/////////////////////////////////////////////////////////////////////////////
// Rev 11/12/2003                                               
// 
// 
//                           JPEG2JPEG.C
//                           -----------
// 
// 
// Sylvain MARECHAL - sylvain.marechal1@libertysurf.fr
/////////////////////////////////////////////////////////////////////////////
// 
//  Convert a jpeg file to another jpeg file
//  Quality and width can be specified
//  should be linked with :
//  -the jpeglib-6b (http://www.ijg.org/)
//  -dcpjpeg.c
//
//  Usage :
//	jpeg2jpeg <source.jpg> 
//		<destfile.jpg> 
//		<width in pixels>
//		<quality(1 =poor, 100=good)> 
// 
// 
/////////////////////////////////////////////////////////////////////////////
#ifdef _WIN32
#include <io.h>
#else
#define O_BINARY    0
#endif

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <setjmp.h>
#include "parcoursdir.h"
#include "dcpjpeg.h"
#include "jpeg2jpeg.h"


// Structure utilisee pour la lecture
typedef struct tagReadJpeg
{
    int hFile;	    
    char *pBuffer;
    int cbBuffer;
} ReadJpeg;

// Structure pour l'ecriture
typedef struct tagWriteJpeg
{
    int hFile;
} WriteJpeg;


// Callbacks
static int ReadJpegFile( void *, char ** ppBuffer, int * pcbBuffer );
static int WriteJpegFile( void *, char * pBuffer, int cbBuffer );
static void ErrorMessage( void *, char * pszBuffer );


#define MAIN
#ifdef MAIN
// The test program
int main( int argc, char * argv[] )
{
    if( argc < 4 )
    {
	printf( "Usage : %s <file_in.jpg> <file_out.jpg> <width> <quality>\n" );
	return 1;
    }
    Jpeg2Jpeg( argv[1], argv[2], atoi(argv[3]), atoi(argv[4]) );
    return 0;
}
#endif




/////////////////////////////////////////////////////////////////////////////
//
//        JPEG2JPEG
/////////////////////////////////////////////////////////////////////////////
//
//  DESCRIPTION
//       --Jpeg2Jpeg--
//
//	Utilisation des structures DcpJpeg et CpJpeg.
//	On decompresse 1 jpeg puis on le recompresse a la
//	volee en changeant la qualite et l'echelle
//
//  ARGUMENTS
//        Argument1:  char *pszFileSource
//        Argument2: char *pszFileDest
//        Argument3: int nWidth
//        Argument4: int nQuality
//  RETOUR/RESULTAT
//        void 
//  REMARQUE
//  Rev 11/12/2003 
//////////////////////////////////////////////////////////////////////////////
void Jpeg2Jpeg( char *pszFileSource, char *pszFileDest, int nWidth, int nQuality )
    {
    int fFirst = TRUE;
    ReadJpeg rj;
    WriteJpeg wj;
    DcpJpeg * pDcpJpeg = DcpJpegInit( ReadJpegFile, (void * )&rj, ErrorMessage );
    CpJpeg * pCpJpeg = CpJpegInit( WriteJpegFile, (void * )&wj, ErrorMessage );

    // Changement d'echelle
    if( nWidth > 0 )
	DcpJpegInitScale( pDcpJpeg, 0, 0, nWidth );

    rj.pBuffer = (char *)malloc(1024);
    rj.cbBuffer = 1024;
    if( ! rj.pBuffer )
	{
	DcpJpegDestroy( pDcpJpeg );
	CpJpegDestroy( pCpJpeg );
	return;
	}
    
    /*  Fichier source  */
    rj.hFile = open( pszFileSource, O_RDONLY | O_BINARY, 0666 );
    if( rj.hFile == -1 )
	{
	DcpJpegDestroy( pDcpJpeg );
	CpJpegDestroy( pCpJpeg );
	return;
	}

    /*  Fichier de destination : Si NULL, Sortie standard  */
    if( pszFileDest == NULL )
	{
	wj.hFile = 1;
#ifdef _WIN32
	_setmode ( 1, O_BINARY );
#endif
	}
    else
        {
        wj.hFile = open( pszFileDest, O_CREAT | O_TRUNC | O_BINARY | O_RDWR , 0666 );
        if( wj.hFile == -1 )
	    {
	    close( rj.hFile );
	    DcpJpegDestroy( pDcpJpeg );
	    CpJpegDestroy( pCpJpeg );
	    return;
	    }
	}

    
    /*  Ecriture ds fichier de destination  */
    for(;;)
	{
	int err;
	char *pDecompress; int cbDecompress;
	
	err = DcpJpegDecode( pDcpJpeg, &pDecompress, &cbDecompress );
	if( cbDecompress > 0 )
	    {
	    if( fFirst )
		{
		unsigned int image_width;
		unsigned int image_height;
		int input_components;
		int in_color_space;

		DcpJpegGetParam( pDcpJpeg, &image_width, &image_height, &input_components, &in_color_space );
		CpJpegSetParam( pCpJpeg, image_width, image_height, input_components, in_color_space, nQuality );
		fFirst = FALSE;
		}
	    CpJpegEncode( pCpJpeg, pDecompress, cbDecompress );
	    }
	if( err < 0 )
	    break;
	}

    
    /*  Liberation memoire et fermeture fichiers  */
    DcpJpegDestroy( pDcpJpeg );
    CpJpegDestroy( pCpJpeg );
    close( rj.hFile );
    free( rj.pBuffer );
    if( wj.hFile != 1 )
	close( wj.hFile );
    }




/////////////////////////////////////////////////////////////////////////////
//
//        READJPEGFILE
/////////////////////////////////////////////////////////////////////////////
//
//  DESCRIPTION
//       --ReadJpegFile--
//  ARGUMENTS
//        Argument1:  void * lParam
//        Argument2: char **ppBuffer
//        Argument3: int *pcbBuffer
//  RETOUR/RESULTAT
//        int 
//  REMARQUE
//  Rev 11/12/2003 
//////////////////////////////////////////////////////////////////////////////
int ReadJpegFile( void * lParam, char **ppBuffer, int *pcbBuffer )
{
    ReadJpeg *prj = (ReadJpeg *)lParam;
    int nRet;
    
    nRet = read( prj->hFile, prj->pBuffer, prj->cbBuffer );
    *ppBuffer = (nRet <= 0 ? NULL : prj->pBuffer);
    *pcbBuffer = (nRet <= 0 ? 0 : nRet);
    
    if( nRet <= 0 )
    {
	nRet = -1;
    }
    
    return nRet;
}




/////////////////////////////////////////////////////////////////////////////
//
//        WRITEJPEGFILE
/////////////////////////////////////////////////////////////////////////////
//
//  DESCRIPTION
//       --WriteJpegFile--
//
//	Ecriture dans fichier de destination
//
//  ARGUMENTS
//        Argument1:  void * lParam
//        Argument2: char * pBuffer
//        Argument3: int cbBuffer
//  RETOUR/RESULTAT
//        int 
//  REMARQUE
//  Rev 11/12/2003 
//////////////////////////////////////////////////////////////////////////////
int WriteJpegFile( void * lParam, char * pBuffer, int cbBuffer )
{
    WriteJpeg *pwj = (WriteJpeg*)lParam;
    
    write( pwj->hFile, pBuffer, cbBuffer );
    return 0;
}


/*---------------------------------------------------------------------------
**        ERRORMESSAGE
**---------------------------------------------------------------------------
**        --ErrorMessage--
**
**	La fonction pour afficher les erreurs
**
**  Rev 17/04/2000 
**--------------------------------------------------------------------------*/
void ErrorMessage( void * lParam, char * pszBuffer )
{
    //printf( pszBuffer );
}



/**********************************************************************/
/*
GROS COPIER-COLLER depuis example.c pour recuperer les dimensions d'un jpeg
*/
 
 /* Here's the extended error handler struct:
 */

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);
}



/////////////////////////////////////////////////////////////////////////////
//
//        GETJPEGSIZE
/////////////////////////////////////////////////////////////////////////////
//
//  DESCRIPTION
//       --GetJpegSize--
//
//	Recuperation de la taille de l'image Jpeg
//
//
//  ARGUMENTS
//        Argument1: char * filename [IN]   File
//        Argument2: int * pWidth    [OUT]  Width
//        Argument3: int * pHeight   [OUT]  Height
//  RETOUR/RESULTAT
//        int 
//  REMARQUE
//  Rev 11/12/2003 
//////////////////////////////////////////////////////////////////////////////
int GetJpegSize(char * filename, int * pWidth, int * pHeight )
{
  /* 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 */
#if 0
  JSAMPARRAY buffer;		/* Output row buffer */
  int row_stride;		/* physical row width in output buffer */
#endif

  /* 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.
   */

  /*  On veut juste la taille ... */
  *pWidth = cinfo.image_width;
  *pHeight = cinfo.image_height;

#if 0
  /* 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.
   */
  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);
    /* Assume put_scanline_someplace wants a pointer and sample count. */
    put_scanline_someplace(buffer[0], row_stride);
  }

  /* 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);
#endif /*0*/

  /* 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;
}