/*
	Counter.c : Image counter CGI.

	Programed by Kaburaya Seiden.
	http://www2.justnet.ne.jp/~kabstudio/
	kab-studio@multimedia.design.co.jp

	This program is "Copyleft".
*/


/* If you compile in DEBUG mode, set 1.*/
/* else(Release mode), set 0 */
#define MODE_DEBUG 0


/* If you use "flock", set 1 */
/* If you use "lockf", set 0 */
#define MODE_FLOCK 1


#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#if MODE_FLOCK
	#include <sys/file.h>
#else
	#include <unistd.h>
#endif


#if MODE_DEBUG
	#define TRACE(sz) printf("%s\n",sz)
#else
	#define TRACE(st)
#endif


#define MAX_URL_LEN	257
#define IMG_DEFAULT	"./TPDot.gif"


/*		programs	*/


void GetCountImg( p_chRetImg, p_chImgDir, p_iCount, p_iKeta )
char	*p_chRetImg;	/* Return image file name. */
char	*p_chImgDir;	/* Image directory. */
int	p_iCount;
int	p_iKeta;
{
	int	iCountLen, iStrLen;
	char	chCount[10];

	sprintf( chCount, "%d", p_iCount );	/* itoa */
	iCountLen = strlen( chCount );	/* Get count text length. */

	/* Concatenate strings. */
	if( p_iKeta <= iCountLen )
	{
		strcpy( p_chRetImg, "./" );
		strcat( p_chRetImg, p_chImgDir );
		strcat( p_chRetImg, "/" );
		iStrLen = strlen( p_chRetImg );
		p_chRetImg[iStrLen] = chCount[iCountLen - p_iKeta];
		p_chRetImg[iStrLen + 1] = '\0';
		strcat( p_chRetImg, ".gif" );
	}
	else
		strcpy( p_chRetImg, IMG_DEFAULT );

	return;
}



int GetCount( p_pfLogFile )
FILE	*p_pfLogFile;
{
	int 	iRetCount, iScanRes;
	char	chCount[10];

	rewind( p_pfLogFile );	/* Go to top. */
	iScanRes = fscanf( p_pfLogFile, "%s", chCount );		/* Read count. */
	if( iScanRes != EOF )
		iRetCount = atoi( chCount );
	else
		iRetCount = 0;

	return iRetCount;
}



int IncCount( p_pchFile, p_iIncCount )
char	*p_pchFile;	/* Count data file name. */
int	p_iIncCount;	/* Increment Number. */
{
	int	iRetCount, iLockRes, iFileNo;
	long	lFilePos;
	FILE	*pfLogFile;

	if( p_iIncCount == 0 )	/* Display only. */
	{
		pfLogFile = fopen( p_pchFile, "r" );	/* Read only. */
		if( pfLogFile == NULL )
			return 0;
		iRetCount = GetCount( pfLogFile );	/* Get count. */
	}
	else	/* Increment. */
	{
		pfLogFile = fopen( p_pchFile, "r+" );	/* Read and write. */
		if( pfLogFile == NULL )
			return 0;

		iFileNo = fileno( pfLogFile );
#if MODE_FLOCK
		iLockRes = flock( iFileNo, LOCK_EX );
#else
		lseek( iFileNo, 0L, 0 );
		iLockRes = lockf( iFileNo, F_LOCK, 0L );
#endif
		if( iLockRes == -1 )
		{
			fclose( pfLogFile );
			return 0;
		}
		/* Lock Start!! */

		iRetCount = GetCount( pfLogFile ) + p_iIncCount;	/* Get count and increment. */
		rewind( pfLogFile );	/* Go to top. */
		fprintf( pfLogFile, "%d\n", iRetCount );	/* Write count. */

		/* Lock End */
#if MODE_FLOCK
		flock( iFileNo, LOCK_UN );
#else
		lseek( iFileNo, 0L, 0 );
		lockf( iFileNo, F_ULOCK, 0L );
#endif
	}

	fclose( pfLogFile );

	return iRetCount;
}



int WriteImg( p_pchFile )
char	*p_pchFile;
{
	int	iChar, iScanRes;
	FILE	*pfImg;

	printf( "Content-type: image/gif\n\n" );

	pfImg = fopen( p_pchFile, "rb" ); /* Read Only, Bynary mode */
	if( pfImg == NULL )
	{
		pfImg = fopen( IMG_DEFAULT, "rb" ); /* Open default image file. */
		if( pfImg == NULL )
			return 0;
	}

	rewind( pfImg );	/* Go to Top */
	while( !feof( pfImg ) )
		putchar( fgetc( pfImg ) );	/* Output */
	fclose( pfImg );

	return 1;
}



/* Arguments
0: Command ( Counter.cgi )
1: Count file ( ex: test.txt )
2: Imgs dir
3: Keta
4: Increment Count
*/
int main( argc, argv )
int argc;
char *argv[];
{
	int	iIncCount, iCount, iKeta;
	char	chCountImg[2];
	char 	chImgDir[MAX_URL_LEN];

	if( argc == 5 )
		iIncCount = atoi( argv[4] );
	else if( argc == 4 )
		iIncCount = 0;
	else
		exit( 1 );

	iKeta = atoi( argv[3] );
	strcpy( chImgDir, argv[2] );

	/*  Count */
	iCount = IncCount( argv[1], iIncCount );
	GetCountImg( chCountImg, chImgDir, iCount, iKeta );
	WriteImg( chCountImg );

	exit( 0 );
}