AuroraMiddleware/lz4
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Always Bump Offset by 64 KB in LZ4_loadDict()

Browse Source 
This actually ensures the guarantee referred to in the comment in
LZ4_compress_fast_continue().
This commit is contained in:
W. Felix Handte 2018-04-17 14:01:44 -04:00
parent 27f52724dc
commit aedc447804
1 changed files with 9 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
lib/lz4.c
View File

@ -1173,11 +1173,18 @@ int LZ4_loadDict (LZ4_stream_t* LZ4_dict, const char* dictionary, int dictSize)
LZ4_prepareTable(dict, 0, tableType);
/* We always increment the offset by 64 KB, since, if the dict is longer,
* we truncate it to the last 64k, and if it's shorter, we still want to
* advance by a whole window length so we can provide the guarantee that
* there are only valid offsets in the window, which allows an optimization
* in LZ4_compress_fast_continue() where it uses noDictIssue even when the
* dictionary isn't a full 64k. */
if ((dictEnd - p) > 64 KB) p = dictEnd - 64 KB;
base = p - dict->currentOffset;
base = dictEnd - 64 KB - dict->currentOffset;
dict->dictionary = p;
dict->dictSize = (U32)(dictEnd - p);
dict->currentOffset += dict->dictSize;
dict->currentOffset += 64 KB;
dict->tableType = tableType;
if (dictSize < (int)HASH_UNIT) {