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/*\
* $Id: bmp.h,v 1.3 1992/11/24 19:39:56 dws Exp dws $
*
* bmp.h - routines to calculate sizes of parts of BMP files
*
* Some fields in BMP files contain offsets to other parts
* of the file. These routines allow us to calculate these
* offsets, so that we can read and write BMP files without
* the need to fseek().
*
* Copyright (C) 1992 by David W. Sanderson.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose and without fee is hereby granted,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. This software is provided "as is"
* without express or implied warranty.
*
* $Log: bmp.h,v $
* Revision 1.3 1992/11/24 19:39:56 dws
* Added copyright.
*
* Revision 1.2 1992/11/17 02:13:37 dws
* Adjusted a string's name.
*
* Revision 1.1 1992/11/16 19:54:44 dws
* Initial revision
*
\*/
#ifndef _BMP_H_
#define _BMP_H_
#include "pbmplus.h"
/* prototypes */
static unsigned long BMPlenfileheader ARGS((int class));
static unsigned long BMPleninfoheader ARGS((int class));
static unsigned long BMPlenrgbtable ARGS((int class, unsigned long bitcount));
static unsigned long BMPlenline ARGS((int class, unsigned long bitcount, unsigned long x));
static unsigned long BMPlenbits ARGS((int class, unsigned long bitcount, unsigned long x, unsigned long y));
static unsigned long BMPlenfile ARGS((int class, unsigned long bitcount, unsigned long x, unsigned long y));
static unsigned long BMPoffbits ARGS((int class, unsigned long bitcount));
/*
* Classes of BMP files
*/
#define C_WIN 1
#define C_OS2 2
static char er_internal[] = "%s: internal error!";
static unsigned long
BMPlenfileheader(class)
int class;
{
switch (class)
{
case C_WIN:
return 14;
case C_OS2:
return 14;
default:
pm_error(er_internal, "BMPlenfileheader");
return 0;
}
}
static unsigned long
BMPleninfoheader(class)
int class;
{
switch (class)
{
case C_WIN:
return 40;
case C_OS2:
return 12;
default:
pm_error(er_internal, "BMPleninfoheader");
return 0;
}
}
static unsigned long
BMPlenrgbtable(class, bitcount)
int class;
unsigned long bitcount;
{
unsigned long lenrgb;
if (bitcount < 1)
{
pm_error(er_internal, "BMPlenrgbtable");
return 0;
}
switch (class)
{
case C_WIN:
lenrgb = 4;
break;
case C_OS2:
lenrgb = 3;
break;
default:
pm_error(er_internal, "BMPlenrgbtable");
return 0;
}
return (1 << bitcount) * lenrgb;
}
/*
* length, in bytes, of a line of the image
*
* Evidently each row is padded on the right as needed to make it a
* multiple of 4 bytes long. This appears to be true of both
* OS/2 and Windows BMP files.
*/
static unsigned long
BMPlenline(class, bitcount, x)
int class;
unsigned long bitcount;
unsigned long x;
{
unsigned long bitsperline;
switch (class)
{
case C_WIN:
break;
case C_OS2:
break;
default:
pm_error(er_internal, "BMPlenline");
return 0;
}
bitsperline = x * bitcount;
/*
* if bitsperline is not a multiple of 32, then round
* bitsperline up to the next multiple of 32.
*/
if ((bitsperline % 32) != 0)
{
bitsperline += (32 - (bitsperline % 32));
}
if ((bitsperline % 32) != 0)
{
pm_error(er_internal, "BMPlenline");
return 0;
}
/* number of bytes per line == bitsperline/8 */
return bitsperline >> 3;
}
/* return the number of bytes used to store the image bits */
static unsigned long
BMPlenbits(class, bitcount, x, y)
int class;
unsigned long bitcount;
unsigned long x;
unsigned long y;
{
return y * BMPlenline(class, bitcount, x);
}
/* return the offset to the BMP image bits */
static unsigned long
BMPoffbits(class, bitcount)
int class;
unsigned long bitcount;
{
return BMPlenfileheader(class)
+ BMPleninfoheader(class)
+ BMPlenrgbtable(class, bitcount);
}
/* return the size of the BMP file in bytes */
static unsigned long
BMPlenfile(class, bitcount, x, y)
int class;
unsigned long bitcount;
unsigned long x;
unsigned long y;
{
return BMPoffbits(class, bitcount)
+ BMPlenbits(class, bitcount, x, y);
}
#endif /* _BMP_H_ */
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