From ca2283bdc00529967f9ccd9bf0097714447af351 Mon Sep 17 00:00:00 2001
From: Matthew Krupcale <mkrupcale@matthewkrupcale.com>
Date: Sun, 9 Aug 2020 09:37:19 -0400
Subject: Add iterator-based versions of find_option{,_prefix}

This allows one to use all of the properties of iterators to manipulate the
found option.
---
 libbuild2/utility.hxx | 16 +++++++++++++---
 libbuild2/utility.ixx | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 3 deletions(-)

diff --git a/libbuild2/utility.hxx b/libbuild2/utility.hxx
index 7a6ada2..b747667 100644
--- a/libbuild2/utility.hxx
+++ b/libbuild2/utility.hxx
@@ -633,7 +633,8 @@ namespace build2
                         F&& get = [] (const string& s) {return s;});
 
   // Check if a specified option is present in the variable or value. T is
-  // either target or scope.
+  // either target or scope. For the interator version use rbegin()/rend() to
+  // search backwards.
   //
   template <typename T>
   bool
@@ -649,6 +650,10 @@ namespace build2
                const char* variable,
                bool ignore_case = false);
 
+  template <typename I>
+  I
+  find_option (const char* option, I begin, I end, bool ignore_case = false);
+
   LIBBUILD2_SYMEXPORT bool
   find_option (const char* option, const lookup&, bool ignore_case = false);
 
@@ -691,8 +696,9 @@ namespace build2
 
   // As above but look for an option that has the specified prefix. Return the
   // pointer to option or NULL if not found (thus can be used as bool).
-  // Search backward (which is normall consistent with how options override
-  // each other).
+  // Search backward (which is normally consistent with how options override
+  // each other). For the interator version use rbegin()/rend() to do the
+  // same.
   //
   template <typename T>
   const string*
@@ -702,6 +708,10 @@ namespace build2
   const string*
   find_option_prefix (const char* prefix, T&, const char*, bool = false);
 
+  template <typename I>
+  I
+  find_option_prefix (const char* prefix, I begin, I end, bool = false);
+
   LIBBUILD2_SYMEXPORT const string*
   find_option_prefix (const char* prefix, const lookup&, bool = false);
 
diff --git a/libbuild2/utility.ixx b/libbuild2/utility.ixx
index da9f58b..9a77fae 100644
--- a/libbuild2/utility.ixx
+++ b/libbuild2/utility.ixx
@@ -139,6 +139,29 @@ namespace build2
     return find_option (o, s[var], ic);
   }
 
+  inline bool
+  compare_option (const char* o, const char* s, bool ic)
+  {
+    return s != nullptr && (ic ? icasecmp (s, o) : strcmp (s, o)) == 0;
+  }
+
+  inline bool
+  compare_option (const char* o, const string& s, bool ic)
+  {
+    return ic ? icasecmp (s, o) == 0 : s == o;
+  }
+
+  template <typename I>
+  inline I
+  find_option (const char* o, I b, I e, bool ic)
+  {
+    for (; b != e; ++b)
+      if (compare_option (o, *b, ic))
+        return b;
+
+    return e;
+  }
+
   template <typename T>
   inline bool
   find_options (const initializer_list<const char*>& os,
@@ -173,6 +196,31 @@ namespace build2
     return find_option_prefix (p, s[var], ic);
   }
 
+  inline bool
+  compare_option_prefix (const char* p, size_t n, const char* s, bool ic)
+  {
+    return s != nullptr && (ic ? icasecmp (s, p, n) : strncmp (s, p, n)) == 0;
+  }
+
+  inline bool
+  compare_option_prefix (const char* p, size_t n, const string& s, bool ic)
+  {
+    return (ic ? icasecmp (s, p, n) : s.compare (0, n, p)) == 0;
+  }
+
+  template <typename I>
+  inline I
+  find_option_prefix (const char* p, I b, I e, bool ic)
+  {
+    size_t n (strlen (p));
+
+    for (; b != e; ++b)
+      if (compare_option_prefix (p, n, *b, ic))
+        return b;
+
+    return e;
+  }
+
   template <typename T>
   inline const string*
   find_option_prefixes (const initializer_list<const char*>& ps,
-- 
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