talksik/Blob.js
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Use TextEncoder and TextDecoder

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This commit is contained in:
Jimmy Wärting
2019-04-18 00:21:36 +02:00
parent a8d8821e81
commit 04210bc55c
1 changed files with 172 additions and 72 deletions
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Blob.js
+172 -72
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@@ -89,67 +89,166 @@
BlobConstructor.prototype = Blob.prototype
}
function FakeBlobBuilder () {
function toUTF8Array (str) {
var utf8 = []
for (var i = 0; i < str.length; i++) {
var charcode = str.charCodeAt(i)
if (charcode < 0x80) utf8.push(charcode)
else if (charcode < 0x800) {
utf8.push(0xc0 | (charcode >> 6),
0x80 | (charcode & 0x3f))
} else if (charcode < 0xd800 || charcode >= 0xe000) {
utf8.push(0xe0 | (charcode >> 12),
0x80 | ((charcode >> 6) & 0x3f),
0x80 | (charcode & 0x3f))
}
// surrogate pair
else {
i++
// UTF-16 encodes 0x10000-0x10FFFF by
// subtracting 0x10000 and splitting the
// 20 bits of 0x0-0xFFFFF into two halves
charcode = 0x10000 + (((charcode & 0x3ff) << 10)
| (str.charCodeAt(i) & 0x3ff))
utf8.push(0xf0 | (charcode >> 18),
0x80 | ((charcode >> 12) & 0x3f),
0x80 | ((charcode >> 6) & 0x3f),
0x80 | (charcode & 0x3f))
}
}
return utf8
}
function fromUtf8Array (array) {
var out, i, len, c
var char2, char3
out = ''
len = array.length
i = 0
while (i < len) {
c = array[i++]
switch (c >> 4) {
case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
// 0xxxxxxx
out += String.fromCharCode(c)
break
case 12: case 13:
// 110x xxxx 10xx xxxx
char2 = array[i++]
out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F))
break
case 14:
// 1110 xxxx 10xx xxxx 10xx xxxx
char2 = array[i++]
char3 = array[i++]
out += String.fromCharCode(((c & 0x0F) << 12) |
((char2 & 0x3F) << 6) |
((char3 & 0x3F) << 0))
break
/********************************************************/
/* String Encoder fallback */
/********************************************************/
function stringEncode (string) {
var pos = 0
var len = string.length
var out = []
var Arr = global.Uint8Array || Array // Use byte array when possible
var at = 0 // output position
var tlen = Math.max(32, len + (len >> 1) + 7) // 1.5x size
var target = new Arr((tlen >> 3) << 3) // ... but at 8 byte offset
while (pos < len) {
var value = string.charCodeAt(pos++)
if (value >= 0xd800 && value <= 0xdbff) {
// high surrogate
if (pos < len) {
var extra = string.charCodeAt(pos)
if ((extra & 0xfc00) === 0xdc00) {
++pos
value = ((value & 0x3ff) << 10) + (extra & 0x3ff) + 0x10000
}
}
if (value >= 0xd800 && value <= 0xdbff) {
continue // drop lone surrogate
}
}
return out
// expand the buffer if we couldn't write 4 bytes
if (at + 4 > target.length) {
tlen += 8 // minimum extra
tlen *= (1.0 + (pos / string.length) * 2) // take 2x the remaining
tlen = (tlen >> 3) << 3 // 8 byte offset
const update = new Uint8Array(tlen)
update.set(target)
target = update
}
if ((value & 0xffffff80) === 0) { // 1-byte
target[at++] = value // ASCII
continue
} else if ((value & 0xfffff800) === 0) { // 2-byte
target[at++] = ((value >> 6) & 0x1f) | 0xc0
} else if ((value & 0xffff0000) === 0) { // 3-byte
target[at++] = ((value >> 12) & 0x0f) | 0xe0
target[at++] = ((value >> 6) & 0x3f) | 0x80
} else if ((value & 0xffe00000) === 0) { // 4-byte
target[at++] = ((value >> 18) & 0x07) | 0xf0
target[at++] = ((value >> 12) & 0x3f) | 0x80
target[at++] = ((value >> 6) & 0x3f) | 0x80
} else {
// FIXME: do we care
continue
}
target[at++] = (value & 0x3f) | 0x80
}
return target.slice(0, at)
}
/********************************************************/
/* String Decoder fallback */
/********************************************************/
function stringDecode (buf) {
var end = buf.length
var res = []
var i = 0
while (i < end) {
var firstByte = buf[i]
var codePoint = null
var bytesPerSequence = (firstByte > 0xEF) ? 4
: (firstByte > 0xDF) ? 3
: (firstByte > 0xBF) ? 2
: 1
if (i + bytesPerSequence <= end) {
var secondByte, thirdByte, fourthByte, tempCodePoint
switch (bytesPerSequence) {
case 1:
if (firstByte < 0x80) {
codePoint = firstByte
}
break
case 2:
secondByte = buf[i + 1]
if ((secondByte & 0xC0) === 0x80) {
tempCodePoint = (firstByte & 0x1F) << 0x6 | (secondByte & 0x3F)
if (tempCodePoint > 0x7F) {
codePoint = tempCodePoint
}
}
break
case 3:
secondByte = buf[i + 1]
thirdByte = buf[i + 2]
if ((secondByte & 0xC0) === 0x80 && (thirdByte & 0xC0) === 0x80) {
tempCodePoint = (firstByte & 0xF) << 0xC | (secondByte & 0x3F) << 0x6 | (thirdByte & 0x3F)
if (tempCodePoint > 0x7FF && (tempCodePoint < 0xD800 || tempCodePoint > 0xDFFF)) {
codePoint = tempCodePoint
}
}
break
case 4:
secondByte = buf[i + 1]
thirdByte = buf[i + 2]
fourthByte = buf[i + 3]
if ((secondByte & 0xC0) === 0x80 && (thirdByte & 0xC0) === 0x80 && (fourthByte & 0xC0) === 0x80) {
tempCodePoint = (firstByte & 0xF) << 0x12 | (secondByte & 0x3F) << 0xC | (thirdByte & 0x3F) << 0x6 | (fourthByte & 0x3F)
if (tempCodePoint > 0xFFFF && tempCodePoint < 0x110000) {
codePoint = tempCodePoint
}
}
}
}
if (codePoint === null) {
// we did not generate a valid codePoint so insert a
// replacement char (U+FFFD) and advance only 1 byte
codePoint = 0xFFFD
bytesPerSequence = 1
} else if (codePoint > 0xFFFF) {
// encode to utf16 (surrogate pair dance)
codePoint -= 0x10000
res.push(codePoint >>> 10 & 0x3FF | 0xD800)
codePoint = 0xDC00 | codePoint & 0x3FF
}
res.push(codePoint)
i += bytesPerSequence
}
var len = res.length
var str = ''
var i = 0
while (i < len) {
str += String.fromCharCode.apply(String, res.slice(i, i += 0x1000))
}
return str
}
// string -> buffer
var textEncode = typeof TextEncoder === 'object'
? TextEncoder.prototype.encode.bind(new TextEncoder())
: stringEncode
// buffer -> string
var textDecode = typeof TextDecoder === 'object'
? TextDecoder.prototype.decode.bind(new TextDecoder())
: stringDecode
function FakeBlobBuilder () {
function isDataView (obj) {
return obj && DataView.prototype.isPrototypeOf(obj)
}
@@ -162,7 +261,7 @@
}
return view
}
function encodeByteArray (input) {
function array2base64 (input) {
var byteToCharMap = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
var output = []
@@ -188,8 +287,9 @@
}
output.push(
byteToCharMap[outByte1], byteToCharMap[outByte2],
byteToCharMap[outByte3], byteToCharMap[outByte4])
byteToCharMap[outByte1], byteToCharMap[outByte2],
byteToCharMap[outByte3], byteToCharMap[outByte4]
)
}
return output.join('')
@@ -229,13 +329,13 @@
if (chunk instanceof Blob) {
chunks[i] = chunk._buffer
} else if (typeof chunk === 'string') {
chunks[i] = toUTF8Array(chunk)
chunks[i] = textEncode(chunk)
} else if (arrayBufferSupported && (ArrayBuffer.prototype.isPrototypeOf(chunk) || isArrayBufferView(chunk))) {
chunks[i] = bufferClone(chunk)
} else if (arrayBufferSupported && isDataView(chunk)) {
chunks[i] = bufferClone(chunk.buffer)
} else {
chunks[i] = toUTF8Array(String(chunk))
chunks[i] = textEncode(String(chunk))
}
}
@@ -283,9 +383,9 @@
/* FileReader constructor */
/********************************************************/
function FileReader () {
if (!(this instanceof FileReader)) {
throw new TypeError("Failed to construct 'FileReader': Please use the 'new' operator, this DOM object constructor cannot be called as a function.")
}
if (!(this instanceof FileReader)) {
throw new TypeError("Failed to construct 'FileReader': Please use the 'new' operator, this DOM object constructor cannot be called as a function.")
}
var delegate = document.createDocumentFragment()
this.addEventListener = delegate.addEventListener
@@ -298,9 +398,9 @@
}
function _read (fr, blob, kind) {
if (!(blob instanceof Blob)) {
throw new TypeError("Failed to execute '" + kind + "' on 'FileReader': parameter 1 is not of type 'Blob'.")
}
if (!(blob instanceof Blob)) {
throw new TypeError("Failed to execute '" + kind + "' on 'FileReader': parameter 1 is not of type 'Blob'.")
}
fr.result = ''
@@ -324,12 +424,12 @@
FileReader.prototype.readAsDataURL = function (blob) {
_read(this, blob, 'readAsDataURL')
this.result = 'data:' + blob.type + ';base64,' + encodeByteArray(blob._buffer)
this.result = 'data:' + blob.type + ';base64,' + array2base64(blob._buffer)
}
FileReader.prototype.readAsText = function (blob) {
_read(this, blob, 'readAsText')
this.result = fromUtf8Array(blob._buffer)
this.result = textDecode(blob._buffer)
}
FileReader.prototype.readAsArrayBuffer = function (blob) {
@@ -344,7 +444,7 @@
/********************************************************/
URL.createObjectURL = function (blob) {
return blob instanceof Blob
? 'data:' + blob.type + ';base64,' + encodeByteArray(blob._buffer)
? 'data:' + blob.type + ';base64,' + array2base64(blob._buffer)
: createObjectURL.call(URL, blob)
}
@@ -360,7 +460,7 @@
XMLHttpRequest.prototype.send = function (data) {
if (data instanceof Blob) {
this.setRequestHeader('Content-Type', data.type)
_send.call(this, fromUtf8Array(data._buffer))
_send.call(this, textDecode(data._buffer))
} else {
_send.call(this, data)
}