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igzip: Allow decoding symbol pairs

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Change-Id: I306404d7821cf4e43c28ae6477038b17a29b0c47
Signed-off-by: Roy Oursler <roy.j.oursler@intel.com>
This commit is contained in:
Roy Oursler 2018-03-01 17:37:17 -07:00 committed by Greg Tucker
parent 021afc5911
commit bf4c2dab27
1 changed files with 41 additions and 1 deletions
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42
igzip/igzip_inflate.c
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@ -234,9 +234,11 @@ static void inline make_inflate_huff_code_large(struct inflate_huff_code_large *
uint32_t code_list_len;
uint32_t count_total[17], count_total_tmp[17];
uint32_t insert_index;
uint32_t last_length;
uint32_t last_length, min_length;
uint32_t copy_size;
uint32_t *short_code_lookup = result->short_code_lookup;
int index1, index2, sym1, sym2;
uint32_t sym1_code, sym2_code, sym1_len, sym2_len;
count_total[0] = 0;
count_total[1] = 0;
@ -290,6 +292,7 @@ static void inline make_inflate_huff_code_large(struct inflate_huff_code_large *
/* Initialize short_code_lookup, so invalid lookups process data */
memset(short_code_lookup, 0x00, copy_size * sizeof(*short_code_lookup));
min_length = last_length;
k = 0;
for (; last_length <= ISAL_DECODE_LONG_BITS; last_length++) {
/* Copy forward previosly set codes */
@ -297,6 +300,7 @@ static void inline make_inflate_huff_code_large(struct inflate_huff_code_large *
sizeof(*short_code_lookup) * copy_size);
copy_size <<= 1;
/* Encode code singletons */
while (k < code_list_len
&& huff_code_table[code_list[k]].length == last_length) {
i = code_list[k];
@ -310,6 +314,42 @@ static void inline make_inflate_huff_code_large(struct inflate_huff_code_large *
short_code_lookup[huff_code_table[i].code] = 0;
k++;
}
/* Continue if no pairs are possible */
if (last_length < 2 * min_length)
continue;
/* Encode code pairs */
for (index1 = count_total[min_length];
index1 < count_total[last_length - min_length + 1]; index1++) {
sym1 = code_list[index1];
sym1_len = huff_code_table[sym1].length;
sym1_code = huff_code_table[sym1].code;
/*Check that sym1 is a literal */
if (sym1 >= 256) {
index1 = count_total[sym1_len + 1] - 1;
continue;
}
sym2_len = last_length - sym1_len;
for (index2 = count_total[sym2_len];
index2 < count_total[sym2_len + 1]; index2++) {
sym2 = code_list[index2];
/* Check that sym2 is an existing symbol */
if (sym2 >= max_symbol)
break;
sym2_code = huff_code_table[sym2].code;
code = sym1_code | (sym2_code << sym1_len);
code_length = sym1_len + sym2_len;
short_code_lookup[code] =
sym1 | (sym2 << 8) |
(code_length << LARGE_SHORT_CODE_LEN_OFFSET)
| (2 << LARGE_SYM_COUNT_OFFSET);
}
}
}
for (i = 0; i < long_code_length; i++) {