+/**
+ * Byte-swap buffer 16-bit.
+ *
+ * Len must be even, dst and src must be either the same or non-overlapping.
+ *
+ * @param dst Destination buffer.
+ * @param src Source buffer.
+ * @param len Length of source (and destination) buffer, in bytes.
+ */
+static inline void buf_bswap16(uint8_t *dst, const uint8_t *src, size_t len)
+{
+ assert(len % 2 == 0);
+ assert(dst == src || dst + len <= src || src + len <= dst);
+
+ for (size_t n = 0; n < len; n += 2) {
+ uint16_t x = be_to_h_u16(src + n);
+ h_u16_to_le(dst + n, x);
+ }
+}
+
+/**
+ * Byte-swap buffer 32-bit.
+ *
+ * Len must be divisible by four, dst and src must be either the same or non-overlapping.
+ *
+ * @param dst Destination buffer.
+ * @param src Source buffer.
+ * @param len Length of source (and destination) buffer, in bytes.
+ */
+static inline void buf_bswap32(uint8_t *dst, const uint8_t *src, size_t len)
+{
+ assert(len % 4 == 0);
+ assert(dst == src || dst + len <= src || src + len <= dst);
+
+ for (size_t n = 0; n < len; n += 4) {
+ uint32_t x = be_to_h_u32(src + n);
+ h_u32_to_le(dst + n, x);
+ }
+}
+
+/**
+ * Calculate the (even) parity of a 32-bit datum.
+ * @param x The datum.
+ * @return 1 if the number of set bits in x is odd, 0 if it is even.
+ */
+static inline int parity_u32(uint32_t x)
+{
+#ifdef __GNUC__
+ return __builtin_parityl(x);
+#else
+ x ^= x >> 16;
+ x ^= x >> 8;
+ x ^= x >> 4;
+ x ^= x >> 2;
+ x ^= x >> 1;
+ return x & 1;
+#endif
+}
+
+#if defined(__ECOS)
+
+/* eCos plain lacks these definition... A series of upstream patches
+ * could probably repair it, but it seems like too much work to be
+ * worth it.
+ */
+
+#if !defined(_STDINT_H)
+#define PRId32 "d"
+#define PRIi32 "i"
+#define PRIo32 "o"
+#define PRIu32 "u"
+#define PRIx32 "x"
+#define PRIX32 "X"
+#define SCNx32 "x"
+#define PRId8 PRId32
+#define SCNx64 "llx"
+#define PRId64 "lld"
+#define PRIi64 "lli"
+#define PRIo64 "llo"
+#define PRIu64 "llu"
+#define PRIx64 "llx"
+#define PRIX64 "llX"