luci-base: add urldecode() and urlencode() C implementations

[project/luci.git] / modules / luci-base / src / template_utils.c

diff --git a/modules/luci-base/src/template_utils.c b/modules/luci-base/src/template_utils.c
index 6c4baa6..eefdd17 100644 (file)
--- a/modules/luci-base/src/template_utils.c
+++ b/modules/luci-base/src/template_utils.c
@@ -1,7 +1,7 @@
 /*
  * LuCI Template - Utility functions
  *
- *   Copyright (C) 2010 Jo-Philipp Wich <xm@subsignal.org>
+ *   Copyright (C) 2010-2018 Jo-Philipp Wich <jo@mein.io>
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -428,6 +428,128 @@ char * striptags(const char *s, unsigned int l)
        return buf_destroy(buf);
 }
 
+
+static inline bool is_urlencode_char(char c)
+{
+       return !((c >= 'a' && c <= 'z') ||
+                (c >= 'A' && c <= 'Z') ||
+                (c >= '0' && c <= '9') ||
+                (c == '$') || (c == '_') ||
+                (c == '-') || (c == '.') ||
+                (c == '~'));
+}
+
+/*
+ * URL-encode all special characters in given string and return
+ * encoded copy.
+ *
+ * If no encoding was required, returns NULL. If an encoded_len
+ * pointer is passed, it is set to the length of the encoded string.
+ *
+ * Sets encoded_len and returns NULL if memory allocation failed.
+ */
+char *urlencode(const char *s, size_t *encoded_len)
+{
+       size_t i, enc_len;
+       char *enc, *ptr;
+
+       for (i = 0, enc_len = 0; s[i]; i++)
+               if (is_urlencode_char(s[i]))
+                       enc_len += 3;
+               else
+                       enc_len++;
+
+       if (i != enc_len)
+       {
+               if (encoded_len)
+                       *encoded_len = enc_len;
+
+               enc = calloc(1, enc_len + 1);
+
+               if (!enc)
+                       return NULL;
+
+               for (i = 0, ptr = enc; s[i]; i++)
+                       if (is_urlencode_char(s[i]))
+                               ptr += snprintf(ptr, 4, "%%%02x", (unsigned char)s[i]);
+                       else
+                               *ptr++ = s[i];
+
+               return enc;
+       }
+
+       return NULL;
+}
+
+/*
+ * URL-decode given string and return decoded copy.
+ *
+ * If no decoding was required, returns NULL. If an decoded_len
+ * pointer is passed, it is set to the length of the decoded string.
+ *
+ * When keep_plus is true, skip decoding of plus ("+") signs into
+ * space (0x20) characters.
+ *
+ * Sets decoded_len and returns NULL if memory allocation failed.
+ */
+
+#define hex(x) \
+       (((x) <= '9') ? ((x) - '0') : \
+               (((x) <= 'F') ? ((x) - 'A' + 10) : \
+                       ((x) - 'a' + 10)))
+
+char *urldecode(const char *s, size_t *decoded_len, bool keep_plus)
+{
+       bool changed = false;
+       size_t i, dec_len;
+       char *dec, *ptr;
+
+       for (i = 0, dec_len = 0; s[i]; i++, dec_len++)
+       {
+               if (s[i] == '%' && isxdigit(s[i+1]) && isxdigit(s[i+2]))
+               {
+                       changed = true;
+                       i += 2;
+               }
+               else if (!keep_plus && s[i] == '+')
+               {
+                       changed = true;
+               }
+       }
+
+       if (changed)
+       {
+               if (decoded_len)
+                       *decoded_len = dec_len;
+
+               dec = calloc(1, dec_len + 1);
+
+               if (!dec)
+                       return NULL;
+
+               for (i = 0, ptr = dec; s[i]; i++)
+               {
+                       if (s[i] == '%' && isxdigit(s[i+1]) && isxdigit(s[i+2]))
+                       {
+                               *ptr++ = (char)(16 * hex(s[i+1]) + hex(s[i+2]));
+                               i += 2;
+                       }
+                       else if (!keep_plus && s[i] == '+')
+                       {
+                               *ptr++ = ' ';
+                       }
+                       else
+                       {
+                               *ptr++ = s[i];
+                       }
+               }
+
+               return dec;
+       }
+
+       return NULL;
+}
+
 void luastr_escape(struct template_buffer *out, const char *s, unsigned int l,
                                   int escape_xml)
 {