0;
}
pub fn resize(self: &Buffer, new_len: usize) -> %void {
%return self.list.resize(new_len + 1);
self.list.items[self.len()] = 0;
}
pub fn isNull(self: &const Buffer) -> bool {
return self.list.len == 0;
}
pub fn len(self: &const Buffer) -> usize {
return self.list.len - 1;
}
pub fn append(self: &Buffer, m: []const u8) -> %void {
const old_len = self.len();
%return self.resize(old_len + m.len);
mem.copy(u8, self.list.toSlice()[old_len..], m);
}
// TODO: remove, use OutStream for this
pub fn appendFormat(self: &Buffer, comptime format: []const u8, args: ...) -> %void {
return fmt.format(self, append, format, args);
}
// TODO: remove, use OutStream for this
pub fn appendByte(self: &Buffer, byte: u8) -> %void {
return self.appendByteNTimes(byte, 1);
}
// TODO: remove, use OutStream for this
pub fn appendByteNTimes(self: &Buffer, byte: u8, count: usize) -> %void {
var prev_size: usize = self.len();
%return self.resize(prev_size + count);
var i: usize = 0;
while (i < count) : (i += 1) {
self.list.items[prev_size + i] = byte;
}
}
pub fn eql(self: &const Buffer, m: []const u8) -> bool {
mem.eql(u8, self.toSliceConst(), m)
}
pub fn startsWith(self: &const Buffer, m: []const u8) -> bool {
if (self.len() < m.len) return false;
return mem.eql(u8, self.list.items[0..m.len], m);
}
pub fn endsWith(self: &const Buffer, m: []const u8) -> bool {
const l = self.len();
if (l < m.len) return false;
const start = l - m.len;
return mem.eql(u8, self.list.items[start..l], m);
}
pub fn replaceContents(self: &const Buffer, m: []const u8) -> %void {
%return self.resize(m.len);
mem.copy(u8, self.list.toSlice(), m);
}
};
test "simple Buffer" {
const cstr = @import("cstr.zig");
var buf = %%Buffer.init(debug.global_allocator, "");
assert(buf.len() == 0);
%%buf.append("hello");
%%buf.appendByte(' ');
%%buf.append("world");
assert(buf.eql("hello world"));
assert(mem.eql(u8, cstr.toSliceConst(buf.toSliceConst().ptr), buf.toSliceConst()));
var buf2 = %%Buffer.initFromBuffer(&buf);
assert(buf.eql(buf2.toSliceConst()));
assert(buf.startsWith("hell"));
assert(buf.endsWith("orld"));
%%buf2.resize(4);
assert(buf.startsWith(buf2.toSliceConst()));
}