From 5f27918e56f7cb89226556836e35a1a64ba5cd99 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Sat, 19 Oct 2019 17:11:24 +0200
Subject: Add find_stem() utility function

---
 libbuild2/utility.ixx | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'libbuild2/utility.ixx')

diff --git a/libbuild2/utility.ixx b/libbuild2/utility.ixx
index 2846756..514d4ee 100644
--- a/libbuild2/utility.ixx
+++ b/libbuild2/utility.ixx
@@ -2,6 +2,8 @@
 // copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
 // license   : MIT; see accompanying LICENSE file
 
+#include <cstring> // strlen() strchr()
+
 namespace build2
 {
   inline void
@@ -152,4 +154,23 @@ namespace build2
   {
     return find_option_prefixes (ps, s[var], ic);
   }
+
+  inline size_t
+  find_stem (const string& s, size_t s_p, size_t s_n,
+             const char* stem, const char* seps)
+  {
+    auto sep = [seps] (char c) -> bool
+    {
+      return strchr (seps, c) != nullptr;
+    };
+
+    size_t m (strlen (stem));
+    size_t p (s.find (stem, s_p, m));
+
+    return (p != string::npos &&
+            (      p == s_p || sep (s[p - 1])) && // Separated beginning.
+            ((p + m) == s_n || sep (s[p + m])))   // Separated end.
+      ? p
+      : string::npos;
+  }
 }
-- 
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