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Diffstat (limited to 'src/liblzma/rangecoder/range_encoder.h')
-rw-r--r--src/liblzma/rangecoder/range_encoder.h111
1 files changed, 111 insertions, 0 deletions
diff --git a/src/liblzma/rangecoder/range_encoder.h b/src/liblzma/rangecoder/range_encoder.h
index 4f3b30ca..1bcfd7a5 100644
--- a/src/liblzma/rangecoder/range_encoder.h
+++ b/src/liblzma/rangecoder/range_encoder.h
@@ -30,6 +30,9 @@ typedef struct {
uint32_t range;
uint8_t cache;
+ /// Number of bytes written out by rc_encode() -> rc_shift_low()
+ uint64_t out_total;
+
/// Number of symbols in the tables
size_t count;
@@ -58,12 +61,22 @@ rc_reset(lzma_range_encoder *rc)
rc->cache_size = 1;
rc->range = UINT32_MAX;
rc->cache = 0;
+ rc->out_total = 0;
rc->count = 0;
rc->pos = 0;
}
static inline void
+rc_forget(lzma_range_encoder *rc)
+{
+ // This must not be called when rc_encode() is partially done.
+ assert(rc->pos == 0);
+ rc->count = 0;
+}
+
+
+static inline void
rc_bit(lzma_range_encoder *rc, probability *prob, uint32_t bit)
{
rc->symbols[rc->count] = bit;
@@ -132,6 +145,7 @@ rc_shift_low(lzma_range_encoder *rc,
out[*out_pos] = rc->cache + (uint8_t)(rc->low >> 32);
++*out_pos;
+ ++rc->out_total;
rc->cache = 0xFF;
} while (--rc->cache_size != 0);
@@ -147,6 +161,31 @@ rc_shift_low(lzma_range_encoder *rc,
static inline bool
+rc_shift_low_dummy(uint64_t *low, uint64_t *cache_size, uint8_t *cache,
+ size_t *out_pos, size_t out_size)
+{
+ if ((uint32_t)(*low) < (uint32_t)(0xFF000000)
+ || (uint32_t)(*low >> 32) != 0) {
+ do {
+ if (*out_pos == out_size)
+ return true;
+
+ ++*out_pos;
+ *cache = 0xFF;
+
+ } while (--*cache_size != 0);
+
+ *cache = (*low >> 24) & 0xFF;
+ }
+
+ ++*cache_size;
+ *low = (*low & 0x00FFFFFF) << RC_SHIFT_BITS;
+
+ return false;
+}
+
+
+static inline bool
rc_encode(lzma_range_encoder *rc,
uint8_t *out, size_t *out_pos, size_t out_size)
{
@@ -222,6 +261,78 @@ rc_encode(lzma_range_encoder *rc,
}
+static inline bool
+rc_encode_dummy(const lzma_range_encoder *rc, size_t out_size)
+{
+ assert(rc->count <= RC_SYMBOLS_MAX);
+
+ uint64_t low = rc->low;
+ uint64_t cache_size = rc->cache_size;
+ uint32_t range = rc->range;
+ uint8_t cache = rc->cache;
+ uint64_t out_pos = rc->out_total;
+
+ size_t pos = rc->pos;
+
+ while (pos < rc->count) {
+ // Normalize
+ if (range < RC_TOP_VALUE) {
+ if (rc_shift_low_dummy(&low, &cache_size, &cache,
+ &out_pos, out_size))
+ return true;
+
+ range <<= RC_SHIFT_BITS;
+ }
+
+ // Encode a bit
+ switch (rc->symbols[pos]) {
+ case RC_BIT_0: {
+ probability prob = *rc->probs[pos];
+ range = (range >> RC_BIT_MODEL_TOTAL_BITS)
+ * prob;
+ break;
+ }
+
+ case RC_BIT_1: {
+ probability prob = *rc->probs[pos];
+ const uint32_t bound = prob * (range
+ >> RC_BIT_MODEL_TOTAL_BITS);
+ low += bound;
+ range -= bound;
+ break;
+ }
+
+ case RC_DIRECT_0:
+ range >>= 1;
+ break;
+
+ case RC_DIRECT_1:
+ range >>= 1;
+ low += range;
+ break;
+
+ case RC_FLUSH:
+ default:
+ assert(0);
+ break;
+ }
+
+ ++pos;
+ }
+
+ // Flush the last bytes. This isn't in rc->symbols[] so we do
+ // it after the above loop to take into account the size of
+ // the flushing that will be done at the end of the stream.
+ for (pos = 0; pos < 5; ++pos) {
+ if (rc_shift_low_dummy(&low, &cache_size,
+ &cache, &out_pos, out_size))
+ return true;
+ }
+
+ return false;
+}
+
+
static inline uint64_t
rc_pending(const lzma_range_encoder *rc)
{