libwebsockets
Lightweight C library for HTML5 websockets
lws-jpeg.h
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/*
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* lws jpeg
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*
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* Copyright (C) 2019 - 2022 Andy Green <andy@warmcat.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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* Based on public domain original with notice -->
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*
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* picojpeg.c v1.1 - Public domain, Rich Geldreich <richgel99@gmail.com>
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* Nov. 27, 2010 - Initial release
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* Feb. 9, 2013 - Added H1V2/H2V1 support, cleaned up macros, signed shift fixes
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* Also integrated and tested changes from Chris Phoenix <cphoenix@gmail.com>.
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*
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* This version is rewritten for lws, changing the whole approach to decode on
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* demand to issue a line of output at a time, statefully. This version is
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* licensed MIT to match the rest of lws.
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*/
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typedef
struct
lws_jpeg
lws_jpeg_t
;
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/**
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* lws_jpeg_new() - Create new JPEG decode object
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*
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* Returns a new jpeg decoding object, which should be destroyed with
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* lws_jpeg_free() when done with, or NULL if OOM.
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*/
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LWS_VISIBLE LWS_EXTERN
lws_jpeg_t
*
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lws_jpeg_new
(
void
);
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/**
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* lws_jpeg_free() - Destroy a JPEG decode object
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*
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* \param j: Pointer to the decode object to destroy and set to NULL
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*
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* This also frees any sub-allocations in the object.
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*/
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LWS_VISIBLE LWS_EXTERN
void
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lws_jpeg_free
(
lws_jpeg_t
**j);
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/**
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* lws_jpeg_emit_next_line() - deocde the next line
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*
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* \param j: the decode object
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* \param ppix: pointer to a pointer set to the line's decoded pixel data
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* \param buf: pointer to a const uint8_t array of jpeg input
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* \param size: pointer to the count of bytes available at *buf
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* \param hold_at_metadata: true if we should not advance to decode
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*
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* Make jpeg input available to the decoder so it can issue the next line's
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* worth of pixels. If the call consumed any input, *buf and *size are
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* adjusted accordingly.
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*
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* The decoder is stateful so it is not sensitive to the chunk size for the
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* input.
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*
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* If \p hold_at_metadata is set, then the decoder will only go as far as
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* picking out the metadata like image dimensions, but not start the decode,
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* which requires the >30KB heap allocation. This lets you put off for as long
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* as possible committing to the decode allocation... this only helps overall
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* if you have flow controlled the incoming PNG data.
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*
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* Return will be one of LWS_SRET_WANT_INPUT is the decoder is stalled waiting
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* for more input to be provided, LWS_SRET_WANT_OUTPUT is the decoder stopped
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* because it had produced a whole line of output pixels (which can be found
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* starting at *ppix), LWS_SRET_OK is it completed and LWS_SRET_FATAL or larger
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* if the decode failed.
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*
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* The output at *ppix is either 3-byte per pixel RGB, or 1-byte grayscale, you
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* can query lws_jpeg_get_components() to find out how many bytes per pixel.
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*/
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LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t
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lws_jpeg_emit_next_line(lws_jpeg_t *j,
const
uint8_t **ppix,
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const
uint8_t **buf, size_t *size,
char
hold_at_metadata);
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LWS_VISIBLE LWS_EXTERN
unsigned
int
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lws_jpeg_get_width
(
const
lws_jpeg_t
*j);
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LWS_VISIBLE LWS_EXTERN
unsigned
int
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lws_jpeg_get_height
(
const
lws_jpeg_t
*j);
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LWS_VISIBLE LWS_EXTERN
unsigned
int
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lws_jpeg_get_bpp
(
const
lws_jpeg_t
*j);
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LWS_VISIBLE LWS_EXTERN
unsigned
int
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lws_jpeg_get_bitdepth
(
const
lws_jpeg_t
*j);
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LWS_VISIBLE LWS_EXTERN
unsigned
int
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lws_jpeg_get_components
(
const
lws_jpeg_t
*j);
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LWS_VISIBLE LWS_EXTERN
unsigned
int
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lws_jpeg_get_pixelsize
(
const
lws_jpeg_t
*j);
include
libwebsockets
lws-jpeg.h
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