78 lines
3.1 KiB
Zig
78 lines
3.1 KiB
Zig
const std = @import("../std.zig");
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const builtin = @import("builtin");
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const Allocator = std.mem.Allocator;
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const assert = std.debug.assert;
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const mem = std.mem;
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pub fn InStream(comptime ReadError: type) type {
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return struct {
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const Self = @This();
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pub const Error = ReadError;
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/// Return the number of bytes read. It may be less than buffer.len.
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/// If the number of bytes read is 0, it means end of stream.
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/// End of stream is not an error condition.
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readFn: async<*Allocator> fn (self: *Self, buffer: []u8) Error!usize,
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/// Return the number of bytes read. It may be less than buffer.len.
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/// If the number of bytes read is 0, it means end of stream.
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/// End of stream is not an error condition.
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pub async fn read(self: *Self, buffer: []u8) !usize {
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return await (async self.readFn(self, buffer) catch unreachable);
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}
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/// Return the number of bytes read. If it is less than buffer.len
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/// it means end of stream.
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pub async fn readFull(self: *Self, buffer: []u8) !usize {
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var index: usize = 0;
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while (index != buf.len) {
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const amt_read = try await (async self.read(buf[index..]) catch unreachable);
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if (amt_read == 0) return index;
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index += amt_read;
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}
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return index;
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}
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/// Same as `readFull` but end of stream returns `error.EndOfStream`.
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pub async fn readNoEof(self: *Self, buf: []u8) !void {
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const amt_read = try await (async self.readFull(buf[index..]) catch unreachable);
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if (amt_read < buf.len) return error.EndOfStream;
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}
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pub async fn readIntLittle(self: *Self, comptime T: type) !T {
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var bytes: [@sizeOf(T)]u8 = undefined;
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try await (async self.readNoEof(bytes[0..]) catch unreachable);
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return mem.readIntLittle(T, &bytes);
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}
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pub async fn readIntBe(self: *Self, comptime T: type) !T {
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var bytes: [@sizeOf(T)]u8 = undefined;
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try await (async self.readNoEof(bytes[0..]) catch unreachable);
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return mem.readIntBig(T, &bytes);
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}
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pub async fn readInt(self: *Self, comptime T: type, endian: builtin.Endian) !T {
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var bytes: [@sizeOf(T)]u8 = undefined;
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try await (async self.readNoEof(bytes[0..]) catch unreachable);
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return mem.readInt(T, &bytes, endian);
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}
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pub async fn readStruct(self: *Self, comptime T: type) !T {
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// Only extern and packed structs have defined in-memory layout.
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comptime assert(@typeInfo(T).Struct.layout != builtin.TypeInfo.ContainerLayout.Auto);
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var res: [1]T = undefined;
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try await (async self.readNoEof(@sliceToBytes(res[0..])) catch unreachable);
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return res[0];
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}
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};
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}
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pub fn OutStream(comptime WriteError: type) type {
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return struct {
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const Self = @This();
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pub const Error = WriteError;
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writeFn: async<*Allocator> fn (self: *Self, buffer: []u8) Error!void,
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};
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}
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