vue hello world项目
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3 years ago
var assert = require('minimalistic-assert');
var Buffer = require('buffer').Buffer;
function WBuf() {
this.buffers = [];
this.toReserve = 0;
this.size = 0;
this.maxSize = 0;
this.avail = 0;
this.last = null;
this.offset = 0;
// Used in slicing
this.sliceQueue = null;
this.forceReserve = false;
// Mostly a constant
this.reserveRate = 64;
}
module.exports = WBuf;
WBuf.prototype.reserve = function reserve(n) {
this.toReserve += n;
// Force reservation of extra bytes
if (this.forceReserve)
this.toReserve = Math.max(this.toReserve, this.reserveRate);
};
WBuf.prototype._ensure = function _ensure(n) {
if (this.avail >= n)
return;
if (this.toReserve === 0)
this.toReserve = this.reserveRate;
this.toReserve = Math.max(n - this.avail, this.toReserve);
if (this.avail === 0)
this._next();
};
WBuf.prototype._next = function _next() {
var buf;
if (this.sliceQueue === null) {
// Most common case
buf = new Buffer(this.toReserve);
} else {
// Only for `.slice()` results
buf = this.sliceQueue.shift();
if (this.sliceQueue.length === 0)
this.sliceQueue = null;
}
this.toReserve = 0;
this.buffers.push(buf);
this.avail = buf.length;
this.offset = 0;
this.last = buf;
};
WBuf.prototype._rangeCheck = function _rangeCheck() {
if (this.maxSize !== 0 && this.size > this.maxSize)
throw new RangeError('WBuf overflow');
};
WBuf.prototype._move = function _move(n) {
this.size += n;
if (this.avail === 0)
this.last = null;
this._rangeCheck();
};
WBuf.prototype.slice = function slice(start, end) {
assert(0 <= start && start <= this.size);
assert(0 <= end && end <= this.size);
if (this.last === null)
this._next();
var res = new WBuf();
// Only last chunk is requested
if (start >= this.size - this.offset) {
res.buffers.push(this.last);
res.last = this.last;
res.offset = start - this.size + this.offset;
res.maxSize = end - start;
res.avail = res.maxSize;
return res;
}
var startIndex = -1;
var startOffset = 0;
var endIndex = -1;
// Find buffer indices
var offset = 0;
for (var i = 0; i < this.buffers.length; i++) {
var buf = this.buffers[i];
var next = offset + buf.length;
// Found the start
if (start >= offset && start <= next) {
startIndex = i;
startOffset = start - offset;
if (endIndex !== -1)
break;
}
if (end >= offset && end <= next) {
endIndex = i;
if (startIndex !== -1)
break;
}
offset = next;
}
res.last = this.buffers[startIndex];
res.offset = startOffset;
res.maxSize = end - start;
// Multi-buffer slice
if (startIndex < endIndex) {
res.sliceQueue = this.buffers.slice(startIndex + 1, endIndex + 1);
res.last = res.last.slice(res.offset);
res.offset = 0;
}
res.avail = res.last.length - res.offset;
res.buffers.push(res.last);
return res;
};
WBuf.prototype.skip = function skip(n) {
if (n === 0)
return this.slice(this.size, this.size);
this._ensure(n);
var left = n;
while (left > 0) {
var toSkip = Math.min(left, this.avail);
left -= toSkip;
this.size += toSkip;
if (toSkip === this.avail) {
if (left !== 0) {
this._next();
} else {
this.avail -= toSkip;
this.offset += toSkip;
}
} else {
this.offset += toSkip;
this.avail -= toSkip;
}
}
this._rangeCheck();
return this.slice(this.size - n, this.size);
};
WBuf.prototype.write = function write(str) {
var len = 0;
for (var i = 0; i < str.length; i++) {
var c = str.charCodeAt(i);
if (c > 255)
len += 2;
else
len += 1;
}
this.reserve(len);
for (var i = 0; i < str.length; i++) {
var c = str.charCodeAt(i);
var hi = c >>> 8;
var lo = c & 0xff;
if (hi)
this.writeUInt8(hi);
this.writeUInt8(lo);
}
};
WBuf.prototype.copyFrom = function copyFrom(buf, start, end) {
var off = start === undefined ? 0 : start;
var len = end === undefined ? buf.length : end;
if (off === len)
return;
this._ensure(len - off);
while (off < len) {
var toCopy = Math.min(len - off, this.avail);
buf.copy(this.last, this.offset, off, off + toCopy);
off += toCopy;
this.size += toCopy;
if (toCopy === this.avail) {
if (off !== len) {
this._next();
} else {
this.avail = 0;
this.offset += toCopy;
}
} else {
this.offset += toCopy;
this.avail -= toCopy;
}
}
this._rangeCheck();
};
WBuf.prototype.writeUInt8 = function writeUInt8(v) {
this._ensure(1);
this.last[this.offset++] = v;
this.avail--;
this._move(1);
};
WBuf.prototype.writeUInt16BE = function writeUInt16BE(v) {
this._ensure(2);
// Fast case - everything fits into the last buffer
if (this.avail >= 2) {
this.last.writeUInt16BE(v, this.offset);
this.offset += 2;
this.avail -= 2;
// One byte here, one byte there
} else {
this.last[this.offset] = (v >>> 8);
this._next();
this.last[this.offset++] = v & 0xff;
this.avail--;
}
this._move(2);
};
WBuf.prototype.writeUInt24BE = function writeUInt24BE(v) {
this._ensure(3);
// Fast case - everything fits into the last buffer
if (this.avail >= 3) {
this.last.writeUInt16BE(v >>> 8, this.offset);
this.last[this.offset + 2] = v & 0xff;
this.offset += 3;
this.avail -= 3;
this._move(3);
// Two bytes here
} else if (this.avail >= 2) {
this.last.writeUInt16BE(v >>> 8, this.offset);
this._next();
this.last[this.offset++] = v & 0xff;
this.avail--;
this._move(3);
// Just one byte here
} else {
this.last[this.offset] = v >>> 16;
this._move(1);
this._next();
this.writeUInt16BE(v & 0xffff);
}
};
WBuf.prototype.writeUInt32BE = function writeUInt32BE(v) {
this._ensure(4);
// Fast case - everything fits into the last buffer
if (this.avail >= 4) {
this.last.writeUInt32BE(v, this.offset);
this.offset += 4;
this.avail -= 4;
this._move(4);
// Three bytes here
} else if (this.avail >= 3) {
this.writeUInt24BE(v >>> 8);
this._next();
this.last[this.offset++] = v & 0xff;
this.avail--;
this._move(1);
// Slow case, who cares
} else {
this.writeUInt16BE(v >>> 16);
this.writeUInt16BE(v & 0xffff);
}
};
WBuf.prototype.writeUInt16LE = function writeUInt16LE(num) {
var r = ((num & 0xff) << 8) | (num >>> 8);
this.writeUInt16BE(r);
};
WBuf.prototype.writeUInt24LE = function writeUInt24LE(num) {
var r = ((num & 0xff) << 16) | (((num >>> 8) & 0xff) << 8) | (num >>> 16);
this.writeUInt24BE(r);
};
WBuf.prototype.writeUInt32LE = function writeUInt32LE(num) {
this._ensure(4);
// Fast case - everything fits into the last buffer
if (this.avail >= 4) {
this.last.writeUInt32LE(num, this.offset);
this.offset += 4;
this.avail -= 4;
this._move(4);
// Three bytes here
} else if (this.avail >= 3) {
this.writeUInt24LE(num & 0xffffff);
this._next();
this.last[this.offset++] = num >>> 24;
this.avail--;
this._move(1);
// Slow case, who cares
} else {
this.writeUInt16LE(num & 0xffff);
this.writeUInt16LE(num >>> 16);
}
};
WBuf.prototype.render = function render() {
var left = this.size;
var out = [];
for (var i = 0; i < this.buffers.length && left >= 0; i++) {
var buf = this.buffers[i];
left -= buf.length;
if (left >= 0) {
out.push(buf);
} else {
out.push(buf.slice(0, buf.length + left));
}
}
return out;
};
// Signed APIs
WBuf.prototype.writeInt8 = function writeInt8(num) {
if (num < 0)
return this.writeUInt8(0x100 + num);
else
return this.writeUInt8(num);
};
function toUnsigned16(num) {
if (num < 0)
return 0x10000 + num;
else
return num;
}
WBuf.prototype.writeInt16LE = function writeInt16LE(num) {
this.writeUInt16LE(toUnsigned16(num));
};
WBuf.prototype.writeInt16BE = function writeInt16BE(num) {
this.writeUInt16BE(toUnsigned16(num));
};
function toUnsigned24(num) {
if (num < 0)
return 0x1000000 + num;
else
return num;
}
WBuf.prototype.writeInt24LE = function writeInt24LE(num) {
this.writeUInt24LE(toUnsigned24(num));
};
WBuf.prototype.writeInt24BE = function writeInt24BE(num) {
this.writeUInt24BE(toUnsigned24(num));
};
function toUnsigned32(num) {
if (num < 0)
return (0xffffffff + num) + 1;
else
return num;
}
WBuf.prototype.writeInt32LE = function writeInt32LE(num) {
this.writeUInt32LE(toUnsigned32(num));
};
WBuf.prototype.writeInt32BE = function writeInt32BE(num) {
this.writeUInt32BE(toUnsigned32(num));
};
WBuf.prototype.writeComb = function writeComb(size, endian, value) {
if (size === 1)
return this.writeUInt8(value);
if (endian === 'le') {
if (size === 2)
this.writeUInt16LE(value);
else if (size === 3)
this.writeUInt24LE(value);
else if (size === 4)
this.writeUInt32LE(value);
} else {
if (size === 2)
this.writeUInt16BE(value);
else if (size === 3)
this.writeUInt24BE(value);
else if (size === 4)
this.writeUInt32BE(value);
}
};