read_csv crashes when reading a csv file with only one column (Bug #1981)

The function read_csv crashes when reading data who only has one column.

Here is the code:

 1// read the first line and determine the number of variables
 2std::vector<char> _buf(M);
 3char* buf = &_buf[0];
 4if( !fgets_chomp( buf, M, file ))
 5{
 6    fclose(file);
 7    return -1;
 8}
 9for( ptr = buf; *ptr != '\0'; ptr++ )
10    cols_count += (*ptr == delimiter);
11
12if ( cols_count == 0)
13{
14    fclose(file);
15    return -1;
16}
17cols_count++;

If the values have no commas before the newline it crashes in if ( cols_count == 0) if they have a comma before the newline it crashes when you use get_values() (Access Violation).