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/* NSBitmapImageRep+PNM
Methods for reading PNM images
Copyright (C) 2003 Free Software Foundation, Inc.
Written by: Adam Fedor <fedor@gnu.org>
Date: Oct 2003
This file is part of the GNUstep GUI Library.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
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 GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; see the file COPYING.LIB.
If not, see <http://www.gnu.org/licenses/> or write to the
Free Software Foundation, 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#import <Foundation/NSData.h>
#import <Foundation/NSString.h>
#import "AppKit/NSGraphics.h"
#import "NSBitmapImageRep+PNM.h"
@implementation NSBitmapImageRep (PNM)
/* Return YES if this is a pgm or ppm file (raw only for now) */
+ (BOOL) _bitmapIsPNM: (NSData *)imageData
{
const char *bytes = [imageData bytes];
/*
3/4 bytes header line, 4/5 bytes size, 2/3 bytes depth. Thus, the image
must have a least 9 bytes.
*/
if ([imageData length]<9)
return NO;
if (bytes[0] == 'P' && (bytes[2]=='\n' || bytes[2]=='\r'))
{
if (bytes[1] == '5' || bytes[1] == '6')
return YES;
}
return NO;
}
#define GET_LINE() \
do \
{ \
char *p = buffer; \
while (*ptr != '\n' && *ptr != '\r' && (ptr-bytes) < length) \
{ \
*p++ = *ptr++; \
if (p == &buffer[sizeof(buffer)]) \
{ \
ERRMSG(@"PNM header line too long"); \
} \
} \
ptr++; \
*p = '\0'; \
} while (0)
#define ERRMSG(msg) \
do { NSLog(@"Error loading PNM: %@", msg); if (error) *error = msg; RELEASE(self); return nil; } while (0)
/* Read the ppm image. Assume it is a ppm file and imageData is not nil */
-(id) _initBitmapFromPNM: (NSData *)imageData errorMessage: (NSString **)error
{
int num, xsize, ysize, levels;
char ptype;
char buffer[256];
unsigned char *pchar;
unsigned length;
id colorspace;
const char *ptr;
const char *bytes = [imageData bytes];
/* magic number */
ptr = bytes;
length = [imageData length];
GET_LINE();
if (bytes[0] != 'P')
ERRMSG(@"Invalid PNM header (magic number)");
ptype = bytes[1];
if (ptype != '5' && ptype != '6')
ERRMSG(@"Unsupported PNM type");
do
{
GET_LINE();
} while (buffer[0] == '#');
num = sscanf(buffer, "%d %d", &xsize, &ysize);
if (num != 2 || xsize <= 0 || ysize <= 0)
ERRMSG(@"Invalid PNM header (xsize/ysize)");
if (xsize * ysize > (1 << 31))
ERRMSG(@"Invalid PNM header (image size:xsize*ysize too large)");
GET_LINE();
num = sscanf(buffer, "%d", &levels);
if (num != 1)
ERRMSG(@"Invalid PNM header (levels)");
colorspace = (ptype == '5') ? NSDeviceBlackColorSpace : NSDeviceRGBColorSpace;
self = [self initWithBitmapDataPlanes: NULL
pixelsWide: xsize
pixelsHigh: ysize
bitsPerSample: 8
samplesPerPixel: (ptype == '5') ? 1 : 3
hasAlpha: NO
isPlanar: NO
colorSpaceName: colorspace
bytesPerRow: 0
bitsPerPixel: 0];
if ([self bytesPerRow] * ysize > (length - (ptr - bytes)))
ERRMSG(@"Invalid PNM file (short data)");
pchar = [self bitmapData];
if (levels < 256)
{
memcpy(pchar, ptr, [self bytesPerRow] * ysize);
}
else
{
ERRMSG(@"Cannot handle > 256 level PNM files");
}
return self;
}
@end
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