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Easdif

0.8.1

Introduction

Easdif is a C++ interface based on IRCAM's Sdif library. The Easdif library includes all sdif functions and provides a much simpler API. Easdif requires Sdif version 3.7 to compile.

Example

To use the library the include file easdif.h has to be included All Below, is an complete example : for reading and writing a file with modifications

#include "easdif/easdif.h"

using namespace Easdif;

int main(int argc, char** argv)
{  

    /* initialise the SDIF library and install exceptions*/
    EasdifInit();

    SDIFEntity readentity;
    SDIFEntity entity;
   
    SDIFFrame frame;
    SDIFFrame frameTowrite;

    int i = 0;
    int y = 0;

    /******** NAME VALUE TABLE ********/
    /* for making NameValueTables to the EntityToWrite */
    SDIFNameValueTable NameValueTable;
    NameValueTable.AddNameValue("name", "value");
    NameValueTable.AddNameValue("the_name","the_value");
    NameValueTable.AddNameValue("Eas","dif");

    SDIFNameValueTable NameValueTable2;
    NameValueTable2.AddNameValue("an", "other");
    NameValueTable2.AddNameValue("name","value");

    /*for adding the Name Value Tables to the EntityToWrite*/
    entity.AddNVT(NameValueTable);
    /*for adding with a StreamID number 3 for example */
    entity.AddNVT(NameValueTable2, 3);

    /*for adding the Name Value Tables of the EntityRead, the file of
     *EntityToRead must be Open */
    try {
      if (!readentity.OpenRead(argv[1]) ) {
        std::cerr << "Could not open input file :"<<argv[1]<<std::endl;
        exit(1);
      }
    }
    /* Openread may through BadHeader exception in case the input file
 is not a valid SDIF file */
    catch(SDIFBadHeader& e)
      {
        e.ErrorMessage();
        exit(1);
      }


    y = readentity.GetNbNVT();
    if( y != 0)
    {
        for (i = 0 ; i < y ; i++)
        {
            entity.AddNVT(readentity.GetNVT(i));
        }       
        entity.GetNVT(0).PrintNameValue("the_name");
        entity.GetNVT(0).PrintNameValue("notthere");
    }

    /******** DESCRIPTION TYPE ********/
    /*to copy the descriptions type of EntityRead to EntityToWrite*/
    /*entity.SetTypeString(readentity.GetTypeString()); in comment 
     *for exception*/

    /*for adding descriptions types : the description must be done before
     *the opening of the EntityToWrite (they are writing when opening)*/
    /* Add a matrix type must be done before to add a frame type*/
    entity.AddMatrixType("1FQ0", "ColumnToAdd1, ColumnToAdd2");
    entity.AddMatrixType("1NEW", "col1, col2, col3, col_i, col_n");
   
    entity.AddFrameType("1NEW", "1NEW NewMatrix; 1FQ0 New1FQ0");

    /* to open a file for writing */
    if(!entity.OpenWrite("FileToWrite.sdif")) {
        std::cerr << "Could not open output file : FileToWrite.sdif"<<std::endl;
        exit(1);
    }

    /******** SELECTION ********/
    /* if you want to change the selection of the EntityRead use the same 
 notation as for selecting when opening the file */
    readentity.ChangeSelection(":1FOB,1HRM/1FOF,1HRM");

    /******** READ AND WRITE  ********/
    /* to show the exception : we break the loop with an exception */
    try{
      while (1) {
        /* an alternative way to finish reading without using exceptions
 would be:
         */
        // while(!readentity.eof()) {

        /* reading the next frame of the EntityRead, return the number of
 bytes read, return 0 if the frame is not selected and -1 if this is 
 the last frame of the file */
        if(!readentity.ReadNextFrame(frame))        
          continue;
        
        /* for adding new matrix in EntityToWrite */
        for (unsigned int i=0 ; i < frame.GetNbMatrix() ; i++)
          {
            /*take the matrix number "i" and put it in tmpMatrix */
            SDIFMatrix tmpMatrix = frame.GetMatrix(i);
            
            /*add a matrix in the matrix vector of the frame*/
            frameTowrite.AddMatrix(tmpMatrix);
            /*an other method to add just the frame selected in file:
 frameTowrite.AddMatrixSelected(readentity.GetFile(),
 tmpMatrix);*/
            
            /* if you want to access to the data : an example, if we want 
 to multiply with 2 the last column of a matrix : */
            double dou;
            int ncols = tmpMatrix.GetNbCols();
            for(int i = 0 ; i < tmpMatrix.GetNbRows() ; i++)
              {
                //dou = tmpMatrix.GetDouble(i, ncols-1);
                /* to get the value in the double dou*/
                tmpMatrix.Get(i, ncols-1,dou);
                /* an other method can be :
                   dou = tmpMatrix.GetDouble(i, ncols-1);
                */
                tmpMatrix.Set(i, ncols-1,2.*dou);
              }
          }
        
        /* to set the header of the new frame with the one of a frame :*/
        frameTowrite.SetHeader(frame.GetSignature(),
                               frame.GetStreamID(),
                               frame.GetTime() );
        
        /* an other method can be :
           frameTowrite.SetStreamID(frame.GetStreamID());
           frameTowrite.SetTime(frame.GetTime());
           frameTowrite.SetSignature(frame.GetSignature());
        */
        
        /* to write the EntityToWrite */
        frameTowrite.Write(entity);
        
        /* for reading a frame of the EntityToWrite, this make an 
 exception because the file is at end*/
        //frame.Read(entity);
        
        /* clean the frames */
        frameTowrite.ClearData();
        frame.ClearData();
      }
    }
    
    /* to catch an exception */
    catch(SDIFEof& e)
      {
        /* if we want an access to the file */
        const SdifFileT *sf = e.sdifFile();

        std::cerr << " Catch EOF for file " <<sf->Name << " -- ending program " << std::endl;
        /* to have the error message */
      }
    
    catch(SDIFUnDefined& e)
      {
        std::cerr << " Catch Undefined " << std::endl;  
        e.ErrorMessage();
      }
    
    catch(Easdif::SDIFException&e)
      {
        std::cerr << " Catch other SDIFException " << std::endl;
        e.ErrorMessage();
      }
    catch(std::exception &e)
      {
        std::cerr << " Catch other Exception: " << e.what() <<std::endl;

      }
    
    /* deinitialise the SDIF library */
    EasdifEnd();
    return 0;
}

This example compiles with the command

g++ -I/usr/local/include testeas.cpp -otesteas -L/usr/local/lib  -lEasdif

provided you have stored the code under filename testeas.cpp. It will add two new name value tables and two new matrix types and a frame type to the given input file and will select all 1HRM/1HRM and 1FOB/1FOF data and store the result in FileToWrite.sdif.

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