lzms_decompress.c: pack states together in struct lzms_decompressor

[wimlib] / src / lzms_decompress.c

diff --git a/src/lzms_decompress.c b/src/lzms_decompress.c
index b4c1894fca9ca02402179164349c10b7b58e1286..bafe85ee35f5786eaed25fa5194aea1f649ab7a4 100644 (file)
--- a/src/lzms_decompress.c
+++ b/src/lzms_decompress.c
@@ -335,22 +335,18 @@ struct lzms_decompressor {
        /* States and probability entries for item type disambiguation  */
 
        u32 main_state;
-       struct lzms_probability_entry main_probs[LZMS_NUM_MAIN_PROBS];
-
        u32 match_state;
-       struct lzms_probability_entry match_probs[LZMS_NUM_MATCH_PROBS];
-
        u32 lz_state;
-       struct lzms_probability_entry lz_probs[LZMS_NUM_LZ_PROBS];
-
        u32 delta_state;
-       struct lzms_probability_entry delta_probs[LZMS_NUM_DELTA_PROBS];
-
        u32 lz_rep_states[LZMS_NUM_LZ_REP_DECISIONS];
+       u32 delta_rep_states[LZMS_NUM_DELTA_REP_DECISIONS];
+
+       struct lzms_probability_entry main_probs[LZMS_NUM_MAIN_PROBS];
+       struct lzms_probability_entry match_probs[LZMS_NUM_MATCH_PROBS];
+       struct lzms_probability_entry lz_probs[LZMS_NUM_LZ_PROBS];
+       struct lzms_probability_entry delta_probs[LZMS_NUM_DELTA_PROBS];
        struct lzms_probability_entry lz_rep_probs[LZMS_NUM_LZ_REP_DECISIONS]
                                                  [LZMS_NUM_LZ_REP_PROBS];
-
-       u32 delta_rep_states[LZMS_NUM_DELTA_REP_DECISIONS];
        struct lzms_probability_entry delta_rep_probs[LZMS_NUM_DELTA_REP_DECISIONS]
                                                     [LZMS_NUM_DELTA_REP_PROBS];
 
@@ -481,16 +477,25 @@ lzms_range_decoder_init(struct lzms_range_decoder *rd,
 }
 
 /*
- * Decode and return the next bit from the range decoder.
- *
- * @prob is the probability out of LZMS_PROBABILITY_DENOMINATOR that the next
- * bit is 0 rather than 1.
+ * Decode a bit using the range coder.  The current state specifies the
+ * probability entry to use.  The state and probability entry will be updated
+ * based on the decoded bit.
  */
 static inline int
-lzms_range_decode_bit(struct lzms_range_decoder *rd, u32 prob)
+lzms_decode_bit(struct lzms_range_decoder *rd, u32 *state_p, u32 num_states,
+               struct lzms_probability_entry *probs)
 {
+       struct lzms_probability_entry *prob_entry;
+       u32 prob;
        u32 bound;
 
+       /* Load the probability entry corresponding to the current state.  */
+       prob_entry = &probs[*state_p];
+
+       /* Get the probability (out of LZMS_PROBABILITY_DENOMINATOR) that the
+        * next bit is 0.  */
+       prob = lzms_get_probability(prob_entry);
+
        /* Normalize if needed.  */
        if (rd->range <= 0xffff) {
                rd->range <<= 16;
@@ -506,44 +511,23 @@ lzms_range_decode_bit(struct lzms_range_decoder *rd, u32 prob)
        if (rd->code < bound) {
                /* Current code is in the 0-bit region of the range.  */
                rd->range = bound;
+
+               /* Update the state and probability entry based on the decoded bit.  */
+               *state_p = ((*state_p << 1) | 0) & (num_states - 1);
+               lzms_update_probability_entry(prob_entry, 0);
                return 0;
        } else {
                /* Current code is in the 1-bit region of the range.  */
                rd->range -= bound;
                rd->code -= bound;
+
+               /* Update the state and probability entry based on the decoded bit.  */
+               *state_p = ((*state_p << 1) | 1) & (num_states - 1);
+               lzms_update_probability_entry(prob_entry, 1);
                return 1;
        }
 }
 
-/*
- * Decode a bit.  This wraps around lzms_range_decode_bit() to handle using and
- * updating the state and its corresponding probability entry.
- */
-static inline int
-lzms_decode_bit(struct lzms_range_decoder *rd, u32 *state_p, u32 num_states,
-               struct lzms_probability_entry *probs)
-{
-       struct lzms_probability_entry *prob_entry;
-       u32 prob;
-       int bit;
-
-       /* Load the probability entry corresponding to the current state.  */
-       prob_entry = &probs[*state_p];
-
-       /* Get the probability that the next bit is 0.  */
-       prob = lzms_get_probability(prob_entry);
-
-       /* Decode the next bit.  */
-       bit = lzms_range_decode_bit(rd, prob);
-
-       /* Update the state and probability entry based on the decoded bit.  */
-       *state_p = ((*state_p << 1) | bit) & (num_states - 1);
-       lzms_update_probability_entry(prob_entry, bit);
-
-       /* Return the decoded bit.  */
-       return bit;
-}
-
 static int
 lzms_decode_main_bit(struct lzms_decompressor *d)
 {