Add CFRangeToNSRange

Adds a utility function for converting CFRanges to NSRanges, asserting
if any of the CFRange's values are outside of NSUInteger's range.

BUG=517791

Review URL: https://codereview.chromium.org/1314753003

Cr-Commit-Position: refs/heads/master@{#346668}

3 files changed, 34 insertions, 0 deletions

diff --git a/base/mac/foundation_util.h b/base/mac/foundation_util.h
index 353ed7c..6e8505d 100644
--- a/base/mac/foundation_util.h
+++ b/base/mac/foundation_util.h
@@ -373,6 +373,14 @@ BASE_EXPORT NSString* FilePathToNSString(const FilePath& path);
 // Converts |str| to a FilePath. Returns an empty path if |str| is nil.
 BASE_EXPORT FilePath NSStringToFilePath(NSString* str);
 
+#if defined(__OBJC__)
+// Converts |range| to an NSRange, returning the new range in |range_out|.
+// Returns true if conversion was successful, false if the values of |range|
+// could not be converted to NSUIntegers.
+BASE_EXPORT bool CFRangeToNSRange(CFRange range,
+                                  NSRange* range_out) WARN_UNUSED_RESULT;
+#endif  // defined(__OBJC__)
+
 }  // namespace mac
 }  // namespace base
 
diff --git a/base/mac/foundation_util.mm b/base/mac/foundation_util.mm
index 27d6e7c..bd5d514 100644
--- a/base/mac/foundation_util.mm
+++ b/base/mac/foundation_util.mm
@@ -11,6 +11,7 @@
 #include "base/logging.h"
 #include "base/mac/bundle_locations.h"
 #include "base/mac/mac_logging.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/strings/sys_string_conversions.h"
 
 #if !defined(OS_IOS)
@@ -430,6 +431,19 @@ FilePath NSStringToFilePath(NSString* str) {
   return FilePath([str fileSystemRepresentation]);
 }
 
+bool CFRangeToNSRange(CFRange range, NSRange* range_out) {
+  if (base::IsValueInRangeForNumericType<decltype(range_out->location)>(
+          range.location) &&
+      base::IsValueInRangeForNumericType<decltype(range_out->length)>(
+          range.length) &&
+      base::IsValueInRangeForNumericType<decltype(range_out->location)>(
+          range.location + range.length)) {
+    *range_out = NSMakeRange(range.location, range.length);
+    return true;
+  }
+  return false;
+}
+
 }  // namespace mac
 }  // namespace base
 
diff --git a/base/mac/foundation_util_unittest.mm b/base/mac/foundation_util_unittest.mm
index e60a0f6..c688442 100644
--- a/base/mac/foundation_util_unittest.mm
+++ b/base/mac/foundation_util_unittest.mm
@@ -317,6 +317,18 @@ TEST(FoundationUtilTest, NSStringToFilePath) {
   EXPECT_EQ(FilePath("/a/b"), NSStringToFilePath(@"/a/b"));
 }
 
+TEST(FoundationUtilTest, CFRangeToNSRange) {
+  NSRange range_out;
+  EXPECT_TRUE(CFRangeToNSRange(CFRangeMake(10, 5), &range_out));
+  EXPECT_EQ(10UL, range_out.location);
+  EXPECT_EQ(5UL, range_out.length);
+  EXPECT_FALSE(CFRangeToNSRange(CFRangeMake(-1, 5), &range_out));
+  EXPECT_FALSE(CFRangeToNSRange(CFRangeMake(5, -1), &range_out));
+  EXPECT_FALSE(CFRangeToNSRange(CFRangeMake(-1, -1), &range_out));
+  EXPECT_FALSE(CFRangeToNSRange(CFRangeMake(LONG_MAX, LONG_MAX), &range_out));
+  EXPECT_FALSE(CFRangeToNSRange(CFRangeMake(LONG_MIN, LONG_MAX), &range_out));
+}
+
 TEST(StringNumberConversionsTest, FormatNSInteger) {
   // The PRI[dxu]NS macro assumes that NSInteger is a typedef to "int" on
   // 32-bit architecture and a typedef to "long" on 64-bit architecture