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Return LZMA_HEADER_ERROR if LZMA_SYNC_FLUSH is used with any

of the so called simple filters. If there is demand, limited
support for LZMA_SYNC_FLUSH may be added in future.

After this commit, using LZMA_SYNC_FLUSH shouldn't cause
undefined behavior in any situation.
This commit is contained in:
Lasse Collin 2008-01-26 00:25:34 +02:00
parent e988ea1d1a
commit f9842f7127
2 changed files with 17 additions and 0 deletions

View file

@ -64,6 +64,15 @@
*
* If options with non-default values have been specified when encoding,
* the same options must also be specified when decoding.
*
* \note At the moment, none of the simple filters support
* LZMA_SYNC_FLUSH. If LZMA_SYNC_FLUSH is specified,
* LZMA_HEADER_ERROR will be returned. If there is need,
* partial support for LZMA_SYNC_FLUSH can be added in future.
* Partial means that flushing would be possible only at
* offsets that are multiple of 2, 4, or 16 depending on
* the filter, except x86 which cannot be made to support
* LZMA_SYNC_FLUSH predictably.
*/
typedef struct {
/**

View file

@ -101,6 +101,14 @@ simple_code(lzma_coder *coder, lzma_allocator *allocator,
size_t in_size, uint8_t *restrict out,
size_t *restrict out_pos, size_t out_size, lzma_action action)
{
// TODO: Add partial support for LZMA_SYNC_FLUSH. We can support it
// in cases when the filter is able to filter everything. With most
// simple filters it can be done at offset that is a multiple of 2,
// 4, or 16. With x86 filter, it needs good luck, and thus cannot
// be made to work predictably.
if (action == LZMA_SYNC_FLUSH)
return LZMA_HEADER_ERROR;
// Flush already filtered data from coder->buffer[] to out[].
if (coder->pos < coder->filtered) {
bufcpy(coder->buffer, &coder->pos, coder->filtered,