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, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21
  22 /*
  23  * This file is derived from RFC 3492bis written by Adam M. Costello.
  24  *
  25  * Disclaimer and license: Regarding this entire document or any
  26  * portion of it (including the pseudocode and C code), the author
  27  * makes no guarantees and is not responsible for any damage resulting
  28  * from its use.  The author grants irrevocable permission to anyone
  29  * to use, modify, and distribute it in any way that does not diminish
  30  * the rights of anyone else to use, modify, and distribute it,
  31  * provided that redistributed derivative works do not contain
  32  * misleading author or version information.  Derivative works need
  33  * not be licensed under similar terms.
  34  *
  35  * Copyright (C) The Internet Society (2003).  All Rights Reserved.
  36  *
  37  * This document and translations of it may be copied and furnished to
  38  * others, and derivative works that comment on or otherwise explain it
  39  * or assist in its implementation may be prepared, copied, published
  40  * and distributed, in whole or in part, without restriction of any
  41  * kind, provided that the above copyright notice and this paragraph are
  42  * included on all such copies and derivative works.  However, this
  43  * document itself may not be modified in any way, such as by removing
  44  * the copyright notice or references to the Internet Society or other
  45  * Internet organizations, except as needed for the purpose of
  46  * developing Internet standards in which case the procedures for
  47  * copyrights defined in the Internet Standards process must be
  48  * followed, or as required to translate it into languages other than
  49  * English.
  50  *
  51  * The limited permissions granted above are perpetual and will not be
  52  * revoked by the Internet Society or its successors or assigns.
  53  *
  54  * This document and the information contained herein is provided on an
  55  * "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
  56  * TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
  57  * BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
  58  * HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
  59  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  60  */
  61
  62 #ifndef _PUNYCODE_H
  63 #define _PUNYCODE_H
  64
  65 #ifdef __cplusplus
  66 extern "C"
  67 {
  68 #endif
  69
  70 #include <stddef.h>             /* size_t */
  71 #include <stdint.h>             /* uint32_t */
  72
  73   enum punycode_status
  74   {
  75     punycode_success = 0,
  76     punycode_bad_input = 1,     /* Input is invalid.                       */
  77     punycode_big_output = 2,    /* Output would exceed the space provided. */
  78     punycode_overflow = 3       /* Wider integers needed to process input. */
  79   };
  80
  81   typedef enum
  82   {
  83     PUNYCODE_SUCCESS = punycode_success,
  84     PUNYCODE_BAD_INPUT = punycode_bad_input,
  85     PUNYCODE_BIG_OUTPUT = punycode_big_output,
  86     PUNYCODE_OVERFLOW = punycode_overflow
  87   } Punycode_status;
  88
  89 /* punycode_uint needs to be unsigned and needs to be */
  90 /* at least 26 bits wide.                             */
  91
  92   typedef uint32_t punycode_uint;
  93
  94   extern int punycode_encode (size_t input_length,
  95                               const punycode_uint input[],
  96                               const unsigned char case_flags[],
  97                               size_t * output_length, char output[]);
  98
  99 /*
 100     punycode_encode() converts a sequence of code points (presumed to be
 101     Unicode code points) to Punycode.
 102
 103     Input arguments (to be supplied by the caller):
 104
 105         input_length
 106             The number of code points in the input array and the number
 107             of flags in the case_flags array.
 108
 109         input
 110             An array of code points.  They are presumed to be Unicode
 111             code points, but that is not strictly REQUIRED.  The
 112             array contains code points, not code units.  UTF-16 uses
 113             code units D800 through DFFF to refer to code points
 114             10000..10FFFF.  The code points D800..DFFF do not occur in
 115             any valid Unicode string.  The code points that can occur in
 116             Unicode strings (0..D7FF and E000..10FFFF) are also called
 117             Unicode scalar values.
 118
 119         case_flags
 120             A null pointer or an array of boolean values parallel to
 121             the input array.  Nonzero (true, flagged) suggests that the
 122             corresponding Unicode character be forced to uppercase after
 123             being decoded (if possible), and zero (false, unflagged)
 124             suggests that it be forced to lowercase (if possible).
 125             ASCII code points (0..7F) are encoded literally, except that
 126             ASCII letters are forced to uppercase or lowercase according
 127             to the corresponding case flags.  If case_flags is a null
 128             pointer then ASCII letters are left as they are, and other
 129             code points are treated as unflagged.
 130
 131     Output arguments (to be filled in by the function):
 132
 133         output
 134             An array of ASCII code points.  It is *not* null-terminated;
 135             it will contain zeros if and only if the input contains
 136             zeros.  (Of course the caller can leave room for a
 137             terminator and add one if needed.)
 138
 139     Input/output arguments (to be supplied by the caller and overwritten
 140     by the function):
 141
 142         output_length
 143             The caller passes in the maximum number of ASCII code points
 144             that it can receive.  On successful return it will contain
 145             the number of ASCII code points actually output.
 146
 147     Return value:
 148
 149         Can be any of the punycode_status values defined above except
 150         punycode_bad_input.  If not punycode_success, then output_size
 151         and output might contain garbage.
 152 */
 153
 154   extern int punycode_decode (size_t input_length,
 155                               const char input[],
 156                               size_t * output_length,
 157                               punycode_uint output[],
 158                               unsigned char case_flags[]);
 159
 160 /*
 161     punycode_decode() converts Punycode to a sequence of code points
 162     (presumed to be Unicode code points).
 163
 164     Input arguments (to be supplied by the caller):
 165
 166         input_length
 167             The number of ASCII code points in the input array.
 168
 169         input
 170             An array of ASCII code points (0..7F).
 171
 172     Output arguments (to be filled in by the function):
 173
 174         output
 175             An array of code points like the input argument of
 176             punycode_encode() (see above).
 177
 178         case_flags
 179             A null pointer (if the flags are not needed by the caller)
 180             or an array of boolean values parallel to the output array.
 181             Nonzero (true, flagged) suggests that the corresponding
 182             Unicode character be forced to uppercase by the caller (if
 183             possible), and zero (false, unflagged) suggests that it
 184             be forced to lowercase (if possible).  ASCII code points
 185             (0..7F) are output already in the proper case, but their
 186             flags will be set appropriately so that applying the flags
 187             would be harmless.
 188
 189     Input/output arguments (to be supplied by the caller and overwritten
 190     by the function):
 191
 192         output_length
 193             The caller passes in the maximum number of code points
 194             that it can receive into the output array (which is also
 195             the maximum number of flags that it can receive into the
 196             case_flags array, if case_flags is not a null pointer).  On
 197             successful return it will contain the number of code points
 198             actually output (which is also the number of flags actually
 199             output, if case_flags is not a null pointer).  The decoder
 200             will never need to output more code points than the number
 201             of ASCII code points in the input, because of the way the
 202             encoding is defined.  The number of code points output
 203             cannot exceed the maximum possible value of a punycode_uint,
 204             even if the supplied output_length is greater than that.
 205
 206     Return value:
 207
 208         Can be any of the punycode_status values defined above.  If not
 209         punycode_success, then output_length, output, and case_flags
 210         might contain garbage.
 211 */
 212
 213 #ifdef __cplusplus
 214 }
 215 #endif
 216 #endif                          /* _PUNYCODE_H */