Convert FX_STRSIZE int->size_t

Change the underlying type for FX_STRSIZE to size_t from int. This
will make the value unsigned and thus all values in the range of the
type will be valid. This allows for the final remove of negative
length strings, but also introduces a some casting and functional 
errors, since many parts of the code base assume that FX_STRSIZE is 
int or another signed type. This also CL fixes these errors.

BUG=pdfium:828

Change-Id: I231dca59e96fc9330cbb099eecbdfc41fcf86f5b
Reviewed-on: https://pdfium-review.googlesource.com/11830
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>

1 files changed, 12 insertions, 18 deletions

diff --git a/core/fxcrt/cfx_bytestring.cpp b/core/fxcrt/cfx_bytestring.cpp
index ab7c9aee99..20497ecc32 100644
--- a/core/fxcrt/cfx_bytestring.cpp
+++ b/core/fxcrt/cfx_bytestring.cpp
@@ -90,20 +90,14 @@ static_assert(sizeof(CFX_ByteString) <= sizeof(char*),
               "Strings must not require more space than pointers");
 
 CFX_ByteString::CFX_ByteString(const char* pStr, FX_STRSIZE nLen) {
-  ASSERT(nLen >= 0);
-  if (nLen < 0)
-    nLen = pStr ? FXSYS_strlen(pStr) : 0;
-
   if (nLen)
     m_pData.Reset(StringData::Create(pStr, nLen));
 }
 
 CFX_ByteString::CFX_ByteString(const uint8_t* pStr, FX_STRSIZE nLen) {
-  ASSERT(nLen >= 0);
-  if (nLen > 0) {
+  if (nLen)
     m_pData.Reset(
         StringData::Create(reinterpret_cast<const char*>(pStr), nLen));
-  }
 }
 
 CFX_ByteString::CFX_ByteString() {}
@@ -302,7 +296,7 @@ void CFX_ByteString::ReallocBeforeWrite(FX_STRSIZE nNewLength) {
   if (m_pData && m_pData->CanOperateInPlace(nNewLength))
     return;
 
-  if (nNewLength <= 0) {
+  if (nNewLength == 0) {
     clear();
     return;
   }
@@ -323,7 +317,7 @@ void CFX_ByteString::AllocBeforeWrite(FX_STRSIZE nNewLength) {
   if (m_pData && m_pData->CanOperateInPlace(nNewLength))
     return;
 
-  if (nNewLength <= 0) {
+  if (nNewLength == 0) {
     clear();
     return;
   }
@@ -332,7 +326,6 @@ void CFX_ByteString::AllocBeforeWrite(FX_STRSIZE nNewLength) {
 }
 
 void CFX_ByteString::ReleaseBuffer(FX_STRSIZE nNewLength) {
-  ASSERT(nNewLength >= 0);
   if (!m_pData)
     return;
 
@@ -387,7 +380,8 @@ FX_STRSIZE CFX_ByteString::Delete(FX_STRSIZE index, FX_STRSIZE count) {
     return 0;
 
   FX_STRSIZE old_length = m_pData->m_nDataLength;
-  if (count <= 0 || index != pdfium::clamp(index, 0, old_length))
+  if (count == 0 ||
+      index != pdfium::clamp(index, static_cast<FX_STRSIZE>(0), old_length))
     return old_length;
 
   FX_STRSIZE removal_length = index + count;
@@ -403,7 +397,7 @@ FX_STRSIZE CFX_ByteString::Delete(FX_STRSIZE index, FX_STRSIZE count) {
 }
 
 void CFX_ByteString::Concat(const char* pSrcData, FX_STRSIZE nSrcLen) {
-  if (!pSrcData || nSrcLen <= 0)
+  if (!pSrcData || nSrcLen == 0)
     return;
 
   if (!m_pData) {
@@ -460,7 +454,7 @@ CFX_ByteString CFX_ByteString::Right(FX_STRSIZE count) const {
 void CFX_ByteString::AllocCopy(CFX_ByteString& dest,
                                FX_STRSIZE nCopyLen,
                                FX_STRSIZE nCopyIndex) const {
-  if (nCopyLen <= 0)
+  if (nCopyLen == 0)
     return;
 
   CFX_RetainPtr<StringData> pNewData(
@@ -700,13 +694,13 @@ int CFX_ByteString::Compare(const CFX_ByteStringC& str) const {
 }
 
 void CFX_ByteString::TrimRight(const CFX_ByteStringC& pTargets) {
-  if (!m_pData || pTargets.IsEmpty()) {
+  if (!m_pData || pTargets.IsEmpty())
     return;
-  }
+
   FX_STRSIZE pos = GetLength();
-  if (pos < 1) {
+  if (pos == 0)
     return;
-  }
+
   while (pos) {
     FX_STRSIZE i = 0;
     while (i < pTargets.GetLength() &&
@@ -738,7 +732,7 @@ void CFX_ByteString::TrimLeft(const CFX_ByteStringC& pTargets) {
     return;
 
   FX_STRSIZE len = GetLength();
-  if (len < 1)
+  if (len == 0)
     return;
 
   FX_STRSIZE pos = 0;