blob: 6b35ae3f87f2a1aff4fdc8134b309e454b05589a (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
#include "draco/compression/bit_coders/symbol_bit_decoder.h"
#include "draco/compression/entropy/symbol_decoding.h"
namespace draco {
bool SymbolBitDecoder::StartDecoding(DecoderBuffer *source_buffer) {
uint32_t size;
if (!source_buffer->Decode(&size))
return false;
symbols_.resize(size);
if (!DecodeSymbols(size, 1, source_buffer, symbols_.data()))
return false;
std::reverse(symbols_.begin(), symbols_.end());
return true;
}
bool SymbolBitDecoder::DecodeNextBit() {
uint32_t symbol;
DecodeLeastSignificantBits32(1, &symbol);
DRACO_DCHECK(symbol == 0 || symbol == 1);
return symbol == 1;
}
void SymbolBitDecoder::DecodeLeastSignificantBits32(int nbits,
uint32_t *value) {
DRACO_DCHECK_LE(1, nbits);
DRACO_DCHECK_LE(nbits, 32);
DRACO_DCHECK_NE(value, nullptr);
// Testing: check to make sure there is something to decode.
DRACO_DCHECK_GT(symbols_.size(), 0);
(*value) = symbols_.back();
symbols_.pop_back();
const int discarded_bits = 32 - nbits;
(*value) <<= discarded_bits;
(*value) >>= discarded_bits;
}
void SymbolBitDecoder::Clear() {
symbols_.clear();
symbols_.shrink_to_fit();
}
} // namespace draco
|
