From 2d8577655b5e5cbcc414330029b4c7585d6a9fa2 Mon Sep 17 00:00:00 2001
From: Arne Juul <arnej@verizonmedia.com>
Date: Mon, 20 Apr 2020 08:14:28 +0000
Subject: add utility for replacing a variable in a string

---
 vespalib/src/tests/stllike/CMakeLists.txt          |  8 ++++
 .../src/tests/stllike/replace_variable_test.cpp    | 24 ++++++++++
 vespalib/src/vespa/vespalib/stllike/CMakeLists.txt |  1 +
 .../vespa/vespalib/stllike/replace_variable.cpp    | 51 ++++++++++++++++++++++
 .../src/vespa/vespalib/stllike/replace_variable.h  |  9 ++++
 5 files changed, 93 insertions(+)
 create mode 100644 vespalib/src/tests/stllike/replace_variable_test.cpp
 create mode 100644 vespalib/src/vespa/vespalib/stllike/replace_variable.cpp
 create mode 100644 vespalib/src/vespa/vespalib/stllike/replace_variable.h

(limited to 'vespalib')

diff --git a/vespalib/src/tests/stllike/CMakeLists.txt b/vespalib/src/tests/stllike/CMakeLists.txt
index 04c1a420f5e..ebf7de9c747 100644
--- a/vespalib/src/tests/stllike/CMakeLists.txt
+++ b/vespalib/src/tests/stllike/CMakeLists.txt
@@ -47,3 +47,11 @@ vespa_add_executable(vespalib_lookup_benchmark_app
     vespalib
 )
 vespa_add_test(NAME vespalib_lookup_benchmark_app COMMAND vespalib_lookup_benchmark_app BENCHMARK)
+vespa_add_executable(vespalib_replace_variable_test_app TEST
+    SOURCES
+    replace_variable_test.cpp
+    DEPENDS
+    vespalib
+    gtest
+)
+vespa_add_test(NAME vespalib_replace_variable_test_app COMMAND vespalib_replace_variable_test_app)
diff --git a/vespalib/src/tests/stllike/replace_variable_test.cpp b/vespalib/src/tests/stllike/replace_variable_test.cpp
new file mode 100644
index 00000000000..d32bf67a23d
--- /dev/null
+++ b/vespalib/src/tests/stllike/replace_variable_test.cpp
@@ -0,0 +1,24 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include <vespa/vespalib/stllike/replace_variable.h>
+#include <vespa/vespalib/gtest/gtest.h>
+
+using namespace vespalib;
+
+TEST(ReplaceVariableTest, simple_usage)
+{
+    EXPECT_EQ("vv", replace_variable("x", "x", "vv"));
+    EXPECT_EQ("f(vv)", replace_variable("f(x)", "x", "vv"));
+    EXPECT_EQ("vv(f)", replace_variable("x(f)", "x", "vv"));
+    EXPECT_EQ("3*vv", replace_variable("3*x", "x", "vv"));
+    EXPECT_EQ("f(vv,vv,y)", replace_variable("f(x,x,y)", "x", "vv"));
+
+    EXPECT_EQ("f(xx)", replace_variable("f(xx)", "x", "vv"));
+    EXPECT_EQ("f(ax)", replace_variable("f(ax)", "x", "vv"));
+    EXPECT_EQ("f(xa)", replace_variable("f(xa)", "x", "vv"));
+    EXPECT_EQ("f(axa)", replace_variable("f(axa)", "x", "vv"));
+
+    EXPECT_EQ("f(vv)", replace_variable("f(x_y)", "x_y", "vv"));
+}
+
+GTEST_MAIN_RUN_ALL_TESTS()
diff --git a/vespalib/src/vespa/vespalib/stllike/CMakeLists.txt b/vespalib/src/vespa/vespalib/stllike/CMakeLists.txt
index aaada6fdcc4..f8b9e90dc62 100644
--- a/vespalib/src/vespa/vespalib/stllike/CMakeLists.txt
+++ b/vespalib/src/vespa/vespalib/stllike/CMakeLists.txt
@@ -7,6 +7,7 @@ vespa_add_library(vespalib_vespalib_stllike OBJECT
     hash_fun.cpp
     hash_set.cpp
     hash_map.cpp
+    replace_variable.cpp
     string.cpp
     DEPENDS
 )
diff --git a/vespalib/src/vespa/vespalib/stllike/replace_variable.cpp b/vespalib/src/vespa/vespalib/stllike/replace_variable.cpp
new file mode 100644
index 00000000000..fbbcff48963
--- /dev/null
+++ b/vespalib/src/vespa/vespalib/stllike/replace_variable.cpp
@@ -0,0 +1,51 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include "replace_variable.h"
+#include "asciistream.h"
+#include <ctype.h>
+ 
+namespace vespalib {
+
+vespalib::string
+replace_variable(const vespalib::string &input,
+                 const vespalib::string &variable,
+                 const vespalib::string &replacement)
+{
+    vespalib::asciistream result;
+    bool is_in_word = false;
+    size_t last_word_start = 0;
+    size_t last_word_size = 0;
+    for (size_t i = 0; i < input.size(); ++i) {
+        char c = input[i];
+        if (isalnum(c) || (c == '_')) {
+            if (! is_in_word) {
+                last_word_start = i;
+                last_word_size = 0;
+                is_in_word = true;
+            }
+            ++last_word_size;
+        } else {
+            if (is_in_word) {
+                vespalib::string last_word = input.substr(last_word_start, last_word_size);
+                if (last_word == variable) {
+                    result << replacement;
+                } else {
+                    result << last_word;
+                }
+                is_in_word = false;
+            }
+            result << c;
+       }
+   }
+   if (is_in_word) {
+       vespalib::string last_word = input.substr(last_word_start, last_word_size);
+       if (last_word == variable) {
+           result << replacement;
+       } else {
+           result << last_word;
+       }
+   }
+   return result.str();
+}
+
+} // namespace
diff --git a/vespalib/src/vespa/vespalib/stllike/replace_variable.h b/vespalib/src/vespa/vespalib/stllike/replace_variable.h
new file mode 100644
index 00000000000..8caf1c54bfd
--- /dev/null
+++ b/vespalib/src/vespa/vespalib/stllike/replace_variable.h
@@ -0,0 +1,9 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include "string.h"
+
+namespace vespalib {
+vespalib::string replace_variable(const vespalib::string &input,
+                                  const vespalib::string &variable,
+                                  const vespalib::string &replacement);
+} // namespace vespalib
-- 
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