libc: Add strings.h

libs/libc/include/string.h

@@ -80,9 +80,6 @@ extern "C"
     /* Returns the error string associated with the error number err. */
     char* strerror(int err);
 
-    /* Clears n bytes of buf. */
-    void* bzero(void* buf, size_t n);
-
     /* Copies the string src into dest. This function is unsafe, use strlcpy instead. */
     __lc_deprecated("strcpy is unsafe and should not be used; use strlcpy instead") char* strcpy(char* dest,
                                                                                                  const char* src);

libs/libc/include/strings.h

@@ -0,0 +1,27 @@
+#ifndef _STRINGS_H
+#define _STRINGS_H
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    /* Clears n bytes of buf. */
+    void bzero(void* buf, size_t n);
+
+    /* Copies n bytes of src into dest. */
+    void bcopy(void* dest, const void* src, size_t n);
+
+    /* Compares strings a and b while treating uppercase and lowercase characters as the same. */
+    int strcasecmp(const char* a, const char* b);
+
+    /* Compares at most max bytes of strings a and b while treating uppercase and lowercase characters as the same. */
+    int strncasecmp(const char* a, const char* b, size_t max);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libs/libc/src/string.cpp

@@ -230,11 +230,6 @@ extern "C"
         return NULL;
     }
 
-    void* bzero(void* buf, size_t n)
-    {
-        return memset(buf, 0, n);
-    }
-
     char* strstr(const char* haystack, const char* needle)
     {
         size_t needle_size = strlen(needle);

libs/libc/src/strings.cpp

@@ -0,0 +1,43 @@
+#include <ctype.h>
+#include <string.h>
+#include <strings.h>
+
+static char fold(char c)
+{
+    if (isalpha(c)) return tolower(c);
+    return c;
+}
+
+extern "C"
+{
+    void bzero(void* buf, size_t n)
+    {
+        memset(buf, 0, n);
+    }
+
+    void bcopy(void* dest, const void* src, size_t n)
+    {
+        memcpy(dest, src, n);
+    }
+
+    int strcasecmp(const char* a, const char* b)
+    {
+        while (*a && (fold(*a) == fold(*b)))
+        {
+            a++;
+            b++;
+        }
+        return (unsigned char)fold(*a) - (unsigned char)fold(*b);
+    }
+
+    int strncasecmp(const char* a, const char* b, size_t max)
+    {
+        const char* base = a;
+        while (*a && (fold(*a) == fold(*b)) && (size_t)(a - base) < (max - 1))
+        {
+            a++;
+            b++;
+        }
+        return (unsigned char)fold(*a) - (unsigned char)fold(*b);
+    }
+}