From 067031eaed11e91d9914e1e872738c7bdf075e0b Mon Sep 17 00:00:00 2001 From: Vincent Rabaud Date: Mon, 11 Mar 2019 16:53:06 +0100 Subject: [PATCH] Speedups for unused Huffman groups. If we know a Huffman group is unused, do not build it: just check that it is valid. Change-Id: Ie8223fe1afa1e769085a23ab92e730edd9060176 --- src/dec/vp8l_dec.c | 125 +++++++++++++++++++------------------- src/utils/huffman_utils.c | 26 +++++--- src/utils/huffman_utils.h | 2 + 3 files changed, 82 insertions(+), 71 deletions(-) diff --git a/src/dec/vp8l_dec.c b/src/dec/vp8l_dec.c index 333bb3e8..d3e27119 100644 --- a/src/dec/vp8l_dec.c +++ b/src/dec/vp8l_dec.c @@ -362,12 +362,8 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize, VP8LMetadata* const hdr = &dec->hdr_; uint32_t* huffman_image = NULL; HTreeGroup* htree_groups = NULL; - // When reading htrees, some might be unused, as the format allows it. - // We will still read them but put them in this htree_group_bogus. - HTreeGroup htree_group_bogus; HuffmanCode* huffman_tables = NULL; - HuffmanCode* huffman_tables_bogus = NULL; - HuffmanCode* next = NULL; + HuffmanCode* huffman_table = NULL; int num_htree_groups = 1; int num_htree_groups_max = 1; int max_alphabet_size = 0; @@ -418,12 +414,6 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize, if (*mapped_group == -1) *mapped_group = num_htree_groups++; huffman_image[i] = *mapped_group; } - huffman_tables_bogus = (HuffmanCode*)WebPSafeMalloc( - table_size, sizeof(*huffman_tables_bogus)); - if (huffman_tables_bogus == NULL) { - dec->status_ = VP8_STATUS_OUT_OF_MEMORY; - goto Error; - } } else { num_htree_groups = num_htree_groups_max; } @@ -453,63 +443,71 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize, goto Error; } - next = huffman_tables; + huffman_table = huffman_tables; for (i = 0; i < num_htree_groups_max; ++i) { - // If the index "i" is unused in the Huffman image, read the coefficients - // but store them to a bogus htree_group. - const int is_bogus = (mapping != NULL && mapping[i] == -1); - HTreeGroup* const htree_group = - is_bogus ? &htree_group_bogus : - &htree_groups[(mapping == NULL) ? i : mapping[i]]; - HuffmanCode** const htrees = htree_group->htrees; - HuffmanCode* huffman_tables_i = is_bogus ? huffman_tables_bogus : next; - int size; - int total_size = 0; - int is_trivial_literal = 1; - int max_bits = 0; - for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) { - int alphabet_size = kAlphabetSize[j]; - htrees[j] = huffman_tables_i; - if (j == 0 && color_cache_bits > 0) { - alphabet_size += 1 << color_cache_bits; - } - size = - ReadHuffmanCode(alphabet_size, dec, code_lengths, huffman_tables_i); - if (size == 0) { - goto Error; - } - if (is_trivial_literal && kLiteralMap[j] == 1) { - is_trivial_literal = (huffman_tables_i->bits == 0); - } - total_size += huffman_tables_i->bits; - huffman_tables_i += size; - if (j <= ALPHA) { - int local_max_bits = code_lengths[0]; - int k; - for (k = 1; k < alphabet_size; ++k) { - if (code_lengths[k] > local_max_bits) { - local_max_bits = code_lengths[k]; - } + // If the index "i" is unused in the Huffman image, just make sure the + // coefficients are valid but do not store them. + if (mapping != NULL && mapping[i] == -1) { + for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) { + int alphabet_size = kAlphabetSize[j]; + if (j == 0 && color_cache_bits > 0) { + alphabet_size += (1 << color_cache_bits); + } + // Passing in NULL so that nothing gets filled. + if (!ReadHuffmanCode(alphabet_size, dec, code_lengths, NULL)) { + goto Error; } - max_bits += local_max_bits; } - } - if (!is_bogus) next = huffman_tables_i; - htree_group->is_trivial_literal = is_trivial_literal; - htree_group->is_trivial_code = 0; - if (is_trivial_literal) { - const int red = htrees[RED][0].value; - const int blue = htrees[BLUE][0].value; - const int alpha = htrees[ALPHA][0].value; - htree_group->literal_arb = ((uint32_t)alpha << 24) | (red << 16) | blue; - if (total_size == 0 && htrees[GREEN][0].value < NUM_LITERAL_CODES) { - htree_group->is_trivial_code = 1; - htree_group->literal_arb |= htrees[GREEN][0].value << 8; + } else { + HTreeGroup* const htree_group = + &htree_groups[(mapping == NULL) ? i : mapping[i]]; + HuffmanCode** const htrees = htree_group->htrees; + int size; + int total_size = 0; + int is_trivial_literal = 1; + int max_bits = 0; + for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) { + int alphabet_size = kAlphabetSize[j]; + htrees[j] = huffman_table; + if (j == 0 && color_cache_bits > 0) { + alphabet_size += (1 << color_cache_bits); + } + size = ReadHuffmanCode(alphabet_size, dec, code_lengths, huffman_table); + if (size == 0) { + goto Error; + } + if (is_trivial_literal && kLiteralMap[j] == 1) { + is_trivial_literal = (huffman_table->bits == 0); + } + total_size += huffman_table->bits; + huffman_table += size; + if (j <= ALPHA) { + int local_max_bits = code_lengths[0]; + int k; + for (k = 1; k < alphabet_size; ++k) { + if (code_lengths[k] > local_max_bits) { + local_max_bits = code_lengths[k]; + } + } + max_bits += local_max_bits; + } } + htree_group->is_trivial_literal = is_trivial_literal; + htree_group->is_trivial_code = 0; + if (is_trivial_literal) { + const int red = htrees[RED][0].value; + const int blue = htrees[BLUE][0].value; + const int alpha = htrees[ALPHA][0].value; + htree_group->literal_arb = ((uint32_t)alpha << 24) | (red << 16) | blue; + if (total_size == 0 && htrees[GREEN][0].value < NUM_LITERAL_CODES) { + htree_group->is_trivial_code = 1; + htree_group->literal_arb |= htrees[GREEN][0].value << 8; + } + } + htree_group->use_packed_table = + !htree_group->is_trivial_code && (max_bits < HUFFMAN_PACKED_BITS); + if (htree_group->use_packed_table) BuildPackedTable(htree_group); } - htree_group->use_packed_table = - !htree_group->is_trivial_code && (max_bits < HUFFMAN_PACKED_BITS); - if (htree_group->use_packed_table) BuildPackedTable(htree_group); } ok = 1; @@ -521,7 +519,6 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize, Error: WebPSafeFree(code_lengths); - WebPSafeFree(huffman_tables_bogus); WebPSafeFree(mapping); if (!ok) { WebPSafeFree(huffman_image); diff --git a/src/utils/huffman_utils.c b/src/utils/huffman_utils.c index 7a69963c..0cba0fbb 100644 --- a/src/utils/huffman_utils.c +++ b/src/utils/huffman_utils.c @@ -91,7 +91,8 @@ static int BuildHuffmanTable(HuffmanCode* const root_table, int root_bits, assert(code_lengths_size != 0); assert(code_lengths != NULL); - assert(root_table != NULL); + assert((root_table != NULL && sorted != NULL) || + (root_table == NULL && sorted == NULL)); assert(root_bits > 0); // Build histogram of code lengths. @@ -120,16 +121,22 @@ static int BuildHuffmanTable(HuffmanCode* const root_table, int root_bits, for (symbol = 0; symbol < code_lengths_size; ++symbol) { const int symbol_code_length = code_lengths[symbol]; if (code_lengths[symbol] > 0) { - sorted[offset[symbol_code_length]++] = symbol; + if (sorted != NULL) { + sorted[offset[symbol_code_length]++] = symbol; + } else { + offset[symbol_code_length]++; + } } } // Special case code with only one value. if (offset[MAX_ALLOWED_CODE_LENGTH] == 1) { - HuffmanCode code; - code.bits = 0; - code.value = (uint16_t)sorted[0]; - ReplicateValue(table, 1, total_size, code); + if (sorted != NULL) { + HuffmanCode code; + code.bits = 0; + code.value = (uint16_t)sorted[0]; + ReplicateValue(table, 1, total_size, code); + } return total_size; } @@ -151,6 +158,7 @@ static int BuildHuffmanTable(HuffmanCode* const root_table, int root_bits, if (num_open < 0) { return 0; } + if (root_table == NULL) continue; for (; count[len] > 0; --count[len]) { HuffmanCode code; code.bits = (uint8_t)len; @@ -169,6 +177,7 @@ static int BuildHuffmanTable(HuffmanCode* const root_table, int root_bits, if (num_open < 0) { return 0; } + if (root_table == NULL) continue; for (; count[len] > 0; --count[len]) { HuffmanCode code; if ((key & mask) != low) { @@ -206,7 +215,10 @@ int VP8LBuildHuffmanTable(HuffmanCode* const root_table, int root_bits, const int code_lengths[], int code_lengths_size) { int total_size; assert(code_lengths_size <= MAX_CODE_LENGTHS_SIZE); - if (code_lengths_size <= SORTED_SIZE_CUTOFF) { + if (root_table == NULL) { + total_size = BuildHuffmanTable(NULL, root_bits, + code_lengths, code_lengths_size, NULL); + } else if (code_lengths_size <= SORTED_SIZE_CUTOFF) { // use local stack-allocated array. uint16_t sorted[SORTED_SIZE_CUTOFF]; total_size = BuildHuffmanTable(root_table, root_bits, diff --git a/src/utils/huffman_utils.h b/src/utils/huffman_utils.h index ff7ef17f..13b7ad1a 100644 --- a/src/utils/huffman_utils.h +++ b/src/utils/huffman_utils.h @@ -78,6 +78,8 @@ void VP8LHtreeGroupsFree(HTreeGroup* const htree_groups); // the huffman table. // Returns built table size or 0 in case of error (invalid tree or // memory error). +// If root_table is NULL, it returns 0 if a lookup cannot be built, something +// > 0 otherwise (but not the table size). int VP8LBuildHuffmanTable(HuffmanCode* const root_table, int root_bits, const int code_lengths[], int code_lengths_size);