Move regex code to wsutil

1 files changed, 117 insertions, 0 deletions

diff --git a/wsutil/regex.c b/wsutil/regex.c
new file mode 100644
index 0000000000..00ad2df050
--- /dev/null
+++ b/wsutil/regex.c
@@ -0,0 +1,117 @@
+/*
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+
+#include "regex.h"
+
+#include <wsutil/ws_return.h>
+#include <pcre2.h>
+
+
+struct _ws_regex {
+    pcre2_code *code;
+    char *pattern;
+};
+
+#define ERROR_MAXLEN_IN_CODE_UNITS   128
+
+static pcre2_code *
+_pcre2_compile(const char *patt, char **errmsg)
+{
+    pcre2_code *code;
+    int errorcode;
+    PCRE2_SIZE erroroffset;
+    char *error_buffer;
+
+    /* By default UTF-8 is off. */
+    code = pcre2_compile_8((PCRE2_SPTR)patt,
+                PCRE2_ZERO_TERMINATED,
+                PCRE2_NEVER_UTF,
+                &errorcode,
+                &erroroffset,
+                NULL);
+
+    if (code == NULL) {
+        /*
+         * We have to provide a buffer and we don't know how long the
+         * error message is or even the maximum size. From pcre2api(3):
+         *     "None of the messages are very long; a
+         *     buffer size of 120 code units is ample."
+         */
+        /* Code unit = one byte */
+        error_buffer = g_malloc(ERROR_MAXLEN_IN_CODE_UNITS);
+        /* Message is returned with a trailing zero. */
+        pcre2_get_error_message(errorcode, error_buffer, ERROR_MAXLEN_IN_CODE_UNITS);
+        /* One more at the end for good luck. */
+        error_buffer[ERROR_MAXLEN_IN_CODE_UNITS-1] = '\0';
+        *errmsg = error_buffer;
+        return NULL;
+    }
+
+    return code;
+}
+
+
+ws_regex_t *
+ws_regex_compile(const char *patt, char **errmsg)
+{
+    ws_return_val_if_null(patt, NULL);
+
+    pcre2_code *code = _pcre2_compile(patt, errmsg);
+    if (code == NULL)
+        return NULL;
+
+    ws_regex_t *re = g_new(ws_regex_t, 1);
+    re->code = code;
+    re->pattern = g_strdup(patt);
+    return re;
+}
+
+
+static bool
+_pcre2_matches(pcre2_code *code, const char *subj, gssize subj_size)
+{
+    PCRE2_SIZE length;
+    pcre2_match_data *match_data;
+    int rc;
+
+    length = subj_size < 0 ? PCRE2_ZERO_TERMINATED : (PCRE2_SIZE)subj_size;
+    match_data = pcre2_match_data_create_from_pattern(code, NULL);
+
+    rc = pcre2_match(code, subj, length, 0, 0, match_data, NULL);
+    pcre2_match_data_free(match_data);
+
+    return rc < 0 ? FALSE : TRUE;
+}
+
+
+bool
+ws_regex_matches(const ws_regex_t *re, const char *subj, gssize subj_size)
+{
+    ws_return_val_if_null(re, FALSE);
+    ws_return_val_if_null(subj, FALSE);
+
+    return _pcre2_matches(re->code, subj, subj_size);
+}
+
+
+void
+ws_regex_free(ws_regex_t *re)
+{
+    pcre2_code_free(re->code);
+    g_free(re->pattern);
+    g_free(re);
+}
+
+
+const char *
+ws_regex_pattern(const ws_regex_t *re)
+{
+    return re->pattern;
+}