Implement simple caching for compiled regular expressions

1 files changed, 23 insertions, 12 deletions

diff --git a/src/stringutils.cpp b/src/stringutils.cpp
index 4f6ff6a..74cb0e7 100644
--- a/src/stringutils.cpp
+++ b/src/stringutils.cpp
@@ -28,6 +28,7 @@
 #include <cstdio>
 #include <ctime>
 #include <list>
+#include <unordered_map>
 
 #include <sys/stat.h>
 
@@ -709,29 +710,39 @@ void secureChatCommand(std::string &str)
 bool isMatch(const std::string &str,
              const std::string &exp)
 {
-    jp::Regex re(exp, "x");
-    if (!re)
+    static std::unordered_map<std::string, jp::Regex> re_cache;
+    if (re_cache.find(exp) == re_cache.end())
     {
-        printf("Invalid regular expression '%s': %s at offset %d\n", exp.c_str(),
-               re.getErrorMessage().c_str(), re.getErrorOffset());
-        exit(1);
+        jp::Regex re(exp, "x");
+        if (!re)
+        {
+            printf("Invalid regular expression '%s': %s at offset %d\n", exp.c_str(),
+                   re.getErrorMessage().c_str(), re.getErrorOffset());
+            exit(1);
+        }
+        re_cache[exp] = re;
     }
-    return re.match(str);
+    return re_cache[exp].match(str);
 }
 
 bool isMatch(const std::string &str,
              const std::string &exp,
              jp::VecNum &m)
 {
-    jp::Regex re(exp, "x");
-    if (!re)
+    static std::unordered_map<std::string, jp::Regex> re_cache;
+    if (re_cache.find(exp) == re_cache.end())
     {
-        printf("Invalid regular expression '%s': %s at offset %d\n", exp.c_str(),
-               re.getErrorMessage().c_str(), re.getErrorOffset());
-        exit(1);
+        jp::Regex re(exp, "x");
+        if (!re)
+        {
+            printf("Invalid regular expression '%s': %s at offset %d\n", exp.c_str(),
+                   re.getErrorMessage().c_str(), re.getErrorOffset());
+            exit(1);
+        }
+        re_cache[exp] = re;
     }
     jp::RegexMatch rm;
-    size_t count = rm.setRegexObject(&re)
+    size_t count = rm.setRegexObject(&re_cache[exp])
                      .setSubject(&str)
                      .setNumberedSubstringVector(&m)
                      .match();