megaco_flex_scanner
Interface module to the flex scanner linked in driver.
This module contains the public interface to the flex scanner linked in driver. The flex scanner performs the scanning phase of text message decoding.
The flex scanner is written using a tool called flex. In order to be able to compile the flex scanner driver, this tool has to be available.
By default the flex scanner reports line-number of an error.
But it can be built without line-number reporting. Instead
token number is used. This will speed up the scanning some
5-10%. Use --disable-megaco-flex-scanner-lineno
when
configuring the application.
The scanner will, by default, be built as a reentrant scanner if the
flex utility supports this (it depends on the version of flex).
It is possible to explicitly disable this even when flex support this.
Use --disable-megaco-reentrant-flex-scanner
when
configuring the application.
DATA TYPES
megaco_ports() = term() megaco_version() = integer() >= 1
Functions
start() -> {ok, PortOrPorts} | {error, Reason}
PortOrPorts = megaco_ports()
Reason = term()
This function is used to start the flex scanner. It locates the library and loads the linked in driver.
On a single core system or if it's a non-reentrant scanner, a single port is created. On a multi-core system with a reentrant scanner, several ports will be created (one for each scheduler).
Note that the process that calls this function must be permanent. If it dies, the port(s) will exit and the driver unload.
stop(PortOrPorts) -> stopped
PortOrPorts = megaco_ports()
This function is used to stop the flex scanner. It also unloads the driver.
is_reentrant_enabled() -> Boolean
Boolean = boolean()
Is the flex scanner reentrant or not.
is_scanner_port(Port, PortOrPorts) -> Boolean
Port = port()
PortOrPorts = megaco_ports()
Boolean = boolean()
Checks if a port is a flex scanner port or not (usefull when if a port exits).
scan(Binary, PortOrPorts) -> {ok, Tokens, Version, LatestLine} | {error, Reason, LatestLine}
Binary = binary()
PortOrPorts = megaco_ports()
Tokens = list()
Version = megaco_version()
LatestLine = integer()
Reason = term()
Scans a megaco message and generates a token list to be passed on the parser.