Function decode [src]

Prototype

pub fn decode(in: *Reader, remaining: *Limit, buffer: []u8) DecodeError!LiteralsSection

Parameters

in: *Readerremaining: *Limitbuffer: []u8

Possible Errors

EndOfStream

Not enough bytes to complete the section.

MalformedAccuracyLog

Compressed literals have invalid accuracy.

MalformedFseTable

Compressed literals have invalid FSE table.

MalformedHuffmanTree

Failed decoding a Huffamn tree.

MalformedLiteralsHeader

Invalid header.

MalformedLiteralsSection

Decoding errors.

MissingStartBit

ReadFailed

Source

  pub fn decode(in: *Reader, remaining: *Limit, buffer: []u8) DecodeError!LiteralsSection {
    const header = try Header.decode(in, remaining);
    switch (header.block_type) {
        .raw => {
            if (buffer.len < header.regenerated_size) return error.MalformedLiteralsSection;
            remaining.* = remaining.subtract(header.regenerated_size) orelse return error.EndOfStream;
            try in.readSliceAll(buffer[0..header.regenerated_size]);
            return .{
                .header = header,
                .huffman_tree = null,
                .streams = .{ .one = buffer },
            };
        },
        .rle => {
            remaining.* = remaining.subtract(1) orelse return error.EndOfStream;
            buffer[0] = try in.takeByte();
            return .{
                .header = header,
                .huffman_tree = null,
                .streams = .{ .one = buffer[0..1] },
            };
        },
        .compressed, .treeless => {
            const before_remaining = remaining.*;
            const huffman_tree = if (header.block_type == .compressed)
                try HuffmanTree.decode(in, remaining)
            else
                null;
            const huffman_tree_size = @intFromEnum(before_remaining) - @intFromEnum(remaining.*);
            const total_streams_size = std.math.sub(usize, header.compressed_size.?, huffman_tree_size) catch
                return error.MalformedLiteralsSection;
            if (total_streams_size > buffer.len) return error.MalformedLiteralsSection;
            remaining.* = remaining.subtract(total_streams_size) orelse return error.EndOfStream;
            try in.readSliceAll(buffer[0..total_streams_size]);
            const stream_data = buffer[0..total_streams_size];
            const streams = try Streams.decode(header.size_format, stream_data);
            return .{
                .header = header,
                .huffman_tree = huffman_tree,
                .streams = streams,
            };
        },
    }
}  