1 files changed, 23 insertions, 0 deletions
diff --git a/src/string/strchr.c b/src/string/strchr.c
new file mode 100644
index 0000000..e606f4f
--- /dev/null
+++ b/src/string/strchr.c
@@ -0,0 +1,23 @@
+#include <string.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <limits.h>
+
+#define ALIGN (sizeof(size_t)-1)
+#define ONES ((size_t)-1/UCHAR_MAX)
+#define HIGHS (ONES * (UCHAR_MAX/2+1))
+#define HASZERO(x) ((x)-ONES & ~(x) & HIGHS)
+
+char *strchr(const char *s, int c)
+{
+	c = (char)c;
+	if (!c) return (char *)s + strlen(s);
+	for (; ((uintptr_t)s & ALIGN) && *s && *s != c; s++);
+	if (*s && *s != c) {
+		const size_t *w;
+		size_t k = ONES * c;
+		for (w = (const void *)s; !HASZERO(*w) && !HASZERO(*w^k); w++);
+		for (s = (const void *)w; *s && *s != c; s++);
+	}
+	return *s ? (char *)s : 0;
+}