Replace raw value for constant error value in string operations

Currently Find() and other methods that return a FX_STRSIZE return -1
to indicate error/failure. This means that there is a lot of magic
numbers and magic checks floating around. The standard library for
similar operations uses a npos constant. This CL implements
FX_STRNPOS, and replaces usages of magic number checking. It also does
some type cleanup along the way where it was obvious that FX_STRSIZE
should be being used.

Removing the magic numbers should make eventually changing FX_STRSIZE
to be unsigned easier in the future.

BUG=pdfium:828

Change-Id: I67e481e44cf2f75a1698afa8fbee4f375a74c490
Reviewed-on: https://pdfium-review.googlesource.com/9651
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

8 files changed, 40 insertions, 34 deletions

diff --git a/core/fxge/android/cfpf_skiafontmgr.cpp b/core/fxge/android/cfpf_skiafontmgr.cpp
index 23fcd5bbec..3cee6decac 100644
--- a/core/fxge/android/cfpf_skiafontmgr.cpp
+++ b/core/fxge/android/cfpf_skiafontmgr.cpp
@@ -194,13 +194,13 @@ bool FPF_SkiaIsCJK(uint8_t uCharset) {
 bool FPF_SkiaMaybeSymbol(const CFX_ByteStringC& bsFacename) {
   CFX_ByteString bsName(bsFacename);
   bsName.MakeLower();
-  return bsName.Find("symbol") > -1;
+  return bsName.Find("symbol") != FX_STRNPOS;
 }
 
 bool FPF_SkiaMaybeArabic(const CFX_ByteStringC& bsFacename) {
   CFX_ByteString bsName(bsFacename);
   bsName.MakeLower();
-  return bsName.Find("arabic") > -1;
+  return bsName.Find("arabic") != FX_STRNPOS;
 }
 
 const uint32_t g_FPFSkiaFontCharsets[] = {
diff --git a/core/fxge/apple/fx_mac_imp.cpp b/core/fxge/apple/fx_mac_imp.cpp
index 78fe16459c..54aac7bfa6 100644
--- a/core/fxge/apple/fx_mac_imp.cpp
+++ b/core/fxge/apple/fx_mac_imp.cpp
@@ -52,7 +52,7 @@ const char JAPAN_GOTHIC[] = "Hiragino Kaku Gothic Pro W6";
 const char JAPAN_MINCHO[] = "Hiragino Mincho Pro W6";
 
 void GetJapanesePreference(CFX_ByteString* face, int weight, int pitch_family) {
-  if (face->Find("Gothic") >= 0) {
+  if (face->Find("Gothic") != FX_STRNPOS) {
     *face = JAPAN_GOTHIC;
     return;
   }
@@ -82,7 +82,7 @@ void* CFX_MacFontInfo::MapFont(int weight,
   // Times New Roman. A more sophisticated approach would be to find all the
   // fonts in |m_FontList| with |face| in the name, and examine the fonts to
   // see which best matches the requested characteristics.
-  if (face.Find("Bold") == -1 && face.Find("Italic") == -1) {
+  if (face.Find("Bold") == FX_STRNPOS && face.Find("Italic") == FX_STRNPOS) {
     CFX_ByteString new_face = face;
     if (weight > 400)
       new_face += " Bold";
diff --git a/core/fxge/cfx_folderfontinfo.cpp b/core/fxge/cfx_folderfontinfo.cpp
index 12e7dd25fc..f16722c4d6 100644
--- a/core/fxge/cfx_folderfontinfo.cpp
+++ b/core/fxge/cfx_folderfontinfo.cpp
@@ -251,11 +251,11 @@ void CFX_FolderFontInfo::ReportFace(const CFX_ByteString& path,
   m_pMapper->AddInstalledFont(facename, FX_CHARSET_ANSI);
   pInfo->m_Charsets |= CHARSET_FLAG_ANSI;
   pInfo->m_Styles = 0;
-  if (style.Find("Bold") > -1)
+  if (style.Find("Bold") != FX_STRNPOS)
     pInfo->m_Styles |= FXFONT_BOLD;
-  if (style.Find("Italic") > -1 || style.Find("Oblique") > -1)
+  if (style.Find("Italic") != FX_STRNPOS || style.Find("Oblique") != FX_STRNPOS)
     pInfo->m_Styles |= FXFONT_ITALIC;
-  if (facename.Find("Serif") > -1)
+  if (facename.Find("Serif") != FX_STRNPOS)
     pInfo->m_Styles |= FXFONT_SERIF;
 
   m_FontList[facename] = std::move(pInfo);
@@ -289,7 +289,7 @@ void* CFX_FolderFontInfo::FindFont(int weight,
       continue;
 
     int32_t index = bsName.Find(family);
-    if (bMatchName && index < 0)
+    if (bMatchName && index == FX_STRNPOS)
       continue;
 
     int32_t iSimilarValue =
diff --git a/core/fxge/cfx_font.cpp b/core/fxge/cfx_font.cpp
index a8e271dd9a..1fd08f2676 100644
--- a/core/fxge/cfx_font.cpp
+++ b/core/fxge/cfx_font.cpp
@@ -447,7 +447,7 @@ bool CFX_Font::IsItalic() const {
 
   CFX_ByteString str(FXFT_Get_Face_Style_Name(m_Face));
   str.MakeLower();
-  return str.Find("italic") != -1;
+  return str.Find("italic") != FX_STRNPOS;
 }
 
 bool CFX_Font::IsBold() const {
diff --git a/core/fxge/cfx_fontmapper.cpp b/core/fxge/cfx_fontmapper.cpp
index 4c0073ab73..b8ffe047a3 100644
--- a/core/fxge/cfx_fontmapper.cpp
+++ b/core/fxge/cfx_fontmapper.cpp
@@ -172,7 +172,7 @@ const struct CODEPAGE_MAP {
 int CompareFontFamilyString(const void* key, const void* element) {
   CFX_ByteString str_key((const char*)key);
   const AltFontFamily* family = reinterpret_cast<const AltFontFamily*>(element);
-  if (str_key.Find(family->m_pFontName) != -1)
+  if (str_key.Find(family->m_pFontName) != FX_STRNPOS)
     return 0;
   return FXSYS_stricmp(reinterpret_cast<const char*>(key), family->m_pFontName);
 }
@@ -187,8 +187,8 @@ CFX_ByteString TT_NormalizeName(const char* family) {
   norm.Remove(' ');
   norm.Remove('-');
   norm.Remove(',');
-  int pos = norm.Find('+');
-  if (pos > 0)
+  FX_STRSIZE pos = norm.Find('+');
+  if (pos != 0 && pos != FX_STRNPOS)
     norm = norm.Left(pos);
   norm.MakeLower();
   return norm;
diff --git a/core/fxge/cfx_renderdevice.cpp b/core/fxge/cfx_renderdevice.cpp
index 279e720d1e..310a16512c 100644
--- a/core/fxge/cfx_renderdevice.cpp
+++ b/core/fxge/cfx_renderdevice.cpp
@@ -337,7 +337,7 @@ bool ShouldDrawDeviceText(const CFX_Font* pFont, uint32_t text_flags) {
     return false;
 
   const CFX_ByteString bsPsName = pFont->GetPsName();
-  if (bsPsName.Find("+ZJHL") != -1)
+  if (bsPsName.Find("+ZJHL") != FX_STRNPOS)
     return false;
 
   if (bsPsName == "CNAAJI+cmex10")
diff --git a/core/fxge/fx_ge_linux.cpp b/core/fxge/fx_ge_linux.cpp
index d9fac3f54c..0552f1c58c 100644
--- a/core/fxge/fx_ge_linux.cpp
+++ b/core/fxge/fx_ge_linux.cpp
@@ -45,17 +45,18 @@ size_t GetJapanesePreference(const char* facearr,
                              int weight,
                              int pitch_family) {
   CFX_ByteString face = facearr;
-  if (face.Find("Gothic") >= 0 ||
-      face.Find("\x83\x53\x83\x56\x83\x62\x83\x4e") >= 0) {
-    if (face.Find("PGothic") >= 0 ||
-        face.Find("\x82\x6f\x83\x53\x83\x56\x83\x62\x83\x4e") >= 0) {
+  if (face.Find("Gothic") != FX_STRNPOS ||
+      face.Find("\x83\x53\x83\x56\x83\x62\x83\x4e") != FX_STRNPOS) {
+    if (face.Find("PGothic") != FX_STRNPOS ||
+        face.Find("\x82\x6f\x83\x53\x83\x56\x83\x62\x83\x4e") != FX_STRNPOS) {
       return 0;
     }
     return 1;
   }
-  if (face.Find("Mincho") >= 0 || face.Find("\x96\xbe\x92\xa9") >= 0) {
-    if (face.Find("PMincho") >= 0 ||
-        face.Find("\x82\x6f\x96\xbe\x92\xa9") >= 0) {
+  if (face.Find("Mincho") != FX_STRNPOS ||
+      face.Find("\x96\xbe\x92\xa9") != FX_STRNPOS) {
+    if (face.Find("PMincho") != FX_STRNPOS ||
+        face.Find("\x82\x6f\x96\xbe\x92\xa9") != FX_STRNPOS) {
       return 2;
     }
     return 3;
diff --git a/core/fxge/win32/fx_win32_device.cpp b/core/fxge/win32/fx_win32_device.cpp
index 4427755cf5..b707a76c08 100644
--- a/core/fxge/win32/fx_win32_device.cpp
+++ b/core/fxge/win32/fx_win32_device.cpp
@@ -503,7 +503,7 @@ void* CFX_Win32FallbackFontInfo::MapFont(int weight,
 void CFX_Win32FontInfo::GetGBPreference(CFX_ByteString& face,
                                         int weight,
                                         int picth_family) {
-  if (face.Find("KaiTi") >= 0 || face.Find("\xbf\xac") >= 0) {
+  if (face.Find("KaiTi") != FX_STRNPOS || face.Find("\xbf\xac") != FX_STRNPOS) {
     if (m_KaiTi.IsEmpty()) {
       m_KaiTi = FindFont("KaiTi");
       if (m_KaiTi.IsEmpty()) {
@@ -511,7 +511,8 @@ void CFX_Win32FontInfo::GetGBPreference(CFX_ByteString& face,
       }
     }
     face = m_KaiTi;
-  } else if (face.Find("FangSong") >= 0 || face.Find("\xb7\xc2\xcb\xce") >= 0) {
+  } else if (face.Find("FangSong") != FX_STRNPOS ||
+             face.Find("\xb7\xc2\xcb\xce") != FX_STRNPOS) {
     if (m_FangSong.IsEmpty()) {
       m_FangSong = FindFont("FangSong");
       if (m_FangSong.IsEmpty()) {
@@ -519,9 +520,11 @@ void CFX_Win32FontInfo::GetGBPreference(CFX_ByteString& face,
       }
     }
     face = m_FangSong;
-  } else if (face.Find("SimSun") >= 0 || face.Find("\xcb\xce") >= 0) {
+  } else if (face.Find("SimSun") != FX_STRNPOS ||
+             face.Find("\xcb\xce") != FX_STRNPOS) {
     face = "SimSun";
-  } else if (face.Find("SimHei") >= 0 || face.Find("\xba\xda") >= 0) {
+  } else if (face.Find("SimHei") != FX_STRNPOS ||
+             face.Find("\xba\xda") != FX_STRNPOS) {
     face = "SimHei";
   } else if (!(picth_family & FF_ROMAN) && weight > 550) {
     face = "SimHei";
@@ -533,15 +536,16 @@ void CFX_Win32FontInfo::GetGBPreference(CFX_ByteString& face,
 void CFX_Win32FontInfo::GetJapanesePreference(CFX_ByteString& face,
                                               int weight,
                                               int picth_family) {
-  if (face.Find("Gothic") >= 0 ||
-      face.Find("\x83\x53\x83\x56\x83\x62\x83\x4e") >= 0) {
-    if (face.Find("PGothic") >= 0 ||
-        face.Find("\x82\x6f\x83\x53\x83\x56\x83\x62\x83\x4e") >= 0) {
+  if (face.Find("Gothic") != FX_STRNPOS ||
+      face.Find("\x83\x53\x83\x56\x83\x62\x83\x4e") != FX_STRNPOS) {
+    if (face.Find("PGothic") != FX_STRNPOS ||
+        face.Find("\x82\x6f\x83\x53\x83\x56\x83\x62\x83\x4e") != FX_STRNPOS) {
       face = "MS PGothic";
-    } else if (face.Find("UI Gothic") >= 0) {
+    } else if (face.Find("UI Gothic") != FX_STRNPOS) {
       face = "MS UI Gothic";
     } else {
-      if (face.Find("HGSGothicM") >= 0 || face.Find("HGMaruGothicMPRO") >= 0) {
+      if (face.Find("HGSGothicM") != FX_STRNPOS ||
+          face.Find("HGMaruGothicMPRO") != FX_STRNPOS) {
         face = "MS PGothic";
       } else {
         face = "MS Gothic";
@@ -549,9 +553,10 @@ void CFX_Win32FontInfo::GetJapanesePreference(CFX_ByteString& face,
     }
     return;
   }
-  if (face.Find("Mincho") >= 0 || face.Find("\x96\xbe\x92\xa9") >= 0) {
-    if (face.Find("PMincho") >= 0 ||
-        face.Find("\x82\x6f\x96\xbe\x92\xa9") >= 0) {
+  if (face.Find("Mincho") != FX_STRNPOS ||
+      face.Find("\x96\xbe\x92\xa9") != FX_STRNPOS) {
+    if (face.Find("PMincho") != FX_STRNPOS ||
+        face.Find("\x82\x6f\x96\xbe\x92\xa9") != FX_STRNPOS) {
       face = "MS PMincho";
     } else {
       face = "MS Mincho";
@@ -635,7 +640,7 @@ void* CFX_Win32FontInfo::MapFont(int weight,
       face = "Gulim";
       break;
     case FX_CHARSET_ChineseTraditional:
-      if (face.Find("MSung") >= 0) {
+      if (face.Find("MSung") != FX_STRNPOS) {
         face = "MingLiU";
       } else {
         face = "PMingLiU";