std/string: add strchr(), strrchr(), and strchrnul()

CMakeLists.txt

@@ -52,6 +52,7 @@ set(SOURCES_COMMON
   src/std/memset.s
   src/std/print.c
   src/std/string.c
+  src/std/string-ext.c
   src/tmu/inth-etmu.s
   src/tmu/inth-tmu.s
   src/tmu/sleep.c

include/gint/std/string.h

@@ -31,4 +31,13 @@ char *strcat(char *dest, const char *src);
 /* strcmp(): Compare NUL-terminated strings */
 int strcmp(char const *s1, char const *s2);
 
+/* strchr(): Find the first occurrence of a character in a string */
+char *strchr(char const *s, int c);
+
+/* strrchr(): Find the last occurrence of a character in a string */
+char *strrchr(char const *s, int c);
+
+/* strchrnul(): Like strchr(), but returns end-of-string instead of NUL */
+char *strchrnul(char const *s, int c);
+
 #endif /* GINT_STD_STRING */

src/std/string-ext.c

@@ -0,0 +1,12 @@
+//---
+//	gint:std:string-ext: Extensions to the standard for <string.h>
+//---
+
+#include <gint/defs/attributes.h>
+#include <gint/std/string.h>
+
+GWEAK char *strchrnul(char const *s, int c)
+{
+	while(*s && *s != c) s++;
+	return (char *)s;
+}

src/std/string.c

@@ -4,6 +4,7 @@
 
 #include <gint/defs/types.h>
 #include <gint/defs/attributes.h>
+#include <gint/std/string.h>
 #include <stdarg.h>
 
 GWEAK size_t strlen(char const *str)
@@ -33,3 +34,20 @@ GWEAK int strcmp(char const *s1, char const *s2)
 	while(*s1 && *s1 == *s2) s1++, s2++;
 	return *s1 - *s2;
 }
+
+GWEAK char *strchr(char const *s, int c)
+{
+	while(*s && *s != c) s++;
+	return (*s) ? (char *)s : NULL;
+}
+
+GWEAK char *strrchr(char const *s, int c)
+{
+	char const *found = NULL;
+	while(*s)
+	{
+		if(*s == c) found = s;
+		s++;
+	}
+	return (char *)found;
+}