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/* atlc - arbitrary transmission line calculator, for the analysis of
transmission lines are directional couplers.
Copyright (C) 2002. Dr. David Kirkby, PhD (G8WRB).
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either package_version 2
of the License, or (at your option) any later package_version.
This program 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
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.
Dr. David Kirkby, e-mail drkirkby at gmail.com
*/
#include "config.h"
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include "definitions.h"
#include "exit_codes.h"
unsigned char *bmp_buff;
/* We make the bitmap header public, as we write it back
later, when saving bmp files. It saves a lot of hassle,
just writing what we read back, rather than correctly
calculating all the data in the header correctly */
#define BITMAP_HEADER_SIZE 0x36 /* 54 */
void read_bitmap_file_headers(char *filename, int *offset, size_t *size, int *width, int *height)
{
FILE *fp;
struct Bitmap_File_Head_Struct Bitmap_File_Head;
struct Bitmap_Head_Struct Bitmap_Head;
int ColormapSize, Maps;
int length_of_file; /* Appently Photoshop versions < 7.01
don't write this into Bitmap_Head.biSizeIm
so it causes a problem. So we will work out
the length by seeking to the end of the file
and finding the position of the file
pointer */
bmp_buff=ustring(0,BITMAP_HEADER_SIZE);
if(strcmp(filename,"-")==0)
{
fp=stdin;
}
else
fp=fopen(filename,"rb");
if(fp==NULL)
{
fprintf(stderr,"cannot open %s\n", filename);
exit_with_msg_and_exit_code("",CANT_OPEN_FILE_FOR_READING);
}
/* deternine the length of the file, as its not always
written into the bitmap. I thought it needed to be, but
apparently it does not and photoshop versions < 7.01
don't do it. */
if( fseek(fp, 0, SEEK_END) == -1)
{
fprintf(stderr," Can't seek to the end of the file in read_bitmap_file_headers.c\n");
exit(FSEEK_FAILURE);
}
if( (length_of_file=ftell(fp)) == -1)
exit_with_msg_and_exit_code("Can't find length of file in read_bitmap_file_headers.c",FTELL_FAILURE);
if( (fseek(fp, 0, SEEK_SET) ) == -1)
{
fprintf(stderr," Can't seek to the beggining of the file in read_bitmap_file_headers.c\n");
exit(FSEEK_FAILURE);
}
/* Read the .bmp file header into a bmp_buff */
if (!(fread(bmp_buff, 1,BITMAP_HEADER_SIZE,fp))||(strncmp((char *) bmp_buff,"BM",2)))
{
fprintf(stderr,"%s is not a valid BMP file\n", filename);
exit_with_msg_and_exit_code("",NOT_A_VALID_BITMAP_FILE);
}
/* On most machines, sizeof(short)==2 and sizeof(int)==4. This is so no matter
if the machine is 32 or 64 bis. An exception is the Cray Y-MP, which has
sizeof(short)=8
sizeof(int)=8
sizeof(long)=8.
In this case, it is much more difficult to write the header for the bitmap. But in
the aid of portability, this is done. So these is a section of code that will work
even if sizeof(short)=8 and sizeof(int)=8. See below for that. */
/* Read the bmp_buff into the two structures we want */
Bitmap_File_Head.zzMagic[0x0] = bmp_buff[0];
Bitmap_File_Head.zzMagic[0x1] = bmp_buff[1];
Bitmap_File_Head.bfSize = bmp_buff[0x2] + ((bmp_buff[3] + ((bmp_buff[4] + (bmp_buff[5] << 8)) << 8)) <<8);
Bitmap_File_Head.zzHotX = bmp_buff[0x6] + (bmp_buff[7] << 8);
Bitmap_File_Head.zzHotY = bmp_buff[0x8] + (bmp_buff[0x09] << 8);
Bitmap_File_Head.bfOffs = bmp_buff[0x0a] + ((bmp_buff[0xb] + ((bmp_buff[0xc] + (bmp_buff[0x0d] << 8)) << 8)) <<8);
Bitmap_File_Head.biSize = bmp_buff[0x0E] + ((bmp_buff[0x0f] + ((bmp_buff[0x10] + (bmp_buff[0x11] << 8)) << 8)) <<8);
Bitmap_Head.biWidth=bmp_buff[0x12] + ((bmp_buff[0x13] + ((bmp_buff[0x14] + (bmp_buff[0x15] << 8)) << 8)) <<8);
Bitmap_Head.biHeight=bmp_buff[0x16] + ((bmp_buff[0x17] + ((bmp_buff[0x18] + (bmp_buff[0x19] << 8)) << 8)) <<8);
Bitmap_Head.biPlanes = bmp_buff[0x1A] + (bmp_buff[0x1b] << 8);
Bitmap_Head.biBitCnt = bmp_buff[0x1C] + (bmp_buff[0x1d] << 8);
Bitmap_Head.biCompr= bmp_buff[0x1E] + ((bmp_buff[0x1f] + ((bmp_buff[0x20] + (bmp_buff[0x21] << 8)) << 8)) <<8);
Bitmap_Head.biSizeIm=bmp_buff[0x22] + ((bmp_buff[0x23] + ((bmp_buff[0x24] + (bmp_buff[0x25] << 8)) << 8)) <<8);
/* I thought the length of the image was always stored in Bitmap_Head.biSizeIm, but
this appears not to be so. Hence it is now calculated from the length of the file
*/
Bitmap_Head.biSizeIm=length_of_file-BITMAP_HEADER_SIZE;
Bitmap_Head.biXPels = bmp_buff[0x26] + ((bmp_buff[0x27] + ((bmp_buff[0x28] + (bmp_buff[0x29] << 8)) << 8)) <<8);
Bitmap_Head.biYPels= bmp_buff[0x2A] + ((bmp_buff[0x2b] + ((bmp_buff[0x2c] + (bmp_buff[0x2d] << 8)) << 8)) <<8);
Bitmap_Head.biClrUsed = bmp_buff[0x2E] + ((bmp_buff[0x2f] + ((bmp_buff[0x30] + (bmp_buff[0x31] << 8)) << 8)) <<8);
Bitmap_Head.biClrImp = bmp_buff[0x32] + ((bmp_buff[0x33] + ((bmp_buff[0x34] + (bmp_buff[0x35] << 8)) << 8)) <<8);
Maps=4;
if(Bitmap_Head.biBitCnt!=24)
{
fprintf(stderr,"Sorry, the .bmp bitmap must have 24 bits per colour,\n");
fprintf(stderr,"but it has %d bits. Resave the \n",Bitmap_Head.biBitCnt);
fprintf(stderr,"image using 24-bit colour\n");
exit_with_msg_and_exit_code("mage using 24-bit colour",BITMAP_NOT_24_BIT);
}
ColormapSize = (Bitmap_File_Head.bfOffs - Bitmap_File_Head.biSize - 14) / Maps;
if ((Bitmap_Head.biClrUsed == 0) && (Bitmap_Head.biBitCnt <= 8))
Bitmap_Head.biClrUsed = ColormapSize;
/* Sanity checks */
if (Bitmap_Head.biHeight == 0 || Bitmap_Head.biWidth == 0)
{
fprintf(stderr,"error reading BMP file header of %s - width or height is zero\n",filename);
exit_with_msg_and_exit_code("",WIDTH_OR_HEIGHT_ZERO_IN_BITMAP);
}
if (Bitmap_Head.biPlanes != 1)
{
fprintf(stderr,"error reading BMP file header of %s - bitplanes not equal to 1\n",filename);
exit_with_msg_and_exit_code("",BITPLANES_NOT_1_IN_BITMAP);
}
if (ColormapSize > 256 || Bitmap_Head.biClrUsed > 256)
{
fprintf(stderr,"error reading BMP file header of %s - colourmap size error\n",filename);
exit_with_msg_and_exit_code("",COLOURMAP_GREATER_THAN_256);
}
/* Windows and OS/2 declare filler so that rows are a multiple of
word length (32 bits == 4 bytes)
*/
fclose(fp);
*width=Bitmap_Head.biWidth;
*height=Bitmap_Head.biHeight;
*offset=Bitmap_File_Head.bfOffs;
*size=Bitmap_Head.biSizeIm;
if( *size < 3 * (*width) * (*height) )
{
fprintf(stderr,"Internal error in read_bitmap_file_headers.c\n");
exit(1);
}
}
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