Add ParseInt (and ParseUint).

strtol and family are hard to use correctly, and most callers don't
even try.

Change-Id: I2833622a92cccd4662c0c5bdbbef5eeb4e496914

3 files changed, 140 insertions, 0 deletions

diff --git a/base/Android.mk b/base/Android.mk
index 51dd73600..a09a747c8 100644
--- a/base/Android.mk
+++ b/base/Android.mk
@@ -26,6 +26,7 @@ libbase_src_files := \
 libbase_test_src_files := \
     file_test.cpp \
     logging_test.cpp \
+    parseint_test.cpp \
     stringprintf_test.cpp \
     strings_test.cpp \
     test_main.cpp \
diff --git a/base/include/base/parseint.h b/base/include/base/parseint.h
new file mode 100644
index 000000000..9ecbfbce9
--- /dev/null
+++ b/base/include/base/parseint.h
@@ -0,0 +1,71 @@
+/*
+ * 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_PARSEINT_H
+#define BASE_PARSEINT_H
+
+#include <errno.h>
+#include <stdlib.h>
+
+#include <limits>
+
+namespace android {
+namespace base {
+
+// Parses the unsigned decimal integer in the string 's' and sets 'out' to
+// that value. Optionally allows the caller to define a 'max' beyond which
+// otherwise valid values will be rejected. Returns boolean success.
+template <typename T>
+bool ParseUint(const char* s, T* out,
+               T max = std::numeric_limits<T>::max()) {
+  errno = 0;
+  char* end;
+  unsigned long long int result = strtoull(s, &end, 10);
+  if (errno != 0 || s == end || *end != '\0') {
+    return false;
+  }
+  if (max < result) {
+    return false;
+  }
+  *out = static_cast<T>(result);
+  return true;
+}
+
+// Parses the signed decimal integer in the string 's' and sets 'out' to
+// that value. Optionally allows the caller to define a 'min' and 'max
+// beyond which otherwise valid values will be rejected. Returns boolean
+// success.
+template <typename T>
+bool ParseInt(const char* s, T* out,
+              T min = std::numeric_limits<T>::min(),
+              T max = std::numeric_limits<T>::max()) {
+  errno = 0;
+  char* end;
+  long long int result = strtoll(s, &end, 10);
+  if (errno != 0 || s == end || *end != '\0') {
+    return false;
+  }
+  if (result < min || max < result) {
+    return false;
+  }
+  *out = static_cast<T>(result);
+  return true;
+}
+
+}  // namespace base
+}  // namespace android
+
+#endif  // BASE_PARSEINT_H
diff --git a/base/parseint_test.cpp b/base/parseint_test.cpp
new file mode 100644
index 000000000..6a109f44c
--- /dev/null
+++ b/base/parseint_test.cpp
@@ -0,0 +1,68 @@
+/*
+ * 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/parseint.h"
+
+#include <gtest/gtest.h>
+
+TEST(parseint, signed_smoke) {
+  int i;
+  ASSERT_EQ(false, android::base::ParseInt("x", &i));
+  ASSERT_EQ(false, android::base::ParseInt("123x", &i));
+
+  ASSERT_EQ(true, android::base::ParseInt("123", &i));
+  ASSERT_EQ(123, i);
+  ASSERT_EQ(true, android::base::ParseInt("-123", &i));
+  ASSERT_EQ(-123, i);
+
+  short s;
+  ASSERT_EQ(true, android::base::ParseInt("1234", &s));
+  ASSERT_EQ(1234, s);
+
+  ASSERT_EQ(true, android::base::ParseInt("12", &i, 0, 15));
+  ASSERT_EQ(12, i);
+  ASSERT_EQ(false, android::base::ParseInt("-12", &i, 0, 15));
+  ASSERT_EQ(false, android::base::ParseInt("16", &i, 0, 15));
+}
+
+TEST(parseint, unsigned_smoke) {
+  unsigned int i;
+  ASSERT_EQ(false, android::base::ParseUint("x", &i));
+  ASSERT_EQ(false, android::base::ParseUint("123x", &i));
+
+  ASSERT_EQ(true, android::base::ParseUint("123", &i));
+  ASSERT_EQ(123u, i);
+  ASSERT_EQ(false, android::base::ParseUint("-123", &i));
+
+  unsigned short s;
+  ASSERT_EQ(true, android::base::ParseUint("1234", &s));
+  ASSERT_EQ(1234u, s);
+
+  ASSERT_EQ(true, android::base::ParseUint("12", &i, 15u));
+  ASSERT_EQ(12u, i);
+  ASSERT_EQ(false, android::base::ParseUint("-12", &i, 15u));
+  ASSERT_EQ(false, android::base::ParseUint("16", &i, 15u));
+}
+
+TEST(parseint, no_implicit_octal) {
+  int i;
+  ASSERT_EQ(true, android::base::ParseInt("0123", &i));
+  ASSERT_EQ(123, i);
+
+  unsigned int u;
+  ASSERT_EQ(true, android::base::ParseUint("0123", &u));
+  ASSERT_EQ(123u, u);
+}