1 files changed, 66 insertions, 0 deletions
diff --git a/src/endian.h b/src/endian.h
new file mode 100644
index 0000000..2a63b4b
--- /dev/null
+++ b/src/endian.h
@@ -0,0 +1,66 @@
+#pragma once
+/**********************************************************************
+* Endianess Independent Byte Extraction
+***********************************************************************/
+/* prne_getmsbN(x, n)
+*
+* Extract nth most significant byte of x.
+*/
+#define prne_getmsb(x, n, w, s)\
+	(uint8_t)(((w)(x) & (w)0xFF << (s - 8 * (n))) >> (s - 8 * (n)))
+#define prne_getmsb64(x, n) prne_getmsb((x), (n), uint_fast64_t, 56)
+#define prne_getmsb32(x, n) prne_getmsb((x), (n), uint_fast32_t, 24)
+#define prne_getmsb16(x, n) prne_getmsb((x), (n), uint_fast16_t, 8)
+
+/* prne_recmb_msbN(...)
+*
+* Recombine bytes in big-endian order to uintN.
+*/
+#define prne_recmb_msb64(a, b, c, d, e, f, g, h) (\
+	((uint_fast64_t)(a) << 56) |\
+	((uint_fast64_t)(b) << 48) |\
+	((uint_fast64_t)(c) << 40) |\
+	((uint_fast64_t)(d) << 32) |\
+	((uint_fast64_t)(e) << 24) |\
+	((uint_fast64_t)(f) << 16) |\
+	((uint_fast64_t)(g) << 8) |\
+	((uint_fast64_t)(h) << 0)\
+)
+#define prne_recmb_msb32(a, b, c, d) (\
+	((uint_fast32_t)(a) << 24) |\
+	((uint_fast32_t)(b) << 16) |\
+	((uint_fast32_t)(c) << 8) |\
+	((uint_fast32_t)(d) << 0)\
+)
+#define prne_recmb_msb16(a, b) (\
+	((uint_fast16_t)(a) << 8) |\
+	((uint_fast16_t)(b) << 0)\
+)
+
+/* Machine Characteristics
+*/
+#define PRNE_ENDIAN_LITTLE 1
+#define PRNE_ENDIAN_BIG 2
+
+#ifdef __GNUC__
+	#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+		#define PRNE_HOST_ENDIAN PRNE_ENDIAN_BIG
+	#elif __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+		#define PRNE_HOST_ENDIAN PRNE_ENDIAN_LITTLE
+	#else
+		#error "FIXME!"
+	#endif
+#else
+	#error "FIXME!"
+#endif
+
+#define prne_einv16(x) (((0xFF00 & x) >> 8) | ((0x00FF & x) << 8))
+
+#if PRNE_HOST_ENDIAN == PRNE_ENDIAN_BIG
+#define prne_htobe16(x) (x)
+#define prne_be16toh(x) (x)
+#elif PRNE_HOST_ENDIAN == PRNE_ENDIAN_LITTLE
+#define prne_htobe16(x) prne_einv16(x)
+#define prne_be16toh(x) prne_einv16(x)
+#else
+#endif