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| 1 | const std = @import("std"); |
| 2 | const nio = @import("./nio.zig"); |
| 3 | |
| 4 | pub fn BufferedReader(comptime buffer_size: usize, comptime ReaderType: type) type { |
| 5 | return struct { |
| 6 | unbuffered_reader: ReaderType, |
| 7 | buf: [buffer_size]u8, |
| 8 | start: usize, |
| 9 | end: usize, |
| 10 | |
| 11 | const Self = @This(); |
| 12 | |
| 13 | pub fn init(unbuffered_reader: ReaderType) Self { |
| 14 | return .{ |
| 15 | .unbuffered_reader = unbuffered_reader, |
| 16 | .buf = undefined, |
| 17 | .start = 0, |
| 18 | .end = 0, |
| 19 | }; |
| 20 | } |
| 21 | |
| 22 | pub const ReadError = ReaderType.ReadError; |
| 23 | pub usingnamespace nio.Readable(@This(), ._var); |
| 24 | pub fn read(self: *Self, dest: []u8) ReadError!usize { |
| 25 | // First try reading from the already buffered data onto the destination. |
| 26 | const current = self.buf[self.start..self.end]; |
| 27 | if (current.len != 0) { |
| 28 | const to_transfer = @min(current.len, dest.len); |
| 29 | @memcpy(dest[0..to_transfer], current[0..to_transfer]); |
| 30 | self.start += to_transfer; |
| 31 | return to_transfer; |
| 32 | } |
| 33 | |
| 34 | // If dest is large, read from the unbuffered reader directly into the destination. |
| 35 | if (dest.len >= buffer_size) { |
| 36 | return self.unbuffered_reader.read(dest); |
| 37 | } |
| 38 | |
| 39 | // If dest is small, read from the unbuffered reader into our own internal buffer, |
| 40 | // and then transfer to destination. |
| 41 | self.end = try self.unbuffered_reader.read(&self.buf); |
| 42 | const to_transfer = @min(self.end, dest.len); |
| 43 | @memcpy(dest[0..to_transfer], self.buf[0..to_transfer]); |
| 44 | self.start = to_transfer; |
| 45 | return to_transfer; |
| 46 | } |
| 47 | |
| 48 | pub fn anyReadable(self: *Self) nio.AnyReadable { |
| 49 | const S = struct { |
| 50 | fn read(s: *allowzero anyopaque, buffer: []u8) anyerror!usize { |
| 51 | const br: *Self = @ptrCast(@alignCast(s)); |
| 52 | return br.read(buffer); |
| 53 | } |
| 54 | }; |
| 55 | return .{ |
| 56 | .vtable = &.{ .read = S.read }, |
| 57 | .state = @ptrCast(self), |
| 58 | }; |
| 59 | } |
| 60 | }; |
| 61 | } |
Meghan Denny <hello@nektro.net> 2026-02-04 18:11:56 -08:00