separating: there will be libk and libc

libk/string.c

@@ -0,0 +1,134 @@
+// String operations implementation for blankos/libk
+// Author: xamidev
+// Licensed under the Unlicense. See the repo below.
+// https://github.com/xamidev/blankos
+
+#include <stdint.h>
+#include "../kernel/system.h"
+
+int strlen(const char* str)
+{
+  int len = 0;
+  while (*str++)
+  {
+    len++;
+  }
+  return len;
+}
+
+int strcmp(const char* str1, const char* str2)
+{
+  while (*str1 && (*str1 == *str2))
+  {
+    str1++;
+    str2++;
+  }
+  return *(const unsigned char*)str1 - *(const unsigned char*)str2;
+}
+
+char* strchr(const char* str, int c)
+{
+	while (*str)
+	{
+		if (*str == (char)c)
+		{
+			return (char*)str;
+		}
+		str++;
+	}
+	if (c == '\0')
+	{
+		return (char*)str;
+	}
+	return NULL;
+}
+
+char* strtok(char* str, const char* delimiter)
+{
+	static char* last;
+	if (str)
+	{
+		last = str;
+	} else {
+		str = last;
+	}
+
+	if (!str || *str == '\0')
+	{
+		return NULL;
+	}
+
+	char* token_start = str;
+	while (*str && !strchr(delimiter, *str))
+	{
+		str++;
+	}
+
+	if (*str)
+	{
+		*str = '\0';
+		last = str + 1;
+	} else {
+		last = NULL;
+	}
+
+	return token_start;
+}
+
+int atoi(char* str)
+{
+	int result = 0;
+
+	for (int i=0; str[i] != '\0'; i++)
+	{
+		result = result*10 + str[i] - '0';
+	}
+
+	return result;
+}
+
+void strcat(char* dest, const char* src)
+{
+	while (*dest)
+	{
+		dest++;
+	}
+
+	while (*src)
+	{
+		*dest = *src;
+		dest++;
+		src++;
+	}
+
+	*dest = '\0';
+}
+
+size_t strnlen(const char* str, size_t max_len)
+{
+	size_t len = 0;
+	while (*str && len < max_len)
+	{
+		len++;
+		str++;
+	}
+	return len;
+}
+
+void strncat(char* dest, const char* src, size_t n)
+{
+	while (*dest)
+	{
+		dest++;
+	}
+
+	while (*src && n > 0)
+	{
+		*dest = *src;
+		dest++;
+		src++;
+		n--;
+	}
+
+	*dest = '\0';
+}