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/*

* extsprintf.js: extended POSIX-style sprintf

*/

var mod_assert = require('assert');

var mod_util = require('util');

/*

* Public interface

*/

exports.sprintf = jsSprintf;

exports.printf = jsPrintf;

exports.fprintf = jsFprintf;

/*

* Stripped down version of s[n]printf(3c). We make a best effort to throw an

* exception when given a format string we don't understand, rather than

* ignoring it, so that we won't break existing programs if/when we go implement

* the rest of this.

*

* This implementation currently supports specifying

* - field alignment ('-' flag),

* - zero-pad ('0' flag)

* - always show numeric sign ('+' flag),

* - field width

* - conversions for strings, decimal integers, and floats (numbers).

* - argument size specifiers. These are all accepted but ignored, since

* Javascript has no notion of the physical size of an argument.

*

* Everything else is currently unsupported, most notably precision, unsigned

* numbers, non-decimal numbers, and characters.

*/

function jsSprintf(fmt)

{

var regex = [

'([^%]*)', /* normal text */

'%', /* start of format */

'([\'\\-+ #0]*?)', /* flags (optional) */

'([1-9]\\d*)?', /* width (optional) */

'(\\.([1-9]\\d*))?', /* precision (optional) */

'[lhjztL]*?', /* length mods (ignored) */

'([diouxXfFeEgGaAcCsSp%jr])' /* conversion */

].join('');

var re = new RegExp(regex);

var args = Array.prototype.slice.call(arguments, 1);

var flags, width, precision, conversion;

var left, pad, sign, arg, match;

var ret = '';

var argn = 1;

mod_assert.equal('string', typeof (fmt));

while ((match = re.exec(fmt)) !== null) {

ret += match[1];

fmt = fmt.substring(match[0].length);

flags = match[2] || '';

width = match[3] || 0;

precision = match[4] || '';

conversion = match[6];

left = false;

sign = false;

pad = ' ';

if (conversion == '%') {

ret += '%';

continue;

}

if (args.length === 0)

throw (new Error('too few args to sprintf'));

arg = args.shift();

argn++;

if (flags.match(/[\' #]/))

throw (new Error(

'unsupported flags: ' + flags));

if (precision.length > 0)

throw (new Error(

'non-zero precision not supported'));

if (flags.match(/-/))

left = true;

if (flags.match(/0/))

pad = '0';

if (flags.match(/\+/))

sign = true;

switch (conversion) {

case 's':

if (arg === undefined || arg === null)

throw (new Error('argument ' + argn +

': attempted to print undefined or null ' +

'as a string'));

ret += doPad(pad, width, left, arg.toString());

break;

case 'd':

arg = Math.floor(arg);

/*jsl:fallthru*/

case 'f':

sign = sign && arg > 0 ? '+' : '';

ret += sign + doPad(pad, width, left,

arg.toString());

break;

case 'x':

ret += doPad(pad, width, left, arg.toString(16));

break;

case 'j': /* non-standard */

if (width === 0)

width = 10;

ret += mod_util.inspect(arg, false, width);

break;

case 'r': /* non-standard */

ret += dumpException(arg);

break;

default:

throw (new Error('unsupported conversion: ' +

conversion));

}

}

ret += fmt;

return (ret);

}

function jsPrintf() {

var args = Array.prototype.slice.call(arguments);

args.unshift(process.stdout);

jsFprintf.apply(null, args);

}

function jsFprintf(stream) {

var args = Array.prototype.slice.call(arguments, 1);

return (stream.write(jsSprintf.apply(this, args)));

}

function doPad(chr, width, left, str)

{

var ret = str;

while (ret.length < width) {

if (left)

ret += chr;

else

ret = chr + ret;

}

return (ret);

}

/*

* This function dumps long stack traces for exceptions having a cause() method.

* See node-verror for an example.

*/

function dumpException(ex)

{

var ret;

if (!(ex instanceof Error))

throw (new Error(jsSprintf('invalid type for %%r: %j', ex)));

/* Note that V8 prepends "ex.stack" with ex.toString(). */

ret = 'EXCEPTION: ' + ex.constructor.name + ': ' + ex.stack;

if (ex.cause && typeof (ex.cause) === 'function') {

var cex = ex.cause();

if (cex) {

ret += '\nCaused by: ' + dumpException(cex);

}

}

return (ret);

}