exchange

Base system with REST service to issue digital coins, run by the payment service provider
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xml.c (2126B)

      1 /*
      2   This file is part of TALER
      3   Copyright (C) 2026 Taler Systems SA
      4 
      5   TALER is free software; you can redistribute it and/or modify it under the
      6   terms of the GNU General Public License as published by the Free Software
      7   Foundation; either version 3, or (at your option) any later version.
      8 
      9   TALER is distributed in the hope that it will be useful, but WITHOUT ANY
     10   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
     11   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
     12 
     13   You should have received a copy of the GNU General Public License along with
     14   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
     15 */
     16 /**
     17  * @file xml.c
     18  * @brief Common utility functions for XML handling
     19  * @author Christian Grothoff
     20  */
     21 #include "taler/taler_util.h"
     22 
     23 
     24 /**
     25  * We allow [a-zA-Z0-9-.:] in extra_wire_subject_metadata.
     26  * Test @a c for it.
     27  *
     28  * @param c character to test
     29  * @return true if OK
     30  */
     31 static inline bool
     32 is_allowed_metachar (char c)
     33 {
     34   return (c >= 'a' && c <= 'z') ||
     35          (c >= 'A' && c <= 'Z') ||
     36          (c >= '0' && c <= '9') ||
     37          c == '-' ||
     38          c == '.' ||
     39          c == ':';
     40 }
     41 
     42 
     43 bool
     44 TALER_is_valid_subject_metadata_string (const char *src)
     45 {
     46   unsigned int len = 0;
     47   if (NULL == src)
     48     return true;
     49 
     50   while (*src)
     51   {
     52     if (! is_allowed_metachar (*src++))
     53       return false;
     54     if (++len > 40)
     55       return false;
     56   }
     57   return true;
     58 }
     59 
     60 
     61 char *
     62 TALER_escape_xml (const char *str)
     63 {
     64   struct GNUNET_Buffer out = { 0 };
     65   const char *p = str;
     66 
     67   while (*p)
     68   {
     69     const char *esc = NULL;
     70 
     71     switch (*p)
     72     {
     73     case '&':
     74       esc = "&amp;";
     75       break;
     76     case '<':
     77       esc = "&lt;";
     78       break;
     79     case '>':
     80       esc = "&gt;";
     81       break;
     82     case '"':
     83       esc = "&quot;";
     84       break;
     85     case '\'':
     86       esc = "&apos;";
     87       break;
     88     }
     89     if (NULL != esc)
     90       GNUNET_buffer_write_str (&out,
     91                                esc);
     92     else
     93       GNUNET_buffer_write (&out,
     94                            p,
     95                            1);
     96     p++;
     97   }
     98   return GNUNET_buffer_reap_str (&out);
     99 }