liblbx: Convert lbx_fopen to use the packing routines from libupkg.

[liblbx.git] / src / pack.c

diff --git a/src/pack.c b/src/pack.c
new file mode 100644 (file)
index 0000000..1128a19
--- /dev/null
+++ b/src/pack.c
@@ -0,0 +1,123 @@
+/*
+ *  Portable binary serialisation of integral types.
+ *  Copyright (C) 2009 Nick Bowler
+ *
+ *  Copying and distribution of this file, with or without modification,
+ *  are permitted in any medium without royalty provided the copyright
+ *  notice and this notice are preserved.  This file is offered as-is,
+ *  without any warranty.
+ */
+
+#include "pack.h"
+
+/* Unsigned integer packing. */
+#define DEFPACK_BE(bits, type) void pack_ ## bits ## _be ( \
+       unsigned char *out, type v \
+) { \
+       unsigned i; \
+       for (i = 1; i <= bits/8; i++) { \
+               out[bits/8 - i] = v % 256; \
+               v /= 256; \
+       } \
+}
+
+#define DEFPACK_LE(bits, type) void pack_ ## bits ## _le ( \
+       unsigned char *out, type v \
+) { \
+       unsigned i; \
+       for (i = 0; i < bits/8; i++) { \
+               out[i] = v % 256; \
+               v /= 256; \
+       } \
+}
+
+DEFPACK_BE(16, unsigned short)
+DEFPACK_BE(32, unsigned long)
+#if PACK_HAVE_64BIT
+DEFPACK_BE(64, unsigned long long)
+#endif
+
+DEFPACK_LE(16, unsigned short)
+DEFPACK_LE(32, unsigned long)
+#if PACK_HAVE_64BIT
+DEFPACK_LE(64, unsigned long long)
+#endif
+
+#define DEFUNPACK_BE(bits, type) type unpack_ ## bits ## _be ( \
+       const unsigned char *in \
+) { \
+       type v = 0; \
+       unsigned i; \
+       for (i = 0; i < bits/8; i++) { \
+               v *= 256; \
+               v += in[i]; \
+       } \
+       return v; \
+}
+
+#define DEFUNPACK_LE(bits, type) type unpack_ ## bits ## _le ( \
+       const unsigned char *in \
+) { \
+       type v = 0; \
+       unsigned i; \
+       for (i = 1; i <= bits/8; i++) { \
+               v *= 256; \
+               v += in[bits/8 - i]; \
+       } \
+       return v; \
+}
+
+DEFUNPACK_BE(16, unsigned short)
+DEFUNPACK_BE(32, unsigned long)
+#if PACK_HAVE_64BIT
+DEFUNPACK_BE(64, unsigned long long)
+#endif
+
+DEFUNPACK_LE(16, unsigned short)
+DEFUNPACK_LE(32, unsigned long)
+#if PACK_HAVE_64BIT
+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)
+#if PACK_HAVE_64BIT
+DEFUNPACK_SBE(64, 9223372036854775807ll, long long)
+#endif
+
+DEFUNPACK_SLE(16, 32767, short)
+DEFUNPACK_SLE(32, 2147483647l, long)
+#if PACK_HAVE_64BIT
+DEFUNPACK_SLE(64, 9223372036854775807ll, long long)
+#endif