/*
Calculates size of the part after the header and tree of an LZ77 block, in bits.
*/
static size_t CalculateBlockSymbolSize(const unsigned* ll_lengths,
const unsigned* d_lengths,
const unsigned short* litlens,
const unsigned short* dists,
size_t lstart, size_t lend) {
size_t result = 0;
size_t i;
for (i = lstart; i < lend; i++) {
if (dists[i] == 0) {
result += ll_lengths[litlens[i]];
} else {
result += ll_lengths[ZopfliGetLengthSymbol(litlens[i])];
result += d_lengths[ZopfliGetDistSymbol(dists[i])];
result += ZopfliGetLengthExtraBits(litlens[i]);
result += ZopfliGetDistExtraBits(dists[i]);
}
}
result += ll_lengths[256]; /*end symbol*/
return result;
}
/*
Calculates size of the part after the header and tree of an LZ77 block, in bits.
*/
static size_t CalculateBlockSymbolSize(const unsigned* ll_lengths,
const unsigned* d_lengths,
const ZopfliLZ77Store* lz77,
size_t lstart, size_t lend) {
size_t result = 0;
size_t i;
if (lstart + ZOPFLI_NUM_LL * 3 > lend) {
for (i = lstart; i < lend; i++) {
assert(i < lz77->size);
assert(lz77->litlens[i] < 259);
if (lz77->dists[i] == 0) {
result += ll_lengths[lz77->litlens[i]];
} else {
int ll_symbol = ZopfliGetLengthSymbol(lz77->litlens[i]);
int d_symbol = ZopfliGetDistSymbol(lz77->dists[i]);
result += ll_lengths[ll_symbol];
result += d_lengths[d_symbol];
result += ZopfliGetLengthSymbolExtraBits(ll_symbol);
result += ZopfliGetDistSymbolExtraBits(d_symbol);
}
}
} else {
size_t ll_counts[ZOPFLI_NUM_LL];
size_t d_counts[ZOPFLI_NUM_D];
ZopfliLZ77GetHistogram(lz77, lstart, lend, ll_counts, d_counts);
for (i = 0; i < 256; i++) {
result += ll_lengths[i] * ll_counts[i];
}
for (i = 257; i < 286; i++) {
result += ll_lengths[i] * ll_counts[i];
result += ZopfliGetLengthSymbolExtraBits(i) * ll_counts[i];
}
for (i = 0; i < 30; i++) {
result += d_lengths[i] * d_counts[i];
result += ZopfliGetDistSymbolExtraBits(i) * d_counts[i];
}
}
result += ll_lengths[256]; /*end symbol*/
return result;
}
/*
Adds all lit/len and dist codes from the lists as huffman symbols. Does not add
end code 256. expected_data_size is the uncompressed block size, used for
assert, but you can set it to 0 to not do the assertion.
*/
static void AddLZ77Data(const unsigned short* litlens,
const unsigned short* dists,
size_t lstart, size_t lend,
size_t expected_data_size,
const unsigned* ll_symbols, const unsigned* ll_lengths,
const unsigned* d_symbols, const unsigned* d_lengths,
unsigned char* bp,
unsigned char** out, size_t* outsize) {
size_t testlength = 0;
size_t i;
for (i = lstart; i < lend; i++) {
unsigned dist = dists[i];
unsigned litlen = litlens[i];
if (dist == 0) {
assert(litlen < 256);
assert(ll_lengths[litlen] > 0);
AddHuffmanBits(ll_symbols[litlen], ll_lengths[litlen], bp, out, outsize);
testlength++;
} else {
unsigned lls = ZopfliGetLengthSymbol(litlen);
unsigned ds = ZopfliGetDistSymbol(dist);
assert(litlen >= 3 && litlen <= 288);
assert(ll_lengths[lls] > 0);
assert(d_lengths[ds] > 0);
AddHuffmanBits(ll_symbols[lls], ll_lengths[lls], bp, out, outsize);
AddBits(ZopfliGetLengthExtraBitsValue(litlen),
ZopfliGetLengthExtraBits(litlen),
bp, out, outsize);
AddHuffmanBits(d_symbols[ds], d_lengths[ds], bp, out, outsize);
AddBits(ZopfliGetDistExtraBitsValue(dist),
ZopfliGetDistExtraBits(dist),
bp, out, outsize);
testlength += litlen;
}
}
assert(expected_data_size == 0 || testlength == expected_data_size);
}
/*
Same as CalculateBlockSymbolSize, but for block size smaller than histogram
size.
*/
static size_t CalculateBlockSymbolSizeSmall(const unsigned* ll_lengths,
const unsigned* d_lengths,
const ZopfliLZ77Store* lz77,
size_t lstart, size_t lend) {
size_t result = 0;
size_t i;
for (i = lstart; i < lend; i++) {
assert(i < lz77->size);
assert(lz77->litlens[i] < 259);
if (lz77->dists[i] == 0) {
result += ll_lengths[lz77->litlens[i]];
} else {
int ll_symbol = ZopfliGetLengthSymbol(lz77->litlens[i]);
int d_symbol = ZopfliGetDistSymbol(lz77->dists[i]);
result += ll_lengths[ll_symbol];
result += d_lengths[d_symbol];
result += ZopfliGetLengthSymbolExtraBits(ll_symbol);
result += ZopfliGetDistSymbolExtraBits(d_symbol);
}
}
result += ll_lengths[256]; /*end symbol*/
return result;
}
void ZopfliLZ77Counts(const unsigned short* litlens,
const unsigned short* dists,
size_t start, size_t end,
size_t* ll_count, size_t* d_count) {
size_t i;
for (i = 0; i < 288; i++) {
ll_count[i] = 0;
}
for (i = 0; i < 32; i++) {
d_count[i] = 0;
}
for (i = start; i < end; i++) {
if (dists[i] == 0) {
ll_count[litlens[i]]++;
} else {
ll_count[ZopfliGetLengthSymbol(litlens[i])]++;
d_count[ZopfliGetDistSymbol(dists[i])]++;
}
}
ll_count[256] = 1; /* End symbol. */
}