exchange

Base system with REST service to issue digital coins, run by the payment service provider
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xml.c (2154B)

      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/platform.h"
     22 #include "taler/taler_util.h"
     23 
     24 
     25 /**
     26  * We allow [a-zA-Z0-9-.:] in extra_wire_subject_metadata.
     27  * Test @a c for it.
     28  *
     29  * @param c character to test
     30  * @return true if OK
     31  */
     32 static inline bool
     33 is_allowed_metachar (char c)
     34 {
     35   return (c >= 'a' && c <= 'z') ||
     36          (c >= 'A' && c <= 'Z') ||
     37          (c >= '0' && c <= '9') ||
     38          c == '-' ||
     39          c == '.' ||
     40          c == ':';
     41 }
     42 
     43 
     44 bool
     45 TALER_is_valid_subject_metadata_string (const char *src)
     46 {
     47   unsigned int len = 0;
     48   if (NULL == src)
     49     return true;
     50 
     51   while (*src)
     52   {
     53     if (! is_allowed_metachar (*src++))
     54       return false;
     55     if (++len > 40)
     56       return false;
     57   }
     58   return true;
     59 }
     60 
     61 
     62 char *
     63 TALER_escape_xml (const char *str)
     64 {
     65   struct GNUNET_Buffer out = { 0 };
     66   const char *p = str;
     67 
     68   while (*p)
     69   {
     70     const char *esc = NULL;
     71 
     72     switch (*p)
     73     {
     74     case '&':
     75       esc = "&amp;";
     76       break;
     77     case '<':
     78       esc = "&lt;";
     79       break;
     80     case '>':
     81       esc = "&gt;";
     82       break;
     83     case '"':
     84       esc = "&quot;";
     85       break;
     86     case '\'':
     87       esc = "&apos;";
     88       break;
     89     }
     90     if (NULL != esc)
     91       GNUNET_buffer_write_str (&out,
     92                                esc);
     93     else
     94       GNUNET_buffer_write (&out,
     95                            p,
     96                            1);
     97     p++;
     98   }
     99   return GNUNET_buffer_reap_str (&out);
    100 }