module.exports = function sscanf (str, format) {
// discuss at: https://locutus.io/php/sscanf/
// original by: Brett Zamir (https://brett-zamir.me)
// example 1: sscanf('SN/2350001', 'SN/%d')
// returns 1: [2350001]
// example 2: var myVar = {}
// example 2: sscanf('SN/2350001', 'SN/%d', myVar)
// example 2: var $result = myVar.value
// returns 2: 2350001
// example 3: sscanf("10--20", "%2$d--%1$d") // Must escape '$' in PHP, but not JS
// returns 3: [20, 10]
const retArr = []
const _NWS = /\S/
const args = arguments
let digit
const _setExtraConversionSpecs = function (offset) {
// Since a mismatched character sets us off track from future
// legitimate finds, we just scan
// to the end for any other conversion specifications (besides a percent literal),
// setting them to null
// sscanf seems to disallow all conversion specification components (of sprintf)
// except for type specifiers
// Do not allow % in last char. class
// var matches = format.match(/%[+-]?([ 0]|'.)?-?\d*(\.\d+)?[bcdeufFosxX]/g);
// Do not allow % in last char. class:
const matches = format.slice(offset).match(/%[cdeEufgosxX]/g)
// b, F,G give errors in PHP, but 'g', though also disallowed, doesn't
if (matches) {
let lgth = matches.length
while (lgth--) {
retArr.push(null)
}
}
return _finish()
}
var _finish = function () {
if (args.length === 2) {
return retArr
}
for (var i = 0; i < retArr.length; ++i) {
args[i + 2].value = retArr[i]
}
return i
}
const _addNext = function (j, regex, cb) {
if (assign) {
const remaining = str.slice(j)
const check = width ? remaining.substr(0, width) : remaining
const match = regex.exec(check)
// @todo: Make this more readable
const key = digit !== undefined
? digit
: retArr.length
const testNull = retArr[key] = match
? (cb
? cb.apply(null, match)
: match[0])
: null
if (testNull === null) {
throw new Error('No match in string')
}
return j + match[0].length
}
return j
}
if (arguments.length < 2) {
throw new Error('Not enough arguments passed to sscanf')
}
// PROCESS
for (let i = 0, j = 0; i < format.length; i++) {
var width = 0
var assign = true
if (format.charAt(i) === '%') {
if (format.charAt(i + 1) === '%') {
if (str.charAt(j) === '%') {
// a matched percent literal
// skip beyond duplicated percent
++i
++j
continue
}
// Format indicated a percent literal, but not actually present
return _setExtraConversionSpecs(i + 2)
}
// CHARACTER FOLLOWING PERCENT IS NOT A PERCENT
// We need 'g' set to get lastIndex
const prePattern = /^(?:(\d+)\$)?(\*)?(\d*)([hlL]?)/g
const preConvs = prePattern.exec(format.slice(i + 1))
const tmpDigit = digit
if (tmpDigit && preConvs[1] === undefined) {
let msg = 'All groups in sscanf() must be expressed as numeric if '
msg += 'any have already been used'
throw new Error(msg)
}
digit = preConvs[1] ? parseInt(preConvs[1], 10) - 1 : undefined
assign = !preConvs[2]
width = parseInt(preConvs[3], 10)
const sizeCode = preConvs[4]
i += prePattern.lastIndex
// @todo: Does PHP do anything with these? Seems not to matter
if (sizeCode) {
// This would need to be processed later
switch (sizeCode) {
case 'h':
case 'l':
case 'L':
// Treats subsequent as short int (for d,i,n) or unsigned short int (for o,u,x)
// Treats subsequent as long int (for d,i,n), or unsigned long int (for o,u,x);
// or as double (for e,f,g) instead of float or wchar_t instead of char
// Treats subsequent as long double (for e,f,g)
break
default:
throw new Error('Unexpected size specifier in sscanf()!')
}
}
// PROCESS CHARACTER
try {
// For detailed explanations, see https://web.archive.org/web/20031128125047/https://www.uwm.edu/cgi-bin/IMT/wwwman?topic=scanf%283%29&msection=
// Also https://www.mathworks.com/access/helpdesk/help/techdoc/ref/sscanf.html
// p, S, C arguments in C function not available
// DOCUMENTED UNDER SSCANF
switch (format.charAt(i + 1)) {
case 'F':
// Not supported in PHP sscanf; the argument is treated as a float, and
// presented as a floating-point number (non-locale aware)
// sscanf doesn't support locales, so no need for two (see %f)
break
case 'g':
// Not supported in PHP sscanf; shorter of %e and %f
// Irrelevant to input conversion
break
case 'G':
// Not supported in PHP sscanf; shorter of %E and %f
// Irrelevant to input conversion
break
case 'b':
// Not supported in PHP sscanf; the argument is treated as an integer,
// and presented as a binary number
// Not supported - couldn't distinguish from other integers
break
case 'i':
// Integer with base detection (Equivalent of 'd', but base 0 instead of 10)
var pattern = /([+-])?(?:(?:0x([\da-fA-F]+))|(?:0([0-7]+))|(\d+))/
j = _addNext(j, pattern, function (num, sign, hex,
oct, dec) {
return hex ? parseInt(num, 16) : oct ? parseInt(num, 8) : parseInt(num, 10)
})
break
case 'n':
// Number of characters processed so far
retArr[digit !== undefined ? digit : retArr.length - 1] = j
break
// DOCUMENTED UNDER SPRINTF
case 'c':
// Get character; suppresses skipping over whitespace!
// (but shouldn't be whitespace in format anyways, so no difference here)
// Non-greedy match
j = _addNext(j, new RegExp('.{1,' + (width || 1) + '}'))
break
case 'D':
case 'd':
// sscanf documented decimal number; equivalent of 'd';
// Optionally signed decimal integer
j = _addNext(j, /([+-])?(?:0*)(\d+)/, function (num, sign, dec) {
// Ignores initial zeroes, unlike %i and parseInt()
const decInt = parseInt((sign || '') + dec, 10)
if (decInt < 0) {
// PHP also won't allow less than -2147483648
// integer overflow with negative
return decInt < -2147483648 ? -2147483648 : decInt
} else {
// PHP also won't allow greater than -2147483647
return decInt < 2147483647 ? decInt : 2147483647
}
})
break
case 'f':
case 'E':
case 'e':
// Although sscanf doesn't support locales,
// this is used instead of '%F'; seems to be same as %e
// These don't discriminate here as both allow exponential float of either case
j = _addNext(j, /([+-])?(?:0*)(\d*\.?\d*(?:[eE]?\d+)?)/, function (num, sign, dec) {
if (dec === '.') {
return null
}
// Ignores initial zeroes, unlike %i and parseFloat()
return parseFloat((sign || '') + dec)
})
break
case 'u':
// unsigned decimal integer
// We won't deal with integer overflows due to signs
j = _addNext(j, /([+-])?(?:0*)(\d+)/, function (num, sign, dec) {
// Ignores initial zeroes, unlike %i and parseInt()
const decInt = parseInt(dec, 10)
if (sign === '-') {
// PHP also won't allow greater than 4294967295
// integer overflow with negative
return 4294967296 - decInt
} else {
return decInt < 4294967295 ? decInt : 4294967295
}
})
break
case 'o':
// Octal integer // @todo: add overflows as above?
j = _addNext(j, /([+-])?(?:0([0-7]+))/, function (num, sign, oct) {
return parseInt(num, 8)
})
break
case 's':
// Greedy match
j = _addNext(j, /\S+/)
break
case 'X':
case 'x':
// Same as 'x'?
// @todo: add overflows as above?
// Initial 0x not necessary here
j = _addNext(j, /([+-])?(?:(?:0x)?([\da-fA-F]+))/, function (num, sign, hex) {
return parseInt(num, 16)
})
break
case '':
// If no character left in expression
throw new Error('Missing character after percent mark in sscanf() format argument')
default:
throw new Error('Unrecognized character after percent mark in sscanf() format argument')
}
} catch (e) {
if (e === 'No match in string') {
// Allow us to exit
return _setExtraConversionSpecs(i + 2)
}
// Calculate skipping beyond initial percent too
}
++i
} else if (format.charAt(i) !== str.charAt(j)) {
// @todo: Double-check i whitespace ignored in string and/or formats
_NWS.lastIndex = 0
if ((_NWS)
.test(str.charAt(j)) || str.charAt(j) === '') {
// Whitespace doesn't need to be an exact match)
return _setExtraConversionSpecs(i + 1)
} else {
// Adjust strings when encounter non-matching whitespace,
// so they align in future checks above
// Ok to replace with j++;?
str = str.slice(0, j) + str.slice(j + 1)
i--
}
} else {
j++
}
}
// POST-PROCESSING
return _finish()
}