Remove hand-written bsearch from XFA_GetAttributeByName()

Also fix potential for collisions by checking exact name.

Change-Id: I48cd609d28a23f738f7a6c946820a688a4163024
Reviewed-on: https://pdfium-review.googlesource.com/4314
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

2 files changed, 19 insertions, 13 deletions

diff --git a/xfa/fxfa/parser/xfa_utils.cpp b/xfa/fxfa/parser/xfa_utils.cpp
index 6bd04c322f..75d017b070 100644
--- a/xfa/fxfa/parser/xfa_utils.cpp
+++ b/xfa/fxfa/parser/xfa_utils.cpp
@@ -6,6 +6,8 @@
 
 #include "xfa/fxfa/parser/xfa_utils.h"
 
+#include <algorithm>
+
 #include "core/fxcrt/fx_ext.h"
 #include "xfa/fde/xml/cfde_xmlchardata.h"
 #include "xfa/fde/xml/cfde_xmlelement.h"
@@ -432,19 +434,14 @@ const XFA_ATTRIBUTEINFO* XFA_GetAttributeByName(const CFX_WideStringC& wsName) {
   if (wsName.IsEmpty())
     return nullptr;
 
-  uint32_t uHash = FX_HashCode_GetW(wsName, false);
-  int32_t iStart = 0;
-  int32_t iEnd = g_iXFAAttributeCount - 1;
-  do {
-    int32_t iMid = (iStart + iEnd) / 2;
-    const XFA_ATTRIBUTEINFO* pInfo = g_XFAAttributeData + iMid;
-    if (uHash == pInfo->uHash)
-      return pInfo;
-    if (uHash < pInfo->uHash)
-      iEnd = iMid - 1;
-    else
-      iStart = iMid + 1;
-  } while (iStart <= iEnd);
+  auto* it = std::lower_bound(g_XFAAttributeData,
+                              g_XFAAttributeData + g_iXFAAttributeCount,
+                              FX_HashCode_GetW(wsName, false),
+                              [](const XFA_ATTRIBUTEINFO& arg, uint32_t hash) {
+                                return arg.uHash < hash;
+                              });
+  if (it != g_XFAAttributeData + g_iXFAAttributeCount && wsName == it->pName)
+    return it;
   return nullptr;
 }
 
diff --git a/xfa/fxfa/parser/xfa_utils_unittest.cpp b/xfa/fxfa/parser/xfa_utils_unittest.cpp
index e4dd09419e..1898a797ec 100644
--- a/xfa/fxfa/parser/xfa_utils_unittest.cpp
+++ b/xfa/fxfa/parser/xfa_utils_unittest.cpp
@@ -273,3 +273,12 @@ TEST_F(XFANodeIteratorTest, ChildAsRootNext) {
   EXPECT_EQ(child6(), iter.MoveToNext());
   EXPECT_EQ(nullptr, iter.MoveToNext());
 }
+
+TEST(XFAUtilsTest, GetAttributeByName) {
+  EXPECT_EQ(nullptr, XFA_GetAttributeByName(L""));
+  EXPECT_EQ(nullptr, XFA_GetAttributeByName(L"clams"));
+  EXPECT_EQ(XFA_ATTRIBUTE_H, XFA_GetAttributeByName(L"h")->eName);
+  EXPECT_EQ(XFA_ATTRIBUTE_Short, XFA_GetAttributeByName(L"short")->eName);
+  EXPECT_EQ(XFA_ATTRIBUTE_DecipherOnly,
+            XFA_GetAttributeByName(L"decipherOnly")->eName);
+}