jpeg-utils.c

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#include "jpeg-utils/jpeg-utils.h"
 
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
 
int readImage(const char *path, ImageData *img)
{
    // Init variables
    int retval = EXIT_FAILURE;
 
    FILE *fptr = NULL;
    int width = 0, height = 0;
    long imgSize = 0;
    unsigned char nComponent = 3, *compImg = NULL, *decompImg = NULL;
    tjhandle jpegDecompressor = NULL;
 
    // Check inputs
    assert(path);
    assert(img);
 
    // Find file and get size
    if ((fptr = fopen(path, "rb")) == NULL)
        goto cleanup;
    if (fseek(fptr, 0, SEEK_END) < 0 || ((imgSize = ftell(fptr)) < 0) || fseek(fptr, 0, SEEK_SET) < 0)
        goto cleanup;
    if (imgSize == 0)
        goto cleanup;
 
    // Read file
    compImg = (unsigned char *)malloc(imgSize * sizeof(unsigned char));
    if (!compImg || (fread(compImg, imgSize, 1, fptr) < 1))
        goto cleanup;
 
    // Decompress
    jpegDecompressor = tjInitDecompress();
    if (!jpegDecompressor)
        goto cleanup;
 
    retval = tjDecompressHeader(jpegDecompressor, compImg, imgSize, &width, &height);
    if (retval < 0)
        goto cleanup;
    decompImg = (unsigned char *)malloc((unsigned long long)width * height * nComponent * sizeof(unsigned char));
    if (!decompImg)
        goto cleanup;
    retval = tjDecompress(jpegDecompressor, compImg, imgSize, decompImg, width, 0, height, nComponent, TJFLAG_FASTDCT);
    if (retval < 0)
        goto cleanup;
 
    // Set output
    img->width = width;
    img->height = height;
    img->nComponents = nComponent;
    img->data = decompImg;
    decompImg = NULL;
 
cleanup:
    tjDestroy(jpegDecompressor);
    fclose(fptr);
 
    free(compImg);
    free(decompImg);
 
    return retval;
}
 
int saveImage(const char *path, ImageData *img, enum TJPF pixelFormat, enum TJSAMP samplingFormat, int jpegQuality)
{
    // Init variables
    int retval = EXIT_FAILURE;
 
    FILE *fptr = NULL;
    long unsigned int outSize = 0;
    unsigned char *compImg = NULL;
    tjhandle jpegCompressor = NULL;
 
    // Check inputs
    assert(path);
    assert(img);
 
    // Compress
    jpegCompressor = tjInitCompress();
    if (!jpegCompressor)
        goto cleanup;
 
    retval = tjCompress2(jpegCompressor, img->data, img->width, 0, img->height, pixelFormat, &compImg, &outSize,
                         samplingFormat, jpegQuality, TJFLAG_FASTDCT);
    if (retval < 0)
        goto cleanup;
 
    // Write file
    retval = EXIT_FAILURE; // To simplify if checks
    if ((fptr = fopen(path, "wb")) == NULL)
        goto cleanup;
    if (fwrite(compImg, outSize, 1, fptr) < 1)
        goto cleanup;
    if (fflush(fptr))
        goto cleanup;
 
    retval = EXIT_SUCCESS;
 
cleanup:
    fclose(fptr);
    tjDestroy(jpegCompressor);
    tjFree(compImg);
 
    return retval;
}
 
int initImageData(ImageData *img, int width, int height, int nComponents)
{
    img->data = (unsigned char *)malloc((unsigned long long)width * height * nComponents);
    if (!img->data)
        return EXIT_FAILURE;
 
    img->height = height;
    img->nComponents = nComponents;
    img->width = width;
    return EXIT_SUCCESS;
}
 
void deInitImageData(ImageData *img)
{
    if (img)
    {
        free(img->data);
        img->data = NULL;
    }
}