*/
bool use_delta_matches;
+ /* If true, the compressor need not preserve the input buffer if it
+ * compresses the data successfully. */
+ bool destructive;
+
/* 'last_target_usages' is a large array that is only needed for
* preprocessing, so it is in union with fields that don't need to be
* initialized until after preprocessing. */
u32 next_delta_hashes[NUM_POWERS_TO_CONSIDER];
/* The per-byte graph nodes for near-optimal parsing */
- struct lzms_optimum_node optimum_nodes[NUM_OPTIM_NODES + MAX_FAST_LENGTH];
+ struct lzms_optimum_node optimum_nodes[NUM_OPTIM_NODES + MAX_FAST_LENGTH +
+ 1 + MAX_FAST_LENGTH];
/* Table: length => current cost for small match lengths */
u32 fast_length_cost_tab[MAX_FAST_LENGTH + 1];
}
/******************************************************************************
- * Cost evalution *
+ * Cost evaluation *
******************************************************************************/
/*
span);
const u32 raw_offset = offset >> power;
+
+ if (unlikely(raw_offset > DELTA_SOURCE_RAW_OFFSET_MASK -
+ (LZMS_NUM_DELTA_REPS - 1)))
+ continue;
+
const u32 pair = (power << DELTA_SOURCE_POWER_SHIFT) |
raw_offset;
const u32 source = DELTA_SOURCE_TAG |
}
static u64
-lzms_get_needed_memory(size_t max_bufsize, unsigned compression_level)
+lzms_get_needed_memory(size_t max_bufsize, unsigned compression_level,
+ bool destructive)
{
u64 size = 0;
size += sizeof(struct lzms_compressor);
- /* in_buffer */
- size += max_bufsize;
+ if (!destructive)
+ size += max_bufsize; /* in_buffer */
/* mf */
size += lcpit_matchfinder_get_needed_memory(max_bufsize);
static int
lzms_create_compressor(size_t max_bufsize, unsigned compression_level,
- void **c_ret)
+ bool destructive, void **c_ret)
{
struct lzms_compressor *c;
u32 nice_match_len;
if (!c)
goto oom0;
+ c->destructive = destructive;
+
/* Scale nice_match_len with the compression level. But to allow an
* optimization for length cost calculations, don't allow nice_match_len
* to exceed MAX_FAST_LENGTH. */
c->try_lit_lzrep0 = (compression_level >= 60);
c->try_lzrep_lit_lzrep0 = (compression_level >= 60);
- c->in_buffer = MALLOC(max_bufsize);
- if (!c->in_buffer)
- goto oom1;
+ if (!c->destructive) {
+ c->in_buffer = MALLOC(max_bufsize);
+ if (!c->in_buffer)
+ goto oom1;
+ }
if (!lcpit_matchfinder_init(&c->mf, max_bufsize, 2, nice_match_len))
goto oom2;
return 0;
oom2:
- FREE(c->in_buffer);
+ if (!c->destructive)
+ FREE(c->in_buffer);
oom1:
ALIGNED_FREE(c);
oom0:
void *out, size_t out_nbytes_avail, void *_c)
{
struct lzms_compressor *c = _c;
+ size_t result;
/* Don't bother trying to compress extremely small inputs. */
if (in_nbytes < 4)
return 0;
/* Copy the input data into the internal buffer and preprocess it. */
- memcpy(c->in_buffer, in, in_nbytes);
+ if (c->destructive)
+ c->in_buffer = (void *)in;
+ else
+ memcpy(c->in_buffer, in, in_nbytes);
c->in_nbytes = in_nbytes;
lzms_x86_filter(c->in_buffer, in_nbytes, c->last_target_usages, false);
lzms_range_encoder_init(&c->rc, out, out_nbytes_avail / sizeof(le16));
lzms_output_bitstream_init(&c->os, out, out_nbytes_avail / sizeof(le16));
lzms_init_states_and_probabilities(c);
- lzms_init_huffman_codes(c, lzms_get_num_offset_slots(in_nbytes));
+ lzms_init_huffman_codes(c, lzms_get_num_offset_slots(c->in_nbytes));
/* The main loop: parse and encode. */
lzms_near_optimal_parse(c);
/* Return the compressed data size or 0. */
- return lzms_finalize(c);
+ result = lzms_finalize(c);
+ if (!result && c->destructive)
+ lzms_x86_filter(c->in_buffer, c->in_nbytes, c->last_target_usages, true);
+ return result;
}
static void
{
struct lzms_compressor *c = _c;
- FREE(c->in_buffer);
+ if (!c->destructive)
+ FREE(c->in_buffer);
lcpit_matchfinder_destroy(&c->mf);
ALIGNED_FREE(c);
}