lzms_decompress.c: make 'lens' and 'decode_table' share memory

[wimlib] / src / lzms_decompress.c

diff --git a/src/lzms_decompress.c b/src/lzms_decompress.c
index a54cc804aea9b64794cecb7e99774000a055e641..b0d0670ea4a0a8a82d39ae2543d2c3b9789549f3 100644 (file)
--- a/src/lzms_decompress.c
+++ b/src/lzms_decompress.c
@@ -307,7 +307,6 @@ struct lzms_huffman_rebuild_info {
        unsigned num_syms;
        unsigned rebuild_freq;
        u32 *codewords;
-       u8 *lens;
        u32 *freqs;
        u16 *decode_table;
        unsigned table_bits;
@@ -386,7 +385,6 @@ struct lzms_decompressor {
        struct lzms_huffman_rebuild_info delta_power_rebuild_info;
 
        u32 codewords[LZMS_MAX_NUM_SYMS];
-       u8 lens[LZMS_MAX_NUM_SYMS];
 
        }; // struct
 
@@ -430,9 +428,7 @@ lzms_ensure_bits(struct lzms_input_bitstream *is, unsigned num_bits)
 static inline bitbuf_t
 lzms_peek_bits(struct lzms_input_bitstream *is, unsigned num_bits)
 {
-       if (unlikely(num_bits == 0))
-               return 0;
-       return is->bitbuf >> (sizeof(is->bitbuf) * 8 - num_bits);
+       return (is->bitbuf >> 1) >> (sizeof(is->bitbuf) * 8 - num_bits - 1);
 }
 
 /* Remove @num_bits bits from the bitbuffer variable.  */
@@ -551,28 +547,28 @@ lzms_decode_match_bit(struct lzms_decompressor *d)
 }
 
 static int
-lzms_decode_lz_match_bit(struct lzms_decompressor *d)
+lzms_decode_lz_bit(struct lzms_decompressor *d)
 {
        return lzms_decode_bit(&d->rd, &d->lz_state,
                               LZMS_NUM_LZ_PROBS, d->lz_probs);
 }
 
 static int
-lzms_decode_delta_match_bit(struct lzms_decompressor *d)
+lzms_decode_delta_bit(struct lzms_decompressor *d)
 {
        return lzms_decode_bit(&d->rd, &d->delta_state,
                               LZMS_NUM_DELTA_PROBS, d->delta_probs);
 }
 
 static noinline int
-lzms_decode_lz_repeat_match_bit(struct lzms_decompressor *d, int idx)
+lzms_decode_lz_rep_bit(struct lzms_decompressor *d, int idx)
 {
        return lzms_decode_bit(&d->rd, &d->lz_rep_states[idx],
                               LZMS_NUM_LZ_REP_PROBS, d->lz_rep_probs[idx]);
 }
 
 static noinline int
-lzms_decode_delta_repeat_match_bit(struct lzms_decompressor *d, int idx)
+lzms_decode_delta_rep_bit(struct lzms_decompressor *d, int idx)
 {
        return lzms_decode_bit(&d->rd, &d->delta_rep_states[idx],
                               LZMS_NUM_DELTA_REP_PROBS, d->delta_rep_probs[idx]);
@@ -584,13 +580,13 @@ lzms_build_huffman_code(struct lzms_huffman_rebuild_info *rebuild_info)
        make_canonical_huffman_code(rebuild_info->num_syms,
                                    LZMS_MAX_CODEWORD_LENGTH,
                                    rebuild_info->freqs,
-                                   rebuild_info->lens,
+                                   (u8 *)rebuild_info->decode_table,
                                    rebuild_info->codewords);
 
        make_huffman_decode_table(rebuild_info->decode_table,
                                  rebuild_info->num_syms,
                                  rebuild_info->table_bits,
-                                 rebuild_info->lens,
+                                 (u8 *)rebuild_info->decode_table,
                                  LZMS_MAX_CODEWORD_LENGTH);
 
        rebuild_info->num_syms_until_rebuild = rebuild_info->rebuild_freq;
@@ -599,13 +595,12 @@ lzms_build_huffman_code(struct lzms_huffman_rebuild_info *rebuild_info)
 static void
 lzms_init_huffman_code(struct lzms_huffman_rebuild_info *rebuild_info,
                       unsigned num_syms, unsigned rebuild_freq,
-                      u32 *codewords, u8 *lens, u32 *freqs,
+                      u32 *codewords, u32 *freqs,
                       u16 *decode_table, unsigned table_bits)
 {
        rebuild_info->num_syms = num_syms;
        rebuild_info->rebuild_freq = rebuild_freq;
        rebuild_info->codewords = codewords;
-       rebuild_info->lens = lens;
        rebuild_info->freqs = freqs;
        rebuild_info->decode_table = decode_table;
        rebuild_info->table_bits = table_bits;
@@ -753,19 +748,19 @@ lzms_decode_items(struct lzms_decompressor * const restrict d,
                                d->pending_lz_offset = 0;
                        }
 
-                       if (!lzms_decode_lz_match_bit(d)) {
+                       if (!lzms_decode_lz_bit(d)) {
                                /* Explicit offset  */
                                offset = lzms_decode_lz_offset(d);
                        } else {
                                /* Repeat offset  */
 
                                BUILD_BUG_ON(LZMS_NUM_LZ_REPS != 3);
-                               if (!lzms_decode_lz_repeat_match_bit(d, 0)) {
+                               if (!lzms_decode_lz_rep_bit(d, 0)) {
                                        offset = d->recent_lz_offsets[0];
                                        d->recent_lz_offsets[0] = d->recent_lz_offsets[1];
                                        d->recent_lz_offsets[1] = d->recent_lz_offsets[2];
                                        d->recent_lz_offsets[2] = d->recent_lz_offsets[3];
-                               } else if (!lzms_decode_lz_repeat_match_bit(d, 1)) {
+                               } else if (!lzms_decode_lz_rep_bit(d, 1)) {
                                        offset = d->recent_lz_offsets[1];
                                        d->recent_lz_offsets[1] = d->recent_lz_offsets[2];
                                        d->recent_lz_offsets[2] = d->recent_lz_offsets[3];
@@ -818,7 +813,7 @@ lzms_decode_items(struct lzms_decompressor * const restrict d,
                                d->pending_delta_pair = 0;
                        }
 
-                       if (!lzms_decode_delta_match_bit(d)) {
+                       if (!lzms_decode_delta_bit(d)) {
                                /* Explicit offset  */
                                power = lzms_decode_delta_power(d);
                                raw_offset = lzms_decode_delta_offset(d);
@@ -827,12 +822,12 @@ lzms_decode_items(struct lzms_decompressor * const restrict d,
                                u64 val;
 
                                BUILD_BUG_ON(LZMS_NUM_DELTA_REPS != 3);
-                               if (!lzms_decode_delta_repeat_match_bit(d, 0)) {
+                               if (!lzms_decode_delta_rep_bit(d, 0)) {
                                        val = d->recent_delta_pairs[0];
                                        d->recent_delta_pairs[0] = d->recent_delta_pairs[1];
                                        d->recent_delta_pairs[1] = d->recent_delta_pairs[2];
                                        d->recent_delta_pairs[2] = d->recent_delta_pairs[3];
-                               } else if (!lzms_decode_delta_repeat_match_bit(d, 1)) {
+                               } else if (!lzms_decode_delta_rep_bit(d, 1)) {
                                        val = d->recent_delta_pairs[1];
                                        d->recent_delta_pairs[1] = d->recent_delta_pairs[2];
                                        d->recent_delta_pairs[2] = d->recent_delta_pairs[3];
@@ -936,7 +931,6 @@ lzms_init_decompressor(struct lzms_decompressor *d, const void *in,
                               LZMS_NUM_LITERAL_SYMS,
                               LZMS_LITERAL_CODE_REBUILD_FREQ,
                               d->codewords,
-                              d->lens,
                               d->literal_freqs,
                               d->literal_decode_table,
                               LZMS_LITERAL_TABLEBITS);
@@ -945,7 +939,6 @@ lzms_init_decompressor(struct lzms_decompressor *d, const void *in,
                               num_offset_slots,
                               LZMS_LZ_OFFSET_CODE_REBUILD_FREQ,
                               d->codewords,
-                              d->lens,
                               d->lz_offset_freqs,
                               d->lz_offset_decode_table,
                               LZMS_LZ_OFFSET_TABLEBITS);
@@ -954,7 +947,6 @@ lzms_init_decompressor(struct lzms_decompressor *d, const void *in,
                               LZMS_NUM_LENGTH_SYMS,
                               LZMS_LENGTH_CODE_REBUILD_FREQ,
                               d->codewords,
-                              d->lens,
                               d->length_freqs,
                               d->length_decode_table,
                               LZMS_LENGTH_TABLEBITS);
@@ -963,7 +955,6 @@ lzms_init_decompressor(struct lzms_decompressor *d, const void *in,
                               num_offset_slots,
                               LZMS_DELTA_OFFSET_CODE_REBUILD_FREQ,
                               d->codewords,
-                              d->lens,
                               d->delta_offset_freqs,
                               d->delta_offset_decode_table,
                               LZMS_DELTA_OFFSET_TABLEBITS);
@@ -972,7 +963,6 @@ lzms_init_decompressor(struct lzms_decompressor *d, const void *in,
                               LZMS_NUM_DELTA_POWER_SYMS,
                               LZMS_DELTA_POWER_CODE_REBUILD_FREQ,
                               d->codewords,
-                              d->lens,
                               d->delta_power_freqs,
                               d->delta_power_decode_table,
                               LZMS_DELTA_POWER_TABLEBITS);