--- /dev/null
+/**
+ * @file ntlibc.c
+ * @author Shinichiro Nakamura
+ * @brief NT-Shellで用いる小規模libcの実装。
+ */
+
+/*
+ * ===============================================================
+ * Natural Tiny Shell (NT-Shell)
+ * Version 0.0.8
+ * ===============================================================
+ * Copyright (c) 2010-2011 Shinichiro Nakamura
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ * ===============================================================
+ */
+
+#include "ntlibc.h"
+
+int ntlibc_strlen(const char *s)
+{
+ const char *p = s;
+ int cnt = 0;
+ while (*p) {
+ cnt++;
+ p++;
+ }
+ return cnt;
+}
+
+char *ntlibc_strcpy(char *des, const char *src)
+{
+ char *d = des;
+ const char *s = src;
+ while (*s) {
+ *d = *s;
+ d++;
+ s++;
+ }
+ *d = '\0';
+ return des;
+}
+
+char *ntlibc_strcat(char *des, const char *src)
+{
+ char *d = des;
+ const char *s = src;
+ while (*d) {
+ d++;
+ }
+ while (*s) {
+ *d = *s;
+ d++;
+ s++;
+ }
+ *d = '\0';
+ return des;
+}
+
+int ntlibc_strcmp(const char *s1, const char *s2)
+{
+ char *p1 = (char *)s1;
+ char *p2 = (char *)s2;
+ while (*p1 || *p2) {
+ if (*p1 != *p2) {
+ return (*p1 < *p2) ? -1 : 1;
+ }
+ p1++;
+ p2++;
+ }
+ if (*p1 == *p2) {
+ return 0;
+ } else {
+ return (*p1 < *p2) ? -1 : 1;
+ }
+}
+
+int ntlibc_strncmp(const char *s1, const char *s2, int n)
+{
+ char *p1 = (char *)s1;
+ char *p2 = (char *)s2;
+ int len = 0;
+ while (*p1 || *p2) {
+ if (n <= len) {
+ break;
+ }
+ if (*p1 != *p2) {
+ return (*p1 < *p2) ? -1 : 1;
+ }
+ p1++;
+ p2++;
+ len++;
+ }
+ return 0;
+}
+