1 files changed, 29 insertions, 0 deletions
diff --git a/src/ctype.h b/src/ctype.h
new file mode 100644
index 0000000..98b2283
--- /dev/null
+++ b/src/ctype.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * Specialized constant-time ctype.h reimplementations that aren't locale-specific.
+ */
+
+#ifndef CTYPE_H
+#define CTYPE_H
+
+#include <stdbool.h>
+
+static inline bool char_is_space(int c)
+{
+	unsigned char d = c - 9;
+	return (0x80001FU >> (d & 31)) & (1U >> (d >> 5));
+}
+
+static inline bool char_is_digit(int c)
+{
+	return (unsigned int)(('0' - 1 - c) & (c - ('9' + 1))) >> (sizeof(c) * 8 - 1);
+}
+
+static inline bool char_is_alpha(int c)
+{
+	return (unsigned int)(('a' - 1 - (c | 32)) & ((c | 32) - ('z' + 1))) >> (sizeof(c) * 8 - 1);
+}
+
+#endif