From 6344ccf0e8dd1c4b3ee819987ecd81f67c82bc67 Mon Sep 17 00:00:00 2001
From: Jan de Mooij <jdemooij@mozilla.com>
Date: Tue, 17 Jun 2014 11:28:50 +0200
Subject: [PATCH] Bug 1025875 part 3 - Make CompareStrings and CompareAtoms
 work with Latin1 strings. r=njn

---
 js/src/jit-test/tests/latin1/compare.js | 20 ++++++++++++
 js/src/jsstr.cpp                        | 42 ++++++++++++++++---------
 js/src/jsstr.h                          |  7 +++--
 3 files changed, 52 insertions(+), 17 deletions(-)
 create mode 100644 js/src/jit-test/tests/latin1/compare.js

diff --git a/js/src/jit-test/tests/latin1/compare.js b/js/src/jit-test/tests/latin1/compare.js
new file mode 100644
index 000000000000..c0203d037508
--- /dev/null
+++ b/js/src/jit-test/tests/latin1/compare.js
@@ -0,0 +1,20 @@
+function test() {
+    var arr = [
+	toLatin1("abc"),
+	toLatin1("abcd"),
+	toLatin1("123\u00ff")
+    ];
+    for (var i = 0; i < arr.length; i++) {
+	for (var j = 0; j < arr.length; j++) {
+	    var s1 = arr[i];
+	    var s2 = arr[j];
+	    var s1tb = "\u1200" + s1;
+	    var s2tb = "\u1200" + s2;
+	    assertEq(s1 < s2, s1tb < s2tb);
+	    assertEq(s1 > s2, s1tb > s2tb);
+	    assertEq(s1 <= s2, s1tb <= s2tb);
+	    assertEq(s1 >= s2, s1tb >= s2tb);
+	}
+    }
+}
+test();
diff --git a/js/src/jsstr.cpp b/js/src/jsstr.cpp
index f995aefef3c0..0132264969db 100644
--- a/js/src/jsstr.cpp
+++ b/js/src/jsstr.cpp
@@ -4521,8 +4521,28 @@ js::EqualStrings(JSLinearString *str1, JSLinearString *str2)
     return EqualChars(str1, str2);
 }
 
-static bool
-CompareStringsImpl(JSContext *cx, JSString *str1, JSString *str2, int32_t *result)
+static int32_t
+CompareStringsImpl(JSLinearString *str1, JSLinearString *str2)
+{
+    size_t len1 = str1->length();
+    size_t len2 = str2->length();
+
+    AutoCheckCannotGC nogc;
+    if (str1->hasLatin1Chars()) {
+        const Latin1Char *chars1 = str1->latin1Chars(nogc);
+        return str2->hasLatin1Chars()
+               ? CompareChars(chars1, len1, str2->latin1Chars(nogc), len2)
+               : CompareChars(chars1, len1, str2->twoByteChars(nogc), len2);
+    }
+
+    const jschar *chars1 = str1->twoByteChars(nogc);
+    return str2->hasLatin1Chars()
+           ? CompareChars(chars1, len1, str2->latin1Chars(nogc), len2)
+           : CompareChars(chars1, len1, str2->twoByteChars(nogc), len2);
+}
+
+bool
+js::CompareStrings(JSContext *cx, JSString *str1, JSString *str2, int32_t *result)
 {
     JS_ASSERT(str1);
     JS_ASSERT(str2);
@@ -4532,28 +4552,22 @@ CompareStringsImpl(JSContext *cx, JSString *str1, JSString *str2, int32_t *resul
         return true;
     }
 
-    const jschar *s1 = str1->getChars(cx);
-    if (!s1)
+    JSLinearString *linear1 = str1->ensureLinear(cx);
+    if (!linear1)
         return false;
 
-    const jschar *s2 = str2->getChars(cx);
-    if (!s2)
+    JSLinearString *linear2 = str2->ensureLinear(cx);
+    if (!linear2)
         return false;
 
-    *result = CompareChars(s1, str1->length(), s2, str2->length());
+    *result = CompareStringsImpl(linear1, linear2);
     return true;
 }
 
-bool
-js::CompareStrings(JSContext *cx, JSString *str1, JSString *str2, int32_t *result)
-{
-    return CompareStringsImpl(cx, str1, str2, result);
-}
-
 int32_t
 js::CompareAtoms(JSAtom *atom1, JSAtom *atom2)
 {
-    return CompareChars(atom1->chars(), atom1->length(), atom2->chars(), atom2->length());
+    return CompareStringsImpl(atom1, atom2);
 }
 
 bool
diff --git a/js/src/jsstr.h b/js/src/jsstr.h
index b021daf20a9b..49e3d4d4f1e8 100644
--- a/js/src/jsstr.h
+++ b/js/src/jsstr.h
@@ -48,16 +48,17 @@ SkipSpace(const CharT *s, const CharT *end)
 
 // Return less than, equal to, or greater than zero depending on whether
 // s1 is less than, equal to, or greater than s2.
+template <typename Char1, typename Char2>
 inline int32_t
-CompareChars(const jschar *s1, size_t l1, const jschar *s2, size_t l2)
+CompareChars(const Char1 *s1, size_t len1, const Char2 *s2, size_t len2)
 {
-    size_t n = Min(l1, l2);
+    size_t n = Min(len1, len2);
     for (size_t i = 0; i < n; i++) {
         if (int32_t cmp = s1[i] - s2[i])
             return cmp;
     }
 
-    return (int32_t)(l1 - l2);
+    return int32_t(len1 - len2);
 }
 
 }  /* namespace js */