-const char deanimate_rcs[] = "$Id: $";
+const char deanimate_rcs[] = "$Id: deanimate.c,v 1.4 2001/07/18 12:28:49 oes Exp $";
/*********************************************************************
*
- * File : $Source: $
+ * File : $Source: /cvsroot/ijbswa/current/deanimate.c,v $
*
* Purpose : Declares functions to deanimate GIF images on the fly.
*
* buf_copy, buf_getbyte, gif_skip_data_block, and
* gif_extract_image
*
- * Copyright : Written by and Copyright (C) 2001 Andreas S. Oesterhelt
- * for the SourceForge IJBSWA team. http://ijbswa.sourceforge.net
+ * Copyright : Written by and Copyright (C) 2001 by the the SourceForge
+ * IJBSWA team. http://ijbswa.sourceforge.net
*
* Based on the GIF file format specification (see
* http://tronche.com/computer-graphics/gif/gif89a.html)
* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Revisions :
- * $Log: $
+ * $Log: deanimate.c,v $
+ * Revision 1.4 2001/07/18 12:28:49 oes
+ * - Added feature for extracting the first frame
+ * to gif_deanimate
+ * - Separated image buffer extension into buf_extend
+ * - Extended gif deanimation to GIF87a (untested!)
+ * - Cosmetics
+ *
+ * Revision 1.3 2001/07/15 13:57:50 jongfoster
+ * Adding #includes string.h and miscutil.h
+ *
+ * Revision 1.2 2001/07/13 13:46:20 oes
+ * Introduced GIF deanimation feature
+ *
*
**********************************************************************/
\f
#include "config.h"
-#include "project.h"
-#include "deanimate.h"
+#include <string.h>
#include <fcntl.h>
+#include "project.h"
+#include "deanimate.h"
+#include "miscutil.h"
+
const char deanimate_h_rcs[] = DEANIMATE_H_VERSION;
/*********************************************************************
}
+/*********************************************************************
+ *
+ * Function : buf_extend
+ *
+ * Description : Ensure that a given binbuffer can hold a given amount
+ * of bytes, by reallocating its buffer if necessary.
+ * Allocate new mem in chunks of 1000 bytes, so we don't
+ * have to realloc() too often.
+ *
+ * Parameters :
+ * 1 : buf = Pointer to the binbuffer
+ * 2 : length = Desired minimum size
+ *
+ *
+ * Returns : 0 on success, 1 on failiure.
+ *
+ *********************************************************************/
+int buf_extend(struct binbuffer *buf, int length)
+{
+ char *newbuf;
+
+ if (buf->offset + length > buf->size)
+ {
+ buf->size = buf->size + length + 1000 - (buf->size + length) % 1000;
+ newbuf = (char *)realloc(buf->buffer, buf->size);
+
+ if (newbuf == NULL)
+ {
+ freez(buf->buffer);
+ return 1;
+ }
+ else
+ {
+ buf->buffer = newbuf;
+ return 0;
+ }
+ }
+ return 0;
+
+}
+
+
/*********************************************************************
*
* Function : buf_copy
*********************************************************************/
int buf_copy(struct binbuffer *src, struct binbuffer *dst, int length)
{
- char *p;
/*
* Sanity check: Can't copy more data than we have
}
/*
- * If dst can't hold the new data, get mem first. (In chunks
- * of 1000 bytes, so we don't have to realloc() too often)
+ * Ensure that dst can hold the new data
*/
- if (dst->offset + length > dst->size)
+ if (buf_extend(dst, length))
{
- dst->size = dst->size + length + 1000 - (dst->size + length) % 1000;
- p = dst->buffer;
- dst->buffer = (char *)realloc(dst->buffer, dst->size);
-
- if (dst->buffer == NULL)
- {
- free(p);
- return 1;
- }
+ return 1;
}
/*
*
* Description : Safely advances the offset of a given struct binbuffer
* that contains a GIF image and whose offset is
- * positioned at the start of a data block behind
+ * positioned at the start of a data block, behind
* that block.
*
* Parameters :
* by a one-byte length field, with the last chunk having
* zero length.
*/
- while(c = buf_getbyte(buf, 0))
+ while((c = buf_getbyte(buf, 0)))
{
if ((buf->offset += c + 1) >= buf->size - 1)
{
/*
* Copy the image chunk by chunk.
*/
- while(c = buf_getbyte(src, 0))
+ while((c = buf_getbyte(src, 0)))
{
if (buf_copy(src, dst, c + 1)) return 1;
}
/*
* Trim and rewind the dst buffer
*/
- dst->buffer = (char *)realloc(dst->buffer, dst->offset);
+ if (NULL == (dst->buffer = (char *)realloc(dst->buffer, dst->offset))) return 1;
dst->size = dst->offset;
dst->offset = 0;
* Parameters :
* 1 : src = Pointer to the source binbuffer
* 2 : dst = Pointer to the destination binbuffer
+ * 3 : get_first_image = Flag: If set, get the first image
+ * If unset (default), get the last
*
* Returns : 0 on success, or 1 on failiure
*
*********************************************************************/
-int gif_deanimate(struct binbuffer *src, struct binbuffer *dst)
+int gif_deanimate(struct binbuffer *src, struct binbuffer *dst, int get_first_image)
{
unsigned char c;
struct binbuffer *image;
/*
* Check & copy GIF header
*/
- if (strncmp(src->buffer, "GIF89a", 6))
+ if (strncmp(src->buffer, "GIF89a", 6) && strncmp(src->buffer, "GIF87a", 6))
{
- fprintf(stderr, "This is not a GIF98a!\n");
return 1;
}
else
* End-of-GIF Marker: Append current image and return
*/
case 0x3b:
- if (buf_copy(image, dst, image->size) || buf_copy(src, dst, 1))
- {
- goto failed;
- }
- buf_free(image);
- return(0);
+ goto write;
/*
- * Image block: Extract to current image buffer
+ * Image block: Extract to current image buffer.
*/
case 0x2c:
image->offset = 0;
- if (gif_extract_image(src, image))
- {
- goto failed;
- }
+ if (gif_extract_image(src, image)) goto failed;
+ if (get_first_image) goto write;
continue;
/*
image->offset = 0;
if (buf_copy(src, image, 8) || buf_getbyte(src, 0) != 0x2c) goto failed;
if (gif_extract_image(src, image)) goto failed;
+ if (get_first_image) goto write;
continue;
/*
buf_free(image);
return 1;
+ /*
+ * Append the current image to dst and return
+ */
+
+write:
+ if (buf_copy(image, dst, image->size)) goto failed;
+ if (buf_extend(dst, 1)) goto failed;
+ *(dst->buffer + dst->offset++) = 0x3b;
+ buf_free(image);
+ return 0;
+
}
projects / privoxy.git / blobdiff