mirror of
https://github.com/ziglang/zig.git
synced 2025-12-07 14:53:08 +00:00
ba0e3be5cf
The main goal here is to make the function pointers comptime, so that we don't have to do the crazy stuff with async function frames. Since InStream, OutStream, and SeekableStream are already generic across error sets, it's not really worse to make them generic across the vtable as well. See #764 for the open issue acknowledging that using generics for these abstractions is a design flaw. See #130 for the efforts to make these abstractions non-generic. This commit also changes the OutStream API so that `write` returns number of bytes written, and `writeAll` is the one that loops until the whole buffer is written.
67 lines
2.0 KiB
Zig
67 lines
2.0 KiB
Zig
const std = @import("../std.zig");
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const io = std.io;
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pub const FixedBufferInStream = struct {
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bytes: []const u8,
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pos: usize,
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pub const SeekError = error{EndOfStream};
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pub const GetSeekPosError = error{};
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pub const InStream = io.InStream(*FixedBufferInStream, error{}, read);
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pub fn inStream(self: *FixedBufferInStream) InStream {
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return .{ .context = self };
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}
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pub const SeekableStream = io.SeekableStream(
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*FixedBufferInStream,
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SeekError,
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GetSeekPosError,
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seekTo,
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seekBy,
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getPos,
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getEndPos,
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);
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pub fn seekableStream(self: *FixedBufferInStream) SeekableStream {
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return .{ .context = self };
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}
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pub fn read(self: *FixedBufferInStream, dest: []u8) error{}!usize {
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const size = std.math.min(dest.len, self.bytes.len - self.pos);
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const end = self.pos + size;
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std.mem.copy(u8, dest[0..size], self.bytes[self.pos..end]);
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self.pos = end;
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return size;
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}
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pub fn seekTo(self: *FixedBufferInStream, pos: u64) SeekError!void {
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const usize_pos = std.math.cast(usize, pos) catch return error.EndOfStream;
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if (usize_pos > self.bytes.len) return error.EndOfStream;
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self.pos = usize_pos;
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}
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pub fn seekBy(self: *FixedBufferInStream, amt: i64) SeekError!void {
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if (amt < 0) {
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const abs_amt = std.math.cast(usize, -amt) catch return error.EndOfStream;
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if (abs_amt > self.pos) return error.EndOfStream;
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self.pos -= abs_amt;
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} else {
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const usize_amt = std.math.cast(usize, amt) catch return error.EndOfStream;
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if (self.pos + usize_amt > self.bytes.len) return error.EndOfStream;
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self.pos += usize_amt;
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}
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}
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pub fn getEndPos(self: *FixedBufferInStream) GetSeekPosError!u64 {
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return self.bytes.len;
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}
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pub fn getPos(self: *FixedBufferInStream) GetSeekPosError!u64 {
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return self.pos;
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}
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};
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