1 files changed, 109 insertions, 0 deletions
diff --git a/examples/redis-unstable/src/endianconv.c b/examples/redis-unstable/src/endianconv.c
new file mode 100644
index 0000000..12ee03c
--- /dev/null
+++ b/examples/redis-unstable/src/endianconv.c
@@ -0,0 +1,109 @@
+/* endinconv.c -- Endian conversions utilities.
+ *
+ * This functions are never called directly, but always using the macros
+ * defined into endianconv.h, this way we define everything is a non-operation
+ * if the arch is already little endian.
+ *
+ * Redis tries to encode everything as little endian (but a few things that need
+ * to be backward compatible are still in big endian) because most of the
+ * production environments are little endian, and we have a lot of conversions
+ * in a few places because ziplists, intsets, zipmaps, need to be endian-neutral
+ * even in memory, since they are serialized on RDB files directly with a single
+ * write(2) without other additional steps.
+ *
+ * ----------------------------------------------------------------------------
+ *
+ * Copyright (c) 2011-Present, Redis Ltd.
+ * All rights reserved.
+ *
+ * Licensed under your choice of (a) the Redis Source Available License 2.0
+ * (RSALv2); or (b) the Server Side Public License v1 (SSPLv1); or (c) the
+ * GNU Affero General Public License v3 (AGPLv3).
+ */
+
+
+#include <stdint.h>
+
+/* Toggle the 16 bit unsigned integer pointed by *p from little endian to
+ * big endian */
+void memrev16(void *p) {
+    unsigned char *x = p, t;
+
+    t = x[0];
+    x[0] = x[1];
+    x[1] = t;
+}
+
+/* Toggle the 32 bit unsigned integer pointed by *p from little endian to
+ * big endian */
+void memrev32(void *p) {
+    unsigned char *x = p, t;
+
+    t = x[0];
+    x[0] = x[3];
+    x[3] = t;
+    t = x[1];
+    x[1] = x[2];
+    x[2] = t;
+}
+
+/* Toggle the 64 bit unsigned integer pointed by *p from little endian to
+ * big endian */
+void memrev64(void *p) {
+    unsigned char *x = p, t;
+
+    t = x[0];
+    x[0] = x[7];
+    x[7] = t;
+    t = x[1];
+    x[1] = x[6];
+    x[6] = t;
+    t = x[2];
+    x[2] = x[5];
+    x[5] = t;
+    t = x[3];
+    x[3] = x[4];
+    x[4] = t;
+}
+
+uint16_t intrev16(uint16_t v) {
+    memrev16(&v);
+    return v;
+}
+
+uint32_t intrev32(uint32_t v) {
+    memrev32(&v);
+    return v;
+}
+
+uint64_t intrev64(uint64_t v) {
+    memrev64(&v);
+    return v;
+}
+
+#ifdef REDIS_TEST
+#include <stdio.h>
+
+#define UNUSED(x) (void)(x)
+int endianconvTest(int argc, char *argv[], int flags) {
+    char buf[32];
+
+    UNUSED(argc);
+    UNUSED(argv);
+    UNUSED(flags);
+
+    snprintf(buf,sizeof(buf),"ciaoroma");
+    memrev16(buf);
+    printf("%s\n", buf);
+
+    snprintf(buf,sizeof(buf),"ciaoroma");
+    memrev32(buf);
+    printf("%s\n", buf);
+
+    snprintf(buf,sizeof(buf),"ciaoroma");
+    memrev64(buf);
+    printf("%s\n", buf);
+
+    return 0;
+}
+#endif