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Huffman encoder fixes for very large streams

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Allowing Huffman decoder to use different fast bits table sizes
Adding NV and AMD BC1 decoders
This commit is contained in:
richgel999
2020-05-05 23:10:21 -04:00
parent bb64ec604c
commit a1689504ea
6 changed files with 192 additions and 25 deletions
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transcoder/basisu_transcoder_internal.h
+17 -11
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@@ -122,7 +122,7 @@ namespace basist
basisu::clear_vector(m_tree);
}
bool init(uint32_t total_syms, const uint8_t *pCode_sizes)
bool init(uint32_t total_syms, const uint8_t *pCode_sizes, uint32_t fast_lookup_bits = basisu::cHuffmanFastLookupBits)
{
if (!total_syms)
{
@@ -133,8 +133,10 @@ namespace basist
m_code_sizes.resize(total_syms);
memcpy(&m_code_sizes[0], pCode_sizes, total_syms);
const uint32_t huffman_fast_lookup_size = 1 << fast_lookup_bits;
m_lookup.resize(0);
m_lookup.resize(basisu::cHuffmanFastLookupSize);
m_lookup.resize(huffman_fast_lookup_size);
m_tree.resize(0);
m_tree.resize(total_syms * 2);
@@ -172,10 +174,10 @@ namespace basist
for (l = code_size; l > 0; l--, cur_code >>= 1)
rev_code = (rev_code << 1) | (cur_code & 1);
if (code_size <= basisu::cHuffmanFastLookupBits)
if (code_size <= fast_lookup_bits)
{
uint32_t k = (code_size << 16) | sym_index;
while (rev_code < basisu::cHuffmanFastLookupSize)
while (rev_code < huffman_fast_lookup_size)
{
if (m_lookup[rev_code] != 0)
{
@@ -190,9 +192,9 @@ namespace basist
}
int tree_cur;
if (0 == (tree_cur = m_lookup[rev_code & (basisu::cHuffmanFastLookupSize - 1)]))
if (0 == (tree_cur = m_lookup[rev_code & (huffman_fast_lookup_size - 1)]))
{
const uint32_t idx = rev_code & (basisu::cHuffmanFastLookupSize - 1);
const uint32_t idx = rev_code & (huffman_fast_lookup_size - 1);
if (m_lookup[idx] != 0)
{
// Supplied codesizes can't create a valid prefix code.
@@ -210,9 +212,9 @@ namespace basist
return false;
}
rev_code >>= (basisu::cHuffmanFastLookupBits - 1);
rev_code >>= (fast_lookup_bits - 1);
for (int j = code_size; j > (basisu::cHuffmanFastLookupBits + 1); j--)
for (int j = code_size; j > ((int)fast_lookup_bits + 1); j--)
{
tree_cur -= ((rev_code >>= 1) & 1);
@@ -260,6 +262,8 @@ namespace basist
}
const basisu::uint8_vec &get_code_sizes() const { return m_code_sizes; }
const basisu::int_vec get_lookup() const { return m_lookup; }
const basisu::int16_vec get_tree() const { return m_tree; }
bool is_valid() const { return m_code_sizes.size() > 0; }
@@ -436,9 +440,11 @@ namespace basist
return v;
}
inline uint32_t decode_huffman(const huffman_decoding_table &ct)
inline uint32_t decode_huffman(const huffman_decoding_table &ct, int fast_lookup_bits = basisu::cHuffmanFastLookupBits)
{
assert(ct.m_code_sizes.size());
const uint32_t huffman_fast_lookup_size = 1 << fast_lookup_bits;
while (m_bit_buf_size < 16)
{
@@ -454,14 +460,14 @@ namespace basist
int code_len;
int sym;
if ((sym = ct.m_lookup[m_bit_buf & (basisu::cHuffmanFastLookupSize - 1)]) >= 0)
if ((sym = ct.m_lookup[m_bit_buf & (huffman_fast_lookup_size - 1)]) >= 0)
{
code_len = sym >> 16;
sym &= 0xFFFF;
}
else
{
code_len = basisu::cHuffmanFastLookupBits;
code_len = fast_lookup_bits;
do
{
sym = ct.m_tree[~sym + ((m_bit_buf >> code_len++) & 1)]; // ~sym = -sym - 1