Gitweb links: ...log http://git.netsurf-browser.org/libnsgif.git/shortlog/7253a5b36f0f07757b99... ...commit http://git.netsurf-browser.org/libnsgif.git/commit/7253a5b36f0f07757b9989... ...tree http://git.netsurf-browser.org/libnsgif.git/tree/7253a5b36f0f07757b998955... The branch, master has been updated via 7253a5b36f0f07757b99895572ceac0c95022a4e (commit) via 1e61fac24f2adcd0c716c2946f7ab1998ab17adf (commit) from f9b8f113aa8a51ef4a704c129a7e939800efdbc5 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commitdiff http://git.netsurf-browser.org/libnsgif.git/commit/?id=7253a5b36f0f07757b... commit 7253a5b36f0f07757b99895572ceac0c95022a4e Author: Michael Drake <tlsa(a)netsurf-browser.org&gt; Commit: Michael Drake <tlsa(a)netsurf-browser.org&gt; lzw: Remove unused one-code-at-a-time API. diff --git a/src/lzw.c b/src/lzw.c index 3a4bd7b..c865b8d 100644 --- a/src/lzw.c +++ b/src/lzw.c @@ -463,19 +463,8 @@ static inline uint32_t lzw__write_pixels(struct lzw_ctx *ctx, } /* Exported function, documented in lzw.h */ -lzw_result lzw_decode(struct lzw_ctx *ctx, - const uint8_t *restrict* const restrict data, - uint32_t *restrict used) -{ - *used = 0; - *data = ctx->stack_base; - return lzw__decode(ctx, ctx->stack_base, sizeof(ctx->stack_base), - lzw__write_pixels, used); -} - -/* Exported function, documented in lzw.h */ lzw_result lzw_decode_continuous(struct lzw_ctx *ctx, - const uint8_t ** const data, + const uint8_t *restrict *const restrict data, uint32_t *restrict used) { *used = 0; diff --git a/src/lzw.h b/src/lzw.h index c442cff..a227163 100644 --- a/src/lzw.h +++ b/src/lzw.h @@ -77,21 +77,6 @@ lzw_result lzw_decode_init( uint8_t minimum_code_size); /** - * Read a single LZW code and write into lzw context owned output buffer. - * - * Ensure anything in output is used before calling this, as anything - * on the there before this call will be trampled. - * - * \param[in] ctx LZW reading context, updated. - * \param[out] data Returns pointer to array of output values. - * \param[out] used Returns the number of values written to data. - * \return LZW_OK on success, or appropriate error code otherwise. - */ -lzw_result lzw_decode(struct lzw_ctx *ctx, - const uint8_t *restrict *const restrict data, - uint32_t *restrict used); - -/** * Read input codes until end of lzw context owned output buffer. * * Ensure anything in output is used before calling this, as anything @@ -103,7 +88,7 @@ lzw_result lzw_decode(struct lzw_ctx *ctx, * \return LZW_OK on success, or appropriate error code otherwise. */ lzw_result lzw_decode_continuous(struct lzw_ctx *ctx, - const uint8_t ** const data, + const uint8_t *restrict *const restrict data, uint32_t *restrict used); /** commitdiff http://git.netsurf-browser.org/libnsgif.git/commit/?id=1e61fac24f2adcd0c7... commit 1e61fac24f2adcd0c716c2946f7ab1998ab17adf Author: Michael Drake <tlsa(a)netsurf-browser.org&gt; Commit: Michael Drake <tlsa(a)netsurf-browser.org&gt; lzw: Reduce overhead for clear code handling. diff --git a/src/lzw.c b/src/lzw.c index dd30d01..3a4bd7b 100644 --- a/src/lzw.c +++ b/src/lzw.c @@ -224,18 +224,39 @@ static inline lzw_result lzw__read_code( /** - * Clear LZW code table. + * Handle clear code. * - * \param[in] ctx LZW reading context, updated. + * \param[in] ctx LZW reading context, updated. + * \param[out] code_out Returns next code after a clear code. * \return LZW_OK or error code. */ -static inline void lzw__clear_table( - struct lzw_ctx *ctx) +static inline lzw_result lzw__handle_clear( + struct lzw_ctx *ctx, + uint32_t *code_out) { + uint32_t code; + /* Reset table building context */ ctx->code_size = ctx->initial_code_size; ctx->code_max = (1 << ctx->initial_code_size) - 1; ctx->table_size = ctx->eoi_code + 1; + + /* There might be a sequence of clear codes, so process them all */ + do { + lzw_result res = lzw__read_code(&ctx->input, + ctx->code_size, &code); + if (res != LZW_OK) { + return res; + } + } while (code == ctx->clear_code); + + /* The initial code must be from the initial table. */ + if (code > ctx->clear_code) { + return LZW_BAD_ICODE; + } + + *code_out = code; + return LZW_OK; } @@ -248,6 +269,8 @@ lzw_result lzw_decode_init( uint8_t minimum_code_size) { struct lzw_table_entry *table = ctx->table; + lzw_result res; + uint32_t code; if (minimum_code_size >= LZW_CODE_MAX) { return LZW_BAD_ICODE; @@ -276,8 +299,19 @@ lzw_result lzw_decode_init( table[i].count = 1; } - lzw__clear_table(ctx); - ctx->prev_code = ctx->clear_code; + res = lzw__handle_clear(ctx, &code); + if (res != LZW_OK) { + return res; + } + + /* Store details of this code as "previous code" to the context. */ + ctx->prev_code_first = ctx->table[code].first; + ctx->prev_code_count = ctx->table[code].count; + ctx->prev_code = code; + + /* Add code to context for immediate output. */ + ctx->output_code = code; + ctx->output_left = 1; return LZW_OK; } @@ -345,31 +379,27 @@ static inline lzw_result lzw__decode(struct lzw_ctx *ctx, return LZW_BAD_CODE; } else if (code == ctx->clear_code) { - lzw__clear_table(ctx); - } else { - if (ctx->prev_code == ctx->clear_code) { - if (code > ctx->clear_code) { - return LZW_BAD_ICODE; - } - - } else if (ctx->table_size < LZW_TABLE_ENTRY_MAX) { - uint32_t size = ctx->table_size; - lzw__table_add_entry(ctx, (code < size) ? - ctx->table[code].first : - ctx->prev_code_first); - - /* Ensure code size is increased, if needed. */ - if (size == ctx->code_max && - ctx->code_size < LZW_CODE_MAX) { - ctx->code_size++; - ctx->code_max = (1 << ctx->code_size) - 1; - } + res = lzw__handle_clear(ctx, &code); + if (res != LZW_OK) { + return res; } - *used += write_pixels(ctx, output, length, *used, code, - ctx->table[code].count); + } else if (ctx->table_size < LZW_TABLE_ENTRY_MAX) { + uint32_t size = ctx->table_size; + lzw__table_add_entry(ctx, (code < size) ? + ctx->table[code].first : + ctx->prev_code_first); + + /* Ensure code size is increased, if needed. */ + if (size == ctx->code_max && ctx->code_size < LZW_CODE_MAX) { + ctx->code_size++; + ctx->code_max = (1 << ctx->code_size) - 1; + } } + *used += write_pixels(ctx, output, length, *used, code, + ctx->table[code].count); + /* Store details of this code as "previous code" to the context. */ ctx->prev_code_first = ctx->table[code].first; ctx->prev_code_count = ctx->table[code].count; ----------------------------------------------------------------------- Summary of changes: src/lzw.c | 97 ++++++++++++++++++++++++++++++++++++------------------------- src/lzw.h | 17 +---------- 2 files changed, 59 insertions(+), 55 deletions(-) diff --git a/src/lzw.c b/src/lzw.c index dd30d01..c865b8d 100644 --- a/src/lzw.c +++ b/src/lzw.c @@ -224,18 +224,39 @@ static inline lzw_result lzw__read_code( /** - * Clear LZW code table. + * Handle clear code. * - * \param[in] ctx LZW reading context, updated. + * \param[in] ctx LZW reading context, updated. + * \param[out] code_out Returns next code after a clear code. * \return LZW_OK or error code. */ -static inline void lzw__clear_table( - struct lzw_ctx *ctx) +static inline lzw_result lzw__handle_clear( + struct lzw_ctx *ctx, + uint32_t *code_out) { + uint32_t code; + /* Reset table building context */ ctx->code_size = ctx->initial_code_size; ctx->code_max = (1 << ctx->initial_code_size) - 1; ctx->table_size = ctx->eoi_code + 1; + + /* There might be a sequence of clear codes, so process them all */ + do { + lzw_result res = lzw__read_code(&ctx->input, + ctx->code_size, &code); + if (res != LZW_OK) { + return res; + } + } while (code == ctx->clear_code); + + /* The initial code must be from the initial table. */ + if (code > ctx->clear_code) { + return LZW_BAD_ICODE; + } + + *code_out = code; + return LZW_OK; } @@ -248,6 +269,8 @@ lzw_result lzw_decode_init( uint8_t minimum_code_size) { struct lzw_table_entry *table = ctx->table; + lzw_result res; + uint32_t code; if (minimum_code_size >= LZW_CODE_MAX) { return LZW_BAD_ICODE; @@ -276,8 +299,19 @@ lzw_result lzw_decode_init( table[i].count = 1; } - lzw__clear_table(ctx); - ctx->prev_code = ctx->clear_code; + res = lzw__handle_clear(ctx, &code); + if (res != LZW_OK) { + return res; + } + + /* Store details of this code as "previous code" to the context. */ + ctx->prev_code_first = ctx->table[code].first; + ctx->prev_code_count = ctx->table[code].count; + ctx->prev_code = code; + + /* Add code to context for immediate output. */ + ctx->output_code = code; + ctx->output_left = 1; return LZW_OK; } @@ -345,31 +379,27 @@ static inline lzw_result lzw__decode(struct lzw_ctx *ctx, return LZW_BAD_CODE; } else if (code == ctx->clear_code) { - lzw__clear_table(ctx); - } else { - if (ctx->prev_code == ctx->clear_code) { - if (code > ctx->clear_code) { - return LZW_BAD_ICODE; - } - - } else if (ctx->table_size < LZW_TABLE_ENTRY_MAX) { - uint32_t size = ctx->table_size; - lzw__table_add_entry(ctx, (code < size) ? - ctx->table[code].first : - ctx->prev_code_first); - - /* Ensure code size is increased, if needed. */ - if (size == ctx->code_max && - ctx->code_size < LZW_CODE_MAX) { - ctx->code_size++; - ctx->code_max = (1 << ctx->code_size) - 1; - } + res = lzw__handle_clear(ctx, &code); + if (res != LZW_OK) { + return res; } - *used += write_pixels(ctx, output, length, *used, code, - ctx->table[code].count); + } else if (ctx->table_size < LZW_TABLE_ENTRY_MAX) { + uint32_t size = ctx->table_size; + lzw__table_add_entry(ctx, (code < size) ? + ctx->table[code].first : + ctx->prev_code_first); + + /* Ensure code size is increased, if needed. */ + if (size == ctx->code_max && ctx->code_size < LZW_CODE_MAX) { + ctx->code_size++; + ctx->code_max = (1 << ctx->code_size) - 1; + } } + *used += write_pixels(ctx, output, length, *used, code, + ctx->table[code].count); + /* Store details of this code as "previous code" to the context. */ ctx->prev_code_first = ctx->table[code].first; ctx->prev_code_count = ctx->table[code].count; @@ -433,19 +463,8 @@ static inline uint32_t lzw__write_pixels(struct lzw_ctx *ctx, } /* Exported function, documented in lzw.h */ -lzw_result lzw_decode(struct lzw_ctx *ctx, - const uint8_t *restrict* const restrict data, - uint32_t *restrict used) -{ - *used = 0; - *data = ctx->stack_base; - return lzw__decode(ctx, ctx->stack_base, sizeof(ctx->stack_base), - lzw__write_pixels, used); -} - -/* Exported function, documented in lzw.h */ lzw_result lzw_decode_continuous(struct lzw_ctx *ctx, - const uint8_t ** const data, + const uint8_t *restrict *const restrict data, uint32_t *restrict used) { *used = 0; diff --git a/src/lzw.h b/src/lzw.h index c442cff..a227163 100644 --- a/src/lzw.h +++ b/src/lzw.h @@ -77,21 +77,6 @@ lzw_result lzw_decode_init( uint8_t minimum_code_size); /** - * Read a single LZW code and write into lzw context owned output buffer. - * - * Ensure anything in output is used before calling this, as anything - * on the there before this call will be trampled. - * - * \param[in] ctx LZW reading context, updated. - * \param[out] data Returns pointer to array of output values. - * \param[out] used Returns the number of values written to data. - * \return LZW_OK on success, or appropriate error code otherwise. - */ -lzw_result lzw_decode(struct lzw_ctx *ctx, - const uint8_t *restrict *const restrict data, - uint32_t *restrict used); - -/** * Read input codes until end of lzw context owned output buffer. * * Ensure anything in output is used before calling this, as anything @@ -103,7 +88,7 @@ lzw_result lzw_decode(struct lzw_ctx *ctx, * \return LZW_OK on success, or appropriate error code otherwise. */ lzw_result lzw_decode_continuous(struct lzw_ctx *ctx, - const uint8_t ** const data, + const uint8_t *restrict *const restrict data, uint32_t *restrict used); /** -- NetSurf GIF Decoder