diff options
| author | Lasse Collin <lasse.collin@tukaani.org> | 2024-02-12 17:09:10 +0200 |
|---|---|---|
| committer | Lasse Collin <lasse.collin@tukaani.org> | 2024-02-14 18:31:16 +0200 |
| commit | 5e04706b91ca90d6befd4da24a588a55e631d4a9 (patch) | |
| tree | 4e23dedcf5b2f3b184bc0e564d29446e6b1b1f6f | |
| parent | liblzma: Optimize literal_subcoder() macro slightly. (diff) | |
| download | xz-5e04706b91ca90d6befd4da24a588a55e631d4a9.tar.xz | |
liblzma: LZMA decoder: Optimize loop comparison.
But now it needs one more local variable.
| -rw-r--r-- | src/liblzma/lzma/lzma_decoder.c | 5 | ||||
| -rw-r--r-- | src/liblzma/rangecoder/range_decoder.h | 10 |
2 files changed, 11 insertions, 4 deletions
diff --git a/src/liblzma/lzma/lzma_decoder.c b/src/liblzma/lzma/lzma_decoder.c index 66d2818d..f7323061 100644 --- a/src/liblzma/lzma/lzma_decoder.c +++ b/src/liblzma/lzma/lzma_decoder.c @@ -261,7 +261,7 @@ lzma_decode(void *coder_ptr, lzma_dict *restrict dictptr, const size_t dict_start = dict.pos; // Range decoder - rc_to_local(coder->rc, *in_pos); + rc_to_local(coder->rc, *in_pos, LZMA_IN_REQUIRED); // State uint32_t state = coder->state; @@ -340,8 +340,7 @@ lzma_decode(void *coder_ptr, lzma_dict *restrict dictptr, // If there is not enough room for another LZMA symbol // go to Resumable mode. - if (unlikely(rc_in_end - rc_in_ptr < LZMA_IN_REQUIRED - || dict.pos == dict.limit)) + if (unlikely(!rc_is_fast_allowed() || dict.pos == dict.limit)) goto slow; // Decode the first bit from the next LZMA symbol. diff --git a/src/liblzma/rangecoder/range_decoder.h b/src/liblzma/rangecoder/range_decoder.h index 40de80c0..8cc78e6a 100644 --- a/src/liblzma/rangecoder/range_decoder.h +++ b/src/liblzma/rangecoder/range_decoder.h @@ -61,13 +61,21 @@ rc_read_init(lzma_range_decoder *rc, const uint8_t *restrict in, /// Makes local copies of range decoder and *in_pos variables. Doing this /// improves speed significantly. The range decoder macros expect also /// variables 'in' and 'in_size' to be defined. -#define rc_to_local(range_decoder, in_pos) \ +#define rc_to_local(range_decoder, in_pos, fast_mode_in_required) \ lzma_range_decoder rc = range_decoder; \ const uint8_t *rc_in_ptr = in + (in_pos); \ const uint8_t *rc_in_end = in + in_size; \ + const uint8_t *rc_in_fast_end \ + = (rc_in_end - rc_in_ptr) <= (fast_mode_in_required) \ + ? rc_in_ptr \ + : rc_in_end - (fast_mode_in_required); \ uint32_t rc_bound +/// Evaluates to true if there is enough input remaining to use fast mode. +#define rc_is_fast_allowed() (rc_in_ptr < rc_in_fast_end) + + /// Stores the local copes back to the range decoder structure. #define rc_from_local(range_decoder, in_pos) \ do { \ |