From 3382b35975596fc32fd56aa988aba49c1d29de57 Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Mon, 30 Aug 2021 12:09:55 -0700
Subject: [PATCH] testStrMatch() portability

---
 src/pvxs/unittest.h |  4 +++-
 src/unittest.cpp    | 34 +++++++++++++++++++++++++++++++---
 test/testutil.cpp   |  4 +++-
 3 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/src/pvxs/unittest.h b/src/pvxs/unittest.h
index 4849001..c1a2558 100644
--- a/src/pvxs/unittest.h
+++ b/src/pvxs/unittest.h
@@ -79,7 +79,8 @@ public:
     }
 
     //! Override current pass/fail result if input matches a regular expression
-    //! @since 0.1.1
+    //! @since UNRELEASED Expression syntax is POSIX extended.
+    //! @since 0.1.1 Added
     testCase& setPassMatch(const std::string& expr, const std::string& inp);
 
     //! Append to message
@@ -288,6 +289,7 @@ testCase testThrowsMatch(const std::string& expr, FN fn)
 
 //! Macro which asserts that STR matches the regular expression EXPR
 //! Evaluates to a pvxs::testCase
+//! @since UNRELEASED Expression syntax is POSIX extended.
 //! @since 0.1.1
 #define testStrMatch(EXPR, STR) ::pvxs::detail::_testStrMatch(#EXPR, EXPR, #STR, STR)
 
diff --git a/src/unittest.cpp b/src/unittest.cpp
index 6ada8d5..f4d9415 100644
--- a/src/unittest.cpp
+++ b/src/unittest.cpp
@@ -4,7 +4,18 @@
  * in file LICENSE that is included with this distribution.
  */
 
-#include <regex>
+#include "pvxs/version.h"
+
+#if !defined(GCC_VERSION) || GCC_VERSION>VERSION_INT(4,9,0,0)
+#  include <regex>
+
+#else
+// GCC 4.8 provides the regex header and symbols, but with a no-op implementation
+// so fill in the gap with POSIX regex
+#  include <sys/types.h>
+#  include <regex.h>
+#  define USE_POSIX_REGEX
+#endif
 
 #include <epicsUnitTest.h>
 
@@ -96,15 +107,33 @@ testCase::~testCase()
 
 testCase& testCase::setPassMatch(const std::string& expr, const std::string& inp)
 {
+#ifdef USE_POSIX_REGEX
+    regex_t ex{};
+
+    if(auto err = regcomp(&ex, expr.c_str(), REG_EXTENDED|REG_NOSUB)) {
+        auto len = regerror(err, &ex, nullptr, 0u);
+        std::vector<char> msg(len+1);
+        (void)regerror(err, &ex, msg.data(), len);
+        msg[len] = '\0'; // paranoia
+        setPass(false);
+        (*this)<<" expression error: "<<msg.data()<<" :";
+
+    } else {
+        setPass(regexec(&ex, inp.c_str(), 0, nullptr, 0)!=REG_NOMATCH);
+        regfree(&ex);
+    }
+
+#else
     std::regex ex;
     try {
-        ex.assign(expr);
+        ex.assign(expr, std::regex_constants::extended);
         setPass(std::regex_match(inp, ex));
 
     }catch(std::regex_error& e) {
         setPass(false);
         (*this)<<" expression error: "<<e.what()<<" :";
     }
+#endif
     return *this;
 }
 
@@ -174,7 +203,6 @@ testCase _testStrTest(unsigned op, const char *sLHS, const char* rlhs, const cha
 
 testCase _testStrMatch(const char *spat, const std::string& pat, const char *sstr, const std::string& str)
 {
-    std::regex expr;
     testCase ret;
     ret.setPassMatch(pat, str);
     ret<<spat<<" (\""<<pat<<"\") match "<<str<<" (\""<<escape(str)<<"\")";
diff --git a/test/testutil.cpp b/test/testutil.cpp
index e3d72d8..f57862d 100644
--- a/test/testutil.cpp
+++ b/test/testutil.cpp
@@ -200,13 +200,15 @@ void testTestEq()
     testStrNotEq("hello", std::string("world"));
     testStrNotEq(std::string("hello"), "world");
     testStrNotEq(std::string("hello"), std::string("world"));
+
+    testStrMatch("[Hh]ello [Ww]orld", "hello world");
 }
 
 } // namespace
 
 MAIN(testutil)
 {
-    testPlan(24);
+    testPlan(25);
     testTrue(version_abi_check())<<" 0x"<<std::hex<<PVXS_VERSION<<" ~= 0x"<<std::hex<<PVXS_ABI_VERSION;
     testServerGUID();
     testFill();