appjpeg-arm.c

linux下调用libjpeg库函数进行jpeg文件的解压(嵌入式Linux无GUI环境下进行开发)

#include <unistd.h>
#include <stdio.h>
#include <linux/types.h>
#include "jpeglib.h"
#include <setjmp.h>
//#include <stdlib.h>
#include <string.h>
//#include <errno.h>
//#include <time.h>
#include <fcntl.h>

//#include <ctype.h>
//#include <jerror.h>
//#include <jconfig.h>
//#include <pthread.h>
#include <sys/mman.h>
//#include <sys/param.h>

#include "bitmap_convert.h"
/******************** JPEG COMPRESSION SAMPLE INTERFACE *******************/

/* This half of the example shows how to feed data into the JPEG compressor.
 * We present a minimal version that does not worry about refinements such
 * as error recovery (the JPEG code will just exit() if it gets an error).
 */


/*
 * IMAGE DATA FORMATS:
 *
 * The standard input image format is a rectangular array of pixels, with
 * each pixel having the same number of "component" values (color channels).
 * Each pixel row is an array of JSAMPLEs (which typically are unsigned chars).
 * If you are working with color data, then the color values for each pixel
 * must be adjacent in the row; for example, R,G,B,R,G,B,R,G,B,... for 24-bit
 * RGB color.
 *
 * For this example, we'll assume that this data structure matches the way
 * our application has stored the image in memory, so we can just pass a
 * pointer to our image buffer.  In particular, let's say that the image is
 * RGB color and is described by:
 */

extern JSAMPLE * image_buffer;	/* Points to large array of R,G,B-order data */
extern int image_height;	/* Number of rows in image */
extern int image_width;		/* Number of columns in image */


/*
 * Sample routine for JPEG compression.  We assume that the target file name
 * and a compression quality factor are passed in.
 */



struct my_error_mgr {
  struct jpeg_error_mgr pub;	/* "public" fields */

  jmp_buf setjmp_buffer;	/* for return to caller */
};

typedef struct my_error_mgr * my_error_ptr;

/*
 * 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_error_mgr struct, so coerce pointer */
  my_error_ptr myerr = (my_error_ptr) 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);
}


/*
 * Sample routine for JPEG decompression.  We assume that the source file name
 * is passed in.  We want to return 1 on success, 0 on error.
 */


GLOBAL(int)
read_JPEG_file (char * filename,unsigned char* fb_mem)
{
	unsigned char *buffer_addr;
	int offset=0;
  /* 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.
   */
  struct my_error_mgr jerr;
  /* More stuff */
  FILE * infile;		/* source file */
  JSAMPARRAY buffer;		/* Output row buffer */
  int row_stride;		/* physical row width in output buffer */

  /* In this example we want to open the input file before doing anything else,
   * so that the setjmp() error recovery below can assume the file is open.
   * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
   * requires it in order to read binary files.
   */

  if ((infile = fopen(filename, "rb")) == NULL) {
    fprintf(stderr, "can't open %s\n", filename);
    return 0;
  }

  /* 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);
    fclose(infile);
    return 0;
  }
  /* Now we can initialize the JPEG decompression object. */
  jpeg_create_decompress(&cinfo);

  /* Step 2: specify data source (eg, a file) */

  jpeg_stdio_src(&cinfo, infile);

  /* Step 3: read file parameters with jpeg_read_header() */

  (void) 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.doc 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 */

  (void) 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.
   * In this example, we need to make an output work buffer of the right size.
   */ 
  /* JSAMPLEs per row in output buffer */
  row_stride = cinfo.output_width * cinfo.output_components;
  /* Make a one-row-high sample array that will go away when done with image */
  buffer = (*cinfo.mem->alloc_sarray)
		((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);

  /* 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.
   */
   printf("jpeg width: %d\n",cinfo.output_width);
  offset=0; 
  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.
     */
    (void) jpeg_read_scanlines(&cinfo, buffer, 1);

	buffer_addr=buffer[0];
	RGB24_to_RGB565(buffer_addr,fb_mem+offset,cinfo.output_width); //one line : width


/*
		switch (i%4)  //RGB24bit(scanlines)->BGR32bit(PC-Linux)
		{
			case 0:
				*(fb_mem+offset+i)=*(buffer_addr+j+2);
				break;
			case 1:
				*(fb_mem+offset+i)=*(buffer_addr+j);
				break;
			case 2:
				*(fb_mem+offset+i)=*(buffer_addr+j-2);
				break;
			case 3:
				j--;
				break;
		}
		j++;
*/		
	offset+=240*2;
    /* Assume put_scanline_someplace wants a pointer and sample count. */
  //  put_scanline_someplace(buffer[0], row_stride,fb);
  }

  /* Step 7: Finish decompression */

  (void) 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);

  /* After finish_decompress, we can close the input file.
   * Here we postpone it until after no more JPEG errors are possible,
   * so as to simplify the setjmp error logic above.  (Actually, I don't
   * think that jpeg_destroy can do an error exit, but why assume anything...)
   */
  fclose(infile);

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

  /* And we're done! */
  return 1;
}





int main()
{

	int fb;
	unsigned char* fb_mem;

	fb = open ("/dev/fb0", O_RDWR);
	printf("fb: %d\n",fb);
	fb_mem = mmap (NULL, 240*360, PROT_READ|PROT_WRITE,MAP_SHARED,fb,0);
	printf("fb_mem: %d\n",(int)fb_mem);
//	memset (fb_mem, 0, 240*360);
	printf("%x %x\n",*fb_mem,*(fb_mem+1));
	printf("%x %x\n",*(fb_mem+2),*(fb_mem+3));

	read_JPEG_file("testimg.jpg",fb_mem);

	close(fb);
	return 0;

}