read_csv

int CvMLData::read_csv(const char* filename)
{
const int M = 1000000;
const char str_delimiter[3] = { ' ', delimiter, '\0' };
FILE* file = 0;
CvMemStorage* storage;
CvSeq* seq;
char *ptr;
float* el_ptr;
CvSeqReader reader;
int cols_count = 0;
uchar *var_types_ptr = 0;
clear();
file = fopen( filename, "rt" );
if( !file )
return -1;
// read the first line and determine the number of variables
std::vector _buf(M);
char* buf = &_buf[0];
if( !fgets_chomp( buf, M, file ))
{
fclose(file);
return -1;
}
ptr = buf;
while( *ptr == ' ' )
ptr++;
for( ; *ptr != '\0'; )
{
if(*ptr == delimiter || *ptr == ' ')
{
cols_count++;
ptr++;
while( *ptr == ' ' ) ptr++;
}
else
ptr++;
}
cols_count++;
if ( cols_count == 0)
{
fclose(file);
return -1;
}
// create temporary memory storage to store the whole database
el_ptr = new float[cols_count];
storage = cvCreateMemStorage();
seq = cvCreateSeq( 0, sizeof(*seq), cols_count*sizeof(float), storage );
var_types = cvCreateMat( 1, cols_count, CV_8U );
cvZero( var_types );
var_types_ptr = var_types->data.ptr;
for(;;)
{
char *token = NULL;
int type;
token = strtok(buf, str_delimiter);
if (!token)
break;
for (int i = 0; i < cols_count-1; i++)
{
str_to_flt_elem( token, el_ptr[i], type);
var_types_ptr[i] |= type;
token = strtok(NULL, str_delimiter);
if (!token)
{
fclose(file);
delete [] el_ptr;
return -1;
}
}
str_to_flt_elem( token, el_ptr[cols_count-1], type);
var_types_ptr[cols_count-1] |= type;
cvSeqPush( seq, el_ptr );
if( !fgets_chomp( buf, M, file ) )
break;
}
fclose(file);
values = cvCreateMat( seq->total, cols_count, CV_32FC1 );
missing = cvCreateMat( seq->total, cols_count, CV_8U );
var_idx_mask = cvCreateMat( 1, values->cols, CV_8UC1 );
cvSet( var_idx_mask, cvRealScalar(1) );
train_sample_count = seq->total;
cvStartReadSeq( seq, &reader );
for(int i = 0; i < seq->total; i++ )
{
const float* sdata = (float*)reader.ptr;
float* ddata = values->data.fl + cols_count*i;
uchar* dm = missing->data.ptr + cols_count*i;
for( int j = 0; j < cols_count; j++ )
{
ddata[j] = sdata[j];
dm[j] = ( fabs( MISS_VAL - sdata[j] ) <= FLT_EPSILON );
}
CV_NEXT_SEQ_ELEM( seq->elem_size, reader );
}
if ( cvNorm( missing, 0, CV_L1 ) <= FLT_EPSILON )
cvReleaseMat( &missing );
cvReleaseMemStorage( &storage );
delete []el_ptr;
return 0;
}