libidn/punycode.h

   1 /* punycode.h   Declarations for punycode functions.
   2  * Copyright (C) 2002, 2003  Simon Josefsson
   3  *
   4  * This file is part of GNU Libidn.
   5  *
   6  * GNU Libidn is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * GNU Libidn is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with GNU Libidn; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 /*
  21  * This file is derived from RFC 3492bis written by Adam M. Costello.
  22  *
  23  * Disclaimer and license: Regarding this entire document or any
  24  * portion of it (including the pseudocode and C code), the author
  25  * makes no guarantees and is not responsible for any damage resulting
  26  * from its use.  The author grants irrevocable permission to anyone
  27  * to use, modify, and distribute it in any way that does not diminish
  28  * the rights of anyone else to use, modify, and distribute it,
  29  * provided that redistributed derivative works do not contain
  30  * misleading author or version information.  Derivative works need
  31  * not be licensed under similar terms.
  32  *
  33  * Copyright (C) The Internet Society (2003).  All Rights Reserved.
  34  *
  35  * This document and translations of it may be copied and furnished to
  36  * others, and derivative works that comment on or otherwise explain it
  37  * or assist in its implementation may be prepared, copied, published
  38  * and distributed, in whole or in part, without restriction of any
  39  * kind, provided that the above copyright notice and this paragraph are
  40  * included on all such copies and derivative works.  However, this
  41  * document itself may not be modified in any way, such as by removing
  42  * the copyright notice or references to the Internet Society or other
  43  * Internet organizations, except as needed for the purpose of
  44  * developing Internet standards in which case the procedures for
  45  * copyrights defined in the Internet Standards process must be
  46  * followed, or as required to translate it into languages other than
  47  * English.
  48  *
  49  * The limited permissions granted above are perpetual and will not be
  50  * revoked by the Internet Society or its successors or assigns.
  51  *
  52  * This document and the information contained herein is provided on an
  53  * "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
  54  * TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
  55  * BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
  56  * HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
  57  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  58  */
  59
  60 #ifndef _PUNYCODE_H
  61 #define _PUNYCODE_H
  62
  63 #ifdef __cplusplus
  64 extern "C"
  65 {
  66 #endif
  67
  68 #include <stddef.h>             /* size_t */
  69 #include <stdint.h>             /* uint32_t */
  70
  71   enum punycode_status
  72   {
  73     punycode_success = 0,
  74     punycode_bad_input = 1,     /* Input is invalid.                       */
  75     punycode_big_output = 2,    /* Output would exceed the space provided. */
  76     punycode_overflow = 3       /* Wider integers needed to process input. */
  77   };
  78
  79   typedef enum
  80   {
  81     PUNYCODE_SUCCESS = punycode_success,
  82     PUNYCODE_BAD_INPUT = punycode_bad_input,
  83     PUNYCODE_BIG_OUTPUT = punycode_big_output,
  84     PUNYCODE_OVERFLOW = punycode_overflow
  85   } Punycode_status;
  86
  87 /* punycode_uint needs to be unsigned and needs to be */
  88 /* at least 26 bits wide.                             */
  89
  90   typedef uint32_t punycode_uint;
  91
  92   extern int punycode_encode (size_t input_length,
  93                               const punycode_uint input[],
  94                               const unsigned char case_flags[],
  95                               size_t * output_length, char output[]);
  96
  97 /*
  98     punycode_encode() converts a sequence of code points (presumed to be
  99     Unicode code points) to Punycode.
 100
 101     Input arguments (to be supplied by the caller):
 102
 103         input_length
 104             The number of code points in the input array and the number
 105             of flags in the case_flags array.
 106
 107         input
 108             An array of code points.  They are presumed to be Unicode
 109             code points, but that is not strictly REQUIRED.  The
 110             array contains code points, not code units.  UTF-16 uses
 111             code units D800 through DFFF to refer to code points
 112             10000..10FFFF.  The code points D800..DFFF do not occur in
 113             any valid Unicode string.  The code points that can occur in
 114             Unicode strings (0..D7FF and E000..10FFFF) are also called
 115             Unicode scalar values.
 116
 117         case_flags
 118             A null pointer or an array of boolean values parallel to
 119             the input array.  Nonzero (true, flagged) suggests that the
 120             corresponding Unicode character be forced to uppercase after
 121             being decoded (if possible), and zero (false, unflagged)
 122             suggests that it be forced to lowercase (if possible).
 123             ASCII code points (0..7F) are encoded literally, except that
 124             ASCII letters are forced to uppercase or lowercase according
 125             to the corresponding case flags.  If case_flags is a null
 126             pointer then ASCII letters are left as they are, and other
 127             code points are treated as unflagged.
 128
 129     Output arguments (to be filled in by the function):
 130
 131         output
 132             An array of ASCII code points.  It is *not* null-terminated;
 133             it will contain zeros if and only if the input contains
 134             zeros.  (Of course the caller can leave room for a
 135             terminator and add one if needed.)
 136
 137     Input/output arguments (to be supplied by the caller and overwritten
 138     by the function):
 139
 140         output_length
 141             The caller passes in the maximum number of ASCII code points
 142             that it can receive.  On successful return it will contain
 143             the number of ASCII code points actually output.
 144
 145     Return value:
 146
 147         Can be any of the punycode_status values defined above except
 148         punycode_bad_input.  If not punycode_success, then output_size
 149         and output might contain garbage.
 150 */
 151
 152   extern int punycode_decode (size_t input_length,
 153                               const char input[],
 154                               size_t * output_length,
 155                               punycode_uint output[],
 156                               unsigned char case_flags[]);
 157
 158 /*
 159     punycode_decode() converts Punycode to a sequence of code points
 160     (presumed to be Unicode code points).
 161
 162     Input arguments (to be supplied by the caller):
 163
 164         input_length
 165             The number of ASCII code points in the input array.
 166
 167         input
 168             An array of ASCII code points (0..7F).
 169
 170     Output arguments (to be filled in by the function):
 171
 172         output
 173             An array of code points like the input argument of
 174             punycode_encode() (see above).
 175
 176         case_flags
 177             A null pointer (if the flags are not needed by the caller)
 178             or an array of boolean values parallel to the output array.
 179             Nonzero (true, flagged) suggests that the corresponding
 180             Unicode character be forced to uppercase by the caller (if
 181             possible), and zero (false, unflagged) suggests that it
 182             be forced to lowercase (if possible).  ASCII code points
 183             (0..7F) are output already in the proper case, but their
 184             flags will be set appropriately so that applying the flags
 185             would be harmless.
 186
 187     Input/output arguments (to be supplied by the caller and overwritten
 188     by the function):
 189
 190         output_length
 191             The caller passes in the maximum number of code points
 192             that it can receive into the output array (which is also
 193             the maximum number of flags that it can receive into the
 194             case_flags array, if case_flags is not a null pointer).  On
 195             successful return it will contain the number of code points
 196             actually output (which is also the number of flags actually
 197             output, if case_flags is not a null pointer).  The decoder
 198             will never need to output more code points than the number
 199             of ASCII code points in the input, because of the way the
 200             encoding is defined.  The number of code points output
 201             cannot exceed the maximum possible value of a punycode_uint,
 202             even if the supplied output_length is greater than that.
 203
 204     Return value:
 205
 206         Can be any of the punycode_status values defined above.  If not
 207         punycode_success, then output_length, output, and case_flags
 208         might contain garbage.
 209 */
 210
 211 #ifdef __cplusplus
 212 }
 213 #endif
 214 #endif                          /* _PUNYCODE_H */