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-rw-r--r--dviware/catdvi/bytesex.c135
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diff --git a/dviware/catdvi/bytesex.c b/dviware/catdvi/bytesex.c
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+/* catdvi - get text from DVI files
+ Copyright (C) 1999 J.H.M. Dassen (Ray) <jdassen@wi.LeidenUniv.nl>
+ Copyright (C) 1999 Antti-Juhani Kaijanaho <gaia@iki.fi>
+
+ 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 your option) any later 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include <assert.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <string.h>
+#include "bytesex.h"
+#include "util.h"
+
+#define SKIPBYTES_BUFLEN 128
+
+void efread(void *ptr, size_t size, size_t nmemb,
+ FILE *stream, char *errmsg)
+{
+ if (fread(ptr, size, nmemb, stream) != nmemb) {
+ if (feof(stream)) {
+ panic("Unexpected end of file\n");
+ } else {
+ panic("%s\n", strerror(errno));
+ }
+ panic(errmsg);
+ }
+}
+
+byte readbyte(FILE * stream)
+{
+ byte b;
+
+ efread(&b, 1, 1, stream, "Failed to read byte\n");
+
+ return b;
+}
+
+/* A portable reader for unsigned muli-octet big-endian numbers. */
+uint32 u_readbigendiannumber(byte count, FILE *stream)
+{
+ uint32 ures = 0;
+ int i;
+ unsigned char buf[4];
+
+ assert(count <= 4);
+
+ efread(buf, count, 1, stream, "Failed to read big endian number.\n");
+ /* We want to read one chunk of count bytes, not count chunks
+ * of one byte.
+ */
+ for (i = 0; i < count; i++) {
+ ures = (ures << 8) + buf[i];
+ }
+
+ return ures;
+}
+
+/* An extremely portable reader for signed (two's complement)
+ muli-octet big-endian numbers. */
+sint32 s_readbigendiannumber(byte count, FILE *stream)
+{
+ uint32 ures;
+ const uint32 msb_bitmask = ((uint32) 1) << (8 * count - 1);
+ /* Beware of overflow! 2 * msb_bitmask may be too much for
+ uint32. */
+ const uint32 allset_bitmask = msb_bitmask + (msb_bitmask - 1);
+
+ assert(count <= 4);
+
+ /* First read the octets, taking care of the bytesex. */
+ ures = u_readbigendiannumber(count, stream);
+
+ assert(ures <= allset_bitmask);
+
+ /* We need to handle the sign conversion ourselves, as a
+ simple cast is implementation-defined. The value in ures
+ is in two's complement format. */
+
+ if (ures >= msb_bitmask) {
+ /* It is negative. */
+ return - (sint32) (ures ^ allset_bitmask) - 1;
+ }
+ else {
+ /* Positive (or 0). */
+ return ures;
+ }
+}
+
+void readbcblstring(byte * buffer, uint32 slen, FILE * fp)
+{
+ uint32 len;
+
+ len = u_readbigendiannumber(1, fp);
+
+ if (len > slen - 1) {
+ warning("invalid BCBL string length");
+ len = 0;
+ }
+
+ if (len > 0) {
+ efread(buffer, 1, len, fp, "unable to read BCBL string");
+ }
+ buffer[len] = 0;
+
+ skipbytes(slen - len - 1, fp);
+}
+
+void skipbytes(int count, FILE *stream)
+{
+ byte buf[SKIPBYTES_BUFLEN];
+
+ while (count > 0) {
+ int numbytes = count > SKIPBYTES_BUFLEN
+ ? SKIPBYTES_BUFLEN
+ : count;
+ count = count - SKIPBYTES_BUFLEN;
+ efread(buf, 1, numbytes, stream,
+ "Error while skipping bytes\n");
+ }
+}
+