/* Converts 140x192 8-bit PCX file with correct palette to Apple II HGR */

#include <stdio.h>    /* For FILE I/O */
#include <string.h>   /* For strncmp */
#include <fcntl.h>    /* for open()  */
#include <unistd.h>   /* for lseek() */
#include <sys/stat.h> /* for file modes */
#include <stdlib.h>   /* free() */

#define PCX_UNKNOWN    0
#define PCX_8BIT       1
#define PCX_24BIT      2

static int debug=0;

static int vmwGetPCXInfo(char *filename, int *xsize, int *ysize, int *type) {
    
    unsigned char pcx_header[128];
    int xmin,ymin,xmax,ymax,version=PCX_UNKNOWN,bpp,pcx_fd;
    int result;

          /* Open the file */                  
    pcx_fd=open(filename,O_RDONLY);
    
    if (pcx_fd<0) {
       fprintf(stderr,"ERROR!  File \"%s\" not found!\n",filename);
       return -1;
    }
   
    lseek(pcx_fd,0,SEEK_SET);
    
    result=read(pcx_fd,&pcx_header,128);
    if (result<0) {
       fprintf(stderr,"Error!  Could not read header from file %s\n",filename);
       return -1;
    }

    xmin=(pcx_header[5]<<8)+pcx_header[4];
    ymin=(pcx_header[7]<<8)+pcx_header[6];
   
    xmax=(pcx_header[9]<<8)+pcx_header[8];
    ymax=(pcx_header[11]<<8)+pcx_header[10];

    version=pcx_header[1];
    bpp=pcx_header[3];
   
    if (debug) {
	
       printf("Manufacturer: ");
       if (pcx_header[0]==10) printf("Zsoft\n");
       else printf("Unknown %i\n",pcx_header[0]);
   
       printf("Version: ");

       switch(version) {
        case 0: printf("2.5\n"); break;
        case 2: printf("2.8 w palette\n"); break;
        case 3: printf("2.8 w/o palette\n"); break;
        case 4: printf("Paintbrush for Windows\n"); break;
        case 5: printf("3.0+\n"); break;
        default: printf("Unknown %i\n",version);
       }
       printf("Encoding: ");
       if (pcx_header[2]==1) printf("RLE\n");
       else printf("Unknown %i\n",pcx_header[2]);
       
       printf("BitsPerPixelPerPlane: %i\n",bpp);
       printf("File goes from %i,%i to %i,%i\n",xmin,ymin,xmax,ymax);
   
       printf("Horizontal DPI: %i\n",(pcx_header[13]<<8)+pcx_header[12]);
       printf("Vertical   DPI: %i\n",(pcx_header[15]<<8)+pcx_header[14]);
       
       printf("Number of colored planes: %i\n",pcx_header[65]);
       printf("Bytes per line: %i\n",(pcx_header[67]<<8)+pcx_header[66]);
       printf("Palette Type: %i\n",(pcx_header[69]<<8)+pcx_header[68]);
       printf("Hscreen Size: %i\n",(pcx_header[71]<<8)+pcx_header[70]);
       printf("Vscreen Size: %i\n",(pcx_header[73]<<8)+pcx_header[72]);
       
    }
   
   *xsize=(xmax-xmin+1);
   *ysize=(ymax-ymin+1);

   if ((version==5) && (bpp==8) && (pcx_header[65]==3)) *type=PCX_24BIT;
   else if (version==5) *type=PCX_8BIT;
   else *type=PCX_UNKNOWN;

   close(pcx_fd);
   
   return 0;
}

unsigned char colors[256];

static int vmwLoadPCX(char *filename, unsigned char *framebuffer)  {

    int pcx_fd;
    int x,y,i,numacross,xsize,ysize,xmin,ymin;
    unsigned int r,g,b;
    int xmax,ymax;
    unsigned char pcx_header[128];
    unsigned char temp_byte;
    int result;
    unsigned char *pointer=framebuffer;

       /* Open the file */                  
    pcx_fd=open(filename,O_RDONLY);
    
    if (pcx_fd<0) {
       fprintf(stderr,"ERROR!  File \"%s\" not found!\n",filename);
       return -1;
    }
   
    /*************** DECODE THE HEADER *************************/
    result=read(pcx_fd,&pcx_header,128);
    if (result<0) {
       fprintf(stderr,"ERROR opening header of file %s\n",filename);
    }

    xmin=(pcx_header[5]<<8)+pcx_header[4];
    ymin=(pcx_header[7]<<8)+pcx_header[6];
   
    xmax=(pcx_header[9]<<8)+pcx_header[8];
    ymax=(pcx_header[11]<<8)+pcx_header[10];

    xsize=((xmax-xmin)+1);
    ysize=((ymax-ymin)+1);
   
    x=0; y=0;
   
    while (x<xsize*ysize) {

       /* read a byte */
       result=read(pcx_fd,&temp_byte,1);

       /* if > 0xc0, then it's a RLE byte */
       if (0xc0 == (temp_byte&0xc0)) {
	  numacross=temp_byte&0x3f;
	  result=read(pcx_fd,&temp_byte,1);
	  for(i=0;i<numacross;i++) {
	     *pointer=temp_byte;
	     pointer++;
	     x++;
	  }
       }
       else {
	  *pointer=temp_byte;
          pointer++;
	  x++;
       }
    }
    
       /*Load Palette*/
    
    result=lseek(pcx_fd,-769,SEEK_END);
   
    result=read(pcx_fd,&temp_byte,1);
    if (temp_byte!=12) {
       fprintf(stderr,"Error!  No palette found!\n");
       return -1;
    }
	    
    for(i=0;i<255;i++) { 
       result=read(pcx_fd,&temp_byte,1);
       r=temp_byte;
       result=read(pcx_fd,&temp_byte,1);
       g=temp_byte;
       result=read(pcx_fd,&temp_byte,1);
       b=temp_byte;

#if 0
  int colors[8]={0, /* black 0 */
		 1, /* purple  */
		 2, /* green   */
                 3, /* white 0 */
                 0, /* black 1 */
                 1, /* blue */
		 2, /* orange */
		 3, /* white */
  };
#endif
	  
  if ((r==0x00) && (g==0x00) && (b==0x00)) colors[i]=0; /* black */
  else
  if ((r==0xff) && (g==0xff) && (b==0xff)) colors[i]=3; /* white */
  else
  if ((r==0x1b) && (g==0x9a) && (b==0xfe)) colors[i]=0x81; /* blue */
  else
  if ((r==0xe4) && (g==0x34) && (b==0xfe)) colors[i]=0x41; /* purple */
  else
  if ((r==0xcd) && (g==0x5b) && (b==0x1)) colors[i]=0x82; /* orange */
  else
  if ((r==0x1b) && (g==0xcb) && (b==0x1)) colors[i]=0x42; /* green */
  else fprintf(stderr,"Unknown color %i %x %x %x\n",i,r,g,b);
  

  //       printf("%i: 0x%x %x %x\n",i,r,g,b);
       
    }

    close(pcx_fd);

    return 0;
}




static int make_bw_image(unsigned char *in_framebuffer,
			    unsigned char *out_framebuffer,
			    int xsize, int ysize) {

  short fourteen_bits;

  int i,yoffset=0;
  int y,x;
  unsigned char byte1,byte2;

  int page,block,leaf;

  unsigned char *pointer;
  unsigned char *pcx,*hgr;

  pointer=in_framebuffer;

  pcx=in_framebuffer;
  hgr=out_framebuffer;

  for(y=0;y<ysize;y++) {
     for(x=0;x<20;x++) {

       fourteen_bits=0;

       for(i=0;i<14;i++) {
	  fourteen_bits|= ((colors[(*pcx)&0x7]&0x1)<<i);	  
	  pcx++;
       }
       byte1=(fourteen_bits&0x7f)|(0<<7);
       byte2=((fourteen_bits>>7)&0x7f)|(0<<7);

       page=(y%8);
       block=((y/8)%8);
       leaf=(y/64);

       yoffset=(page*1024) + (block*128) + (leaf*40);
       /* 
       printf("%d %d = %x %x %x\n",x,y,fourteen_bits,yoffset,
	      yoffset+(x*2));
       */
       hgr=out_framebuffer+yoffset+(x*2);

       *hgr=byte1;
       *(hgr+1)=byte2;
     }
  }
  return 0;
}

static int make_color_image(unsigned char *in_framebuffer,
			    unsigned char *out_framebuffer,
			    int xsize, int ysize) {

  short fourteen_bits;

  int i,pal[2],yoffset=0;
  int y,x;
  unsigned char byte1,byte2;

  int page,block,leaf;

  unsigned char *pointer;
  unsigned char *pcx,*hgr;

  pointer=in_framebuffer;
#if 0
  for(y=0;y<ysize;y++) {
    for(x=0;x<xsize;x++) {
       printf("%1x",*pointer);
       pointer++;
    }
    printf("\n");
  }
#endif

  pcx=in_framebuffer;
  hgr=out_framebuffer;

  for(y=0;y<ysize;y++) {
     for(x=0;x<20;x++) {

       fourteen_bits=0;
       pal[0]=0; pal[1]=0;

       for(i=0;i<7;i++) {
	  fourteen_bits|= ((colors[(*pcx)&0x7]&0x3)<<(i*2));
	  
	  /* choose which palette */
	  pal[i/4]+= (colors[*pcx]&0x80) - (colors[*pcx]&0x40);

	  pcx++;
       }
       byte1=(fourteen_bits&0x7f)|((pal[0]>0)<<7);
       byte2=((fourteen_bits>>7)&0x7f)|((pal[1]>0)<<7);

       page=(y%8);
       block=((y/8)%8);
       leaf=(y/64);

       yoffset=(page*1024) + (block*128) + (leaf*40);
       /* 
       printf("%d %d = %x %x %x\n",x,y,fourteen_bits,yoffset,
	      yoffset+(x*2));
       */
       hgr=out_framebuffer+yoffset+(x*2);

       *hgr=byte1;
       *(hgr+1)=byte2;
     }
  }
  return 0;
}



int main(int argc, char **argv) {

  int xsize=0,ysize=0,type;
  unsigned char *in_framebuffer;
  unsigned char *out_framebuffer;

  char *filename;

  if (argc<2) {
    fprintf(stderr,"\nUsage: %s PCXFILE\n\n",argv[0]);
    exit(1);
  }

  filename=strdup(argv[1]);


  vmwGetPCXInfo(filename,&xsize,&ysize,&type);

  in_framebuffer=calloc(xsize*ysize,sizeof(unsigned char));
  if (in_framebuffer==NULL) {
     fprintf(stderr,"Error allocating memory!\n");
     return -1;
  }

  vmwLoadPCX(filename,in_framebuffer);

  out_framebuffer=calloc(8192,sizeof(unsigned char));
  if (out_framebuffer==NULL) {
     fprintf(stderr,"Error allocating memory!\n");
     return -1;
  }  

  if ((ysize==160) || (ysize=192)) {
    /* HGR or HGR2 */
  }
  else {
    fprintf(stderr,"Warning, possibly truncating due to ysize: %d\n",ysize);
  }


  if (xsize==140) {
    make_color_image(in_framebuffer,out_framebuffer,xsize,ysize);
  }
  else if (xsize==280) {
    make_bw_image(in_framebuffer,out_framebuffer,xsize,ysize);
  }
  else {
    fprintf(stderr,"Error!  PCX file wrong xsize %d\n",xsize);
  }

  unsigned char header[4];

  
  /* assume HGR page 1 */
  int offset=8192;

  /* Last 8 bytes are ignored anyway; by not saving them we can fit */
  /* in 33 disk sectors rather than 34                              */
  int file_size=8184;

  header[0]=offset&0xff;
  header[1]=(offset>>8)&0xff;
  header[2]=file_size&0xff;
  header[3]=(file_size>>8)&0xff;

  fwrite(header,sizeof(unsigned char),4,stdout);

  /* Don't need the last 8 bytes; makes it fit in one fewer disk sectors */
  fwrite(out_framebuffer,sizeof(unsigned char),8184,stdout);

  free(out_framebuffer);
  free(in_framebuffer);


  return 0;

}