From 6520b63cb25580420e477cba2c776b2639cbf21b Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Wed, 21 Mar 2018 13:19:18 +0200
Subject: Guarantee validity of values returned by scanner for two arguments

---
 cli/runtime-header.cxx | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

(limited to 'cli/runtime-header.cxx')

diff --git a/cli/runtime-header.cxx b/cli/runtime-header.cxx
index 9861166..9f92262 100644
--- a/cli/runtime-header.cxx
+++ b/cli/runtime-header.cxx
@@ -246,7 +246,13 @@ generate_runtime_header (context& ctx)
 
   // scanner
   //
-  os << "class scanner"
+  os << "// Command line argument scanner interface."                  << endl
+     << "//"                                                           << endl
+     << "// The values returned by next() are guaranteed to be valid"  << endl
+     << "// for the two previous arguments up until a call to a third" << endl
+     << "// peek() or next()."                                         << endl
+     << "//"                                                           << endl
+     << "class scanner"
      << "{"
      << "public:" << endl
      << "virtual" << endl
@@ -396,11 +402,16 @@ generate_runtime_header (context& ctx)
        << "const option_info* options_;"
        << "std::size_t options_count_;"
        << endl
-       << "std::string hold_;"
-       << "std::deque<std::string> args_;";
+       << "std::deque<std::string> args_;"
+       << endl
+       << "// Circular buffer of two arguments." << endl
+       << "//" << endl
+       << "std::string hold_[2];"
+       << "std::size_t i_;";
 
     if (!ctx.opt_sep.empty ())
-      os << "bool skip_;";
+      os << endl
+         << "bool skip_;";
 
     os << "};";
   }
-- 
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