Add ctype.h functions to the Luna library

luna/CType.h

@@ -0,0 +1,78 @@
+#pragma once
+
+inline constexpr int _isascii(int c)
+{
+    return !(c & ~0x7f);
+}
+
+inline constexpr int _isblank(int c)
+{
+    return c == ' ' || c == '\t';
+}
+
+inline constexpr int _iscntrl(int c)
+{
+    return (unsigned int)c < 0x20 || c == 0x7f;
+}
+
+inline constexpr int _isdigit(int c)
+{
+    return c >= '0' && c < ':';
+}
+
+inline constexpr int _isgraph(int c)
+{
+    return (unsigned int)c - 0x21 < 0x5e;
+}
+
+inline constexpr int _islower(int c)
+{
+    return c >= 'a' && c < '{';
+}
+
+inline constexpr int _isupper(int c)
+{
+    return c >= 'A' && c < '[';
+}
+
+inline constexpr int _isprint(int c)
+{
+    return (unsigned int)c - 0x20 < 0x5f;
+}
+
+inline constexpr int _isalpha(int c)
+{
+    return _islower(c) || _isupper(c);
+}
+
+inline constexpr int _isalnum(int c)
+{
+    return _isalpha(c) || _isdigit(c);
+}
+
+inline constexpr int _ispunct(int c)
+{
+    return _isgraph(c) && !_isalnum(c);
+}
+
+inline constexpr int _isspace(int c)
+{
+    return c == ' ' || (unsigned int)c - '\t' < 5;
+}
+
+inline constexpr int _isxdigit(int c)
+{
+    return _isdigit(c) || ((unsigned int)c | 32) - 'a' < 6;
+}
+
+inline constexpr int _tolower(int c)
+{
+    if (_isupper(c)) return c | 32;
+    return c;
+}
+
+inline constexpr int _toupper(int c)
+{
+    if (_islower(c)) return c & 0x5f;
+    return c;
+}