diff options
| -rw-r--r-- | src/lzw.c | 21 |
1 files changed, 8 insertions, 13 deletions
@@ -364,7 +364,7 @@ static inline void lzw__table_add_entry( entry->value = code; entry->first = ctx->prev_code_first; entry->count = ctx->prev_code_count + 1; - entry->extends = ctx->prev_code; + entry->extends = ctx->table_size - ctx->prev_code; ctx->table_size++; } @@ -467,7 +467,7 @@ static inline uint32_t lzw__write_fn(struct lzw_ctx *ctx, uint16_t left) { uint8_t *restrict output_pos = (uint8_t *)output_data + output_used; - const struct lzw_table_entry * const table = ctx->table; + const struct lzw_table_entry *entry = ctx->table + code; uint32_t space = output_length - output_used; uint16_t count = left; @@ -483,15 +483,13 @@ static inline uint32_t lzw__write_fn(struct lzw_ctx *ctx, /* Skip over any values we don't have space for. */ for (unsigned i = left; i != 0; i--) { - const struct lzw_table_entry *entry = table + code; - code = entry->extends; + entry -= entry->extends; } output_pos += count; for (unsigned i = count; i != 0; i--) { - const struct lzw_table_entry *entry = table + code; *--output_pos = entry->value; - code = entry->extends; + entry -= entry->extends; } return count; @@ -548,7 +546,7 @@ static inline uint32_t lzw__map_write_fn(struct lzw_ctx *ctx, uint16_t left) { uint32_t *restrict output_pos = (uint32_t *)output_data + output_used; - const struct lzw_table_entry * const table = ctx->table; + const struct lzw_table_entry *entry = ctx->table + code; uint32_t space = output_length - output_used; uint16_t count = left; @@ -563,25 +561,22 @@ static inline uint32_t lzw__map_write_fn(struct lzw_ctx *ctx, ctx->output_left = left; for (unsigned i = left; i != 0; i--) { - const struct lzw_table_entry *entry = table + code; - code = entry->extends; + entry -= entry->extends; } output_pos += count; if (ctx->has_transparency) { for (unsigned i = count; i != 0; i--) { - const struct lzw_table_entry *entry = table + code; --output_pos; if (entry->value != ctx->transparency_idx) { *output_pos = ctx->colour_map[entry->value]; } - code = entry->extends; + entry -= entry->extends; } } else { for (unsigned i = count; i != 0; i--) { - const struct lzw_table_entry *entry = table + code; *--output_pos = ctx->colour_map[entry->value]; - code = entry->extends; + entry -= entry->extends; } } |