From: Alex Malyshev <alexanderm@fb.com>
Date: Tue, 14 Feb 2017 19:09:42 +0000 (-0800)
Subject: Add overloads of Range::{start,end}sWith with custom comparator
X-Git-Tag: v2017.03.06.00~38
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=41cee12b073235250d4df38b6179f8c2977a6b39;p=folly.git

Add overloads of Range::{start,end}sWith with custom comparator

Summary: Intended to be used for case-insensitive prefix/suffix matching.

Reviewed By: yfeldblum

Differential Revision: D4552336

fbshipit-source-id: 0030b883426dd67bea27c3f878279359d51e1d33
---

diff --git a/folly/Range.h b/folly/Range.h
index bfbb4eb0..eb53f937 100644
--- a/folly/Range.h
+++ b/folly/Range.h
@@ -659,6 +659,16 @@ public:
     return !empty() && front() == c;
   }
 
+  template <class Comp>
+  bool startsWith(const const_range_type& other, Comp&& eq) const {
+    if (size() < other.size()) {
+      return false;
+    }
+    auto const trunc = subpiece(0, other.size());
+    return std::equal(
+        trunc.begin(), trunc.end(), other.begin(), std::forward<Comp>(eq));
+  }
+
   /**
    * Does this Range end with another range?
    */
@@ -670,6 +680,16 @@ public:
     return !empty() && back() == c;
   }
 
+  template <class Comp>
+  bool endsWith(const const_range_type& other, Comp&& eq) const {
+    if (size() < other.size()) {
+      return false;
+    }
+    auto const trunc = subpiece(size() - other.size());
+    return std::equal(
+        trunc.begin(), trunc.end(), other.begin(), std::forward<Comp>(eq));
+  }
+
   /**
    * Remove the items in [b, e), as long as this subrange is at the beginning
    * or end of the Range.
diff --git a/folly/test/RangeTest.cpp b/folly/test/RangeTest.cpp
index d4f65865..791df2a0 100644
--- a/folly/test/RangeTest.cpp
+++ b/folly/test/RangeTest.cpp
@@ -315,6 +315,15 @@ TEST(StringPiece, Prefix) {
   EXPECT_FALSE(a.startsWith('x'));
   EXPECT_FALSE(a.startsWith("x"));
 
+  EXPECT_TRUE(a.startsWith("", folly::AsciiCaseInsensitive()));
+  EXPECT_TRUE(a.startsWith("hello", folly::AsciiCaseInsensitive()));
+  EXPECT_TRUE(a.startsWith("hellO", folly::AsciiCaseInsensitive()));
+  EXPECT_TRUE(a.startsWith("HELL", folly::AsciiCaseInsensitive()));
+  EXPECT_TRUE(a.startsWith("H", folly::AsciiCaseInsensitive()));
+  EXPECT_FALSE(a.startsWith("HELLOX", folly::AsciiCaseInsensitive()));
+  EXPECT_FALSE(a.startsWith("x", folly::AsciiCaseInsensitive()));
+  EXPECT_FALSE(a.startsWith("X", folly::AsciiCaseInsensitive()));
+
   {
     auto b = a;
     EXPECT_TRUE(b.removePrefix(""));
@@ -362,6 +371,16 @@ TEST(StringPiece, Suffix) {
   EXPECT_FALSE(a.endsWith("x"));
   EXPECT_FALSE(a.endsWith('x'));
 
+  EXPECT_TRUE(a.endsWith("", folly::AsciiCaseInsensitive()));
+  EXPECT_TRUE(a.endsWith("o", folly::AsciiCaseInsensitive()));
+  EXPECT_TRUE(a.endsWith("O", folly::AsciiCaseInsensitive()));
+  EXPECT_TRUE(a.endsWith("hello", folly::AsciiCaseInsensitive()));
+  EXPECT_TRUE(a.endsWith("hellO", folly::AsciiCaseInsensitive()));
+  EXPECT_FALSE(a.endsWith("xhello", folly::AsciiCaseInsensitive()));
+  EXPECT_FALSE(a.endsWith("Xhello", folly::AsciiCaseInsensitive()));
+  EXPECT_FALSE(a.endsWith("x", folly::AsciiCaseInsensitive()));
+  EXPECT_FALSE(a.endsWith("X", folly::AsciiCaseInsensitive()));
+
   {
     auto b = a;
     EXPECT_TRUE(b.removeSuffix(""));