/* Copyright (C)2004 Landmark Graphics Corporation
   * Copyright (C)2005 Sun Microsystems, Inc.
   * Copyright (C)2010, 2012 D. R. Commander
   *
   * This library is free software and may be redistributed and/or modified under
   * the terms of the wxWindows Library License, Version 3.1 or (at your option)
   * any later version.  The full license is in the LICENSE.txt file included
   * with this distribution.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * wxWindows Library License for more details.
  */
  
  #include <fcntl.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <errno.h>
  #include <stdlib.h>
  #include <stdio.h>
  #include <string.h>
  #ifdef _WIN32
   #include <io.h>
  #else
   #include <unistd.h>
  #endif
  #include "./tjutil.h"
  #include "./bmp.h"
  
  #define byteswap(i) ( \
  	(((i) & 0xff000000) >> 24) | \
  	(((i) & 0x00ff0000) >>  8) | \
  	(((i) & 0x0000ff00) <<  8) | \
  	(((i) & 0x000000ff) << 24) )
  
  #define byteswap16(i) ( \
  	(((i) & 0xff00) >> 8) | \
  	(((i) & 0x00ff) << 8) )
  
  static __inline int littleendian(void)
  {
  	unsigned int value=1;
  	unsigned char *ptr=(unsigned char *)(&value);
  	if(ptr[0]==1 && ptr[3]==0) return 1;
  	else return 0;
  }
  
  #ifndef BI_BITFIELDS
  #define BI_BITFIELDS 3L
  #endif
  #ifndef BI_RGB
  #define BI_RGB 0L
  #endif
  
  #define BMPHDRSIZE 54
  typedef struct _bmphdr
  {
  	unsigned short bfType;
  	unsigned int bfSize;
  	unsigned short bfReserved1, bfReserved2;
  	unsigned int bfOffBits;
  
  	unsigned int biSize;
  	int biWidth, biHeight;
  	unsigned short biPlanes, biBitCount;
  	unsigned int biCompression, biSizeImage;
  	int biXPelsPerMeter, biYPelsPerMeter;
  	unsigned int biClrUsed, biClrImportant;
  } bmphdr;
  
  static const char *__bmperr="No error";
  
  static const int ps[BMPPIXELFORMATS]={3, 4, 3, 4, 4, 4};
  static const int roffset[BMPPIXELFORMATS]={0, 0, 2, 2, 3, 1};
  static const int goffset[BMPPIXELFORMATS]={1, 1, 1, 1, 2, 2};
  static const int boffset[BMPPIXELFORMATS]={2, 2, 0, 0, 1, 3};
  
  #define _throw(m) {__bmperr=m;  retcode=-1;  goto finally;}
  #define _unix(f) {if((f)==-1) _throw(strerror(errno));}
  #define _catch(f) {if((f)==-1) {retcode=-1;  goto finally;}}
  
  #define readme(fd, addr, size) \
  	if((bytesread=read(fd, addr, (size)))==-1) _throw(strerror(errno)); \
  	if(bytesread!=(size)) _throw("Read error");
  
  void pixelconvert(unsigned char *srcbuf, enum BMPPIXELFORMAT srcformat,
  	int srcpitch, unsigned char *dstbuf, enum BMPPIXELFORMAT dstformat, int dstpitch,
  	int w, int h, int flip)
  {
  	unsigned char *srcptr, *srcptr0, *dstptr, *dstptr0;
  	int i, j;
  
  	srcptr=flip? &srcbuf[srcpitch*(h-1)]:srcbuf;
  	for(j=0, dstptr=dstbuf; j<h; j++,
  		srcptr+=flip? -srcpitch:srcpitch, dstptr+=dstpitch)
  	{
  		for(i=0, srcptr0=srcptr, dstptr0=dstptr; i<w; i++,
  			srcptr0+=ps[srcformat], dstptr0+=ps[dstformat])
  		{
  			dstptr0[roffset[dstformat]]=srcptr0[roffset[srcformat]];
  			dstptr0[goffset[dstformat]]=srcptr0[goffset[srcformat]];
  			dstptr0[boffset[dstformat]]=srcptr0[boffset[srcformat]];
  		}
  	}
  }
  
  int loadppm(int *fd, unsigned char **buf, int *w, int *h,
  	enum BMPPIXELFORMAT f, int align, int dstbottomup, int ascii)
  {
  	FILE *fs=NULL;  int retcode=0, scalefactor, dstpitch;
  	unsigned char *tempbuf=NULL;  char temps[255], temps2[255];
  	int numread=0, totalread=0, pixel[3], i, j;
  
  	if((fs=fdopen(*fd, "r"))==NULL) _throw(strerror(errno));
  
  	do
  	{
  		if(!fgets(temps, 255, fs)) _throw("Read error");
  		if(strlen(temps)==0 || temps[0]=='
  ') continue;
  		if(sscanf(temps, "%s", temps2)==1 && temps2[1]=='#') continue;
  		switch(totalread)
  		{
  			case 0:
  				if((numread=sscanf(temps, "%d %d %d", w, h, &scalefactor))==EOF)
  					_throw("Read error");
  				break;
  			case 1:
  				if((numread=sscanf(temps, "%d %d", h, &scalefactor))==EOF)
  					_throw("Read error");
  				break;
  			case 2:
  				if((numread=sscanf(temps, "%d", &scalefactor))==EOF)
  					_throw("Read error");
  				break;
  		}
  		totalread+=numread;
  	} while(totalread<3);
  	if((*w)<1 || (*h)<1 || scalefactor<1) _throw("Corrupt PPM header");
  
  	dstpitch=(((*w)*ps[f])+(align-1))&(~(align-1));
  	if((*buf=(unsigned char *)malloc(dstpitch*(*h)))==NULL)
  		_throw("Memory allocation error");
  	if(ascii)
  	{
  		for(j=0; j<*h; j++)
  		{
  			for(i=0; i<*w; i++)
  			{
  				if(fscanf(fs, "%d%d%d", &pixel[0], &pixel[1], &pixel[2])!=3)
  					_throw("Read error");
  				(*buf)[j*dstpitch+i*ps[f]+roffset[f]]=(unsigned char)(pixel[0]*255/scalefactor);
  				(*buf)[j*dstpitch+i*ps[f]+goffset[f]]=(unsigned char)(pixel[1]*255/scalefactor);
  				(*buf)[j*dstpitch+i*ps[f]+boffset[f]]=(unsigned char)(pixel[2]*255/scalefactor);
  			}
  		}
  	}
  	else
  	{
  		if(scalefactor!=255)
  			_throw("Binary PPMs must have 8-bit components");
  		if((tempbuf=(unsigned char *)malloc((*w)*(*h)*3))==NULL)
  			_throw("Memory allocation error");
  		if(fread(tempbuf, (*w)*(*h)*3, 1, fs)!=1) _throw("Read error");
  		pixelconvert(tempbuf, BMP_RGB, (*w)*3, *buf, f, dstpitch, *w, *h, dstbottomup);
  	}
  
  	finally:
  	if(fs) {fclose(fs);  *fd=-1;}
  	if(tempbuf) free(tempbuf);
  	return retcode;
  }
  
  
  int loadbmp(char *filename, unsigned char **buf, int *w, int *h, 
  	enum BMPPIXELFORMAT f, int align, int dstbottomup)
  {
  	int fd=-1, bytesread, srcpitch, srcbottomup=1, srcps, dstpitch,
  		retcode=0;
  	unsigned char *tempbuf=NULL;
  	bmphdr bh;  int flags=O_RDONLY;
  
  	dstbottomup=dstbottomup? 1:0;
  	#ifdef _WIN32
  	flags|=O_BINARY;
  	#endif
  	if(!filename || !buf || !w || !h || f<0 || f>BMPPIXELFORMATS-1 || align<1)
  		_throw("invalid argument to loadbmp()");
  	if((align&(align-1))!=0)
  		_throw("Alignment must be a power of 2");
  	_unix(fd=open(filename, flags));
  
  	readme(fd, &bh.bfType, sizeof(unsigned short));
  	if(!littleendian())	bh.bfType=byteswap16(bh.bfType);
  
  	if(bh.bfType==0x3650)
  	{
  		_catch(loadppm(&fd, buf, w, h, f, align, dstbottomup, 0));
  		goto finally;
  	}
  	if(bh.bfType==0x3350)
  	{
  		_catch(loadppm(&fd, buf, w, h, f, align, dstbottomup, 1));
  		goto finally;
  	}
  
  	readme(fd, &bh.bfSize, sizeof(unsigned int));
  	readme(fd, &bh.bfReserved1, sizeof(unsigned short));
  	readme(fd, &bh.bfReserved2, sizeof(unsigned short));
  	readme(fd, &bh.bfOffBits, sizeof(unsigned int));
  	readme(fd, &bh.biSize, sizeof(unsigned int));
  	readme(fd, &bh.biWidth, sizeof(int));
  	readme(fd, &bh.biHeight, sizeof(int));
  	readme(fd, &bh.biPlanes, sizeof(unsigned short));
  	readme(fd, &bh.biBitCount, sizeof(unsigned short));
  	readme(fd, &bh.biCompression, sizeof(unsigned int));
  	readme(fd, &bh.biSizeImage, sizeof(unsigned int));
  	readme(fd, &bh.biXPelsPerMeter, sizeof(int));
  	readme(fd, &bh.biYPelsPerMeter, sizeof(int));
  	readme(fd, &bh.biClrUsed, sizeof(unsigned int));
  	readme(fd, &bh.biClrImportant, sizeof(unsigned int));
  
  	if(!littleendian())
  	{
  		bh.bfSize=byteswap(bh.bfSize);
  		bh.bfOffBits=byteswap(bh.bfOffBits);
  		bh.biSize=byteswap(bh.biSize);
  		bh.biWidth=byteswap(bh.biWidth);
  		bh.biHeight=byteswap(bh.biHeight);
  		bh.biPlanes=byteswap16(bh.biPlanes);
  		bh.biBitCount=byteswap16(bh.biBitCount);
  		bh.biCompression=byteswap(bh.biCompression);
  		bh.biSizeImage=byteswap(bh.biSizeImage);
  		bh.biXPelsPerMeter=byteswap(bh.biXPelsPerMeter);
  		bh.biYPelsPerMeter=byteswap(bh.biYPelsPerMeter);
  		bh.biClrUsed=byteswap(bh.biClrUsed);
  		bh.biClrImportant=byteswap(bh.biClrImportant);
  	}
  
  	if(bh.bfType!=0x4d42 || bh.bfOffBits<BMPHDRSIZE
  	|| bh.biWidth<1 || bh.biHeight==0)
  		_throw("Corrupt bitmap header");
  	if((bh.biBitCount!=24 && bh.biBitCount!=32) || bh.biCompression!=BI_RGB)
  		_throw("Only uncompessed RGB bitmaps are supported");
  
  	*w=bh.biWidth;  *h=bh.biHeight;  srcps=bh.biBitCount/8;
  	if(*h<0) {*h=-(*h);  srcbottomup=0;}
  	srcpitch=(((*w)*srcps)+3)&(~3);
  	dstpitch=(((*w)*ps[f])+(align-1))&(~(align-1));
  
  	if(srcpitch*(*h)+bh.bfOffBits!=bh.bfSize) _throw("Corrupt bitmap header");
  	if((tempbuf=(unsigned char *)malloc(srcpitch*(*h)))==NULL
  	|| (*buf=(unsigned char *)malloc(dstpitch*(*h)))==NULL)
  		_throw("Memory allocation error");
  	if(lseek(fd, (long)bh.bfOffBits, SEEK_SET)!=(long)bh.bfOffBits)
  		_throw(strerror(errno));
  	_unix(bytesread=read(fd, tempbuf, srcpitch*(*h)));
  	if(bytesread!=srcpitch*(*h)) _throw("Read error");
  
  	pixelconvert(tempbuf, BMP_BGR, srcpitch, *buf, f, dstpitch, *w, *h, 
  		srcbottomup!=dstbottomup);
  
  	finally:
  	if(tempbuf) free(tempbuf);
  	if(fd!=-1) close(fd);
  	return retcode;
  }
  
  #define writeme(fd, addr, size) \
  	if((byteswritten=write(fd, addr, (size)))==-1) _throw(strerror(errno)); \
  	if(byteswritten!=(size)) _throw("Write error");
  
  int saveppm(char *filename, unsigned char *buf, int w, int h,
  	enum BMPPIXELFORMAT f, int srcpitch, int srcbottomup)
  {
  	FILE *fs=NULL;  int retcode=0;
  	unsigned char *tempbuf=NULL;
  
  	if((fs=fopen(filename, "wb"))==NULL) _throw(strerror(errno));
  	if(fprintf(fs, "P6
  ")<1) _throw("Write error");
  	if(fprintf(fs, "%d %d
  ", w, h)<1) _throw("Write error");
  	if(fprintf(fs, "255
  ")<1) _throw("Write error");
  
  	if((tempbuf=(unsigned char *)malloc(w*h*3))==NULL)
  		_throw("Memory allocation error");
  
  	pixelconvert(buf, f, srcpitch, tempbuf, BMP_RGB, w*3, w, h, 
  		srcbottomup);
  
  	if((fwrite(tempbuf, w*h*3, 1, fs))!=1) _throw("Write error");
  
  	finally:
  	if(tempbuf) free(tempbuf);
  	if(fs) fclose(fs);
  	return retcode;
  }
  
  int savebmp(char *filename, unsigned char *buf, int w, int h,
  	enum BMPPIXELFORMAT f, int srcpitch, int srcbottomup)
  {
  	int fd=-1, byteswritten, dstpitch, retcode=0;
  	int flags=O_RDWR|O_CREAT|O_TRUNC;
  	unsigned char *tempbuf=NULL;  char *temp;
  	bmphdr bh;  int mode;
  
  	#ifdef _WIN32
  	flags|=O_BINARY;  mode=_S_IREAD|_S_IWRITE;
  	#else
  	mode=S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;
  	#endif
  	if(!filename || !buf || w<1 || h<1 || f<0 || f>BMPPIXELFORMATS-1 || srcpitch<0)
  		_throw("bad argument to savebmp()");
  
  	if(srcpitch==0) srcpitch=w*ps[f];
  
  	if((temp=strrchr(filename, '.'))!=NULL)
  	{
  		if(!strcasecmp(temp, ".ppm"))
  			return saveppm(filename, buf, w, h, f, srcpitch, srcbottomup);
  	}
  
  	_unix(fd=open(filename, flags, mode));
  	dstpitch=((w*3)+3)&(~3);
  
  	bh.bfType=0x4d42;
  	bh.bfSize=BMPHDRSIZE+dstpitch*h;
  	bh.bfReserved1=0;  bh.bfReserved2=0;
  	bh.bfOffBits=BMPHDRSIZE;
  	bh.biSize=40;
  	bh.biWidth=w;  bh.biHeight=h;
  	bh.biPlanes=0;  bh.biBitCount=24;
  	bh.biCompression=BI_RGB;  bh.biSizeImage=0;
  	bh.biXPelsPerMeter=0;  bh.biYPelsPerMeter=0;
  	bh.biClrUsed=0;  bh.biClrImportant=0;
  
  	if(!littleendian())
  	{
  		bh.bfType=byteswap16(bh.bfType);
  		bh.bfSize=byteswap(bh.bfSize);
  		bh.bfOffBits=byteswap(bh.bfOffBits);
  		bh.biSize=byteswap(bh.biSize);
  		bh.biWidth=byteswap(bh.biWidth);
  		bh.biHeight=byteswap(bh.biHeight);
  		bh.biPlanes=byteswap16(bh.biPlanes);
  		bh.biBitCount=byteswap16(bh.biBitCount);
  		bh.biCompression=byteswap(bh.biCompression);
  		bh.biSizeImage=byteswap(bh.biSizeImage);
  		bh.biXPelsPerMeter=byteswap(bh.biXPelsPerMeter);
  		bh.biYPelsPerMeter=byteswap(bh.biYPelsPerMeter);
  		bh.biClrUsed=byteswap(bh.biClrUsed);
  		bh.biClrImportant=byteswap(bh.biClrImportant);
  	}
  
  	writeme(fd, &bh.bfType, sizeof(unsigned short));
  	writeme(fd, &bh.bfSize, sizeof(unsigned int));
  	writeme(fd, &bh.bfReserved1, sizeof(unsigned short));
  	writeme(fd, &bh.bfReserved2, sizeof(unsigned short));
  	writeme(fd, &bh.bfOffBits, sizeof(unsigned int));
  	writeme(fd, &bh.biSize, sizeof(unsigned int));
  	writeme(fd, &bh.biWidth, sizeof(int));
  	writeme(fd, &bh.biHeight, sizeof(int));
  	writeme(fd, &bh.biPlanes, sizeof(unsigned short));
  	writeme(fd, &bh.biBitCount, sizeof(unsigned short));
  	writeme(fd, &bh.biCompression, sizeof(unsigned int));
  	writeme(fd, &bh.biSizeImage, sizeof(unsigned int));
  	writeme(fd, &bh.biXPelsPerMeter, sizeof(int));
  	writeme(fd, &bh.biYPelsPerMeter, sizeof(int));
  	writeme(fd, &bh.biClrUsed, sizeof(unsigned int));
  	writeme(fd, &bh.biClrImportant, sizeof(unsigned int));
  
  	if((tempbuf=(unsigned char *)malloc(dstpitch*h))==NULL)
  		_throw("Memory allocation error");
  
  	pixelconvert(buf, f, srcpitch, tempbuf, BMP_BGR, dstpitch, w, h, 
  		!srcbottomup);
  
  	if((byteswritten=write(fd, tempbuf, dstpitch*h))!=dstpitch*h)
  		_throw(strerror(errno));
  
  	finally:
  	if(tempbuf) free(tempbuf);
  	if(fd!=-1) close(fd);
  	return retcode;
  }
  
  const char *bmpgeterr(void)
  {
  	return __bmperr;
  }