1 files changed, 137 insertions, 0 deletions
diff --git a/crawl-ref/source/util/pcre/pcre_try_flipped.c b/crawl-ref/source/util/pcre/pcre_try_flipped.c
new file mode 100644
index 0000000000..0d2f3a2d38
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+++ b/crawl-ref/source/util/pcre/pcre_try_flipped.c
@@ -0,0 +1,137 @@
+/*************************************************
+*      Perl-Compatible Regular Expressions       *
+*************************************************/
+
+/* PCRE is a library of functions to support regular expressions whose syntax
+and semantics are as close as possible to those of the Perl 5 language.
+
+                       Written by Philip Hazel
+           Copyright (c) 1997-2008 University of Cambridge
+
+-----------------------------------------------------------------------------
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright notice,
+      this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+    * Neither the name of the University of Cambridge nor the names of its
+      contributors may be used to endorse or promote products derived from
+      this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+-----------------------------------------------------------------------------
+*/
+
+
+/* This module contains an internal function that tests a compiled pattern to
+see if it was compiled with the opposite endianness. If so, it uses an
+auxiliary local function to flip the appropriate bytes. */
+
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "pcre_internal.h"
+
+
+/*************************************************
+*         Flip bytes in an integer               *
+*************************************************/
+
+/* This function is called when the magic number in a regex doesn't match, in
+order to flip its bytes to see if we are dealing with a pattern that was
+compiled on a host of different endianness. If so, this function is used to
+flip other byte values.
+
+Arguments:
+  value        the number to flip
+  n            the number of bytes to flip (assumed to be 2 or 4)
+
+Returns:       the flipped value
+*/
+
+static unsigned long int
+byteflip(unsigned long int value, int n)
+{
+if (n == 2) return ((value & 0x00ff) << 8) | ((value & 0xff00) >> 8);
+return ((value & 0x000000ff) << 24) |
+       ((value & 0x0000ff00) <<  8) |
+       ((value & 0x00ff0000) >>  8) |
+       ((value & 0xff000000) >> 24);
+}
+
+
+
+/*************************************************
+*       Test for a byte-flipped compiled regex   *
+*************************************************/
+
+/* This function is called from pcre_exec(), pcre_dfa_exec(), and also from
+pcre_fullinfo(). Its job is to test whether the regex is byte-flipped - that
+is, it was compiled on a system of opposite endianness. The function is called
+only when the native MAGIC_NUMBER test fails. If the regex is indeed flipped,
+we flip all the relevant values into a different data block, and return it.
+
+Arguments:
+  re               points to the regex
+  study            points to study data, or NULL
+  internal_re      points to a new regex block
+  internal_study   points to a new study block
+
+Returns:           the new block if is is indeed a byte-flipped regex
+                   NULL if it is not
+*/
+
+real_pcre *
+_pcre_try_flipped(const real_pcre *re, real_pcre *internal_re,
+  const pcre_study_data *study, pcre_study_data *internal_study)
+{
+if (byteflip(re->magic_number, sizeof(re->magic_number)) != MAGIC_NUMBER)
+  return NULL;
+
+*internal_re = *re;           /* To copy other fields */
+internal_re->size = byteflip(re->size, sizeof(re->size));
+internal_re->options = byteflip(re->options, sizeof(re->options));
+internal_re->flags = (pcre_uint16)byteflip(re->flags, sizeof(re->flags));
+internal_re->top_bracket =
+  (pcre_uint16)byteflip(re->top_bracket, sizeof(re->top_bracket));
+internal_re->top_backref =
+  (pcre_uint16)byteflip(re->top_backref, sizeof(re->top_backref));
+internal_re->first_byte =
+  (pcre_uint16)byteflip(re->first_byte, sizeof(re->first_byte));
+internal_re->req_byte =
+  (pcre_uint16)byteflip(re->req_byte, sizeof(re->req_byte));
+internal_re->name_table_offset =
+  (pcre_uint16)byteflip(re->name_table_offset, sizeof(re->name_table_offset));
+internal_re->name_entry_size =
+  (pcre_uint16)byteflip(re->name_entry_size, sizeof(re->name_entry_size));
+internal_re->name_count =
+  (pcre_uint16)byteflip(re->name_count, sizeof(re->name_count));
+
+if (study != NULL)
+  {
+  *internal_study = *study;   /* To copy other fields */
+  internal_study->size = byteflip(study->size, sizeof(study->size));
+  internal_study->options = byteflip(study->options, sizeof(study->options));
+  }
+
+return internal_re;
+}
+
+/* End of pcre_tryflipped.c */