CCmdLine - a C++ class for parsing command lines
Parsing command lines with the standard C string functions (strlen, strcpy, etc.) or even
with the CString operators is a nightmare. But, CCmdLine makes it effortless.
CCmdLine uses STL for its collection classes, so it works in MFC
and non-MFC apps. If you are using this in an MFC app, the switches
and arguments will be returned as CStrings. If you are using this in a
non-MFC app, they will be returned as STL 'string's.
CCmdLine was written for use with console apps, but can be easily used in
any application which requires command-line parsing.
CCmdLine is a simple way to parse a command line into switches and arguments.
Ex :
MyApp.exe -sw1 arg1 arg2 -sw2 arg3 -sw3 -sw4
When using CCmdLine, "-sw1", "-sw2", "-sw3" and "-sw4" are switches and "arg1", "arg2" and "arg3" are arguments.
Example :
Assume the application we're writing uses a command line that has two
required switches and two optional switches. The app should abort
if the required switches are not present and continue with default
values if the optional switches are not present.
MyApp.exe -p1 text1 text2 -p2 "this is a big argument" -opt1 -55 -opt2
Switches -p1 and -p2 are required.
p1 has two arguments and p2 has one.
Switches -opt1 and -opt2 are optional.
opt1 requires a numeric argument.
opt2 has no arguments.
Also, assume that the app displays a 'help' screen if the '-h' switch
is present on the command line.
Here's how you can use CCmdLine to handle the command line processing :
// if this is an MFC app, un-comment the next line
// #include "stdafx.h"
#include "CmdLine.h"
void main(int argc, char **argv)
{
// our cmd line parser object
CCmdLine cmdLine;
// parse the command line.
// in MFC apps, use __argc and __argv here
if (cmdLine.SplitLine(argc, argv) < 1)
{
// no switches were given on the command line, abort
ASSERT(0);
exit(-1);
}
// test for the 'help' case
if (cmdLine.HasSwitch("-h"))
{
show_help();
exit(0);
}
// StringType is defined in CmdLine.h.
// it is CString when using MFC, else STL's 'string'
StringType p1_1, p1_2, p2_1;
// get the required arguments
try
{
// if any of these GetArgument calls fail,
// we'll end up in the catch() block
// get the first -p1 argument (arg number '0')
p1_1 = cmdLine.GetArgument("-p1", 0);
// get the second -p1 argument (arg number '1')
p1_2 = cmdLine.GetArgument("-p1", 1);
// get the first -p2 argument
p2_1 = cmdLine.GetArgument("-p2", 0);
}
catch (...)
{
// one of the required arguments was missing, abort
ASSERT(0);
exit(-1);
}
// get the optional parameters
// the GetSafeArgument member does not throw exceptions, and
// allows for the use of a default value, if the switch is not found.
// get the argument, convert it to an int.
// default to '100', if the argument was not found
int iOpt1Val = atoi( cmdLine.GetSafeArgument( "-opt1", 0, 100 ) );
// since opt2 has no arguments, just test for the presence of
// the '-opt2' switch
bool bOptSwitch2 = cmdLine.HasSwitch("-opt2");
.... and so on....
}
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