From 813f3b8248d8b3f7ef8f641b1ef004c99c8bc9fe Mon Sep 17 00:00:00 2001
From: Kim Kulling <kim.kulling@goolemail.com>
Date: Tue, 30 May 2017 21:10:33 +0200
Subject: [PATCH] ObjLoader: improve performance of obj-import.

---
 code/IOStreamBuffer.h  | 32 +++++++++++++++++++++++---------
 code/ObjFileParser.cpp | 17 +++++++----------
 code/ObjTools.h        |  7 ++++++-
 3 files changed, 36 insertions(+), 20 deletions(-)

diff --git a/code/IOStreamBuffer.h b/code/IOStreamBuffer.h
index d8c7d00ab..d8728aee3 100644
--- a/code/IOStreamBuffer.h
+++ b/code/IOStreamBuffer.h
@@ -45,6 +45,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/IOStream.hpp>
 #include "ParsingUtils.h"
 
+#include <vector>
+
 namespace Assimp {
 
 // ---------------------------------------------------------------------------
@@ -54,6 +56,8 @@ namespace Assimp {
 template<class T>
 class IOStreamBuffer {
 public:
+    typedef typename std::vector<T>::iterator CacheIter;
+
     /// @brief  The class constructor.
     IOStreamBuffer( size_t cache = 4096 * 4096 );
 
@@ -69,8 +73,8 @@ public:
     /// @return true if successful.
     bool close();
 
-    /// @brief  Returns the filesize.
-    /// @return The filesize.
+    /// @brief  Returns the file-size.
+    /// @return The file-size.
     size_t size() const;
     
     /// @brief  Returns the cache size.
@@ -96,7 +100,7 @@ public:
     /// @brief  Will read the next line.
     /// @param  buffer      The buffer for the next line.
     /// @return true if successful.
-    bool getNextLine( std::vector<T> &buffer );
+    bool getNextLine( CacheIter &begin, CacheIter &end );
 
 private:
     IOStream *m_stream;
@@ -106,6 +110,7 @@ private:
     size_t m_blockIdx;
     std::vector<T> m_cache;
     size_t m_cachePos;
+    CacheIter m_it;
     size_t m_filePos;
 };
 
@@ -118,6 +123,7 @@ IOStreamBuffer<T>::IOStreamBuffer( size_t cache )
 , m_numBlocks( 0 )
 , m_blockIdx( 0 )
 , m_cachePos( 0 )
+, m_it()
 , m_filePos( 0 ) {
     m_cache.resize( cache );
     std::fill( m_cache.begin(), m_cache.end(), '\n' );
@@ -203,6 +209,7 @@ bool IOStreamBuffer<T>::readNextBlock() {
     m_filePos += m_cacheSize;
     m_cachePos = 0;
     m_blockIdx++;
+    m_it = m_cache.begin();
 
     return true;
 }
@@ -227,25 +234,32 @@ size_t IOStreamBuffer<T>::getFilePos() const {
 
 template<class T>
 inline
-bool IOStreamBuffer<T>::getNextLine( std::vector<T> &buffer ) {
-    buffer.resize( m_cacheSize );
+bool IOStreamBuffer<T>::getNextLine( CacheIter &begin, CacheIter &end ) {
     if ( m_cachePos == m_cacheSize || 0 == m_filePos ) {
         if ( !readNextBlock() ) {
+            begin = m_it;
+            end = m_it;
             return false;
         }
+        m_it = m_cache.begin();
     }
-    size_t i = 0;
+
+    //size_t i = 0;
+    begin = m_it;
     while ( !IsLineEnd( m_cache[ m_cachePos ] ) ) {
-        buffer[ i ] = m_cache[ m_cachePos ];
         m_cachePos++;
-        i++;
+        ++m_it;
+        //i++;
         if ( m_cachePos >= m_cacheSize ) {
             if ( !readNextBlock() ) {
+                begin = m_it;
+                end = m_it;
                 return false;
             }
         }
     }
-    buffer[ i ] = '\n';
+    ++m_it;
+    end = m_it;
     m_cachePos++;
 
     return true;
diff --git a/code/ObjFileParser.cpp b/code/ObjFileParser.cpp
index decfacbf5..44d171dcc 100644
--- a/code/ObjFileParser.cpp
+++ b/code/ObjFileParser.cpp
@@ -109,7 +109,7 @@ ObjFile::Model *ObjFileParser::GetModel() const {
     return m_pModel;
 }
 
-void ignoreNewLines(IOStreamBuffer<char> &streamBuffer, std::vector<char> &buffer)
+/*void ignoreNewLines(IOStreamBuffer<char> &streamBuffer, std::vector<char> &buffer)
 {
     auto curPosition = buffer.begin();
     do
@@ -129,7 +129,7 @@ void ignoreNewLines(IOStreamBuffer<char> &streamBuffer, std::vector<char> &buffe
             std::copy(tempBuf.cbegin(), tempBuf.cend(), ++curPosition);
         }
     } while (*curPosition!='\n');
-}
+}*/
 
 void ObjFileParser::parseFile( IOStreamBuffer<char> &streamBuffer ) {
     // only update every 100KB or it'll be too slow
@@ -141,11 +141,7 @@ void ObjFileParser::parseFile( IOStreamBuffer<char> &streamBuffer ) {
     unsigned int processed = 0;
     size_t lastFilePos( 0 );
 
-    std::vector<char> buffer;
-    while ( streamBuffer.getNextLine( buffer ) ) {
-        m_DataIt = buffer.begin();
-        m_DataItEnd = buffer.end();
-
+    while ( streamBuffer.getNextLine( m_DataIt, m_DataItEnd ) ) {
         // Handle progress reporting
         const size_t filePos( streamBuffer.getFilePos() );
         if ( lastFilePos < filePos ) {
@@ -245,7 +241,6 @@ void ObjFileParser::parseFile( IOStreamBuffer<char> &streamBuffer ) {
         default:
             {
 pf_skip_line:
-
                 m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
             }
             break;
@@ -595,14 +590,16 @@ void ObjFileParser::getMaterialDesc() {
 // -------------------------------------------------------------------
 //  Get a comment, values will be skipped
 void ObjFileParser::getComment() {
-    while (m_DataIt != m_DataItEnd) {
+    m_DataIt = skipLine<DataArrayIt>( m_DataIt, m_DataItEnd, m_uiLine );
+
+/*    while (m_DataIt != m_DataItEnd) {
         if ( '\n' == (*m_DataIt)) {
             ++m_DataIt;
             break;
         } else {
             ++m_DataIt;
         }
-    }
+    }*/
 }
 
 // -------------------------------------------------------------------
diff --git a/code/ObjTools.h b/code/ObjTools.h
index 7b0bdcedf..1be518700 100644
--- a/code/ObjTools.h
+++ b/code/ObjTools.h
@@ -115,6 +115,9 @@ template<class char_t>
 inline char_t skipLine( char_t it, char_t end, unsigned int &uiLine ) {
     while( !isEndOfBuffer( it, end ) && !IsLineEnd( *it ) ) {
         ++it;
+        if ( *it == '\n' ) {
+            ++it;
+        }
     }
     if ( it != end )
     {
@@ -122,8 +125,10 @@ inline char_t skipLine( char_t it, char_t end, unsigned int &uiLine ) {
         ++uiLine;
     }
     // fix .. from time to time there are spaces at the beginning of a material line
-    while ( it != end && (*it == '\t' || *it == ' ') )
+    while ( it != end && ( *it == '\t' || *it == ' ' ) ) {
         ++it;
+    }
+
     return it;
 }