-const char deanimate_rcs[] = "$Id: deanimate.c,v 1.2 2001/07/13 13:46:20 oes Exp $";
/*********************************************************************
*
* File : $Source: /cvsroot/ijbswa/current/deanimate.c,v $
*
- * Purpose : Declares functions to deanimate GIF images on the fly.
- *
- * Functions declared include: gif_deanimate, buf_free,
- * buf_copy, buf_getbyte, gif_skip_data_block, and
- * gif_extract_image
+ * Purpose : Declares functions to manipulate binary images on the
+ * fly. High-level functions include:
+ * - Deanimation of GIF images
*
- * 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) 2001-2021 by the
+ * Privoxy team. https://www.privoxy.org/
*
* Based on the GIF file format specification (see
- * http://tronche.com/computer-graphics/gif/gif89a.html)
+ * https://tronche.com/computer-graphics/gif/gif89a.html)
* and ideas from the Image::DeAnim Perl module by
* Ken MacFarlane, <ksm+cpan@universal.dca.net>
*
- * This program is free software; you can redistribute it
+ * 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 version 2 of the License, or (at
* or write to the Free Software Foundation, Inc., 59
* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
- * Revisions :
- * $Log: deanimate.c,v $
- * Revision 1.2 2001/07/13 13:46:20 oes
- * Introduced GIF deanimation feature
- *
- *
**********************************************************************/
-\f
+
#include "config.h"
#include <fcntl.h>
#include "project.h"
+#include "errlog.h"
#include "deanimate.h"
#include "miscutil.h"
-const char deanimate_h_rcs[] = DEANIMATE_H_VERSION;
-
/*********************************************************************
- *
+ *
* Function : buf_free
*
* Description : Safely frees a struct binbuffer
/*********************************************************************
- *
+ *
+ * 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 1024 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 failure.
+ *
+ *********************************************************************/
+static int buf_extend(struct binbuffer *buf, size_t length)
+{
+ char *newbuf;
+
+ if (buf->offset + length > buf->size)
+ {
+ buf->size = ((buf->size + length + (size_t)1023) & ~(size_t)1023);
+ 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
*
* Description : Safely copies a given amount of bytes from one
* 2 : dst = Pointer to the destination binbuffer
* 3 : length = Number of bytes to be copied
*
- * Returns : 0 on success, 1 on failiure.
+ * Returns : 0 on success, 1 on failure.
*
*********************************************************************/
-int buf_copy(struct binbuffer *src, struct binbuffer *dst, int length)
+static int buf_copy(struct binbuffer *src, struct binbuffer *dst, size_t length)
{
- char *p;
+ /*
+ * Sanity check: Make sure the source buffer contains
+ * data and there's work to be done.
+ */
+ if (src->buffer == NULL || src->size == 0 || length == 0)
+ {
+ return 1;
+ }
/*
* Sanity check: Can't copy more data than we have
*/
- if (src->offset + length > src->size)
+ if (src->offset + length > src->size)
{
return 1;
}
/*
- * 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;
}
/*
/*********************************************************************
- *
+ *
* Function : buf_getbyte
*
* Description : Safely gets a byte from a given binbuffer at a
* given offset
*
* Parameters :
- * 1 : buf = Pointer to the source binbuffer
+ * 1 : src = Pointer to the source binbuffer
* 2 : offset = Offset to the desired byte
*
- * Returns : The byte on success, or 0 on failiure
+ * Returns : The byte on success, or 0 on failure
*
*********************************************************************/
-unsigned char buf_getbyte(struct binbuffer *src, int offset)
+static unsigned char buf_getbyte(const struct binbuffer *src, size_t offset)
{
if (src->offset + offset < src->size)
{
/*********************************************************************
- *
+ *
* Function : gif_skip_data_block
*
* 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 :
* 1 : buf = Pointer to the binbuffer
*
- * Returns : 0 on success, or 1 on failiure
+ * Returns : 0 on success, or 1 on failure
*
*********************************************************************/
-int gif_skip_data_block(struct binbuffer *buf)
+static int gif_skip_data_block(struct binbuffer *buf)
{
unsigned char c;
- /*
+ /*
* Data blocks are sequences of chunks, which are headed
* 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)) != '\0')
{
- if ((buf->offset += c + 1) >= buf->size - 1)
+ buf->offset += (size_t)c + 1;
+ if (buf->offset >= buf->size - 1)
{
return 1;
}
/*********************************************************************
- *
+ *
* Function : gif_extract_image
*
* Description : Safely extracts an image data block from a given
* struct binbuffer that contains a GIF image and whose
- * offset is positioned at the start of a data block
+ * offset is positioned at the start of a data block
* into a given destination binbuffer.
*
* Parameters :
* 1 : src = Pointer to the source binbuffer
* 2 : dst = Pointer to the destination binbuffer
*
- * Returns : 0 on success, or 1 on failiure
+ * Returns : 0 on success, or 1 on failure
*
*********************************************************************/
-int gif_extract_image(struct binbuffer *src, struct binbuffer *dst)
+static int gif_extract_image(struct binbuffer *src, struct binbuffer *dst)
{
unsigned char c;
-
+
/*
* Remember the colormap flag and copy the image head
*/
*/
if (c & 0x80)
{
- if (buf_copy(src, dst, 3 * (1 << ((c & 0x07) + 1))))
+ int map_length = 3 * (1 << ((c & 0x07) + 1));
+ if (map_length <= 0)
{
+ log_error(LOG_LEVEL_DEANIMATE,
+ "colormap length = %d (%c)?", map_length, c);
return 1;
- }
+ }
+ if (buf_copy(src, dst, (size_t)map_length))
+ {
+ return 1;
+ }
}
if (buf_copy(src, dst, 1)) return 1;
/*
* Copy the image chunk by chunk.
*/
- while(c = buf_getbyte(src, 0))
+ while((c = buf_getbyte(src, 0)) != '\0')
{
- if (buf_copy(src, dst, c + 1)) return 1;
+ if (buf_copy(src, dst, 1 + (size_t) c)) return 1;
}
if (buf_copy(src, dst, 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;
}
/*********************************************************************
- *
+ *
* Function : gif_deanimate
*
* Description : Deanimate a given GIF image, i.e. given a GIF with
* an (optional) image block and an arbitrary number
* of image extension blocks, produce an output GIF with
* only one image block that contains the last image
- * (extenstion) block of the original.
- * Also strip Comments, Application extenstions, etc.
+ * (extension) block of the original.
+ * Also strip Comments, Application extensions, etc.
*
* 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
+ * Returns : 0 on success, or 1 on failure
*
*********************************************************************/
-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;
+ int image_buffered = 0;
if (NULL == src || NULL == dst)
{
return 1;
}
+ if (src->size <= 10)
+ {
+ return 1;
+ }
c = buf_getbyte(src, 10);
/*
- * Check & copy GIF header
+ * 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
/*
* Look for global colormap and copy if found.
*/
- if(c & 0x80)
+ if (c & 0x80)
{
- if (buf_copy(src, dst, 3 * (1 << ((c & 0x07) + 1))))
+ int map_length = 3 * (1 << ((c & 0x07) + 1));
+ if (map_length <= 0)
+ {
+ log_error(LOG_LEVEL_DEANIMATE,
+ "colormap length = %d (%c)?", map_length, c);
+ return 1;
+ }
+ if (buf_copy(src, dst, (size_t)map_length))
{
return 1;
}
/*
* Reserve a buffer for the current image block
*/
- if (NULL == (image = (struct binbuffer *)zalloc(sizeof(*image))))
- {
- return 1;
- }
+ image = zalloc_or_die(sizeof(*image));
/*
* Parse the GIF block by block and copy the relevant
* parts to dst
*/
- while(src->offset < src->size)
+ while (src->offset < src->size)
{
- switch(buf_getbyte(src, 0))
+ switch (buf_getbyte(src, 0))
{
/*
- * End-of-GIF Marker: Append current image and return
+ * End-of-GIF Marker: Append current image if we got
+ * one and return.
*/
case 0x3b:
- if (buf_copy(image, dst, image->size) || buf_copy(src, dst, 1))
- {
- goto failed;
- }
- buf_free(image);
- return(0);
+ if (image->size == 0) goto failed;
+ 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))
+ if (image_buffered == 1)
{
- goto failed;
+ /* Discard previous image. */
+ image->offset = 0;
+ image_buffered = 0;
}
+ if (gif_extract_image(src, image)) goto failed;
+ image_buffered = 1;
+ if (get_first_image) goto write;
continue;
/*
switch (buf_getbyte(src, 1))
{
/*
- * Image extension: Copy extension header and image
- * to the current image buffer
+ * Image extension: Copy extension header
+ * and continue looking for new blocks.
*/
case 0xf9:
- 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 (image_buffered == 1)
+ {
+ image->offset = 0;
+ image_buffered = 0;
+ }
+ if (buf_copy(src, image, 8)) goto failed;
continue;
/*
*/
default:
goto failed;
-
+
}
} /* -END- while src */
/*
* Either we got here by goto, or because the GIF is
- * bogus and EOF was reached before an end-of-gif marker
+ * bogus and EOF was reached before an end-of-gif marker
* was found.
*/
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