Added utility functions for regular expression matching with the PCRE2 library.

server/core/maxscale_pcre2.c

@@ -0,0 +1,139 @@
+/*
+ * This file is distributed as part of the MariaDB Corporation MaxScale. It is free
+ * software: you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation,
+ * version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright MariaDB Corporation Ab 2015
+ *
+ */
+
+/**
+ * @file maxscale_pcre2.c - Utility functions for regular expression matching
+ * with the bundled PCRE2 library.
+ *
+ * @verbatim
+ * Revision History
+ *
+ * Date       Who           Description
+ * 30-10-2015 Markus Makela Initial implementation
+ * @endverbatim
+ */
+
+#include <maxscale_pcre2.h>
+
+/**
+ * Utility wrapper for PCRE2 library function call pcre2_substitute.
+ *
+ * This function replaces all occurences of a pattern with the provided replacement
+ * and places the end result into @c dest. This buffer must be allocated by the caller.
+ * If the size of @c dest is not large enough it will be reallocated to a larger size.
+ * The size of @c dest is stored in @c size if any reallocation takes place.
+ *
+ * @param re Compiled pattern to use
+ * @param subject Subject string
+ * @param replace Replacement string
+ * @param dest Destination buffer
+ * @param size Size of the desination buffer
+ * @return MXS_PCRE2_MATCH if replacements were made, MXS_PCRE2_NOMATCH if nothing
+ * was replaced or MXS_PCRE2_ERROR if memory reallocation failed
+ */
+mxs_pcre2_result_t mxs_pcre2_substitute(pcre2_code *re, const char *subject, const char *replace,
+                                        char** dest, size_t* size)
+{
+    int rc;
+    mxs_pcre2_result_t rval = MXS_PCRE2_ERROR;
+    pcre2_match_data *mdata = pcre2_match_data_create_from_pattern(re, NULL);
+
+    if (mdata)
+    {
+        while ((rc = pcre2_substitute(re, (PCRE2_SPTR) subject, PCRE2_ZERO_TERMINATED, 0,
+                                      PCRE2_SUBSTITUTE_GLOBAL, mdata, NULL,
+                                      (PCRE2_SPTR) replace, PCRE2_ZERO_TERMINATED,
+                                      (PCRE2_UCHAR*) *dest, size)) == PCRE2_ERROR_NOMEMORY)
+        {
+            char *tmp = realloc(*dest, *size * 2);
+            if (tmp == NULL)
+            {
+                break;
+            }
+            *dest = tmp;
+            *size *= 2;
+        }
+
+        if (rc > 0)
+        {
+            rval = MXS_PCRE2_MATCH;
+        }
+        else if (rc == 0)
+        {
+            rval = MXS_PCRE2_NOMATCH;
+        }
+        pcre2_match_data_free(mdata);
+    }
+
+    return rval;
+}
+
+/**
+ * Do a simple matching of a pattern to a string.
+ *
+ * This function compiles the given pattern and checks if the subject string matches
+ * it.
+ * @param pattern Pattern used for matching
+ * @param subject Subject string to match
+ * @param options PCRE2 compilation options
+ * @param error The PCRE2 error code is stored here if one is available
+ * @return MXS_PCRE2_MATCH if @c subject matches @c pattern, MXS_PCRE2_NOMATCH if
+ * they do not match and MXS_PCRE2_ERROR if an error occurred. If an error occurred
+ * within the PCRE2 library, @c error will contain the error code. Otherwise it is
+ * set to 0.
+ */
+mxs_pcre2_result_t mxs_pcre2_simple_match(const char* pattern, const char* subject,
+                                          int options, int *error)
+{
+    int err;
+    size_t erroff;
+    mxs_pcre2_result_t rval = MXS_PCRE2_ERROR;
+    pcre2_code *re = pcre2_compile((PCRE2_SPTR) pattern, PCRE2_ZERO_TERMINATED,
+                                   options, &err, &erroff, NULL);
+    if (re)
+    {
+        pcre2_match_data *mdata = pcre2_match_data_create_from_pattern(re, NULL);
+        if (mdata)
+        {
+            int rc = pcre2_match(re, (PCRE2_SPTR) subject, PCRE2_ZERO_TERMINATED,
+                                 0, 0, mdata, NULL);
+            if (rc == PCRE2_ERROR_NOMATCH)
+            {
+                rval = MXS_PCRE2_NOMATCH;
+            }
+            else if (rc > 0)
+            {
+                /** Since we used the pattern to create the matching data,
+                 * pcre2_match will never return 0 */
+                rval = MXS_PCRE2_MATCH;
+            }
+            pcre2_match_data_free(mdata);
+        }
+        else
+        {
+            *error = 0;
+        }
+        pcre2_code_free(re);
+    }
+    else
+    {
+        *error = err;
+    }
+    return rval;
+}