libupkg: Add signed integer unpacking to fix incorrect signedness issue.

[upkg.git] / src / pack.c

diff --git a/src/pack.c b/src/pack.c
index 49bacd9911af3794be30ca28a1dccecd4c7f8632..e711de19dcb50722d0f5a3e1362c45f31eff1de0 100644 (file)
--- a/src/pack.c
+++ b/src/pack.c
@@ -1,9 +1,28 @@
+/*
+ *  upkg: tool for manipulating Unreal Tournament packages.
+ *  Copyright (C) 2009 Nick Bowler
+ *
+ *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
 #include <stdio.h>
 #include <limits.h>
 
 #include "pack.h"
 
-/* Integer packing. */
+/* Unsigned integer packing. */
 #define DEFPACK_BE(bits, type) void pack_ ## bits ## _be ( \
        unsigned char *out, type v \
 ) { \
@@ -71,3 +90,48 @@ DEFUNPACK_LE(32, unsigned long)
 #ifdef ULLONG_MAX
 DEFUNPACK_LE(64, unsigned long long)
 #endif
+
+/*
+ * Two's complement signed integer packing.  This is unlikely to work on
+ * systems that don't themselves use two's complement.
+ */
+
+#define DEFUNPACK_SBE(bits, max, type) type unpack_s ## bits ## _be ( \
+       unsigned char *in \
+) { \
+       type v = 0; \
+       unsigned i; \
+       int sign = (in[0] & 0x80) ? 1 : 0; \
+       in[0] &= 0x7f; \
+       for (i = 0; i < bits/8; i++) { \
+               v *= 256; \
+               v += in[i]; \
+       } \
+       return sign*(-max-1) + v; \
+}
+
+#define DEFUNPACK_SLE(bits, max, type) type unpack_s ## bits ## _le ( \
+       unsigned char *in \
+) { \
+       type v = 0; \
+       unsigned i; \
+       int sign = (in[bits/8 - 1] & 0x80) ? 1 : 0; \
+       in[bits/8 - 1] &= 0x7f; \
+       for (i = 1; i <= bits/8; i++) { \
+               v *= 256; \
+               v += in[bits/8 - i]; \
+       } \
+       return sign*(-max-1) + v; \
+}
+
+DEFUNPACK_SBE(16, 32767, short)
+DEFUNPACK_SBE(32, 2147483647l, long)
+#ifdef LLONG_MAX
+DEFUNPACK_SBE(64, 9223372036854775807ll, long long)
+#endif
+
+DEFUNPACK_SLE(16, 32767, short)
+DEFUNPACK_SLE(32, 2147483647l, long)
+#ifdef LLONG_MAX
+DEFUNPACK_SLE(64, 9223372036854775807ll, long long)
+#endif