#include "pack.h"
-/* Integer packing. */
+/* Unsigned integer packing. */
#define DEFPACK_BE(bits, type) void pack_ ## bits ## _be ( \
unsigned char *out, type v \
) { \
#endif
#define DEFUNPACK_BE(bits, type) type unpack_ ## bits ## _be ( \
- unsigned char *in \
+ const unsigned char *in \
) { \
type v = 0; \
unsigned i; \
}
#define DEFUNPACK_LE(bits, type) type unpack_ ## bits ## _le ( \
- unsigned char *in \
+ const unsigned char *in \
) { \
type v = 0; \
unsigned i; \
#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 ( \
+ const unsigned char *in \
+) { \
+ type v = 0; \
+ unsigned i; \
+ int sign = (in[0] & 0x80) ? 1 : 0; \
+ for (i = 0; i < bits/8; i++) { \
+ v *= 256; \
+ v += in[i] & (i == 0 ? 0x7f : 0xff); \
+ } \
+ return sign*(-max-1) + v; \
+}
+
+#define DEFUNPACK_SLE(bits, max, type) type unpack_s ## bits ## _le ( \
+ const unsigned char *in \
+) { \
+ type v = 0; \
+ unsigned i; \
+ int sign = (in[bits/8 - 1] & 0x80) ? 1 : 0; \
+ for (i = 1; i <= bits/8; i++) { \
+ v *= 256; \
+ v += in[bits/8 - i] & (i == 1 ? 0x7f : 0xff); \
+ } \
+ 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