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-rw-r--r--libc/unistd/swab.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/libc/unistd/swab.c b/libc/unistd/swab.c
new file mode 100644
index 000000000..c63ca7284
--- /dev/null
+++ b/libc/unistd/swab.c
@@ -0,0 +1,18 @@
+#include <unistd.h>
+#include <sys/types.h>
+
+/* swab() swaps the position of two adjacent bytes, every two bytes.
+ * Contributed by Kensuke Otake <kensuke@phreaker.net> */
+
+void swab(const void *source, void *dest, ssize_t count) {
+ const char *from = (const char *)source;
+ char *to = (char *)dest;
+
+ count &= ~((ssize_t)1);
+
+ while (count > 1) {
+ const char b0 = from[--count], b1 = from[--count];
+ to[count] = b0;
+ to[count + 1] = b1;
+ }
+}