diff options
Diffstat (limited to 'deps/node/deps/brotli/c/enc/bit_cost_inc.h')
-rw-r--r-- | deps/node/deps/brotli/c/enc/bit_cost_inc.h | 127 |
1 files changed, 0 insertions, 127 deletions
diff --git a/deps/node/deps/brotli/c/enc/bit_cost_inc.h b/deps/node/deps/brotli/c/enc/bit_cost_inc.h deleted file mode 100644 index 453c2260..00000000 --- a/deps/node/deps/brotli/c/enc/bit_cost_inc.h +++ /dev/null @@ -1,127 +0,0 @@ -/* NOLINT(build/header_guard) */ -/* Copyright 2013 Google Inc. All Rights Reserved. - - Distributed under MIT license. - See file LICENSE for detail or copy at https://opensource.org/licenses/MIT -*/ - -/* template parameters: FN */ - -#define HistogramType FN(Histogram) - -double FN(BrotliPopulationCost)(const HistogramType* histogram) { - static const double kOneSymbolHistogramCost = 12; - static const double kTwoSymbolHistogramCost = 20; - static const double kThreeSymbolHistogramCost = 28; - static const double kFourSymbolHistogramCost = 37; - const size_t data_size = FN(HistogramDataSize)(); - int count = 0; - size_t s[5]; - double bits = 0.0; - size_t i; - if (histogram->total_count_ == 0) { - return kOneSymbolHistogramCost; - } - for (i = 0; i < data_size; ++i) { - if (histogram->data_[i] > 0) { - s[count] = i; - ++count; - if (count > 4) break; - } - } - if (count == 1) { - return kOneSymbolHistogramCost; - } - if (count == 2) { - return (kTwoSymbolHistogramCost + (double)histogram->total_count_); - } - if (count == 3) { - const uint32_t histo0 = histogram->data_[s[0]]; - const uint32_t histo1 = histogram->data_[s[1]]; - const uint32_t histo2 = histogram->data_[s[2]]; - const uint32_t histomax = - BROTLI_MAX(uint32_t, histo0, BROTLI_MAX(uint32_t, histo1, histo2)); - return (kThreeSymbolHistogramCost + - 2 * (histo0 + histo1 + histo2) - histomax); - } - if (count == 4) { - uint32_t histo[4]; - uint32_t h23; - uint32_t histomax; - for (i = 0; i < 4; ++i) { - histo[i] = histogram->data_[s[i]]; - } - /* Sort */ - for (i = 0; i < 4; ++i) { - size_t j; - for (j = i + 1; j < 4; ++j) { - if (histo[j] > histo[i]) { - BROTLI_SWAP(uint32_t, histo, j, i); - } - } - } - h23 = histo[2] + histo[3]; - histomax = BROTLI_MAX(uint32_t, h23, histo[0]); - return (kFourSymbolHistogramCost + - 3 * h23 + 2 * (histo[0] + histo[1]) - histomax); - } - - { - /* In this loop we compute the entropy of the histogram and simultaneously - build a simplified histogram of the code length codes where we use the - zero repeat code 17, but we don't use the non-zero repeat code 16. */ - size_t max_depth = 1; - uint32_t depth_histo[BROTLI_CODE_LENGTH_CODES] = { 0 }; - const double log2total = FastLog2(histogram->total_count_); - for (i = 0; i < data_size;) { - if (histogram->data_[i] > 0) { - /* Compute -log2(P(symbol)) = -log2(count(symbol)/total_count) = - = log2(total_count) - log2(count(symbol)) */ - double log2p = log2total - FastLog2(histogram->data_[i]); - /* Approximate the bit depth by round(-log2(P(symbol))) */ - size_t depth = (size_t)(log2p + 0.5); - bits += histogram->data_[i] * log2p; - if (depth > 15) { - depth = 15; - } - if (depth > max_depth) { - max_depth = depth; - } - ++depth_histo[depth]; - ++i; - } else { - /* Compute the run length of zeros and add the appropriate number of 0 - and 17 code length codes to the code length code histogram. */ - uint32_t reps = 1; - size_t k; - for (k = i + 1; k < data_size && histogram->data_[k] == 0; ++k) { - ++reps; - } - i += reps; - if (i == data_size) { - /* Don't add any cost for the last zero run, since these are encoded - only implicitly. */ - break; - } - if (reps < 3) { - depth_histo[0] += reps; - } else { - reps -= 2; - while (reps > 0) { - ++depth_histo[BROTLI_REPEAT_ZERO_CODE_LENGTH]; - /* Add the 3 extra bits for the 17 code length code. */ - bits += 3; - reps >>= 3; - } - } - } - } - /* Add the estimated encoding cost of the code length code histogram. */ - bits += (double)(18 + 2 * max_depth); - /* Add the entropy of the code length code histogram. */ - bits += BitsEntropy(depth_histo, BROTLI_CODE_LENGTH_CODES); - } - return bits; -} - -#undef HistogramType |