Add a string(FIND) sub-command (#11795)

2 files changed, 73 insertions, 1 deletions

diff --git a/Source/cmStringCommand.cxx b/Source/cmStringCommand.cxx
index 949fcf5..1f873e2 100644
--- a/Source/cmStringCommand.cxx
+++ b/Source/cmStringCommand.cxx
@@ -72,7 +72,11 @@ bool cmStringCommand
     {
     return this->HandleRandomCommand(args);
     }
-  
+  else if(subCommand == "FIND")
+    {
+    return this->HandleFindCommand(args);
+    }
+
   std::string e = "does not recognize sub-command "+subCommand;
   this->SetError(e.c_str());
   return false;
@@ -499,6 +503,68 @@ void cmStringCommand::StoreMatches(cmMakefile* mf,cmsys::RegularExpression& re)
 }
 
 //----------------------------------------------------------------------------
+bool cmStringCommand::HandleFindCommand(std::vector<std::string> const&
+                                           args)
+{
+  // check if all required parameters were passed
+  if(args.size() < 4 || args.size() > 5)
+    {
+    this->SetError("sub-command FIND requires 3 or 4 parameters.");
+    return false;
+    }
+
+  // check if the reverse flag was set or not
+  bool reverseMode = false;
+  if(args.size() == 5 && args[4] == "REVERSE")
+    {
+    reverseMode = true;
+    }
+
+  // if we have 5 arguments the last one must be REVERSE
+  if(args.size() == 5 && args[4] != "REVERSE")
+    {
+    this->SetError("sub-command FIND: unknown last parameter");
+    return false;
+    }
+
+  // local parameter names.
+  const std::string& sstring = args[1];
+  const std::string& schar = args[2];
+  const std::string& outvar = args[3];
+
+  // ensure that the user cannot accidentally specify REVERSE as a variable
+  if(outvar == "REVERSE")
+    {
+    this->SetError("sub-command FIND does not allow to select REVERSE as "
+                   "the output variable.  "
+                   "Maybe you missed the actual output variable?");
+    return false;
+    }
+
+  // try to find the character and return its position
+  size_t pos;
+  if(!reverseMode)
+    {
+    pos = sstring.find(schar);
+    }
+  else
+    {
+    pos = sstring.rfind(schar);
+    }
+  if(std::string::npos != pos)
+    {
+    std::stringstream s;
+    s << pos;
+    this->Makefile->AddDefinition(outvar.c_str(), s.str().c_str());
+    return true;
+    }
+
+  // the character was not found, but this is not really an error
+  this->Makefile->AddDefinition(outvar.c_str(), "-1");
+  return true;
+}
+
+//----------------------------------------------------------------------------
 bool cmStringCommand::HandleCompareCommand(std::vector<std::string> const&
                                            args)
 {
diff --git a/Source/cmStringCommand.h b/Source/cmStringCommand.h
index 2a916b4..9586449 100644
--- a/Source/cmStringCommand.h
+++ b/Source/cmStringCommand.h
@@ -90,6 +90,7 @@ public:
       "  string(STRIP <string> <output variable>)\n"
       "  string(RANDOM [LENGTH <length>] [ALPHABET <alphabet>]\n"
       "         [RANDOM_SEED <seed>] <output variable>)\n"
+      "  string(FIND <string> <substring> <output variable> [REVERSE])\n"
       "REGEX MATCH will match the regular expression once and store the "
       "match in the output variable.\n"
       "REGEX MATCHALL will match the regular expression as many times as "
@@ -117,6 +118,10 @@ public:
       "characters and default alphabet is all numbers and upper and "
       "lower case letters.  If an integer RANDOM_SEED is given, its "
       "value will be used to seed the random number generator.\n"
+      "FIND will return the position where the given substring was found "
+      "in the supplied string. If the REVERSE flag was used, the command "
+      "will search for the position of the last occurrence of the "
+      "specified substring.\n"
       "The following characters have special meaning in regular expressions:\n"
       "   ^         Matches at beginning of a line\n"
       "   $         Matches at end of a line\n"
@@ -152,6 +157,7 @@ protected:
   bool HandleSubstringCommand(std::vector<std::string> const& args);
   bool HandleStripCommand(std::vector<std::string> const& args);
   bool HandleRandomCommand(std::vector<std::string> const& args);
+  bool HandleFindCommand(std::vector<std::string> const& args);
 
   class RegexReplacement
   {