Improve split speed (#84)

optimize split function for chars

mdal/frmts/mdal_2dm.cpp

@@ -148,7 +148,7 @@ std::unique_ptr<MDAL::Mesh> MDAL::Driver2dm::load( const std::string &meshFile,
   {
     if ( startsWith( line, "E4Q" ) )
     {
-      chunks = split( line,  " ", SplitBehaviour::SkipEmptyParts );
+      chunks = split( line,  ' ' );
       assert( faceIndex < faceCount );
 
       Face &face = faces[faceIndex];
@@ -161,7 +161,7 @@ std::unique_ptr<MDAL::Mesh> MDAL::Driver2dm::load( const std::string &meshFile,
     }
     else if ( startsWith( line, "E3T" ) )
     {
-      chunks = split( line,  " ", SplitBehaviour::SkipEmptyParts );
+      chunks = split( line,  ' ' );
       assert( faceIndex < faceCount );
 
       Face &face = faces[faceIndex];
@@ -181,7 +181,7 @@ std::unique_ptr<MDAL::Mesh> MDAL::Driver2dm::load( const std::string &meshFile,
               startsWith( line, "E9Q" ) )
     {
       // We do not yet support these elements
-      chunks = split( line,  " ", SplitBehaviour::SkipEmptyParts );
+      chunks = split( line,  ' ' );
       assert( faceIndex < faceCount );
 
       //size_t elemID = toSizeT( chunks[1] );
@@ -191,7 +191,7 @@ std::unique_ptr<MDAL::Mesh> MDAL::Driver2dm::load( const std::string &meshFile,
     }
     else if ( startsWith( line, "ND" ) )
     {
-      chunks = split( line,  " ", SplitBehaviour::SkipEmptyParts );
+      chunks = split( line,  ' ' );
       size_t nodeID = toSizeT( chunks[1] ) - 1; // 2dm is numbered from 1
       _parse_vertex_id_gaps( vertexIDtoIndex, vertexIndex, nodeID, status );
       assert( vertexIndex < vertexCount );

mdal/frmts/mdal_ascii_dat.cpp

@@ -95,7 +95,7 @@ void MDAL::DriverAsciiDat::loadOldFormat( std::ifstream &in,
     line = MDAL::trim( line );
 
     // Split to tokens
-    std::vector<std::string> items = split( line,  " ", SplitBehaviour::SkipEmptyParts );
+    std::vector<std::string> items = split( line,  ' ' );
     if ( items.size() < 1 )
       continue; // empty line?? let's skip it
 
@@ -159,7 +159,7 @@ void MDAL::DriverAsciiDat::loadNewFormat( std::ifstream &in,
     line = MDAL::trim( line );
 
     // Split to tokens
-    std::vector<std::string> items = split( line,  " ", SplitBehaviour::SkipEmptyParts );
+    std::vector<std::string> items = split( line,  ' ' );
     if ( items.size() < 1 )
       continue; // empty line?? let's skip it
 
@@ -320,7 +320,7 @@ void MDAL::DriverAsciiDat::readVertexTimestep(
   {
     std::string line;
     std::getline( stream, line );
-    std::vector<std::string> tsItems = split( line,  " ", SplitBehaviour::SkipEmptyParts );
+    std::vector<std::string> tsItems = split( line,  ' ' );
 
     size_t index;
     if ( m2dm )
@@ -374,7 +374,7 @@ void MDAL::DriverAsciiDat::readFaceTimestep(
   {
     std::string line;
     std::getline( stream, line );
-    std::vector<std::string> tsItems = split( line,  " ", SplitBehaviour::SkipEmptyParts );
+    std::vector<std::string> tsItems = split( line, ' ' );
 
     if ( isVector )
     {

mdal/frmts/mdal_flo2d.cpp

@@ -109,7 +109,7 @@ void MDAL::DriverFlo2D::parseCADPTSFile( const std::string &datFileName, std::ve
   // CADPTS.DAT - COORDINATES OF CELL CENTERS (ELEM NUM, X, Y)
   while ( std::getline( cadptsStream, line ) )
   {
-    std::vector<std::string> lineParts = MDAL::split( line, " ", MDAL::SplitBehaviour::SkipEmptyParts );
+    std::vector<std::string> lineParts = MDAL::split( line, ' ' );
     if ( lineParts.size() != 3 )
     {
       throw MDAL_Status::Err_UnknownFormat;
@@ -140,7 +140,7 @@ void MDAL::DriverFlo2D::parseFPLAINFile( std::vector<double> &elevations,
 
   while ( std::getline( fplainStream, line ) )
   {
-    std::vector<std::string> lineParts = MDAL::split( line, " ", MDAL::SplitBehaviour::SkipEmptyParts );
+    std::vector<std::string> lineParts = MDAL::split( line, ' ' );
     if ( lineParts.size() != 7 )
     {
       throw MDAL_Status::Err_UnknownFormat;
@@ -220,7 +220,7 @@ void MDAL::DriverFlo2D::parseTIMDEPFile( const std::string &datFileName, const s
 
   while ( std::getline( inStream, line ) )
   {
-    std::vector<std::string> lineParts = MDAL::split( line, " ", MDAL::SplitBehaviour::SkipEmptyParts );
+    std::vector<std::string> lineParts = MDAL::split( line, ' ' );
     if ( lineParts.size() == 1 )
     {
       time = MDAL::toDouble( line );
@@ -303,7 +303,7 @@ void MDAL::DriverFlo2D::parseDEPTHFile( const std::string &datFileName, const st
   {
     if ( vertex_idx == nVertices ) throw MDAL_Status::Err_IncompatibleMesh;
 
-    std::vector<std::string> lineParts = MDAL::split( line, " ", MDAL::SplitBehaviour::SkipEmptyParts );
+    std::vector<std::string> lineParts = MDAL::split( line, ' ' );
     if ( lineParts.size() != 4 )
     {
       throw MDAL_Status::Err_UnknownFormat;
@@ -348,7 +348,7 @@ void MDAL::DriverFlo2D::parseVELFPVELOCFile( const std::string &datFileName )
     {
       if ( vertex_idx == nVertices ) throw MDAL_Status::Err_IncompatibleMesh;
 
-      std::vector<std::string> lineParts = MDAL::split( line, " ", MDAL::SplitBehaviour::SkipEmptyParts );
+      std::vector<std::string> lineParts = MDAL::split( line, ' ' );
       if ( lineParts.size() != 4 )
       {
         throw MDAL_Status::Err_UnknownFormat;
@@ -378,7 +378,7 @@ void MDAL::DriverFlo2D::parseVELFPVELOCFile( const std::string &datFileName )
     {
       if ( vertex_idx == nVertices ) throw MDAL_Status::Err_IncompatibleMesh;
 
-      std::vector<std::string> lineParts = MDAL::split( line, " ", MDAL::SplitBehaviour::SkipEmptyParts );
+      std::vector<std::string> lineParts = MDAL::split( line, ' ' );
       if ( lineParts.size() != 4 )
       {
         throw MDAL_Status::Err_UnknownFormat;

mdal/frmts/mdal_gdal.cpp

@@ -166,7 +166,7 @@ std::string MDAL::DriverGdal::GDALFileName( const std::string &fileName )
 double MDAL::DriverGdal::parseMetadataTime( const std::string &time_s )
 {
   std::string time_trimmed = MDAL::trim( time_s );
-  std::vector<std::string> times = MDAL::split( time_trimmed, " ", MDAL::SkipEmptyParts );
+  std::vector<std::string> times = MDAL::split( time_trimmed, ' ' );
   return MDAL::toDouble( times[0] );
 }
 
@@ -181,7 +181,7 @@ MDAL::DriverGdal::metadata_hash MDAL::DriverGdal::parseMetadata( GDALMajorObject
     for ( int j = 0; GDALmetadata[j]; ++j )
     {
       std::string metadata_pair = GDALmetadata[j]; //KEY = VALUE
-      std::vector<std::string> metadata = MDAL::split( metadata_pair, "=", MDAL::SkipEmptyParts );
+      std::vector<std::string> metadata = MDAL::split( metadata_pair, '=' );
       if ( metadata.size() > 1 )
       {
         std::string key = MDAL::toLower( metadata[0] );

mdal/mdal.cpp

@@ -22,7 +22,7 @@ static MDAL_Status sLastStatus;
 
 const char *MDAL_Version()
 {
-  return "0.1.4";
+  return "0.1.5";
 }
 
 MDAL_Status MDAL_LastStatus()

mdal/mdal_utils.cpp

@@ -44,27 +44,51 @@ bool MDAL::endsWith( const std::string &str, const std::string &substr, Contains
     return endsWith( toLower( str ), toLower( substr ), ContainsBehaviour::CaseSensitive );
 }
 
-std::vector<std::string> MDAL::split( const std::string &str, const std::string &delimiter, SplitBehaviour behaviour )
+std::vector<std::string> MDAL::split( const std::string &str,
+                                      const char delimiter
+                                    )
 {
-  std::string remaining( str );
   std::vector<std::string> list;
-  size_t pos = 0;
+  std::string::const_iterator start = str.begin();
+  std::string::const_iterator end = str.end();
+  std::string::const_iterator next;
   std::string token;
-  while ( ( pos = remaining.find( delimiter ) ) != std::string::npos )
+  do
   {
-    token = remaining.substr( 0, pos );
+    next = std::find( start, end, delimiter );
+    token = std::string( start, next );
+    if ( !token.empty() )
+      list.push_back( token );
 
-    if ( behaviour == SplitBehaviour::SkipEmptyParts )
-    {
-      if ( !token.empty() )
-        list.push_back( token );
-    }
+    if ( next == end )
+      break;
     else
-      list.push_back( token );
+      start = next + 1;
+  }
+  while ( true );
+  return list;
+}
 
-    remaining.erase( 0, pos + delimiter.length() );
+
+std::vector<std::string> MDAL::split( const std::string &str,
+                                      const std::string &delimiter )
+{
+  std::vector<std::string> list;
+  std::string::size_type start = 0;
+  std::string::size_type next;
+  std::string token;
+  do
+  {
+    next = str.find( delimiter, start );
+    if ( next == std::string::npos )
+      token = str.substr( start ); // rest of the string
+    else
+      token = str.substr( start, next - start ); // part of the string
+    if ( !token.empty() )
+      list.push_back( token );
+    start = next + delimiter.size();
   }
-  list.push_back( remaining );
+  while ( next != std::string::npos );
   return list;
 }
 
@@ -308,7 +332,7 @@ double MDAL::parseTimeUnits( const std::string &units )
   // "seconds since 2001-05-05 00:00:00"
   // "hours since 1900-01-01 00:00:0.0"
   // "days since 1961-01-01 00:00:00"
-  const std::vector<std::string> units_list = MDAL::split( units, " since ", SkipEmptyParts );
+  const std::vector<std::string> units_list = MDAL::split( units, " since " );
   if ( units_list.size() == 2 )
   {
     // Give me hours

mdal/mdal_utils.hpp

@@ -6,6 +6,10 @@
 #ifndef MDAL_UTILS_HPP
 #define MDAL_UTILS_HPP
 
+// Macro for exporting symbols
+// for unit tests (on windows)
+#define MDAL_TEST_EXPORT MDAL_EXPORT
+
 #include <string>
 #include <vector>
 #include <stddef.h>
@@ -59,12 +63,15 @@ namespace MDAL
   bool toBool( const std::string &str );
   bool isNumber( const std::string &str );
 
-  enum SplitBehaviour
-  {
-    SkipEmptyParts,
-    KeepEmptyParts
-  };
-  std::vector<std::string> split( const std::string &str, const std::string &delimiter, SplitBehaviour behaviour );
+  /**
+   * Splits by deliminer and skips empty parts.
+   * Faster than version with std::string
+   */
+  MDAL_TEST_EXPORT std::vector<std::string> split( const std::string &str, const char delimiter );
+
+  //! Splits by deliminer and skips empty parts
+  MDAL_TEST_EXPORT std::vector<std::string> split( const std::string &str, const std::string &delimiter );
+
   std::string join( const std::vector<std::string> parts, const std::string &delimiter );
 
   //! Right trim
@@ -87,7 +94,7 @@ namespace MDAL
 
   // time
   //! Returns a delimiter to get time in hours
-  double parseTimeUnits( const std::string &units );
+  MDAL_TEST_EXPORT double parseTimeUnits( const std::string &units );
 
   // statistics
   void combineStatistics( Statistics &main, const Statistics &other );

tests/CMakeLists.txt

@@ -68,6 +68,7 @@ SET(TESTS
     test_api.cpp
     test_ascii_dat.cpp
     test_binary_dat.cpp
+    test_mdal_utils.cpp
 )
 
 IF(HDF5_FOUND)

tests/test_mdal_utils.cpp

@@ -0,0 +1,99 @@
+/*
+ MDAL - Mesh Data Abstraction Library (MIT License)
+ Copyright (C) 2019 Peter Petrik (zilolv at gmail dot com)
+*/
+#include "gtest/gtest.h"
+#include <limits>
+#include <cmath>
+#include <string>
+#include <vector>
+
+//mdal
+#include "mdal.h"
+#include "mdal_utils.hpp"
+#include "mdal_testutils.hpp"
+
+struct SplitTestData
+{
+  SplitTestData( const std::string &input,
+                 const std::vector<std::string> &results ):
+    mInput( input ), mExpectedResult( results ) {}
+
+  std::string mInput;
+  std::vector<std::string> mExpectedResult;
+};
+
+
+TEST( MdalUtilsTest, SplitString )
+{
+  std::vector<SplitTestData> tests =
+  {
+    SplitTestData( "a;b;c", {"a", "b", "c"} ),
+    SplitTestData( "a;;b;c", {"a", "b", "c"} ),
+    SplitTestData( "a;b;", {"a", "b"} ),
+    SplitTestData( ";b;", {"b"} ),
+    SplitTestData( "a", {"a"} ),
+    SplitTestData( "", {} )
+  };
+  for ( const auto &test : tests )
+  {
+    EXPECT_EQ( test.mExpectedResult, MDAL::split( test.mInput, ";" ) );
+  }
+
+  // now test for string with multiple chars
+  std::vector<SplitTestData> tests2 =
+  {
+    SplitTestData( "a;;;b;c", {"a", "b;c"} ),
+    SplitTestData( "a;;;b;;;c", {"a", "b", "c"} ),
+    SplitTestData( "a;;b;c", {"a;;b;c"} ),
+    SplitTestData( "b;;;", {"b"} )
+  };
+  for ( const auto &test : tests2 )
+  {
+    EXPECT_EQ( test.mExpectedResult, MDAL::split( test.mInput, ";;;" ) );
+  }
+}
+
+TEST( MdalUtilsTest, SplitChar )
+{
+  std::vector<SplitTestData> tests =
+  {
+    SplitTestData( "a;b;c", {"a", "b", "c"} ),
+    SplitTestData( "a;;b;c", {"a", "b", "c"} ),
+    SplitTestData( "a;b;", {"a", "b"} ),
+    SplitTestData( ";b;", {"b"} ),
+    SplitTestData( "a", {"a"} ),
+    SplitTestData( "", {} )
+  };
+  for ( const auto &test : tests )
+  {
+    EXPECT_EQ( test.mExpectedResult, MDAL::split( test.mInput, ';' ) );
+  }
+}
+
+TEST( MdalUtilsTest, TimeParsing )
+{
+  std::vector<std::pair<std::string, double>> tests =
+  {
+    { "seconds since 2001-05-05 00:00:00", 3600 },
+    { "minutes since 2001-05-05 00:00:00", 60 },
+    { "hours since 1900-01-01 00:00:0.0", 1 },
+    { "days since 1961-01-01 00:00:00", 1.0 / 24.0 },
+    { "invalid format of time", 1 }
+  };
+  for ( const auto &test : tests )
+  {
+    EXPECT_EQ( test.second, MDAL::parseTimeUnits( test.first ) );
+  }
+}
+
+
+int main( int argc, char **argv )
+{
+  testing::InitGoogleTest( &argc, argv );
+  init_test();
+  int ret =  RUN_ALL_TESTS();
+  finalize_test();
+  return ret;
+}
+