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Differential D9642 Diff 31357 extern/draco/draco/src/draco/compression/bit_coders/rans_bit_encoder.cc

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extern/draco/draco/src/draco/compression/bit_coders/rans_bit_encoder.cc

  • This file was moved from extern/draco/dracoenc/src/draco/compression/bit_coders/rans_bit_encoder.cc.
Show First 20 Lines • Show All 66 Lines • ▼ Show 20 Lines if (nbits <= remaining) {
local_bits_ = 0; local_bits_ = 0;
CopyBits32(&local_bits_, 0, reversed, remaining, nbits - remaining); CopyBits32(&local_bits_, 0, reversed, remaining, nbits - remaining);
num_local_bits_ = nbits - remaining; num_local_bits_ = nbits - remaining;
} }
} }
void RAnsBitEncoder::EndEncoding(EncoderBuffer *target_buffer) { void RAnsBitEncoder::EndEncoding(EncoderBuffer *target_buffer) {
uint64_t total = bit_counts_[1] + bit_counts_[0]; uint64_t total = bit_counts_[1] + bit_counts_[0];
if (total == 0) if (total == 0) {
total++; total++;
}
// The probability interval [0,1] is mapped to values of [0, 256]. However, // The probability interval [0,1] is mapped to values of [0, 256]. However,
// the coding scheme can not deal with probabilities of 0 or 1, which is why // the coding scheme can not deal with probabilities of 0 or 1, which is why
// we must clamp the values to interval [1, 255]. Specifically 128 // we must clamp the values to interval [1, 255]. Specifically 128
// corresponds to 0.5 exactly. And the value can be given as uint8_t. // corresponds to 0.5 exactly. And the value can be given as uint8_t.
const uint32_t zero_prob_raw = static_cast<uint32_t>( const uint32_t zero_prob_raw = static_cast<uint32_t>(
((bit_counts_[0] / static_cast<double>(total)) * 256.0) + 0.5); ((bit_counts_[0] / static_cast<double>(total)) * 256.0) + 0.5);
uint8_t zero_prob = 255; uint8_t zero_prob = 255;
if (zero_prob_raw < 255) if (zero_prob_raw < 255) {
zero_prob = static_cast<uint8_t>(zero_prob_raw); zero_prob = static_cast<uint8_t>(zero_prob_raw);
}
zero_prob += (zero_prob == 0); zero_prob += (zero_prob == 0);
// Space for 32 bit integer and some extra space. // Space for 32 bit integer and some extra space.
std::vector<uint8_t> buffer((bits_.size() + 8) * 8); std::vector<uint8_t> buffer((bits_.size() + 8) * 8);
AnsCoder ans_coder; AnsCoder ans_coder;
ans_write_init(&ans_coder, buffer.data()); ans_write_init(&ans_coder, buffer.data());
Show All 28 Lines