Tk Source Code

FileMatchGIF(
    Tcl_Channel chan,		/* The image file, open for reading. */
    const char *fileName,	/* The name of the image file. */
    Tcl_Obj *format,		/* User-specified format object, or NULL. */
    int *widthPtr, int *heightPtr,
				/* The dimensions of the image are returned
				 * here if the file is a valid raw GIF file. */
    TCL_UNUSED(Tcl_Interp *),	/* not used */
{
    GIFImageConfig gifConf;

    memset(&gifConf, 0, sizeof(GIFImageConfig));
    return ReadGIFHeader(&gifConf, chan, widthPtr, heightPtr);
}


		     */

		    *top++ = append[code];
		    code = prefix[code];
		}
		firstCode = append[code];

	        /*
	         * Push the head of the code onto the stack.
	         */

	        *top++ = firstCode;

                if (maxCode < (1 << MAX_LWZ_BITS)) {
		    /*
		     * If there's still room in our codes table, add a new entry.
		     * Otherwise don't, and keep using the current table.
                     * See DEFERRED CLEAR CODE IN LZW COMPRESSION in the GIF89a
                     * specification.
		     */

		    prefix[maxCode] = oldCode;
		    append[maxCode] = firstCode;
		    maxCode++;
                }

		/*
		 * maxCode tells us the maximum code value we can accept. If
		 * we see that we need more bits to represent it than we are
		 * requesting from the unpacker, we need to increase the
		 * number we ask for.
		 */

static int
Mread(
    unsigned char *dst,		/* where to put the result */
    size_t chunkSize,		/* size of each transfer */
    size_t numChunks,		/* number of chunks */
    MFile *handle)		/* mmdecode "file" handle */
{
    int c;
    int i, count = chunkSize * numChunks;

    for (i=0; i<count && (c=Mgetc(handle)) != GIF_DONE; i++) {
	*dst++ = c;
    }
    return i;
}


    if (gifConfPtr->fromData == INLINE_DATA_BASE64) {
	return Mread(dst, hunk, count, (MFile *) chan);
    }

    if (gifConfPtr->fromData == INLINE_DATA_BINARY) {
	MFile *handle = (MFile *) chan;

	if ((handle->length <= 0) || ((size_t)handle->length < hunk*count)) {
	    return -1;
	}
	memcpy(dst, handle->data, hunk * count);
	handle->data += hunk * count;
	handle->length -= hunk * count;
	return hunk * count;
    }