jpeg-utils.c File Reference

#include "jpeg-utils/jpeg-utils.h"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>

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Functions
int	readImage (const char *path, ImageData *img)
	Get image data from an input file.
int	saveImage (const char *path, ImageData *img, enum TJPF pixelFormat, enum TJSAMP samplingFormat, int jpegQuality)
	Save image data to an output file.
int	initImageData (ImageData *img, int width, int height, int nComponents)
	Allocates memory for image.
void	deInitImageData (ImageData *img)
	Free memory allocated by read image.

Function Documentation

deInitImageData()

void deInitImageData

(

ImageData *

img

)

Free memory allocated by read image.

Parameters

[in]

img

Image data

Definition at line 122 of file jpeg-utils.c.

{
    if (img)
    {
        free(img->data);
        img->data = NULL;
    }
}

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initImageData()

int initImageData	(	ImageData *	img,
		int	width,
		int	height,
		int	nComponents )

Allocates memory for image.

Parameters

[in]	img	Image data
[in]	width	Width of image
[in]	height	Height of image
[in]	nComponents	Number of components

Returns

int Returns 0 on success

Definition at line 110 of file jpeg-utils.c.

{
    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;
}

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readImage()

int readImage	(	const char *	path,
		ImageData *	img )

Get image data from an input file.

Parameters

[in]	path	Path to input image file
[out]	img	Image data

Returns

int Returns 0 on success

Definition at line 7 of file jpeg-utils.c.

{
    // 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;
}

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saveImage()

int saveImage	(	const char *	path,
		ImageData *	img,
		enum TJPF	pixelFormat,
		enum TJSAMP	samplingFormat,
		int	jpegQuality )

Save image data to an output file.

Parameters

[in]	path	Path to output image file
[in]	img	Image data
[in]	pixelFormat	Pixel format
[in]	samplingFormat	Sampling format
[in]	jpegQuality	Quality of the output image

Returns

int Returns 0 on success

Definition at line 67 of file jpeg-utils.c.

{
    // 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;
}

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