endianess conversion API, to be applied to specially encoded data types for arch...

[redis.git] / src / endian.c

diff --git a/src/endian.c b/src/endian.c
new file mode 100644 (file)
index 0000000..aff2425
--- /dev/null
+++ b/src/endian.c
@@ -0,0 +1,63 @@
+/* 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;
+}
+
+#ifdef TESTMAIN
+#include <stdio.h>
+
+int main(void) {
+    char buf[32];
+
+    sprintf(buf,"ciaoroma");
+    memrev16(buf);
+    printf("%s\n", buf);
+
+    sprintf(buf,"ciaoroma");
+    memrev32(buf);
+    printf("%s\n", buf);
+
+    sprintf(buf,"ciaoroma");
+    memrev64(buf);
+    printf("%s\n", buf);
+
+    return 0;
+}
+#endif