FFE CONFIGURATION

ffe uses the configuration file for extracting fields from the input file and for formatting the fields for output. Every line or binary block of the input file is considered as a record. Default configuration file is ˜/.fferc but another file can be given with ’-c’ option.

Configuration file for ffe is a text file. The file may contain empty lines. Commands are case-sensitive. Comments begin with the #-character and end at the end of the line. The string and char definitions can be enclosed in double quotation ’"’ characters. char is a single character. string and char can contain following escape codes: ’\a’,’\b’,’\t’,’\n’,’\v’,’\f’, ’\r’, ’\"’ and ’\#’. Character ’\’ can be escaped as ’\\’.

Command Substitution allows the output of a command to replace parts of the configuration file. Syntax for command substitution is:
‘command‘
The command is executed and the ‘command‘ is substituted with the standard output of the command, with any trailing newlines deleted. Command substitutions may not be nested.

Before executing the command ffe sets few environment variables:
FFE_STRUCTURE

The name of the structure given using -s,--structure.

FFE_OUIPUT

The name of the output file given using -o,--output.

FFE_FORMAT

The name of the output format given using -p,--print.

FFE_FIRST_FILE

The name of the first input file.

FFE_FILES

A list of all input files.

If variable is already set it will not be replaced.

Input file structure

Input file structures are specified with keyword structure:

structure name {options...}

Options must be ended with newline, options are:
type fixed|binary|separated [char] [*]

Fields in the input are fixed length text fields, fixed length binary fields or text fields separated by char. If * is given, multiple sequential separators are considered as one. Default separator is comma.

quoted [char]

Fields may be quoted with char, default quotation mark is double quotation mark ’"’. A quotation mark is assumed to be escaped as \char or doubling the mark as charchar in input. Non escaped quotation marks are not preserved in output.

header first|all|no

Controls the occurrence of the header line. Default is no. If set as first or all, the first line of the first input file is considered as header line containing the names of the fields. First means that only the first file has a header, all means that all files have a header, although the names are still taken from the header of the first file. Header line is handled according the record definition, meaning that the name positions, separators etc. are the same as for the fields.

output name

All records belonging this structure are printed according output format name. Default is to use output named as ’default’.

record name {options...}

Defines one record for a structure. A structure can contain several record types.

Record options:

id position string
rid position regexp

Identifies a record in the input file. Records are identified by the string or by the regular expression in regexp in input record position position. For fixed length and binary input the position is the byte position of the input record and for separated input the position means the position’th field of the input record. Positions start from one.

Id’s are required only if input structure contains several record types with equal lengths or field counts. Non printable characters can be escaped as \xnn where nn is the hexadecimal value of the character.

A record definition can contain several id’s, then all id’d must match the input line (id’s are combined with logical and).

In a multi-record binary structure every record must have at least one id.

field name|FILLER|* [length]|* [lookup]|* [output]

Specifies one field in a text input structure. length is mandatory for fixed length input structure except for the last field. If the last field of a fixed length input structure has a * in place of length then the last field can have arbitrary length.

Length is also used for printing fields in fixed length format using the %D or %D directive. The order of fields in configuration file is essential, it specifies the field order in a record.

If ’*’ is given instead of the name, then the ’name’ will be the ordinal number of the field, or if the ’header’ option has value ’first’ or ’all’, then the name of the field will taken from the header line (first line of the input).

If lookup is given then the fields contents is used to make a lookup in lookup table lookup. If length is not needed (separated format) but lookup is needed, use asterisk (*) in place of length definition.

If output is given field is printed using output output. Use asterisk in place of lookup if lookup is not needed.

Naming the field as FILLER causes field not to be printed in output.

field name|FILLER|* [length]|type [lookup]|* [output]

Specifies one field in a binary input structure. All other features are same as for the text structure except the type parameter. type specifies field data type and length and can have the following values:

char Printable character.

short Short integer having current system length and byte order.

int Integer having current system length and byte order.

long Long integer having current system length and byte order.

llong Long long integer having current system length and byte order.

ushort Unsigned short integer having current system length and byte order.

uint Unsigned integer having current system length and byte order.

ulong Unsigned long integer having current system length and byte order.

ullong Unsigned long long integer having current system length and byte order.

int8 8 bit integer.

int16_be Big endian 16 bit integer.

int32_be Big endian 32 bit integer.

int64_be Big endian 64 bit integer.

int16_le Little endian 16 bit integer.

int32_le Little endian 32 bit integer.

int64_le Little endian 64 bit integer.

uint8 Unsigned 8 bit integer.

uint16_be Unsigned big endian 16 bit integer.

uint32_be Unsigned big endian 32 bit integer.

uint64_be Unsigned big endian 64 bit integer.

uint16_le Unsigned little endian 16 bit integer.

uint32_le Unsigned little endian 32 bit integer.

uint64_le Unsigned little endian 64 bit integer.

float Float having current system length and byte order.

float_be Float having current system length and big endian byte order.

float_le Float having current system length and little endian byte order.

double Double having current system length and byte order.

double_be Double having current system length and big endian byte order.

double_le Double having current system length and little endian byte order.

bcd_be_len Bcd number having length len and nybbles in big endian order.

bcd_le_len Bcd number having length len and nybbles in little endian order.

hex_be_len Hexadecimal data in big endian order having length len.

If length is given instead of the type, then the field is assumed to be a printable string having length length. String is printed until length characters are printed or NULL character is found.

Bcd number (bcd_be_len and bcd_le_len) is printed until len bytes are read or a nybble having hexadecimal value f is found. Bcd number having big endian order is printed in order: most significant nybble first and least significant nybble second and bcd number having little endian order is printed in order: least significant nybble first and most significant nybble second. Bytes are always read in big endian order.

Hexadecimal data (hex_be_len and hex_le_len) is printed as hexadecimal values. Big endian data is printed starting from the lower address and little endian data starting from the upper address.

field-count number

Same effect as having field * number times. Because length is not specified, this works only with separated structure.

fields-from record

Fields for this record are the same as for record record.

output name

This record is printed according output format name. Default is to use output format specified in the structure.

level number [element_name|*] [group_name]

Level can be used if the contents of a file should be printed as hierarchical multi-level nested form document. Use * instead of the element name if it is not needed. number is the level of the record, starting from number one (highest level), element_name is the name for the record, group_name is used to group records in the same and lower levels. Only number is mandatory parameter.

record-length strict|minimum

strict Input record length and field count must match the record definition in order to get it processed. This is default value.

minimum Input record length and field count can be the same or longer as defined for the record. The rest of the input line is ignored.

Output definitions

There can be several output definitions in the configuration file. Format can be selected with ’-p’ option. Default format is named as ’default’.
output name|default {options...}

Defines one output format. Output named as ’default’ will be used if none is given for structure or record, or none is given with option ’-p’.

There is two predefined output formats no and raw. no suppresses all printing and raw prints the original input data.

Output options

Pictures in output definition can contain printf-style %-directives:

file_header picture

Picture is printed once before file contents.

file_trailer picture

Picture is printed once after file contents.

header picture

If specified, then the header line describing the field names is printed before records. Every field name is printed according the picture using the same separator and fields length as defined for the fields. Picture can contain only %n directive.

data picture

Field contents is printed according picture.

lookup picture

If field is mapped to lookup table, this picture will be used instead of picture from data option. If not given, then picture from data will be used.

separator string

All fields are terminated by string, except the last field of the record. Default is not to print separator.

record_header picture

picture is printed before the record content. Default is not to print header.

record_trailer picture

picture is printed after the record content. Default is newline.

justify left|right|char

Fields are left or right justified. char justifies output according the first occurrence of char in the data picture. Default is left.

indent string

Record contents is intended by string. Field contents is intended by two times the string. Default is not to indent.

field-list name1,name2,...

Only fields or constants named as name1,name2,... are printed, same effect as has ’-f’ option. Default is to print all the fields. Fields are also printed in the same order as they are listed.

no-data-print yes|no

When set as no and field-list is given, suppresses printing of record_header and record_trailer in case where current record contains none of the fields specified in field-list.

field-empty-print yes|no

When set as no, nothing is printed for fields which consist entirely of characters from empty-chars. If none of the fields of a record are printed then the printing of record_trailer is also suppressed. Default is yes.

empty-chars string

string specifies a set of characters which define an "empty" field. Default is " \f\n\r\t\v" (space, form-feed, newline, carriage return, horizontal tab and vertical tab).

output-file file

Output is written to file instead of the default output. If - is given the standard output is used.

group_header string

If a record has a level and group name defined, string is printed before the first record in the same group or if the group name has changed in the same level

group_trailer string

If a record has a level and group name defined, string is printed after the records in lower levels or if the group name has changed in the same level or if a higher level record is found.

element_header string

If record has a level and header name defined, string is printed before the records contents.

element_header string

If record has a level and header name defined, string is printed after the records contents.

hex-caps yes|no

Print hexadecimal numbers in capital letters. Default is no.

Lookup definitions

lookup name {options...}

Defines one lookup table.

Lookup options:

search exact|longest

The search type for lookup table.

default-value value

value is printed if the lookup is not successful.

pair key value

One key/value pair for the lookup table.

file name [separator]

Key/value pairs are read from file name. Every line is considered as a key/value pair separated by separator. Default separator is semicolon.

Constants

Additional to input fields constants values can be printed using option -f,--field-list or output option field-list. Constant will be printed using data output option.

Constants are specified as
const name value

when the name appears in a field list, value will be printed for every record as the name were one of the input fields.

Input Preprocessor

It is possible to define an input preprosessor for ffe. An input preprocessor is simply an executable program which writes the contents of the input file to standard output which will be read by ffe. If the input preprosessor does not write any characters on its standard output, then ffe uses the original file.

To set up an input preprocessor, set the FFEOPEN environment variable to a command line which will invoke your input preprocessor. This command line should include one occurrence of the string %s, which will be replaced by the input filename when the input preprocessor command is invoked.

The input preprocessor is not used if ffe is reading standard input.

EXAMPLES

Example of fixed length flat file containing fields ’FirstName’,’LastName’ and ’Age’:

John Ripper 23
Scott Tiger 45
Mary Moore 41

This file can be printed in XML with the following configuration:

structure personnel {
type fixed
output XML
record person {
field FirstName 9
field LastName 13
field Age 2
}
}

output XML {
file_header "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\n"
data "<%n>%d</%n>\n"
record_header "<%r>\n"
record_trailer "</%r>\n"
indent " "
}

SEE ALSO

More examples in Texinfo manual. If the info and ffe are properly installed, the command

info ffe

should give more information.

AUTHOR

Timo Savinen <tjsa@iki.fi >