extended-header.js
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// An Entry consisting of:
//
// "%d %s=%s\n", <length>, <keyword>, <value>
//
// The length is a decimal number, and includes itself and the \n
// \0 does not terminate anything. Only the length terminates the string.
// Numeric values are decimal strings.
module.exports = ExtendedHeader
var Entry = require("./entry.js")
, inherits = require("inherits")
, tar = require("../tar.js")
, numeric = tar.numeric
, keyTrans = { "SCHILY.dev": "dev"
, "SCHILY.ino": "ino"
, "SCHILY.nlink": "nlink" }
function ExtendedHeader () {
Entry.apply(this, arguments)
this.on("data", this._parse)
this.fields = {}
this._position = 0
this._fieldPos = 0
this._state = SIZE
this._sizeBuf = []
this._keyBuf = []
this._valBuf = []
this._size = -1
this._key = ""
}
inherits(ExtendedHeader, Entry)
ExtendedHeader.prototype._parse = parse
var s = 0
, states = ExtendedHeader.states = {}
, SIZE = states.SIZE = s++
, KEY = states.KEY = s++
, VAL = states.VAL = s++
, ERR = states.ERR = s++
Object.keys(states).forEach(function (s) {
states[states[s]] = states[s]
})
states[s] = null
// char code values for comparison
var _0 = "0".charCodeAt(0)
, _9 = "9".charCodeAt(0)
, point = ".".charCodeAt(0)
, a = "a".charCodeAt(0)
, Z = "Z".charCodeAt(0)
, a = "a".charCodeAt(0)
, z = "z".charCodeAt(0)
, space = " ".charCodeAt(0)
, eq = "=".charCodeAt(0)
, cr = "\n".charCodeAt(0)
function parse (c) {
if (this._state === ERR) return
for ( var i = 0, l = c.length
; i < l
; this._position++, this._fieldPos++, i++) {
// console.error("top of loop, size="+this._size)
var b = c[i]
if (this._size >= 0 && this._fieldPos > this._size) {
error(this, "field exceeds length="+this._size)
return
}
switch (this._state) {
case ERR: return
case SIZE:
// console.error("parsing size, b=%d, rest=%j", b, c.slice(i).toString())
if (b === space) {
this._state = KEY
// this._fieldPos = this._sizeBuf.length
this._size = parseInt(new Buffer(this._sizeBuf).toString(), 10)
this._sizeBuf.length = 0
continue
}
if (b < _0 || b > _9) {
error(this, "expected [" + _0 + ".." + _9 + "], got " + b)
return
}
this._sizeBuf.push(b)
continue
case KEY:
// can be any char except =, not > size.
if (b === eq) {
this._state = VAL
this._key = new Buffer(this._keyBuf).toString()
if (keyTrans[this._key]) this._key = keyTrans[this._key]
this._keyBuf.length = 0
continue
}
this._keyBuf.push(b)
continue
case VAL:
// field must end with cr
if (this._fieldPos === this._size - 1) {
// console.error("finished with "+this._key)
if (b !== cr) {
error(this, "expected \\n at end of field")
return
}
var val = new Buffer(this._valBuf).toString()
if (numeric[this._key]) {
val = parseFloat(val)
}
this.fields[this._key] = val
this._valBuf.length = 0
this._state = SIZE
this._size = -1
this._fieldPos = -1
continue
}
this._valBuf.push(b)
continue
}
}
}
function error (me, msg) {
msg = "invalid header: " + msg
+ "\nposition=" + me._position
+ "\nfield position=" + me._fieldPos
me.error(msg)
me.state = ERR
}