diff options
Diffstat (limited to 'lib/std/compress/flate/bit_reader.zig')
| -rw-r--r-- | lib/std/compress/flate/bit_reader.zig | 64 |
1 files changed, 32 insertions, 32 deletions
diff --git a/lib/std/compress/flate/bit_reader.zig b/lib/std/compress/flate/bit_reader.zig index a31813f42a..40e9b76fb8 100644 --- a/lib/std/compress/flate/bit_reader.zig +++ b/lib/std/compress/flate/bit_reader.zig @@ -34,15 +34,15 @@ pub fn BitReader(comptime ReaderType: type) type { return self; } - // Try to have `nice` bits are available in buffer. Reads from - // forward reader if there is no `nice` bits in buffer. Returns error - // if end of forward stream is reached and internal buffer is empty. - // It will not error if less than `nice` bits are in buffer, only when - // all bits are exhausted. During inflate we usually know what is the - // maximum bits for the next step but usually that step will need less - // bits to decode. So `nice` is not hard limit, it will just try to have - // that number of bits available. If end of forward stream is reached - // it may be some extra zero bits in buffer. + /// Try to have `nice` bits are available in buffer. Reads from + /// forward reader if there is no `nice` bits in buffer. Returns error + /// if end of forward stream is reached and internal buffer is empty. + /// It will not error if less than `nice` bits are in buffer, only when + /// all bits are exhausted. During inflate we usually know what is the + /// maximum bits for the next step but usually that step will need less + /// bits to decode. So `nice` is not hard limit, it will just try to have + /// that number of bits available. If end of forward stream is reached + /// it may be some extra zero bits in buffer. pub inline fn fill(self: *Self, nice: u6) !void { if (self.nbits >= nice) { return; // We have enought bits @@ -67,7 +67,7 @@ pub fn BitReader(comptime ReaderType: type) type { return error.EndOfStream; } - // Read exactly buf.len bytes into buf. + /// Read exactly buf.len bytes into buf. pub fn readAll(self: *Self, buf: []u8) !void { assert(self.alignBits() == 0); // internal bits must be at byte boundary @@ -87,17 +87,17 @@ pub fn BitReader(comptime ReaderType: type) type { pub const reverse: u3 = 0b100; // bit reverse readed bits }; - // Alias for readF(U, 0). + /// Alias for readF(U, 0). pub fn read(self: *Self, comptime U: type) !U { return self.readF(U, 0); } - // Alias for readF with flag.peak set. + /// Alias for readF with flag.peak set. pub inline fn peekF(self: *Self, comptime U: type, comptime how: u3) !U { return self.readF(U, how | flag.peek); } - // Read with flags provided. + /// Read with flags provided. pub fn readF(self: *Self, comptime U: type, comptime how: u3) !U { const n: u6 = @bitSizeOf(U); switch (how) { @@ -140,8 +140,8 @@ pub fn BitReader(comptime ReaderType: type) type { } } - // Read n number of bits. - // Only buffered flag can be used in how. + /// Read n number of bits. + /// Only buffered flag can be used in how. pub fn readN(self: *Self, n: u4, comptime how: u3) !u16 { switch (how) { 0 => { @@ -156,14 +156,14 @@ pub fn BitReader(comptime ReaderType: type) type { return u; } - // Advance buffer for n bits. + /// Advance buffer for n bits. pub fn shift(self: *Self, n: u6) !void { if (n > self.nbits) return error.EndOfStream; self.bits >>= n; self.nbits -= n; } - // Skip n bytes. + /// Skip n bytes. pub fn skipBytes(self: *Self, n: u16) !void { for (0..n) |_| { try self.fill(8); @@ -176,32 +176,32 @@ pub fn BitReader(comptime ReaderType: type) type { return @intCast(self.nbits & 0x7); } - // Align stream to the byte boundary. + /// Align stream to the byte boundary. pub fn alignToByte(self: *Self) void { const ab = self.alignBits(); if (ab > 0) self.shift(ab) catch unreachable; } - // Skip zero terminated string. + /// Skip zero terminated string. pub fn skipStringZ(self: *Self) !void { while (true) { if (try self.readF(u8, 0) == 0) break; } } - // Read deflate fixed fixed code. - // Reads first 7 bits, and then mybe 1 or 2 more to get full 7,8 or 9 bit code. - // ref: https://datatracker.ietf.org/doc/html/rfc1951#page-12 - // Lit Value Bits Codes - // --------- ---- ----- - // 0 - 143 8 00110000 through - // 10111111 - // 144 - 255 9 110010000 through - // 111111111 - // 256 - 279 7 0000000 through - // 0010111 - // 280 - 287 8 11000000 through - // 11000111 + /// Read deflate fixed fixed code. + /// Reads first 7 bits, and then mybe 1 or 2 more to get full 7,8 or 9 bit code. + /// ref: https://datatracker.ietf.org/doc/html/rfc1951#page-12 + /// Lit Value Bits Codes + /// --------- ---- ----- + /// 0 - 143 8 00110000 through + /// 10111111 + /// 144 - 255 9 110010000 through + /// 111111111 + /// 256 - 279 7 0000000 through + /// 0010111 + /// 280 - 287 8 11000000 through + /// 11000111 pub fn readFixedCode(self: *Self) !u16 { try self.fill(7 + 2); const code7 = try self.readF(u7, flag.buffered | flag.reverse); |