From cc42afc14b6e54750a95b0e5fd7f01664280c36e Mon Sep 17 00:00:00 2001
From: Lei Zhang <thestig@chromium.org>
Date: Wed, 20 Dec 2017 19:05:00 +0000
Subject: Combine operator< and ByteString::Compare().

Fix or optimize some ByteString::Compare() callers.

Change-Id: I0fde91afc3d17fe160b46d00a441ad05e56377e7
Reviewed-on: https://pdfium-review.googlesource.com/20851
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
---
 core/fpdfapi/font/cpdf_font.cpp  |  3 +--
 core/fxcrt/bytestring.cpp        | 28 +++++++---------------------
 fxjs/cfxjse_formcalc_context.cpp | 24 ++++++++++++------------
 3 files changed, 20 insertions(+), 35 deletions(-)

diff --git a/core/fpdfapi/font/cpdf_font.cpp b/core/fpdfapi/font/cpdf_font.cpp
index 12e5aaf3a8..8d35739d78 100644
--- a/core/fpdfapi/font/cpdf_font.cpp
+++ b/core/fpdfapi/font/cpdf_font.cpp
@@ -395,9 +395,8 @@ void CPDF_Font::LoadPDFEncoding(CPDF_Object* pEncoding,
   if (iBaseEncoding != PDFFONT_ENCODING_ADOBE_SYMBOL &&
       iBaseEncoding != PDFFONT_ENCODING_ZAPFDINGBATS) {
     ByteString bsEncoding = pDict->GetStringFor("BaseEncoding");
-    if (bsEncoding.Compare("MacExpertEncoding") == 0 && bTrueType) {
+    if (bTrueType && bsEncoding.Compare("MacExpertEncoding") == 0)
       bsEncoding = "WinAnsiEncoding";
-    }
     GetPredefinedEncoding(bsEncoding, &iBaseEncoding);
   }
   if ((!bEmbedded || bTrueType) && iBaseEncoding == PDFFONT_ENCODING_BUILTIN)
diff --git a/core/fxcrt/bytestring.cpp b/core/fxcrt/bytestring.cpp
index 324a2801e4..4c4bd57393 100644
--- a/core/fxcrt/bytestring.cpp
+++ b/core/fxcrt/bytestring.cpp
@@ -317,16 +317,7 @@ bool ByteString::operator<(const char* ptr) const {
 }
 
 bool ByteString::operator<(const ByteStringView& str) const {
-  if (!m_pData && !str.unterminated_c_str())
-    return false;
-  if (c_str() == str.unterminated_c_str())
-    return false;
-
-  size_t len = GetLength();
-  size_t other_len = str.GetLength();
-  int result =
-      memcmp(c_str(), str.unterminated_c_str(), std::min(len, other_len));
-  return result < 0 || (result == 0 && len < other_len);
+  return Compare(str) < 0;
 }
 
 bool ByteString::operator<(const ByteString& other) const {
@@ -717,17 +708,12 @@ int ByteString::Compare(const ByteStringView& str) const {
   size_t this_len = m_pData->m_nDataLength;
   size_t that_len = str.GetLength();
   size_t min_len = std::min(this_len, that_len);
-  for (size_t i = 0; i < min_len; i++) {
-    if (static_cast<uint8_t>(m_pData->m_String[i]) < str[i])
-      return -1;
-    if (static_cast<uint8_t>(m_pData->m_String[i]) > str[i])
-      return 1;
-  }
-  if (this_len < that_len)
-    return -1;
-  if (this_len > that_len)
-    return 1;
-  return 0;
+  int result = memcmp(m_pData->m_String, str.unterminated_c_str(), min_len);
+  if (result != 0)
+    return result;
+  if (this_len == that_len)
+    return 0;
+  return this_len < that_len ? -1 : 1;
 }
 
 void ByteString::Trim() {
diff --git a/fxjs/cfxjse_formcalc_context.cpp b/fxjs/cfxjse_formcalc_context.cpp
index b02e5a9d41..f9d130a119 100644
--- a/fxjs/cfxjse_formcalc_context.cpp
+++ b/fxjs/cfxjse_formcalc_context.cpp
@@ -4976,9 +4976,9 @@ void CFXJSE_FormCalcContext::less_operator(CFXJSE_Value* pThis,
   }
 
   if (argFirst->IsString() && argSecond->IsString()) {
-    args.GetReturnValue()->SetInteger(
-        argFirst->ToString().Compare(argSecond->ToString().AsStringView()) ==
-        -1);
+    int result =
+        argFirst->ToString().Compare(argSecond->ToString().AsStringView()) < 0;
+    args.GetReturnValue()->SetInteger(result);
     return;
   }
 
@@ -5006,9 +5006,9 @@ void CFXJSE_FormCalcContext::lessequal_operator(
   }
 
   if (argFirst->IsString() && argSecond->IsString()) {
-    args.GetReturnValue()->SetInteger(
-        argFirst->ToString().Compare(argSecond->ToString().AsStringView()) !=
-        1);
+    int result =
+        argFirst->ToString().Compare(argSecond->ToString().AsStringView()) <= 0;
+    args.GetReturnValue()->SetInteger(result);
     return;
   }
 
@@ -5034,9 +5034,9 @@ void CFXJSE_FormCalcContext::greater_operator(CFXJSE_Value* pThis,
   }
 
   if (argFirst->IsString() && argSecond->IsString()) {
-    args.GetReturnValue()->SetInteger(
-        argFirst->ToString().Compare(argSecond->ToString().AsStringView()) ==
-        1);
+    int result =
+        argFirst->ToString().Compare(argSecond->ToString().AsStringView()) > 0;
+    args.GetReturnValue()->SetInteger(result);
     return;
   }
 
@@ -5064,9 +5064,9 @@ void CFXJSE_FormCalcContext::greaterequal_operator(
   }
 
   if (argFirst->IsString() && argSecond->IsString()) {
-    args.GetReturnValue()->SetInteger(
-        argFirst->ToString().Compare(argSecond->ToString().AsStringView()) !=
-        -1);
+    int result =
+        argFirst->ToString().Compare(argSecond->ToString().AsStringView()) >= 0;
+    args.GetReturnValue()->SetInteger(result);
     return;
   }
 
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