path: root/TextureLoader/src/JPEGCodec.c

/*
 *  Copyright 2019-2021 Diligent Graphics LLC
 *  Copyright 2015-2019 Egor Yusov
 *  
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  In no event and under no legal theory, whether in tort (including negligence), 
 *  contract, or otherwise, unless required by applicable law (such as deliberate 
 *  and grossly negligent acts) or agreed to in writing, shall any Contributor be
 *  liable for any damages, including any direct, indirect, special, incidental, 
 *  or consequential damages of any character arising as a result of this License or 
 *  out of the use or inability to use the software (including but not limited to damages 
 *  for loss of goodwill, work stoppage, computer failure or malfunction, or any and 
 *  all other commercial damages or losses), even if such Contributor has been advised 
 *  of the possibility of such damages.
 */

#include <stdlib.h>
#include <string.h>
#include <setjmp.h>
#include <stdio.h>

#include "jpeglib.h"

#include "JPEGCodec.h"


struct my_jpeg_error_mgr
{
    struct jpeg_error_mgr pub;
    char                  padding[8];
    jmp_buf               setjmp_buffer; // for return to caller
};
typedef struct my_jpeg_error_mgr my_jpeg_error_mgr;

// Here's the routine that will replace the standard error_exit method:
METHODDEF(void)
my_error_exit(j_common_ptr cinfo)
{
    // cinfo->err really points to a my_jpeg_error_mgr struct, so coerce pointer
    my_jpeg_error_mgr* myerr = (my_jpeg_error_mgr*)cinfo->err;

    /* Always display the message. */
    /* We could postpone this until after returning, if we chose. */
    (*cinfo->err->output_message)(cinfo);

    // Return control to the setjmp point
    longjmp(myerr->setjmp_buffer, 1);
}

DECODE_JPEG_RESULT Diligent_DecodeJpeg(IDataBlob* pSrcJpegBits,
                                       IDataBlob* pDstPixels,
                                       ImageDesc* pDstImgDesc)
{
    if (!pSrcJpegBits || !pDstPixels || !pDstImgDesc)
        return DECODE_JPEG_RESULT_INVALID_ARGUMENTS;

    // https://github.com/LuaDist/libjpeg/blob/master/example.c

    // This struct contains the JPEG decompression parameters and pointers to
    // working space (which is allocated as needed by the JPEG library).
    struct jpeg_decompress_struct cinfo;

    // We use our private extension JPEG error handler.
    // Note that this struct must live as long as the main JPEG parameter
    // struct, to avoid dangling-pointer problems.
    my_jpeg_error_mgr jerr;

    // Step 1: allocate and initialize JPEG decompression object

    // We set up the normal JPEG error routines, then override error_exit.
    cinfo.err           = jpeg_std_error(&jerr.pub);
    jerr.pub.error_exit = my_error_exit;
    // Establish the setjmp return context for my_error_exit to use.
    if (setjmp(jerr.setjmp_buffer))
    {
        // If we get here, the JPEG code has signaled an error.
        // We need to clean up the JPEG object, close the input file, and return.
        jpeg_destroy_decompress(&cinfo);
        return DECODE_JPEG_RESULT_INITIALIZATION_FAILED;
    }

    // Now we can initialize the JPEG decompression object.
    jpeg_create_decompress(&cinfo);

    // Step 2: specify data source
    unsigned char* pSrcPtr = IDataBlob_GetDataPtr(pSrcJpegBits);
    unsigned long  SrcSize = (unsigned long)IDataBlob_GetSize(pSrcJpegBits);
    jpeg_mem_src(&cinfo, pSrcPtr, SrcSize);

    // Step 3: read file parameters with jpeg_read_header()
    jpeg_read_header(&cinfo, TRUE);
    // We can ignore the return value from jpeg_read_header since
    //   (a) suspension is not possible with the stdio data source, and
    //   (b) we passed TRUE to reject a tables-only JPEG file as an error.
    // See libjpeg.txt for more info.


    // Step 4: set parameters for decompression

    // In this example, we don't need to change any of the defaults set by
    // jpeg_read_header(), so we do nothing here.


    // Step 5: Start decompressor

    jpeg_start_decompress(&cinfo);
    // We can ignore the return value since suspension is not possible
    // with the stdio data source.

    // We may need to do some setup of our own at this point before reading
    // the data.  After jpeg_start_decompress() we have the correct scaled
    // output image dimensions available, as well as the output colormap
    // if we asked for color quantization.

    pDstImgDesc->Width         = cinfo.output_width;
    pDstImgDesc->Height        = cinfo.output_height;
    pDstImgDesc->ComponentType = VT_UINT8;
    pDstImgDesc->NumComponents = cinfo.output_components;
    pDstImgDesc->RowStride     = pDstImgDesc->Width * pDstImgDesc->NumComponents;
    pDstImgDesc->RowStride     = (pDstImgDesc->RowStride + 3u) & ~3u;

    IDataBlob_Resize(pDstPixels, pDstImgDesc->RowStride * pDstImgDesc->Height);
    // Step 6: while (scan lines remain to be read)
    //           jpeg_read_scanlines(...);

    // Here we use the library's state variable cinfo.output_scanline as the
    // loop counter, so that we don't have to keep track ourselves.
    while (cinfo.output_scanline < cinfo.output_height)
    {
        // jpeg_read_scanlines expects an array of pointers to scanlines.
        // Here the array is only one element long, but you could ask for
        // more than one scanline at a time if that's more convenient.

        Uint8*   pScanline0   = IDataBlob_GetDataPtr(pDstPixels);
        Uint8*   pDstScanline = pScanline0 + cinfo.output_scanline * pDstImgDesc->RowStride;
        JSAMPROW RowPtrs[1];
        RowPtrs[0] = (JSAMPROW)pDstScanline;
        jpeg_read_scanlines(&cinfo, RowPtrs, 1);
    }

    // Step 7: Finish decompression

    jpeg_finish_decompress(&cinfo);
    // We can ignore the return value since suspension is not possible
    // with the stdio data source.

    // Step 8: Release JPEG decompression object

    // This is an important step since it will release a good deal of memory.
    jpeg_destroy_decompress(&cinfo);

    // At this point you may want to check to see whether any corrupt-data
    // warnings occurred (test whether jerr.pub.num_warnings is nonzero).

    return DECODE_JPEG_RESULT_OK;
}



ENCODE_JPEG_RESULT Diligent_EncodeJpeg(Uint8*     pSrcRGBPixels,
                                       Uint32     Width,
                                       Uint32     Height,
                                       int        quality,
                                       IDataBlob* pDstJpegBits)
{
    if (!pSrcRGBPixels || !pDstJpegBits || quality < 0 || Width == 0 || Height == 0)
        return ENCODE_JPEG_RESULT_INVALID_ARGUMENTS;

    /* This struct contains the JPEG compression parameters and pointers to
     * working space (which is allocated as needed by the JPEG library).
     * It is possible to have several such structures, representing multiple
     * compression/decompression processes, in existence at once.  We refer
     * to any one struct (and its associated working data) as a "JPEG object".
     */
    struct jpeg_compress_struct cinfo;

    /* This struct represents a JPEG error handler.  It is declared separately
     * because applications often want to supply a specialized error handler
     * (see the second half of this file for an example).  But here we just
     * take the easy way out and use the standard error handler, which will
     * print a message on stderr and call exit() if compression fails.
     * Note that this struct must live as long as the main JPEG parameter
     * struct, to avoid dangling-pointer problems.
     */
    struct jpeg_error_mgr jerr;

    /* Step 1: allocate and initialize JPEG compression object */

    /* We have to set up the error handler first, in case the initialization
     * step fails.  (Unlikely, but it could happen if you are out of memory.)
     * This routine fills in the contents of struct jerr, and returns jerr's
     * address which we place into the link field in cinfo.
     */
    cinfo.err = jpeg_std_error(&jerr);
    /* Now we can initialize the JPEG compression object. */
    jpeg_create_compress(&cinfo);

    /* Step 2: specify data destination (memory) */
    /* Note: steps 2 and 3 can be done in either order. */
    unsigned char* mem      = NULL;
    unsigned long  mem_size = 0;
    jpeg_mem_dest(&cinfo, &mem, &mem_size);

    /* Step 3: set parameters for compression */

    /* First we supply a description of the input image.
     * Four fields of the cinfo struct must be filled in:
     */
    cinfo.image_width      = Width; /* image width and height, in pixels */
    cinfo.image_height     = Height;
    cinfo.input_components = 3;       /* # of color components per pixel */
    cinfo.in_color_space   = JCS_RGB; /* colorspace of input image */
    /* Now use the library's routine to set default compression parameters.
     * (You must set at least cinfo.in_color_space before calling this,
     * since the defaults depend on the source color space.)
     */
    jpeg_set_defaults(&cinfo);
    /* Now you can set any non-default parameters you wish to.
     * Here we just illustrate the use of quality (quantization table) scaling:
     */
    jpeg_set_quality(&cinfo, quality, TRUE /* limit to baseline-JPEG values */);

    /* Step 4: Start compressor */

    /* TRUE ensures that we will write a complete interchange-JPEG file.
     * Pass TRUE unless you are very sure of what you're doing.
     */
    jpeg_start_compress(&cinfo, TRUE);

    /* Step 5: while (scan lines remain to be written) */
    /*           jpeg_write_scanlines(...); */

    /* Here we use the library's state variable cinfo.next_scanline as the
     * loop counter, so that we don't have to keep track ourselves.
     * To keep things simple, we pass one scanline per call; you can pass
     * more if you wish, though.
     */
    Uint32 row_stride = Width * 3; /* JSAMPLEs per row in image_buffer */

    while (cinfo.next_scanline < cinfo.image_height)
    {
        /* jpeg_write_scanlines expects an array of pointers to scanlines.
         * Here the array is only one element long, but you could pass
         * more than one scanline at a time if that's more convenient.
         */
        JSAMPROW row_pointer[1];
        row_pointer[0] = &pSrcRGBPixels[cinfo.next_scanline * row_stride];
        jpeg_write_scanlines(&cinfo, row_pointer, 1);
    }

    /* Step 6: Finish compression */
    jpeg_finish_compress(&cinfo);

    IDataBlob_Resize(pDstJpegBits, mem_size);
    void* pDstPtr = IDataBlob_GetDataPtr(pDstJpegBits);
    memcpy(pDstPtr, mem, mem_size);

    /* After finish_compress, we can free memory buffer. */
    free(mem);

    /* Step 7: release JPEG compression object */

    /* This is an important step since it will release a good deal of memory. */
    jpeg_destroy_compress(&cinfo);

    return ENCODE_JPEG_RESULT_OK;
}