cuberite/libdeflate
1
0
Fork 0
mirror of https://github.com/cuberite/libdeflate.git synced 2025-09-12 13:58:35 -04:00
Code Issues Packages Projects Releases Wiki Activity

decompress: fix handling of Huffman codes with one used symbol

Browse Source 
The previous code did not take into account that 'lens' alias 'decode_table'.
This commit is contained in:
Eric Biggers 2016-01-30 21:34:30 -06:00
parent 3aecf2e057
commit 480e0310db
1 changed files with 13 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
src/deflate_decompress.c
View File

@ -533,6 +533,19 @@ build_decode_table(u32 decode_table[],
for (sym = 0; sym < num_syms; sym++)
len_counts[lens[sym]]++;
/* Sort the symbols primarily by increasing codeword length and
* secondarily by increasing symbol value. */
/* Initialize 'offsets' so that offsets[len] is the number of codewords
* shorter than 'len' bits, including length 0. */
offsets[0] = 0;
for (len = 0; len < max_codeword_len; len++)
offsets[len + 1] = offsets[len] + len_counts[len];
/* Use the 'offsets' array to sort the symbols. */
for (sym = 0; sym < num_syms; sym++)
sorted_syms[offsets[lens[sym]]++] = sym;
/* It is already guaranteed that all lengths are <= max_codeword_len,
* but it cannot be assumed they form a complete prefix code. A
* codeword of length n should require a proportion of the codespace
@ -577,19 +590,6 @@ build_decode_table(u32 decode_table[],
return false;
}
/* Sort the symbols primarily by increasing codeword length and
* secondarily by increasing symbol value. */
/* Initialize 'offsets' so that offsets[len] is the number of codewords
* shorter than 'len' bits, including length 0. */
offsets[0] = 0;
for (len = 0; len < max_codeword_len; len++)
offsets[len + 1] = offsets[len] + len_counts[len];
/* Use the 'offsets' array to sort the symbols. */
for (sym = 0; sym < num_syms; sym++)
sorted_syms[offsets[lens[sym]]++] = sym;
/* Generate the decode table entries. Since we process codewords from
* shortest to longest, the main portion of the decode table is filled
* first; then the subtables are filled. Note that it's already been