Makamaka Hannyaharamitu

NAME

Text::CSV_PP - comma-separated values manipulation routines (PP version)

SYNOPSIS

 use Text::CSV_PP;
 
 $csv = Text::CSV_PP->new();           # create a new object
 # If you want to handle non-ascii char.
 $csv = Text::CSV_PP->new({binary => 1});
 
 $status = $csv->combine(@columns);    # combine columns into a string
 $line   = $csv->string();             # get the combined string
 
 $status  = $csv->parse($line);        # parse a CSV string into fields
 @columns = $csv->fields();            # get the parsed fields
 
 $status       = $csv->status ();      # get the most recent status
 $bad_argument = $csv->error_input (); # get the most recent bad argument
 $diag         = $csv->error_diag ();  # if an error occured, explains WHY
 
 $status = $csv->print ($io, $colref); # Write an array of fields
                                       # immediately to a file $io
 $colref = $csv->getline ($io);        # Read a line from file $io,
                                       # parse it and return an array
                                       # ref of fields
 $eof = $csv->eof ();                  # Indicate if last parse or
                                       # getline () hit End Of File
 
 $csv->types(\@t_array);               # Set column types

DESCRIPTION

Text::CSV_PP has almost same functions of Text::CSV_XS which provides facilities for the composition and decomposition of comma-separated values. As its name suggests, Text::CSV_XS is a XS module and Text::CSV_PP is a Puer Perl one.

FUNCTIONS

Most of the documentation was shamelessly copied and replaced from H.Merijn Brand's Text::CSV_XS (0.32).

version ()

(Class method) Returns the current module version.

new (\%attr)

(Class method) Returns a new instance of Text::CSV_PP. The objects attributes are described by the (optional) hash ref \%attr. Currently the following attributes are available:

eol

An end-of-line string to add to rows, usually undef (nothing, default), "\012" (Line Feed) or "\015\012" (Carriage Return, Line Feed). Cannot be longer than 7 (ASCII) characters.

If both $/ and eol equal "\015", parsing lines that end on only a Carriage Return without Line Feed, will be parsed correct. Line endings, whether in $/ or eol, other than undef, "\n", "\r\n", or "\r" are not (yet) supported for parsing.

sep_char

The char used for separating fields, by default a comma. (,). Limited to a single-byte character, usually in the range from 0x20 (space) to 0x7e (tilde).

The separation character can not be equal to the quote character. The separation character can not be equal to the escape character.

allow_whitespace

When this option is set to true, whitespace (TAB's and SPACE's) surrounding the separation character is removed when parsing. So lines like:

  1 , "foo" , bar , 3 , zapp

are now correctly parsed, even though it violates the CSV specs. Note that all whitespace is stripped from start and end of each field. That would make is more a feature than a way to be able to parse bad CSV lines, as

 1,   2.0,  3,   ape  , monkey

will now be parsed as

 ("1", "2.0", "3", "ape", "monkey")

even if the original line was perfectly sane CSV.

quote_char

The char used for quoting fields containing blanks, by default the double quote character ("). A value of undef suppresses quote chars. (For simple cases only). Limited to a single-byte character, usually in the range from 0x20 (space) to 0x7e (tilde).

The quote character can not be equal to the separation character.

allow_loose_quotes

By default, parsing fields that have quote_char characters inside an unquoted field, like

 1,foo "bar" baz,42

would result in a parse error. Though it is still bad practice to allow this format, we cannot help there are some vendors that make their applications spit out lines styled like this.

escape_char

The character used for escaping certain characters inside quoted fields. Limited to a single-byte character, usually in the range from 0x20 (space) to 0x7e (tilde).

The escape_char defaults to being the literal double-quote mark (") in other words, the same as the default quote_char. This means that doubling the quote mark in a field escapes it:

  "foo","bar","Escape ""quote mark"" with two ""quote marks""","baz"

If you change the default quote_char without changing the default escape_char, the escape_char will still be the quote mark. If instead you want to escape the quote_char by doubling it, you will need to change the escape_char to be the same as what you changed the quote_char to.

The escape character can not be equal to the separation character.

allow_loose_escapes

By default, parsing fields that have escape_char characters that escape characters that do not need to be escaped, like:

 my $csv = Text::CSV_PP->new ({ escape_char => "\\" });
 $csv->parse (qq{1,"my bar\'s",baz,42});

would result in a parse error. Though it is still bad practice to allow this format, this option enables you to treat all escape character sequences equal.

binary

If this attribute is TRUE, you may use binary characters in quoted fields, including line feeds, carriage returns and NULL bytes. (The latter must be escaped as "0.) By default this feature is off.

types

A set of column types; this attribute is immediately passed to the types method below. You must not set this attribute otherwise, except for using the types method. For details see the description of the types method below.

always_quote

By default the generated fields are quoted only, if they need to, for example, if they contain the separator. If you set this attribute to a TRUE value, then all fields will be quoted. This is typically easier to handle in external applications.

keep_meta_info

By default, the parsing of input lines is as simple and fast as possible. However, some parsing information - like quotation of the original field - is lost in that process. Set this flag to true to be able to retrieve that information after parsing with the methods meta_info (), is_quoted (), and is_binary () described below. Default is false.

verbatim

This is a quite controversial attribute to set, but it makes hard things possible.

The basic thought behind this is to tell the parser that the normally special characters newline (NL) and Carriage Return (CR) will not be special when this flag is set, and be dealt with as being ordinary binary characters. This will ease working with data with embedded newlines.

When verbatim is used with getline (), getline auto-chomp's every line.

Imagine a file format like

  M^^Hans^Janssen^Klas 2\n2A^Ja^11-06-2007#\r\n

where, the line ending is a very specific "#\r\n", and the sep_char is a ^ (caret). None of the fields is quoted, but embedded binary data is likely to be present. With the specific line ending, that shouldn't be too hard to detect.

By default, Text::CSV_PP' parse function however is instructed to only know about "\n" and "\r" to be legal line endings, and so has to deal with the embedded newline as a real end-of-line, so it can scan the next line if binary is true, and the newline is inside a quoted field. With this attribute however, we can tell parse () to parse the line as if \n is just nothing more than a binary character.

For parse () this means that the parser has no idea about line ending anymore, and getline () chomps line endings on reading.

To sum it up,

 $csv = Text::CSV_PP->new ();

is equivalent to

 $csv = Text::CSV_PP->new ({
     quote_char          => '"',
     escape_char         => '"',
     sep_char            => ',',
     eol                 => '',
     always_quote        => 0,
     binary              => 0,
     keep_meta_info      => 0,
     allow_loose_quotes  => 0,
     allow_loose_escapes => 0,
     allow_whitespace    => 0,
     verbatim            => 0,
     });

For all of the above mentioned flags, there is an accessor method available where you can inquire for the current value, or change the value

 my $quote = $csv->quote_char;
 $csv->binary (1);

It is unwise to change these settings halfway through writing CSV data to a stream. If however, you want to create a new stream using the available CSV object, there is no harm in changing them.

combine
 $status = $csv->combine (@columns);

This object function constructs a CSV string from the arguments, returning success or failure. Failure can result from lack of arguments or an argument containing an invalid character. Upon success, string () can be called to retrieve the resultant CSV string. Upon failure, the value returned by string () is undefined and error_input () can be called to retrieve an invalid argument.

print
 $status = $csv->print ($io, $colref);

Similar to combine, but it expects an array ref as input (not an array!) and the resulting string is not really created, but immediately written to the $io object, typically an IO handle or any other object that offers a print method. Note, this implies that the following is wrong:

 open FILE, ">", "whatever";
 $status = $csv->print (\*FILE, $colref);

The glob \*FILE is not an object, thus it doesn't have a print method. The solution is to use an IO::File object or to hide the glob behind an IO::Wrap object. See IO::File(3) and IO::Wrap(3) for details.

For performance reasons the print method doesn't create a result string. In particular the $csv->string (), $csv->status (), $csv-fields ()> and $csv->error_input () methods are meaningless after executing this method.

string
 $line = $csv->string ();

This object function returns the input to parse () or the resultant CSV string of combine (), whichever was called more recently.

parse
 $status = $csv->parse ($line);

This object function decomposes a CSV string into fields, returning success or failure. Failure can result from a lack of argument or the given CSV string is improperly formatted. Upon success, fields () can be called to retrieve the decomposed fields . Upon failure, the value returned by fields () is undefined and error_input () can be called to retrieve the invalid argument.

You may use the types () method for setting column types. See the description below.

getline
 $colref = $csv->getline ($io);

This is the counterpart to print, like parse is the counterpart to combine: It reads a row from the IO object $io using $io->getline () and parses this row into an array ref. This array ref is returned by the function or undef for failure.

The $csv->string (), $csv->fields () and $csv->status () methods are meaningless, again.

eof
 $eof = $csv->eof ();

If parse () or getline () was used with an IO stream, this method will return true (1) if the last call hit end of file, otherwise it will return false (''). This is useful to see the difference between a failure and end of file.

types
 $csv->types (\@tref);

This method is used to force that columns are of a given type. For example, if you have an integer column, two double columns and a string column, then you might do a

 $csv->types ([Text::CSV_PP::IV (),
               Text::CSV_PP::NV (),
               Text::CSV_PP::NV (),
               Text::CSV_PP::PV ()]);

Column types are used only for decoding columns, in other words by the parse () and getline () methods.

You can unset column types by doing a

 $csv->types (undef);

or fetch the current type settings with

 $types = $csv->types ();
IV

Set field type to integer.

NV

Set field type to numeric/float.

PV

Set field type to string.

fields
 @columns = $csv->fields ();

This object function returns the input to combine () or the resultant decomposed fields of parse (), whichever was called more recently.

meta_info
 @flags = $csv->meta_info ();

This object function returns the flags of the input to combine () or the flags of the resultant decomposed fields of parse (), whichever was called more recently.

For each field, a meta_info field will hold flags that tell something about the field returned by the fields () method or passed to the combine () method. The flags are bitwise-or'd like:

0x0001

The field was quoted.

0x0002

The field was binary.

See the is_*** () methods below.

is_quoted
  my $quoted = $csv->is_quoted ($column_idx);

Where $column_idx is the (zero-based) index of the column in the last result of parse ().

This returns a true value if the data in the indicated column was enclosed in quote_char quotes. This might be important for data where ,20070108, is to be treated as a numeric value, and where ,"20070108", is explicitly marked as character string data.

is_binary
  my $binary = $csv->is_binary ($column_idx);

Where $column_idx is the (zero-based) index of the column in the last result of parse ().

This returns a true value if the data in the indicated column contained any byte in the range [\x00-\x08,\x10-\x1F,\x7F-\xFF]

status
 $status = $csv->status ();

This object function returns success (or failure) of combine () or parse (), whichever was called more recently.

error_input
 $bad_argument = $csv->error_input ();

This object function returns the erroneous argument (if it exists) of combine () or parse (), whichever was called more recently.

error_diag
 $csv->error_diag ();
 $error_code  = 0  + $csv->error_diag ();
 $error_str   = "" . $csv->error_diag ();
 ($cde, $str) =      $csv->error_diag ();

If (and only if) an error occured, this function returns the diagnostics of that error.

If called in void context, it will print the internal error code and the associated error message to STDERR.

If called in list context, it will return the error code and the error message in that order.

If called in scalar context, it will return the diagnostics in a single scalar, a-la $!. It will contain the error code in numeric context, and the diagnostics message in string context.

To achieve this behavior with CSV_PP, the returned diagnostics is blessed object.

DIAGNOSTICS

If an error occured, $csv->error_diag () can be used to get more information on the cause of the failure. Note that for speed reasons, the internal value is never cleared on success, so using the value returned by error_diag () in normal cases - when no error occured - may cause unexpected results.

Note: CSV_PP's diagnostics is different from CSV_XS's:

Text::CSV_XS parses csv strings by dividing one character while Text::CSV_PP by using the regular expressions. That difference makes the different cause of the failure. Though diagnostics number 1001, 2027 and 2110 are common with CSV_XS.

Currently these errors are available:

1001 "sep_char is equal to quote_char or escape_char"
2027 "EIQ - Quoted field not terminated"
2110 "ECB - Binary character in Combine, binary off"
4000 "ECR - Binary character in field, binary off"
4001 "EIQ - Needless ESC in quoted field"
4002 "EIQ - Unescaped ESC in quoted field"

SPEED

Of course Text::CSV_PP is much more slow than CSV_XS. Here is a benchmark test using an example code in Text-CSV_XS-0.29.

 Text::CSV_PP (1.05)
 Benchmark: running combine   1, combine  10, combine 100, parse     1, parse
 10, parse   100 for at least 3 CPU seconds...
 combine   1:  4 wallclock secs ( 3.23 usr +  0.00 sys =  3.23 CPU) @ 12279.22/s (n=39711)
 combine  10:  3 wallclock secs ( 3.16 usr +  0.00 sys =  3.16 CPU) @ 1876.74/s (n=5923)
 combine 100:  3 wallclock secs ( 3.19 usr +  0.00 sys =  3.19 CPU) @ 192.60/s (n=614)
 parse     1:  3 wallclock secs ( 3.25 usr +  0.00 sys =  3.25 CPU) @ 7623.69/s (n=24777)
 parse    10:  3 wallclock secs ( 3.25 usr +  0.00 sys =  3.25 CPU) @ 1334.46/s (n=4337)
 parse   100:  3 wallclock secs ( 3.22 usr +  0.02 sys =  3.24 CPU) @ 132.92/s (n=430)
 Benchmark: timing 50000 iterations of print    io...
 print    io: 32 wallclock secs (30.31 usr +  0.72 sys = 31.03 CPU) @ 1611.24/s (n=50000)
 Benchmark: timing 50000 iterations of getline  io...
 getline  io: 47 wallclock secs (47.33 usr +  0.28 sys = 47.61 CPU) @ 1050.22/s (n=50000)
 File was 46050000 bytes long, line length 920


 Text::CSV_XS (0.29)
 Benchmark: running combine   1, combine  10, combine 100, parse     1, parse
 10, parse   100 for at least 3 CPU seconds...
 combine   1:  3 wallclock secs ( 3.09 usr +  0.00 sys =  3.09 CPU) @ 59718.49/s (n=184769)
 combine  10:  3 wallclock secs ( 3.09 usr +  0.00 sys =  3.09 CPU) @ 26825.09/s (n=82970)
 combine 100:  4 wallclock secs ( 3.16 usr +  0.00 sys =  3.16 CPU) @ 3741.53/s (n=11812)
 parse     1:  3 wallclock secs ( 3.20 usr +  0.00 sys =  3.20 CPU) @ 27434.59/s (n=87873)
 parse    10:  3 wallclock secs ( 3.23 usr +  0.00 sys =  3.23 CPU) @ 4576.38/s (n=14800)
 parse   100:  3 wallclock secs ( 3.19 usr +  0.00 sys =  3.19 CPU) @ 483.53/s (n=1541)
 Benchmark: timing 50000 iterations of print    io...
 print    io:  3 wallclock secs ( 2.11 usr +  0.39 sys =  2.50 CPU) @ 20008.00/s (n=50000)
 Benchmark: timing 50000 iterations of getline  io...
 getline  io: 12 wallclock secs (11.44 usr +  0.19 sys = 11.63 CPU) @ 4300.71/s ( n=50000)
 File was 46050000 bytes long, line length 920

AUTHOR

Makamaka Hannyaharamitu, <makamaka[at]cpan.org>

Text::CSV_XS was written by <joe[at]ispsoft.de> and maintained by <h.m.brand[at]xs4all.nl>.

Text::CSV was written by <alan[at]mfgrtl.com>.

COPYRIGHT AND LICENSE

Copyright 2005-2007 by Makamaka Hannyaharamitu, <makamaka[at]cpan.org>

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

Text::CSV_XS, Text::CSV

I got many regexp bases from http://www.din.or.jp/~ohzaki/perl.htm