// This source file contains the functions needed to read in PCX files.
// (c) 1995 ACK Software (Lary Myers)
#include <stdio.h>
#include <io.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>

//typedef unsigned short USHORT;

#include "ack3d.h"      // Main ACK-3D internal and interface data structures
#include "ackeng.h"     // Internal data structures and constants
#include "ackext.h"     // Defines external (global) variables

typedef struct
{
  char  manufacturer;    // Always set to 0
  char  version;         // Always 5 for 256-color files
  char  encoding;        // Always set to 1
  char  bits_per_pixel;  // Should be 8 for 256-color files
  short xmin,ymin;       // Coordinates for top left corner
  short xmax,ymax;       // Width and height of image
  short hres;            // Horizontal resolution of image
  short vres;            // Vertical resolution of image
  char  palette16[48];   // EGA palette; not used for 256-color files
  char  reserved;        // Reserved for future use
  char  color_planes;    // Color planes
  short bytes_per_line;  // Number of bytes in 1 line of pixels
  short palette_type;    // Should be 2 for color palette
  char  filler[58];      // Reserved
} PcxHeader;

typedef struct
{
    PcxHeader hdr;         // Header information
    UCHAR   *bitmap;       // The bitmap data
    UCHAR   pal[768];      // Color palette for the bitmap data
    unsigned short imagebytes,width,height;   // Size of the bitmap
} PcxFile;

#define PCX_MAX_SIZE 64000L
enum {PCX_OK,PCX_NOMEM,PCX_TOOBIG,PCX_NOFILE};

enum {NORMAL,RLE};
//enum {FALSE,TRUE};

    PcxFile pcxGlobal;       // data structure for reading PCX files

extern unsigned char colordat[];

//=============================================================================
//  This routine loads a 256 color PCX file. The file can be a standalone
// PCX file or it can be combined with a resource. If the data is part
// of a resource, the rshandle flag will be set. The bitmap data is read
// into a buffer that is the size of the bitmap + 4 bytes. The first 4
// bytes in the buffer contain the width and height of the bitmap.
//=============================================================================
unsigned char *AckReadPCX(char *filename)
{
    long i;
    int mode=NORMAL,nbytes;
    char abyte,*p;
    int   handle;
    PcxFile *pcx;

pcx = &pcxGlobal;
// Open the file since no resource is open.
if (!rsHandle)
    {
    handle = open(filename,O_RDONLY|O_BINARY); // Open the file for reading
    if (handle < 1) // Make sure file is opened
        {
        ErrorCode = ERR_BADFILE;
        return NULL;
        }
    }
else // Use the resource instead
    {
    handle = rsHandle; // Use the handle to the resource file
    // Move to the location in the resource where the data is stored
    lseek(handle,rbaTable[(ULONG)filename],SEEK_SET);
    }


read(handle,&pcx->hdr,sizeof(PcxHeader));   // Read in the header data
pcx->width=1+pcx->hdr.xmax-pcx->hdr.xmin;   // Store width and height
pcx->height=1+pcx->hdr.ymax-pcx->hdr.ymin;
// Store number of bytes used for image
pcx->imagebytes=(unsigned int)(pcx->width*pcx->height);

// Make sure bitmap is correct size
if (pcx->imagebytes > PCX_MAX_SIZE)
    {
    if (!rsHandle)
        close(handle);
    ErrorCode = ERR_INVALIDFORM;
    return(NULL);
    }

// Allocate size for bitmap. 4 extra bytes are included to give
// room to store bitmap width and height info.
pcx->bitmap=(char*)AckMalloc(pcx->imagebytes+4);

if (pcx->bitmap == NULL)    // Make sure memory is allocated
    {
    if (!rsHandle)
        close(handle);
    ErrorCode = ERR_NOMEMORY;
    return(NULL);
    }
p=&pcx->bitmap[4];      // Get address of data area

// Loop and read in pixel data for bitmap
// Uses RLE decompression
for (i=0;i<pcx->imagebytes;i++)
    {
    if (mode == NORMAL)     // Normal color read mode
        {
        read(handle,&abyte,1);      // Read in pixel value from file
        if ((unsigned char)abyte > 0xbf) // Value read > 191
            {
            nbytes=abyte & 0x3f;    // Get the RLE counter
            read(handle,&abyte,1);
            if (--nbytes > 0)       // Is counter greater than 1?
                mode=RLE;           // Yes, we're in RLE mode
            }
        }
    else if (--nbytes == 0)         // When counter down to 0
            mode=NORMAL;            // return to color read mode
    *p++=abyte;                     // Store pixel value
    }

// Get palette from PCX file, 256 color palette store 768 bytes from
// end of file. For a resource file we need to find the position where
// the next file starts and then backup 768 bytes
if (rsHandle)
    lseek(handle,rbaTable[(ULONG)(filename + 1)]-768L,SEEK_CUR);
else
    lseek(handle,-768L,SEEK_END);

// Store the palette data in our global colordat array
read(handle,colordat,768);
p=colordat;
for (i=0;i<768;i++)            // bit shift palette
    *p++ = *p >> 2;

if (!rsHandle)                  // Close pcx file if not using a resource
    close(handle);

// Add in bitmap width and height to first 4 bytes of buffer
p = pcx->bitmap;
(*(short *)p) = pcx->width;
p += sizeof(short);
(*(short *)p) = pcx->height;

return(pcx->bitmap);         // return bitmap buffer
}

// **** End of Source ****