punycode.h

   1 /* punycode.h   Declarations for punycode functions.
   2  * Copyright (C) 2002, 2003  Simon Josefsson
   3  * Copyright (C) 2002  Adam M. Costello
   4  *
   5  * This file is part of GNU Libidn.
   6  *
   7  * GNU Libidn is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * GNU Libidn is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with GNU Libidn; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  */
  22
  23 /*
  24  * This file is derived from RFC 3492 written by Adam M. Costello.
  25  *
  26  * Disclaimer and license: Regarding this entire document or any
  27  * portion of it (including the pseudocode and C code), the author
  28  * makes no guarantees and is not responsible for any damage resulting
  29  * from its use.  The author grants irrevocable permission to anyone
  30  * to use, modify, and distribute it in any way that does not diminish
  31  * the rights of anyone else to use, modify, and distribute it,
  32  * provided that redistributed derivative works do not contain
  33  * misleading author or version information.  Derivative works need
  34  * not be licensed under similar terms.
  35  *
  36  */
  37
  38 #ifndef _PUNYCODE_H
  39 #define _PUNYCODE_H
  40
  41 #ifdef __cplusplus
  42 extern "C"
  43 {
  44 #endif
  45
  46   enum
  47   {
  48     PUNYCODE_SUCCESS = 0,
  49     PUNYCODE_BAD_INPUT,         /* Input is invalid.                       */
  50     PUNYCODE_BIG_OUTPUT,        /* Output would exceed the space provided. */
  51     PUNYCODE_OVERFLOW           /* Input needs wider integers to process.  */
  52   };
  53
  54   int punycode_encode (size_t input_length,
  55                        const unsigned long input[],
  56                        const unsigned char case_flags[],
  57                        size_t * output_length, char output[]);
  58 \f
  59 /* punycode_encode() converts Unicode to Punycode.  The input     */
  60 /* is represented as an array of Unicode code points (not code    */
  61 /* units; surrogate pairs are not allowed), and the output        */
  62 /* will be represented as an array of ASCII code points.  The     */
  63 /* output string is *not* null-terminated; it will contain        */
  64 /* zeros if and only if the input contains zeros.  (Of course     */
  65 /* the caller can leave room for a terminator and add one if      */
  66 /* needed.)  The input_length is the number of code points in     */
  67 /* the input.  The output_length is an in/out argument: the       */
  68 /* caller passes in the maximum number of code points that it     */
  69 /* can receive, and on successful return it will contain the      */
  70 /* number of code points actually output.  The case_flags array   */
  71 /* holds input_length boolean values, where nonzero suggests that */
  72 /* the corresponding Unicode character be forced to uppercase     */
  73 /* after being decoded (if possible), and zero suggests that      */
  74 /* it be forced to lowercase (if possible).  ASCII code points    */
  75 /* are encoded literally, except that ASCII letters are forced    */
  76 /* to uppercase or lowercase according to the corresponding       */
  77 /* uppercase flags.  If case_flags is a null pointer then ASCII   */
  78 /* letters are left as they are, and other code points are        */
  79 /* treated as if their uppercase flags were zero.  The return     */
  80 /* value can be any of the punycode_status values defined above   */
  81 /* except punycode_bad_input; if not punycode_success, then       */
  82 /* output_size and output might contain garbage.                  */
  83
  84   int punycode_decode (size_t input_length,
  85                        const char input[],
  86                        size_t * output_length,
  87                        unsigned long output[], unsigned char case_flags[]);
  88
  89 /* punycode_decode() converts Punycode to Unicode.  The input is  */
  90 /* represented as an array of ASCII code points, and the output   */
  91 /* will be represented as an array of Unicode code points.  The   */
  92 /* input_length is the number of code points in the input.  The   */
  93 /* output_length is an in/out argument: the caller passes in      */
  94 /* the maximum number of code points that it can receive, and     */
  95 /* on successful return it will contain the actual number of      */
  96 /* code points output.  The case_flags array needs room for at    */
  97 /* least output_length values, or it can be a null pointer if the */
  98 /* case information is not needed.  A nonzero flag suggests that  */
  99 /* the corresponding Unicode character be forced to uppercase     */
 100 /* by the caller (if possible), while zero suggests that it be    */
 101 /* forced to lowercase (if possible).  ASCII code points are      */
 102 /* output already in the proper case, but their flags will be set */
 103 /* appropriately so that applying the flags would be harmless.    */
 104 /* The return value can be any of the punycode_status values      */
 105 /* defined above; if not punycode_success, then output_length,    */
 106 /* output, and case_flags might contain garbage.  On success, the */
 107 /* decoder will never need to write an output_length greater than */
 108 /* input_length, because of how the encoding is defined.          */
 109
 110 #ifdef __cplusplus
 111 }
 112 #endif
 113 #endif                          /* _PUNYCODE_H */