From f6dafc90ec1a0df8d618efc68c0223f0cdd80ffb Mon Sep 17 00:00:00 2001
From: Lei Zhang <thestig@chromium.org>
Date: Tue, 22 Dec 2015 13:41:54 -0800
Subject: Convert CPDF_Parser::m_CrossRef to a std::map.

This improvements memory usage in case PDFs have sparse object numbers.

The map holds a struct that currently has only one member. The struct
will contain more members as other internal data structures get
converted.

BUG=pdfium:111
R=weili@chromium.org

Review URL: https://codereview.chromium.org/1539573003 .
---
 core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp | 31 +++++++++++++------------
 1 file changed, 16 insertions(+), 15 deletions(-)

(limited to 'core/src/fpdfapi/fpdf_edit')

diff --git a/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp b/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
index 328728ef24..49ec0bae92 100644
--- a/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
+++ b/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
@@ -1319,16 +1319,19 @@ int32_t CPDF_Creator::WriteOldIndirectObject(FX_DWORD objnum) {
   return 1;
 }
 int32_t CPDF_Creator::WriteOldObjs(IFX_Pause* pPause) {
-  FX_DWORD nOldSize = m_pParser->m_CrossRef.GetSize();
+  FX_DWORD nLastObjNum = m_pParser->GetLastObjNum();
+  if (!m_pParser->IsValidObjectNumber(nLastObjNum))
+    return 0;
+
   FX_DWORD objnum = (FX_DWORD)(uintptr_t)m_Pos;
-  for (; objnum < nOldSize; objnum++) {
+  for (; objnum <= nLastObjNum; ++objnum) {
     int32_t iRet = WriteOldIndirectObject(objnum);
-    if (!iRet) {
-      continue;
-    }
-    if (iRet < 0) {
+    if (iRet < 0)
       return iRet;
-    }
+
+    if (!iRet)
+      continue;
+
     m_ObjectSize[objnum] = (FX_DWORD)(m_Offset - m_ObjectOffset[objnum]);
     if (pPause && pPause->NeedToPauseNow()) {
       m_Pos = (void*)(uintptr_t)(objnum + 1);
@@ -1389,7 +1392,6 @@ void CPDF_Creator::InitOldObjNumOffsets() {
 void CPDF_Creator::InitNewObjNumOffsets() {
   FX_BOOL bIncremental = (m_dwFlags & FPDFCREATE_INCREMENTAL) != 0;
   FX_BOOL bNoOriginal = (m_dwFlags & FPDFCREATE_NO_ORIGINAL) != 0;
-  FX_DWORD nOldSize = m_pParser ? m_pParser->m_CrossRef.GetSize() : 0;
   FX_POSITION pos = m_pDocument->m_IndirectObjs.GetStartPosition();
   while (pos) {
     size_t key = 0;
@@ -1403,10 +1405,9 @@ void CPDF_Creator::InitNewObjNumOffsets() {
       if (!pObj->IsModified()) {
         continue;
       }
-    } else {
-      if (objnum < nOldSize && m_pParser->m_V5Type[objnum] != 0) {
-        continue;
-      }
+    } else if (m_pParser->IsValidObjectNumber(objnum) &&
+               m_pParser->m_V5Type[objnum]) {
+      continue;
     }
     AppendNewObjNum(objnum);
   }
@@ -1433,8 +1434,8 @@ void CPDF_Creator::InitNewObjNumOffsets() {
   FX_BOOL bNewStart = FALSE;
   for (; i < iCount; i++) {
     FX_DWORD dwCurObjNum = m_NewObjNumArray.ElementAt(i);
-    FX_BOOL bExist =
-        (dwCurObjNum < nOldSize && m_ObjectOffset.GetPtrAt(dwCurObjNum));
+    bool bExist = m_pParser->IsValidObjectNumber(dwCurObjNum) &&
+                  m_ObjectOffset.GetPtrAt(dwCurObjNum);
     if (bExist || dwCurObjNum - dwLastObjNum > 1) {
       if (!bNewStart) {
         m_ObjectOffset.Add(dwStartObjNum, dwLastObjNum - dwStartObjNum + 1);
@@ -1555,7 +1556,7 @@ int32_t CPDF_Creator::WriteDoc_Stage1(IFX_Pause* pPause) {
             m_pParser->m_V5Type[objnum] == 255) {
           continue;
         }
-        m_ObjectOffset[objnum] = m_pParser->m_CrossRef[objnum];
+        m_ObjectOffset[objnum] = m_pParser->m_ObjectInfo[objnum].pos;
         if (bObjStm) {
           m_pXRefStream->AddObjectNumberToIndexArray(objnum);
         }
-- 
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