am 928cbdd2: Merge "Add common string utilities to libbase."

* commit '928cbdd2c34cd5db9b344e593866f9e1e1e477e2':
  Add common string utilities to libbase.

base/Android.mk

@@ -19,10 +19,12 @@ LOCAL_PATH := $(call my-dir)
 libbase_src_files := \
     file.cpp \
     stringprintf.cpp \
+    strings.cpp \
 
 libbase_test_src_files := \
     file_test.cpp \
     stringprintf_test.cpp \
+    strings_test.cpp \
 
 libbase_cppflags := \
     -Wall \

base/include/base/strings.h

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef BASE_STRINGS_H
+#define BASE_STRINGS_H
+
+#include <string>
+#include <vector>
+
+namespace android {
+namespace base {
+
+// Splits a string using the given separator character into a vector of strings.
+// Empty strings will be omitted.
+void Split(const std::string& s, char separator,
+           std::vector<std::string>* result);
+
+// Trims whitespace off both ends of the given string.
+std::string Trim(const std::string& s);
+
+// Joins a vector of strings into a single string, using the given separator.
+template <typename StringT>
+std::string Join(const std::vector<StringT>& strings, char separator);
+
+// Tests whether 's' starts with 'prefix'.
+bool StartsWith(const std::string& s, const char* prefix);
+
+// Tests whether 's' ends with 'suffix'.
+bool EndsWith(const std::string& s, const char* suffix);
+
+}  // namespace base
+}  // namespace android
+
+#endif  // BASE_STRINGS_H

base/strings.cpp

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "base/strings.h"
+
+#include <string>
+#include <vector>
+
+namespace android {
+namespace base {
+
+void Split(const std::string& s, char separator,
+           std::vector<std::string>* result) {
+  const char* p = s.data();
+  const char* end = p + s.size();
+  while (p != end) {
+    if (*p == separator) {
+      ++p;
+    } else {
+      const char* start = p;
+      while (++p != end && *p != separator) {
+        // Skip to the next occurrence of the separator.
+      }
+      result->push_back(std::string(start, p - start));
+    }
+  }
+}
+
+std::string Trim(const std::string& s) {
+  std::string result;
+
+  if (s.size() == 0) {
+    return result;
+  }
+
+  size_t start_index = 0;
+  size_t end_index = s.size() - 1;
+
+  // Skip initial whitespace.
+  while (start_index < s.size()) {
+    if (!isspace(s[start_index])) {
+      break;
+    }
+    start_index++;
+  }
+
+  // Skip terminating whitespace.
+  while (end_index >= start_index) {
+    if (!isspace(s[end_index])) {
+      break;
+    }
+    end_index--;
+  }
+
+  // All spaces, no beef.
+  if (end_index < start_index) {
+    return "";
+  }
+  // Start_index is the first non-space, end_index is the last one.
+  return s.substr(start_index, end_index - start_index + 1);
+}
+
+template <typename StringT>
+std::string Join(const std::vector<StringT>& strings, char separator) {
+  if (strings.empty()) {
+    return "";
+  }
+
+  std::string result(strings[0]);
+  for (size_t i = 1; i < strings.size(); ++i) {
+    result += separator;
+    result += strings[i];
+  }
+  return result;
+}
+
+// Explicit instantiations.
+template std::string Join<std::string>(const std::vector<std::string>& strings,
+                                       char separator);
+template std::string Join<const char*>(const std::vector<const char*>& strings,
+                                       char separator);
+
+bool StartsWith(const std::string& s, const char* prefix) {
+  return s.compare(0, strlen(prefix), prefix) == 0;
+}
+
+bool EndsWith(const std::string& s, const char* suffix) {
+  size_t suffix_length = strlen(suffix);
+  size_t string_length = s.size();
+  if (suffix_length > string_length) {
+    return false;
+  }
+  size_t offset = string_length - suffix_length;
+  return s.compare(offset, suffix_length, suffix) == 0;
+}
+
+}  // namespace base
+}  // namespace android

base/strings_test.cpp

@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "base/strings.h"
+
+#include <gtest/gtest.h>
+
+#include <string>
+#include <vector>
+
+TEST(strings, split_empty) {
+  std::vector<std::string> parts;
+  android::base::Split("", '\0', &parts);
+  ASSERT_EQ(0U, parts.size());
+}
+
+TEST(strings, split_single) {
+  std::vector<std::string> parts;
+  android::base::Split("foo", ',', &parts);
+  ASSERT_EQ(1U, parts.size());
+  ASSERT_EQ("foo", parts[0]);
+}
+
+TEST(strings, split_simple) {
+  std::vector<std::string> parts;
+  android::base::Split("foo,bar,baz", ',', &parts);
+  ASSERT_EQ(3U, parts.size());
+  ASSERT_EQ("foo", parts[0]);
+  ASSERT_EQ("bar", parts[1]);
+  ASSERT_EQ("baz", parts[2]);
+}
+
+TEST(strings, split_with_empty_part) {
+  std::vector<std::string> parts;
+  android::base::Split("foo,,bar", ',', &parts);
+  ASSERT_EQ(2U, parts.size());
+  ASSERT_EQ("foo", parts[0]);
+  ASSERT_EQ("bar", parts[1]);
+}
+
+TEST(strings, trim_empty) {
+  ASSERT_EQ("", android::base::Trim(""));
+}
+
+TEST(strings, trim_already_trimmed) {
+  ASSERT_EQ("foo", android::base::Trim("foo"));
+}
+
+TEST(strings, trim_left) {
+  ASSERT_EQ("foo", android::base::Trim(" foo"));
+}
+
+TEST(strings, trim_right) {
+  ASSERT_EQ("foo", android::base::Trim("foo "));
+}
+
+TEST(strings, trim_both) {
+  ASSERT_EQ("foo", android::base::Trim(" foo "));
+}
+
+TEST(strings, trim_no_trim_middle) {
+  ASSERT_EQ("foo bar", android::base::Trim("foo bar"));
+}
+
+TEST(strings, trim_other_whitespace) {
+  ASSERT_EQ("foo", android::base::Trim("\v\tfoo\n\f"));
+}
+
+TEST(strings, join_nothing) {
+  std::vector<std::string> list = {};
+  ASSERT_EQ("", android::base::Join(list, ','));
+}
+
+TEST(strings, join_single) {
+  std::vector<std::string> list = {"foo"};
+  ASSERT_EQ("foo", android::base::Join(list, ','));
+}
+
+TEST(strings, join_simple) {
+  std::vector<std::string> list = {"foo", "bar", "baz"};
+  ASSERT_EQ("foo,bar,baz", android::base::Join(list, ','));
+}
+
+TEST(strings, join_separator_in_vector) {
+  std::vector<std::string> list = {",", ","};
+  ASSERT_EQ(",,,", android::base::Join(list, ','));
+}
+
+TEST(strings, startswith_empty) {
+  ASSERT_FALSE(android::base::StartsWith("", "foo"));
+  ASSERT_TRUE(android::base::StartsWith("", ""));
+}
+
+TEST(strings, startswith_simple) {
+  ASSERT_TRUE(android::base::StartsWith("foo", ""));
+  ASSERT_TRUE(android::base::StartsWith("foo", "f"));
+  ASSERT_TRUE(android::base::StartsWith("foo", "fo"));
+  ASSERT_TRUE(android::base::StartsWith("foo", "foo"));
+}
+
+TEST(strings, startswith_prefix_too_long) {
+  ASSERT_FALSE(android::base::StartsWith("foo", "foobar"));
+}
+
+TEST(strings, startswith_contains_prefix) {
+  ASSERT_FALSE(android::base::StartsWith("foobar", "oba"));
+  ASSERT_FALSE(android::base::StartsWith("foobar", "bar"));
+}
+
+TEST(strings, endswith_empty) {
+  ASSERT_FALSE(android::base::EndsWith("", "foo"));
+  ASSERT_TRUE(android::base::EndsWith("", ""));
+}
+
+TEST(strings, endswith_simple) {
+  ASSERT_TRUE(android::base::EndsWith("foo", ""));
+  ASSERT_TRUE(android::base::EndsWith("foo", "o"));
+  ASSERT_TRUE(android::base::EndsWith("foo", "oo"));
+  ASSERT_TRUE(android::base::EndsWith("foo", "foo"));
+}
+
+TEST(strings, endswith_prefix_too_long) {
+  ASSERT_FALSE(android::base::EndsWith("foo", "foobar"));
+}
+
+TEST(strings, endswith_contains_prefix) {
+  ASSERT_FALSE(android::base::EndsWith("foobar", "oba"));
+  ASSERT_FALSE(android::base::EndsWith("foobar", "foo"));
+}