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    1 /*************************************************
    2 *      Perl-Compatible Regular Expressions       *
    3 *************************************************/
    4 
    5 /* PCRE is a library of functions to support regular expressions whose syntax
    6 and semantics are as close as possible to those of the Perl 5 language.
    7 
    8                        Written by Philip Hazel
    9            Copyright (c) 1997-2012 University of Cambridge
   10 
   11 -----------------------------------------------------------------------------
   12 Redistribution and use in source and binary forms, with or without
   13 modification, are permitted provided that the following conditions are met:
   14 
   15     * Redistributions of source code must retain the above copyright notice,
   16       this list of conditions and the following disclaimer.
   17 
   18     * Redistributions in binary form must reproduce the above copyright
   19       notice, this list of conditions and the following disclaimer in the
   20       documentation and/or other materials provided with the distribution.
   21 
   22     * Neither the name of the University of Cambridge nor the names of its
   23       contributors may be used to endorse or promote products derived from
   24       this software without specific prior written permission.
   25 
   26 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   27 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   28 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   29 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
   30 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   31 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   32 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   33 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   34 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   35 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   36 POSSIBILITY OF SUCH DAMAGE.
   37 -----------------------------------------------------------------------------
   38 */
   39 
   40 
   41 /* This module contains a function for converting any UTF-32 character
   42 strings to host byte order. */
   43 
   44 
   45 #ifdef HAVE_CONFIG_H
   46 #include "config.h"
   47 #endif
   48 
   49 /* Generate code with 32 bit character support. */
   50 #define COMPILE_PCRE32
   51 
   52 #include "pcre_internal.h"
   53 
   54 #ifdef SUPPORT_UTF
   55 static pcre_uint32
   56 swap_uint32(pcre_uint32 value)
   57 {
   58 return ((value & 0x000000ff) << 24) |
   59        ((value & 0x0000ff00) <<  8) |
   60        ((value & 0x00ff0000) >>  8) |
   61        (value >> 24);
   62 }
   63 #endif
   64 
   65 
   66 /*************************************************
   67 *  Convert any UTF-32 string to host byte order  *
   68 *************************************************/
   69 
   70 /* This function takes an UTF-32 string and converts
   71 it to host byte order. The length can be explicitly set,
   72 or automatically detected for zero terminated strings.
   73 BOMs can be kept or discarded during the conversion.
   74 Conversion can be done in place (output == input).
   75 
   76 Arguments:
   77   output     the output buffer, its size must be greater
   78              or equal than the input string
   79   input      any UTF-32 string
   80   length     the number of 32-bit units in the input string
   81              can be less than zero for zero terminated strings
   82   host_byte_order
   83              A non-zero value means the input is in host byte
   84              order, which can be dynamically changed by BOMs later.
   85              Initially it contains the starting byte order and returns
   86              with the last byte order so it can be used for stream
   87              processing. It can be NULL, which set the host byte
   88              order mode by default.
   89   keep_boms  for a non-zero value, the BOM (0xfeff) characters
   90              are copied as well
   91 
   92 Returns:     the number of 32-bit units placed into the output buffer,
   93              including the zero-terminator
   94 */
   95 
   96 int
   97 pcre32_utf32_to_host_byte_order(PCRE_UCHAR32 *output, PCRE_SPTR32 input,
   98   int length, int *host_byte_order, int keep_boms)
   99 {
  100 #ifdef SUPPORT_UTF
  101 /* This function converts any UTF-32 string to host byte order and optionally
  102 removes any Byte Order Marks (BOMS). Returns with the remainig length. */
  103 int host_bo = host_byte_order != NULL ? *host_byte_order : 1;
  104 pcre_uchar *optr = (pcre_uchar *)output;
  105 const pcre_uchar *iptr = (const pcre_uchar *)input;
  106 const pcre_uchar *end;
  107 /* The c variable must be unsigned. */
  108 register pcre_uchar c;
  109 
  110 if (length < 0)
  111   end = iptr + STRLEN_UC(iptr) + 1;
  112 else
  113   end = iptr + length;
  114 
  115 while (iptr < end)
  116   {
  117   c = *iptr++;
  118   if (c == 0x0000feffu || c == 0xfffe0000u)
  119     {
  120     /* Detecting the byte order of the machine is unnecessary, it is
  121     enough to know that the UTF-32 string has the same byte order or not. */
  122     host_bo = c == 0x0000feffu;
  123     if (keep_boms != 0)
  124       *optr++ = 0x0000feffu;
  125     }
  126   else
  127     *optr++ = host_bo ? c : swap_uint32(c);
  128   }
  129 if (host_byte_order != NULL)
  130   *host_byte_order = host_bo;
  131 
  132 #else /* SUPPORT_UTF */
  133 (void)(output);  /* Keep picky compilers happy */
  134 (void)(input);
  135 (void)(keep_boms);
  136 (void)(host_byte_order);
  137 #endif /* SUPPORT_UTF */
  138 return length;
  139 }
  140 
  141 /* End of pcre32_utf32_utils.c */