nsgif__parse_extension_application()

static nsgif_error fl::third_party::nsgif__parse_extension_application ( struct nsgif * gif, const fl::u8 * data, fl::size len )

static

Parse the application extension.

Parameters

[in]	gif	The gif object we're decoding.
[in]	data	The data to decode.
[in]	len	Byte length of data.

Returns

NSGIF_ERR_END_OF_DATA if more data is needed, NSGIF_OK for success.

Definition at line 846 of file gif.cpp.hpp.

{
    /* 14-byte+ Application Extension is:
     *
     *  +0    CHAR    Application Extension Label
     *  +1    CHAR    Block Size
     *  +2    8CHARS  Application Identifier
     *  +10   3CHARS  Appl. Authentication Code
     *  +13   1-256   Application Data (Data sub-blocks)
     */
    if (len < 17) {
        return NSGIF_ERR_END_OF_DATA;
    }
 
    if (nsgif__app_ext_is_loop_count(data, len)) {
        enum {
            EXT_LOOP_COUNT_SUB_BLOCK_SIZE = 0x03,
            EXT_LOOP_COUNT_SUB_BLOCK_ID   = 0x01,
        };
        if ((data[13] == EXT_LOOP_COUNT_SUB_BLOCK_SIZE) &&
            (data[14] == EXT_LOOP_COUNT_SUB_BLOCK_ID)) {
            gif->info.loop_max = data[15] | (data[16] << 8);
 
            /* The value in the source data means repeat N times
             * after the first implied play. A value of zero has
             * the special meaning of loop forever. (The only way
             * to play the animation once is  not to have this
             * extension at all. */
            if (gif->info.loop_max > 0) {
                gif->info.loop_max++;
            }
        }
    }
 
    return NSGIF_OK;
}

References FL_NOEXCEPT, nsgif__app_ext_is_loop_count(), NSGIF_ERR_END_OF_DATA, and NSGIF_OK.

Referenced by nsgif__parse_frame_extensions().

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