2025-01-22 17:22:38 +01:00

105 lines
4.2 KiB
C

/*
* lws jpeg
*
* Copyright (C) 2019 - 2022 Andy Green <andy@warmcat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* Based on public domain original with notice -->
*
* picojpeg.c v1.1 - Public domain, Rich Geldreich <richgel99@gmail.com>
* Nov. 27, 2010 - Initial release
* Feb. 9, 2013 - Added H1V2/H2V1 support, cleaned up macros, signed shift fixes
* Also integrated and tested changes from Chris Phoenix <cphoenix@gmail.com>.
*
* This version is rewritten for lws, changing the whole approach to decode on
* demand to issue a line of output at a time, statefully. This version is
* licensed MIT to match the rest of lws.
*/
typedef struct lws_jpeg lws_jpeg_t;
/**
* lws_jpeg_new() - Create new JPEG decode object
*
* Returns a new jpeg decoding object, which should be destroyed with
* lws_jpeg_free() when done with, or NULL if OOM.
*/
LWS_VISIBLE LWS_EXTERN lws_jpeg_t *
lws_jpeg_new(void);
/**
* lws_jpeg_free() - Destroy a JPEG decode object
*
* \param j: Pointer to the decode object to destroy and set to NULL
*
* This also frees any sub-allocations in the object.
*/
LWS_VISIBLE LWS_EXTERN void
lws_jpeg_free(lws_jpeg_t **j);
/**
* lws_jpeg_emit_next_line() - deocde the next line
*
* \param j: the decode object
* \param ppix: pointer to a pointer set to the line's decoded pixel data
* \param buf: pointer to a const uint8_t array of jpeg input
* \param size: pointer to the count of bytes available at *buf
* \param hold_at_metadata: true if we should not advance to decode
*
* Make jpeg input available to the decoder so it can issue the next line's
* worth of pixels. If the call consumed any input, *buf and *size are
* adjusted accordingly.
*
* The decoder is stateful so it is not sensitive to the chunk size for the
* input.
*
* If \p hold_at_metadata is set, then the decoder will only go as far as
* picking out the metadata like image dimensions, but not start the decode,
* which requires the >30KB heap allocation. This lets you put off for as long
* as possible committing to the decode allocation... this only helps overall
* if you have flow controlled the incoming PNG data.
*
* Return will be one of LWS_SRET_WANT_INPUT is the decoder is stalled waiting
* for more input to be provided, LWS_SRET_WANT_OUTPUT is the decoder stopped
* because it had produced a whole line of output pixels (which can be found
* starting at *ppix), LWS_SRET_OK is it completed and LWS_SRET_FATAL or larger
* if the decode failed.
*
* The output at *ppix is either 3-byte per pixel RGB, or 1-byte grayscale, you
* can query lws_jpeg_get_components() to find out how many bytes per pixel.
*/
LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t
lws_jpeg_emit_next_line(lws_jpeg_t *j, const uint8_t **ppix,
const uint8_t **buf, size_t *size, char hold_at_metadata);
LWS_VISIBLE LWS_EXTERN unsigned int
lws_jpeg_get_width(const lws_jpeg_t *j);
LWS_VISIBLE LWS_EXTERN unsigned int
lws_jpeg_get_height(const lws_jpeg_t *j);
LWS_VISIBLE LWS_EXTERN unsigned int
lws_jpeg_get_bpp(const lws_jpeg_t *j);
LWS_VISIBLE LWS_EXTERN unsigned int
lws_jpeg_get_bitdepth(const lws_jpeg_t *j);
LWS_VISIBLE LWS_EXTERN unsigned int
lws_jpeg_get_components(const lws_jpeg_t *j);
LWS_VISIBLE LWS_EXTERN unsigned int
lws_jpeg_get_pixelsize(const lws_jpeg_t *j);