95 lines
2.5 KiB
JavaScript
95 lines
2.5 KiB
JavaScript
'use strict'
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var bindexOf = require('buffer-indexof')
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var equalSign = new Buffer('=')
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module.exports = function (opts) {
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var binary = opts ? opts.binary : false
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var that = {}
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that.encode = function (data, buf, offset) {
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if (!data) data = {}
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if (!offset) offset = 0
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if (!buf) buf = new Buffer(that.encodingLength(data) + offset)
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var oldOffset = offset
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var keys = Object.keys(data)
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if (keys.length === 0) {
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buf[offset] = 0
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offset++
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}
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keys.forEach(function (key) {
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var val = data[key]
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var oldOffset = offset
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offset++
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if (val === true) {
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offset += buf.write(key, offset)
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} else if (Buffer.isBuffer(val)) {
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offset += buf.write(key + '=', offset)
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var len = val.length
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val.copy(buf, offset, 0, len)
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offset += len
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} else {
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offset += buf.write(key + '=' + val, offset)
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}
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buf[oldOffset] = offset - oldOffset - 1
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})
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that.encode.bytes = offset - oldOffset
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return buf
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}
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that.decode = function (buf, offset, len) {
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if (!offset) offset = 0
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if (!Number.isFinite(len)) len = buf.length
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var data = {}
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var oldOffset = offset
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while (offset < len) {
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var b = decodeBlock(buf, offset)
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var i = bindexOf(b, equalSign)
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offset += decodeBlock.bytes
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if (b.length === 0) continue // ignore: most likely a single zero byte
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if (i === -1) data[b.toString().toLowerCase()] = true
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else if (i === 0) continue // ignore: invalid key-length
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else {
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var key = b.slice(0, i).toString().toLowerCase()
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if (key in data) continue // ignore: overwriting not allowed
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data[key] = binary ? b.slice(i + 1) : b.slice(i + 1).toString()
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}
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}
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that.decode.bytes = offset - oldOffset
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return data
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}
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that.encodingLength = function (data) {
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if (!data) return 1 // 1 byte (single empty byte)
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var keys = Object.keys(data)
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if (keys.length === 0) return 1 // 1 byte (single empty byte)
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return keys.reduce(function (total, key) {
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var val = data[key]
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total += Buffer.byteLength(key) + 1 // +1 byte to store field length
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if (Buffer.isBuffer(val)) total += val.length + 1 // +1 byte to fit equal sign
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else if (val !== true) total += Buffer.byteLength(String(val)) + 1 // +1 byte to fit equal sign
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return total
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}, 0)
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}
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return that
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}
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function decodeBlock (buf, offset) {
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var len = buf[offset]
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var to = offset + 1 + len
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var b = buf.slice(offset + 1, to > buf.length ? buf.length : to)
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decodeBlock.bytes = len + 1
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return b
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}
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