diff options
Diffstat (limited to 'src/lzw.h')
| -rw-r--r-- | src/lzw.h | 94 |
1 files changed, 57 insertions, 37 deletions
@@ -16,7 +16,6 @@ * Decoder for GIF LZW data. */ - /** Maximum LZW code size in bits */ #define LZW_CODE_MAX 12 @@ -32,7 +31,9 @@ typedef enum lzw_result { LZW_NO_MEM, /**< Error: Out of memory */ LZW_NO_DATA, /**< Error: Out of data */ LZW_EOI_CODE, /**< Error: End of Information code */ + LZW_NO_COLOUR, /**< Error: No colour map provided. */ LZW_BAD_ICODE, /**< Error: Bad initial LZW code */ + LZW_BAD_PARAM, /**< Error: Bad function parameter. */ LZW_BAD_CODE, /**< Error: Bad LZW code */ } lzw_result; @@ -58,62 +59,81 @@ void lzw_context_destroy( /** * Initialise an LZW decompression context for decoding. * - * Caller owns neither `stack_base_out` or `stack_pos_out`. - * - * \param[in] ctx The LZW decompression context to initialise. - * \param[in] compressed_data The compressed data. - * \param[in] compressed_data_len Byte length of compressed data. - * \param[in] compressed_data_pos Start position in data. Must be position - * of a size byte at sub-block start. - * \param[in] minimum_code_size The LZW Minimum Code Size. - * \param[out] stack_base_out Returns base of decompressed data stack. + * \param[in] ctx The LZW decompression context to initialise. + * \param[in] minimum_code_size The LZW Minimum Code Size. + * \param[in] input_data The compressed data. + * \param[in] input_length Byte length of compressed data. + * \param[in] input_pos Start position in data. Must be position + * of a size byte at sub-block start. * \return LZW_OK on success, or appropriate error code otherwise. */ lzw_result lzw_decode_init( struct lzw_ctx *ctx, - const uint8_t *compressed_data, - uint32_t compressed_data_len, - uint32_t compressed_data_pos, - uint8_t minimum_code_size); + uint8_t minimum_code_size, + const uint8_t *input_data, + uint32_t input_length, + uint32_t input_pos); /** - * Read input codes until end of lzw context owned output buffer. + * Read input codes until end of 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. + * 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. + * \param[in] ctx LZW reading context, updated. + * \param[out] output_data Returns pointer to array of output values. + * \param[out] output_written Returns the number of values written to data. * \return LZW_OK on success, or appropriate error code otherwise. */ -lzw_result lzw_decode_continuous(struct lzw_ctx *ctx, - const uint8_t *restrict *const restrict data, - uint32_t *restrict used); +lzw_result lzw_decode(struct lzw_ctx *ctx, + const uint8_t *restrict *const restrict output_data, + uint32_t *restrict output_written); /** - * Read LZW codes into client buffer, mapping output to colours. - * - * Ensure anything in output is used before calling this, as anything - * on the there before this call will be trampled. + * Initialise an LZW decompression context for decoding to colour map values. * * For transparency to work correctly, the given client buffer must have * the values from the previous frame. The transparency_idx should be a value * of 256 or above, if the frame does not have transparency. * - * \param[in] ctx LZW reading context, updated. - * \param[in] transparency_idx Index representing transparency. - * \param[in] colour_map Index to pixel colour mapping - * \param[in] data Client buffer to fill with colour mapped values. - * \param[in] length Size of output array. - * \param[out] used Returns the number of values written to data. + * \param[in] ctx The LZW decompression context to initialise. + * \param[in] minimum_code_size The LZW Minimum Code Size. + * \param[in] transparency_idx Index representing transparency. + * \param[in] colour_table Index to pixel colour mapping. + * \param[in] input_data The compressed data. + * \param[in] input_length Byte length of compressed data. + * \param[in] input_pos Start position in data. Must be position + * of a size byte at sub-block start. * \return LZW_OK on success, or appropriate error code otherwise. */ -lzw_result lzw_decode_map_continuous(struct lzw_ctx *ctx, +lzw_result lzw_decode_init_map( + struct lzw_ctx *ctx, + uint8_t minimum_code_size, uint32_t transparency_idx, - uint32_t *restrict colour_table, - uint32_t *restrict data, - uint32_t length, - uint32_t *restrict used); + const uint32_t *colour_table, + const uint8_t *input_data, + uint32_t input_length, + uint32_t input_pos); + +/** + * Read LZW codes into client buffer, mapping output to colours. + * + * The context must have been initialised using \ref lzw_decode_init_map + * before calling this function, in order to provide the colour mapping table + * and any transparency index. + * + * Ensure anything in output is used before calling this, as anything + * there before this call will be trampled. + * + * \param[in] ctx LZW reading context, updated. + * \param[in] output_data Client buffer to fill with colour mapped values. + * \param[in] output_length Size of output array. + * \param[out] output_written Returns the number of values written to data. + * \return LZW_OK on success, or appropriate error code otherwise. + */ +lzw_result lzw_decode_map(struct lzw_ctx *ctx, + uint32_t *restrict output_data, + uint32_t output_length, + uint32_t *restrict output_written); #endif |