1 files changed, 53 insertions, 0 deletions
diff --git a/debug/hex2bin.c b/debug/hex2bin.c
new file mode 100644
index 0000000..7324624
--- /dev/null
+++ b/debug/hex2bin.c
@@ -0,0 +1,53 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       hex2bin.c
+/// \brief      Converts hexadecimal input strings to binary
+//
+//  Author:     Lasse Collin
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "sysdefs.h"
+#include <stdio.h>
+#include <ctype.h>
+
+
+static int
+getbin(int x)
+{
+	if (x >= '0' && x <= '9')
+		return x - '0';
+
+	if (x >= 'A' && x <= 'F')
+		return x - 'A' + 10;
+
+	return x - 'a' + 10;
+}
+
+
+int
+main(void)
+{
+	while (true) {
+		int byte = getchar();
+		if (byte == EOF)
+			return 0;
+		if (!isxdigit(byte))
+			continue;
+
+		const int digit = getchar();
+		if (digit == EOF || !isxdigit(digit)) {
+			fprintf(stderr, "Invalid input\n");
+			return 1;
+		}
+
+		byte = (getbin(byte) << 4) | getbin(digit);
+		if (putchar(byte) == EOF) {
+			perror(NULL);
+			return 1;
+		}
+	}
+}