Function decodeLiteralsRingBuffer [src]
Decode literals into dest; see decodeLiteralsSlice().
Prototype
pub fn decodeLiteralsRingBuffer( self: *DecodeState, dest: *RingBuffer, len: usize, ) DecodeLiteralsError!void Parameters
self: *DecodeStatedest: *RingBufferlen: usize Possible Errors
Source
pub fn decodeLiteralsRingBuffer(
self: *DecodeState,
dest: *RingBuffer,
len: usize,
) DecodeLiteralsError!void {
if (self.literal_written_count + len > self.literal_header.regenerated_size)
return error.MalformedLiteralsLength;
switch (self.literal_header.block_type) {
.raw => {
const literals_end = self.literal_written_count + len;
const literal_data = self.literal_streams.one[self.literal_written_count..literals_end];
dest.writeSliceAssumeCapacity(literal_data);
self.literal_written_count += len;
self.written_count += len;
},
.rle => {
for (0..len) |_| {
dest.writeAssumeCapacity(self.literal_streams.one[0]);
}
self.literal_written_count += len;
self.written_count += len;
},
.compressed, .treeless => {
// const written_bytes_per_stream = (literals.header.regenerated_size + 3) / 4;
const huffman_tree = self.huffman_tree orelse unreachable;
const max_bit_count = huffman_tree.max_bit_count;
const starting_bit_count = LiteralsSection.HuffmanTree.weightToBitCount(
huffman_tree.nodes[huffman_tree.symbol_count_minus_one].weight,
max_bit_count,
);
var bits_read: u4 = 0;
var huffman_tree_index: usize = huffman_tree.symbol_count_minus_one;
var bit_count_to_read: u4 = starting_bit_count;
for (0..len) |_| {
var prefix: u16 = 0;
while (true) {
const new_bits = try self.readLiteralsBits(bit_count_to_read);
prefix <<= bit_count_to_read;
prefix |= new_bits;
bits_read += bit_count_to_read;
const result = try huffman_tree.query(huffman_tree_index, prefix);
switch (result) {
.symbol => |sym| {
dest.writeAssumeCapacity(sym);
bit_count_to_read = starting_bit_count;
bits_read = 0;
huffman_tree_index = huffman_tree.symbol_count_minus_one;
break;
},
.index => |index| {
huffman_tree_index = index;
const bit_count = LiteralsSection.HuffmanTree.weightToBitCount(
huffman_tree.nodes[index].weight,
max_bit_count,
);
bit_count_to_read = bit_count - bits_read;
},
}
}
}
self.literal_written_count += len;
self.written_count += len;
},
}
}