Rewrite urldecode in C

2 files changed, 60 insertions, 6 deletions

diff --git a/urldecode.c b/urldecode.c
new file mode 100644
index 0000000..fbd39b3
--- /dev/null
+++ b/urldecode.c
@@ -0,0 +1,60 @@
+/* Copyright (C) 2015 Luke Shumaker <lukeshu@sbcglobal.net> */
+#include <stdio.h>
+
+/* ungetc is only guaranteed for 1 char; use our own buffer */
+int buf[2];
+int cnt = 0;
+int ab = 0;
+int _getchar() {
+	if (cnt > 0)
+		cnt--;
+	else
+		buf[ab] = getchar();
+	int ret = buf[ab];
+	ab = !ab;
+	return ret;
+}
+void _ungetchar() {
+	cnt++;
+	ab = !ab;
+}
+
+int hex(int c) {
+	if ('0' <= c && c <= '9')
+		return c - '0';
+	if ('A' <= c && c <= 'F')
+		return 10 + c - 'A';
+	if ('a' <= c && c <= 'f')
+		return 10 + c - 'a';
+	return -1;
+}
+
+int
+main () {
+	int c, v1, v2;
+	while ((c = _getchar()) != EOF) {
+		switch (c) {
+		case '%':
+			if ((v1 = hex(_getchar())) < 0) {
+				putchar('%');
+				_ungetchar();
+				continue;
+			}
+			if ((v2 = hex(_getchar())) < 0) {
+				putchar('%');
+				_ungetchar();
+				_ungetchar();
+				continue;
+			}
+			putchar(((v1 << 4) & 0xF0) | (v2 & 0x0F));
+			break;
+		case '+':
+			putchar(' ');
+			break;
+		default:
+			putchar(c);
+			break;
+		}
+	}
+	return 0;
+}
diff --git a/urldecode.php b/urldecode.php
deleted file mode 100644
index 5d88b9b..0000000
--- a/urldecode.php
+++ /dev/null
@@ -1,6 +0,0 @@
-#!/usr/bin/php -n
-<?php
-# Copyright (C) 2011, 2014 Luke Shumaker <lukeshu@sbcglobal.net>
-
-$contents = file_get_contents('php://stdin');
-echo urldecode($contents);