将 PHP 代码转换为 Javascript（内爆、打包和解包）
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【中文标题】将 PHP 代码转换为 Javascript（内爆、打包和解包）【英文标题】：Convert PHP code to Javascript (implode, pack and unpack) 【发布时间】：2016-10-14 17:14:42 【问题描述】：我需要在客户端将一些 php 转换为 javascript。
有人能指出我对这行的正确翻译吗？ 如果需要外部库也没问题。
$a = pack("A32", "foobar");
$b = implode("", unpack("H32", ("foobar", "frigobar")));
【问题讨论】：
【参考方案1】：你可以在 locutus.io 找到 PHP 的 pack 函数在 JavaScript 中的实现（它相当长，所以我没有在这里包含它）。
PHP 的 implode 函数等于 JavaScript 的 join：
implode(",", array("first", "second", "third")) // "first,second,third"
和
一样["first", "second", "third"].join(",") // "first,second,third"
Locutus 还创建了一个 unpack 实现，但它已从他的网站上删除。在这里（虽然它被标记为“未准备好生产”）
function unpack(format, data)
// http://kevin.vanzonneveld.net
// + original by: Tim de Koning (http://www.kingsquare.nl)
// + parts by: Jonas Raoni Soares Silva - http://www.jsfromhell.com
// + parts by: Joshua Bell - http://cautionsingularityahead.blogspot.nl/
// +
// + bugfixed by: marcuswestin
// % note 1: Float decoding by: Jonas Raoni Soares Silva
// % note 2: Home: http://www.kingsquare.nl/blog/22-12-2009/13650536
// % note 3: Feedback: phpjs-unpack@kingsquare.nl
// % note 4: 'machine dependant byte order and size' aren't
// % note 5: applicable for JavaScript unpack works as on a 32bit,
// % note 6: little endian machine
// * example 1: unpack('d', "\u0000\u0000\u0000\u0000\u00008YÀ");
// * returns 1: "": -100.875
var formatPointer = 0, dataPointer = 0, result = , instruction = '',
quantifier = '', label = '', currentData = '', i = 0, j = 0,
word = '', fbits = 0, ebits = 0, dataByteLength = 0;
// Used by float decoding - by Joshua Bell
//http://cautionsingularityahead.blogspot.nl/2010/04/javascript-and-ieee754-redux.html
var fromIEEE754 = function(bytes, ebits, fbits)
// Bytes to bits
var bits = [];
for (var i = bytes.length; i; i -= 1)
var byte = bytes[i - 1];
for (var j = 8; j; j -= 1)
bits.push(byte % 2 ? 1 : 0); byte = byte >> 1;
bits.reverse();
var str = bits.join('');
// Unpack sign, exponent, fraction
var bias = (1 << (ebits - 1)) - 1;
var s = parseInt(str.substring(0, 1), 2) ? -1 : 1;
var e = parseInt(str.substring(1, 1 + ebits), 2);
var f = parseInt(str.substring(1 + ebits), 2);
// Produce number
if (e === (1 << ebits) - 1)
return f !== 0 ? NaN : s * Infinity;
else if (e > 0)
return s * Math.pow(2, e - bias) * (1 + f / Math.pow(2, fbits));
else if (f !== 0)
return s * Math.pow(2, -(bias-1)) * (f / Math.pow(2, fbits));
else
return s * 0;
while (formatPointer < format.length)
instruction = format.charAt(formatPointer);
// Start reading 'quantifier'
quantifier = '';
formatPointer++;
while ((formatPointer < format.length) &&
(format.charAt(formatPointer).match(/[\d\*]/) !== null))
quantifier += format.charAt(formatPointer);
formatPointer++;
if (quantifier === '')
quantifier = '1';
// Start reading label
label = '';
while ((formatPointer < format.length) &&
(format.charAt(formatPointer) !== '/'))
label += format.charAt(formatPointer);
formatPointer++;
if (format.charAt(formatPointer) === '/')
formatPointer++;
// Process given instruction
switch (instruction)
case 'a': // NUL-padded string
case 'A': // SPACE-padded string
if (quantifier === '*')
quantifier = data.length - dataPointer;
else
quantifier = parseInt(quantifier, 10);
currentData = data.substr(dataPointer, quantifier);
dataPointer += quantifier;
if (instruction === 'a')
currentResult = currentData.replace(/\0+$/, '');
else
currentResult = currentData.replace(/ +$/, '');
result[label] = currentResult;
break;
case 'h': // Hex string, low nibble first
case 'H': // Hex string, high nibble first
if (quantifier === '*')
quantifier = data.length - dataPointer;
else
quantifier = parseInt(quantifier, 10);
currentData = data.substr(dataPointer, quantifier);
dataPointer += quantifier;
if (quantifier > currentData.length)
throw new Error('Warning: unpack(): Type ' + instruction +
': not enough input, need ' + quantifier);
currentResult = '';
for (i = 0; i < currentData.length; i++)
word = currentData.charCodeAt(i).toString(16);
if (instruction === 'h')
word = word[1] + word[0];
currentResult += word;
result[label] = currentResult;
break;
case 'c': // signed char
case 'C': // unsigned c
if (quantifier === '*')
quantifier = data.length - dataPointer;
else
quantifier = parseInt(quantifier, 10);
currentData = data.substr(dataPointer, quantifier);
dataPointer += quantifier;
for (i = 0; i < currentData.length; i++)
currentResult = currentData.charCodeAt(i);
if ((instruction === 'c') && (currentResult >= 128))
currentResult -= 256;
result[label + (quantifier > 1 ?
(i + 1) :
'')] = currentResult;
break;
case 'S': // unsigned short (always 16 bit, machine byte order)
case 's': // signed short (always 16 bit, machine byte order)
case 'v': // unsigned short (always 16 bit, little endian byte order)
if (quantifier === '*')
quantifier = (data.length - dataPointer) / 2;
else
quantifier = parseInt(quantifier, 10);
currentData = data.substr(dataPointer, quantifier * 2);
dataPointer += quantifier * 2;
for (i = 0; i < currentData.length; i += 2)
// sum per word;
currentResult = ((currentData.charCodeAt(i + 1) & 0xFF) << 8) +
(currentData.charCodeAt(i) & 0xFF);
if ((instruction === 's') && (currentResult >= 32768))
currentResult -= 65536;
result[label + (quantifier > 1 ?
((i / 2) + 1) :
'')] = currentResult;
break;
case 'n': // unsigned short (always 16 bit, big endian byte order)
if (quantifier === '*')
quantifier = (data.length - dataPointer) / 2;
else
quantifier = parseInt(quantifier, 10);
currentData = data.substr(dataPointer, quantifier * 2);
dataPointer += quantifier * 2;
for (i = 0; i < currentData.length; i += 2)
// sum per word;
currentResult = ((currentData.charCodeAt(i) & 0xFF) << 8) +
(currentData.charCodeAt(i + 1) & 0xFF);
result[label + (quantifier > 1 ?
((i / 2) + 1) :
'')] = currentResult;
break;
case 'i': // signed integer (machine dependent size and byte order)
case 'I': // unsigned integer (machine dependent size & byte order)
case 'l': // signed long (always 32 bit, machine byte order)
case 'L': // unsigned long (always 32 bit, machine byte order)
case 'V': // unsigned long (always 32 bit, little endian byte order)
if (quantifier === '*')
quantifier = (data.length - dataPointer) / 4;
else
quantifier = parseInt(quantifier, 10);
currentData = data.substr(dataPointer, quantifier * 4);
dataPointer += quantifier * 4;
for (i = 0; i < currentData.length; i += 4)
currentResult =
((currentData.charCodeAt(i + 3) & 0xFF) << 24) +
((currentData.charCodeAt(i + 2) & 0xFF) << 16) +
((currentData.charCodeAt(i + 1) & 0xFF) << 8) +
((currentData.charCodeAt(i) & 0xFF));
result[label + (quantifier > 1 ?
((i / 4) + 1) :
'')] = currentResult;
break;
case 'N': // unsigned long (always 32 bit, little endian byte order)
if (quantifier === '*')
quantifier = (data.length - dataPointer) / 4;
else
quantifier = parseInt(quantifier, 10);
currentData = data.substr(dataPointer, quantifier * 4);
dataPointer += quantifier * 4;
for (i = 0; i < currentData.length; i += 4)
currentResult =
((currentData.charCodeAt(i) & 0xFF) << 24) +
((currentData.charCodeAt(i + 1) & 0xFF) << 16) +
((currentData.charCodeAt(i + 2) & 0xFF) << 8) +
((currentData.charCodeAt(i + 3) & 0xFF));
result[label + (quantifier > 1 ?
((i / 4) + 1) :
'')] = currentResult;
break;
case 'f': //float
case 'd': //double
ebits = 8;
fbits = (instruction === 'f') ? 23 : 52;
dataByteLength = 4;
if (instruction === 'd')
ebits = 11;
dataByteLength = 8;
if (quantifier === '*')
quantifier = (data.length - dataPointer) / dataByteLength;
else
quantifier = parseInt(quantifier, 10);
currentData = data.substr(dataPointer, quantifier * dataByteLength);
dataPointer += quantifier * dataByteLength;
for (i = 0; i < currentData.length; i += dataByteLength)
data = currentData.substr(i, dataByteLength);
bytes = [];
for (j = data.length - 1; j >= 0; --j)
bytes.push(data.charCodeAt(j));
result[label + (quantifier > 1 ?
((i / 4) + 1) :
'')] = fromIEEE754(bytes, ebits, fbits);
break;
case 'x': // NUL byte
case 'X': // Back up one byte
case '@': // NUL byte
if (quantifier === '*')
quantifier = data.length - dataPointer;
else
quantifier = parseInt(quantifier, 10);
if (quantifier > 0)
if (instruction === 'X')
dataPointer -= quantifier;
else
if (instruction === 'x')
dataPointer += quantifier;
else
dataPointer = quantifier;
break;
default:
throw new Error('Warning: unpack() Type ' + instruction +
': unknown format code');
return result;
所以，最后，你的例子应该是这样写的：
var a = pack("A32", "foobar");
var b = unpack("H32", ["foobar", "frigobar"]).join("");
【讨论】：
某处是否有“生产就绪”解包功能？我到处搜索。还是我应该创建它？ @Rexford 我找不到。在我的示例中，可能在 99% 的情况下都可以，但显然您需要自己进行测试。以上是关于将 PHP 代码转换为 Javascript（内爆、打包和解包）的主要内容，如果未能解决你的问题，请参考以下文章
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