Introduce FX_Number class as a replacement for FX_atonum().

The issue with FX_atonum() is that it doesn't return any information
about whether it range-checked its integer values as a signed or
unsigned type, even though it knows this as part of its processing.

Rather than adding another out parameter to that function, create
a class to hold all this information together.

This is the first place things went astray while diagnosing
bug 882959, in that a large positive value was cast to float as a
negative value. Unfortunately, this doesn't affect the related bug,
but is a step in the right direction.

Change-Id: I0977ec8fccf85e2632a962507bdd30a1cbe6d33c
Reviewed-on: https://pdfium-review.googlesource.com/42353
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

1 files changed, 14 insertions, 17 deletions

diff --git a/core/fpdfapi/page/cpdf_streamcontentparser.cpp b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
index 2244232ecb..20892cc264 100644
--- a/core/fpdfapi/page/cpdf_streamcontentparser.cpp
+++ b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
@@ -338,7 +338,7 @@ void CPDF_StreamContentParser::AddNameParam(const ByteStringView& bsName) {
 void CPDF_StreamContentParser::AddNumberParam(const ByteStringView& str) {
   ContentParam& param = m_ParamBuf[GetNextParamPos()];
   param.m_Type = ContentParam::NUMBER;
-  param.m_Number.m_bInteger = FX_atonum(str, &param.m_Number.m_Integer);
+  param.m_Number = FX_Number(str);
 }
 
 void CPDF_StreamContentParser::AddObjectParam(
@@ -373,9 +373,9 @@ CPDF_Object* CPDF_StreamContentParser::GetObject(uint32_t index) {
   if (param.m_Type == ContentParam::NUMBER) {
     param.m_Type = ContentParam::OBJECT;
     param.m_pObject =
-        param.m_Number.m_bInteger
-            ? pdfium::MakeUnique<CPDF_Number>(param.m_Number.m_Integer)
-            : pdfium::MakeUnique<CPDF_Number>(param.m_Number.m_Float);
+        param.m_Number.IsInteger()
+            ? pdfium::MakeUnique<CPDF_Number>(param.m_Number.GetSigned())
+            : pdfium::MakeUnique<CPDF_Number>(param.m_Number.GetFloat());
     return param.m_pObject.get();
   }
   if (param.m_Type == ContentParam::NAME) {
@@ -411,21 +411,20 @@ ByteString CPDF_StreamContentParser::GetString(uint32_t index) const {
 }
 
 float CPDF_StreamContentParser::GetNumber(uint32_t index) const {
-  if (index >= m_ParamCount) {
+  if (index >= m_ParamCount)
     return 0;
-  }
+
   int real_index = m_ParamStartPos + m_ParamCount - index - 1;
-  if (real_index >= kParamBufSize) {
+  if (real_index >= kParamBufSize)
     real_index -= kParamBufSize;
-  }
+
   const ContentParam& param = m_ParamBuf[real_index];
-  if (param.m_Type == ContentParam::NUMBER) {
-    return param.m_Number.m_bInteger
-               ? static_cast<float>(param.m_Number.m_Integer)
-               : param.m_Number.m_Float;
-  }
+  if (param.m_Type == ContentParam::NUMBER)
+    return param.m_Number.GetFloat();
+
   if (param.m_Type == 0 && param.m_pObject)
     return param.m_pObject->GetNumber();
+
   return 0;
 }
 
@@ -1632,10 +1631,8 @@ void CPDF_StreamContentParser::ParsePathObject() {
         if (nParams == 6)
           break;
 
-        int value;
-        bool bInteger = FX_atonum(m_pSyntax->GetWord(), &value);
-        params[nParams++] = bInteger ? static_cast<float>(value)
-                                     : *reinterpret_cast<float*>(&value);
+        FX_Number number(m_pSyntax->GetWord());
+        params[nParams++] = number.GetFloat();
         break;
       }
       default: