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-rw-r--r--src/liblzma/rangecoder/price_table_init.c33
1 files changed, 20 insertions, 13 deletions
diff --git a/src/liblzma/rangecoder/price_table_init.c b/src/liblzma/rangecoder/price_table_init.c
index 4714dfd6..9c7d799b 100644
--- a/src/liblzma/rangecoder/price_table_init.c
+++ b/src/liblzma/rangecoder/price_table_init.c
@@ -23,25 +23,32 @@
#endif
-#define NUM_BITS (BIT_MODEL_TOTAL_BITS - MOVE_REDUCING_BITS)
-
-
-uint32_t lzma_rc_prob_prices[BIT_MODEL_TOTAL >> MOVE_REDUCING_BITS];
+uint32_t lzma_rc_prices[RC_PRICE_TABLE_SIZE];
extern void
lzma_rc_init(void)
{
- // Initialize lzma_rc_prob_prices[].
- for (int i = NUM_BITS - 1; i >= 0; --i) {
- const uint32_t start = 1 << (NUM_BITS - i - 1);
- const uint32_t end = 1 << (NUM_BITS - i);
-
- for (uint32_t j = start; j < end; ++j) {
- lzma_rc_prob_prices[j] = (i << BIT_PRICE_SHIFT_BITS)
- + (((end - j) << BIT_PRICE_SHIFT_BITS)
- >> (NUM_BITS - i - 1));
+ for (uint32_t i = (UINT32_C(1) << RC_MOVE_REDUCING_BITS) / 2;
+ i < RC_BIT_MODEL_TOTAL;
+ i += (UINT32_C(1) << RC_MOVE_REDUCING_BITS)) {
+ const uint32_t cycles_bits = RC_BIT_PRICE_SHIFT_BITS;
+ uint32_t w = i;
+ uint32_t bit_count = 0;
+
+ for (uint32_t j = 0; j < cycles_bits; ++j) {
+ w *= w;
+ bit_count <<= 1;
+
+ while (w >= (UINT32_C(1) << 16)) {
+ w >>= 1;
+ ++bit_count;
+ }
}
+
+ lzma_rc_prices[i >> RC_MOVE_REDUCING_BITS]
+ = (RC_BIT_MODEL_TOTAL_BITS << cycles_bits)
+ - 15 - bit_count;
}
return;