dev(sell): add simple libc and implement shell

please see the log for detail.

1 files changed, 26 insertions, 0 deletions

diff --git a/include/ulib/ctypes.h b/include/ulib/ctypes.h
new file mode 100644
index 0000000..3e0bc22
--- /dev/null
+++ b/include/ulib/ctypes.h
@@ -0,0 +1,26 @@
+#ifndef _CTYPE_H
+#define _CTYPE_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    static inline int isdigit(int c) { return c >= '0' && c <= '9'; }
+    static inline int islower(int c) { return c >= 'a' && c <= 'z'; }
+    static inline int isupper(int c) { return c >= 'A' && c <= 'Z'; }
+    static inline int isalpha(int c) { return islower(c) || isupper(c); }
+    static inline int isalnum(int c) { return isalpha(c) || isdigit(c); }
+    static inline int isspace(int c) { return c == ' ' || c == '\t' || c == '\n' || c == '\v' || c == '\f' || c == '\r'; }
+    static inline int isprint(int c) { return c >= 32 && c <= 126; }
+    static inline int iscntrl(int c) { return c < 32 || c == 127; }
+    static inline int isxdigit(int c) { return isdigit(c) || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F'); }
+
+    static inline int tolower(int c) { return isupper(c) ? c + 32 : c; }
+    static inline int toupper(int c) { return islower(c) ? c - 32 : c; }
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
\ No newline at end of file