Icard/angular-clarity-master(work.../node_modules/pngjs/lib/sync-inflate.js

169 lines
3.7 KiB
JavaScript

"use strict";
let assert = require("assert").ok;
let zlib = require("zlib");
let util = require("util");
let kMaxLength = require("buffer").kMaxLength;
function Inflate(opts) {
if (!(this instanceof Inflate)) {
return new Inflate(opts);
}
if (opts && opts.chunkSize < zlib.Z_MIN_CHUNK) {
opts.chunkSize = zlib.Z_MIN_CHUNK;
}
zlib.Inflate.call(this, opts);
// Node 8 --> 9 compatibility check
this._offset = this._offset === undefined ? this._outOffset : this._offset;
this._buffer = this._buffer || this._outBuffer;
if (opts && opts.maxLength != null) {
this._maxLength = opts.maxLength;
}
}
function createInflate(opts) {
return new Inflate(opts);
}
function _close(engine, callback) {
if (callback) {
process.nextTick(callback);
}
// Caller may invoke .close after a zlib error (which will null _handle).
if (!engine._handle) {
return;
}
engine._handle.close();
engine._handle = null;
}
Inflate.prototype._processChunk = function (chunk, flushFlag, asyncCb) {
if (typeof asyncCb === "function") {
return zlib.Inflate._processChunk.call(this, chunk, flushFlag, asyncCb);
}
let self = this;
let availInBefore = chunk && chunk.length;
let availOutBefore = this._chunkSize - this._offset;
let leftToInflate = this._maxLength;
let inOff = 0;
let buffers = [];
let nread = 0;
let error;
this.on("error", function (err) {
error = err;
});
function handleChunk(availInAfter, availOutAfter) {
if (self._hadError) {
return;
}
let have = availOutBefore - availOutAfter;
assert(have >= 0, "have should not go down");
if (have > 0) {
let out = self._buffer.slice(self._offset, self._offset + have);
self._offset += have;
if (out.length > leftToInflate) {
out = out.slice(0, leftToInflate);
}
buffers.push(out);
nread += out.length;
leftToInflate -= out.length;
if (leftToInflate === 0) {
return false;
}
}
if (availOutAfter === 0 || self._offset >= self._chunkSize) {
availOutBefore = self._chunkSize;
self._offset = 0;
self._buffer = Buffer.allocUnsafe(self._chunkSize);
}
if (availOutAfter === 0) {
inOff += availInBefore - availInAfter;
availInBefore = availInAfter;
return true;
}
return false;
}
assert(this._handle, "zlib binding closed");
let res;
do {
res = this._handle.writeSync(
flushFlag,
chunk, // in
inOff, // in_off
availInBefore, // in_len
this._buffer, // out
this._offset, //out_off
availOutBefore
); // out_len
// Node 8 --> 9 compatibility check
res = res || this._writeState;
} while (!this._hadError && handleChunk(res[0], res[1]));
if (this._hadError) {
throw error;
}
if (nread >= kMaxLength) {
_close(this);
throw new RangeError(
"Cannot create final Buffer. It would be larger than 0x" +
kMaxLength.toString(16) +
" bytes"
);
}
let buf = Buffer.concat(buffers, nread);
_close(this);
return buf;
};
util.inherits(Inflate, zlib.Inflate);
function zlibBufferSync(engine, buffer) {
if (typeof buffer === "string") {
buffer = Buffer.from(buffer);
}
if (!(buffer instanceof Buffer)) {
throw new TypeError("Not a string or buffer");
}
let flushFlag = engine._finishFlushFlag;
if (flushFlag == null) {
flushFlag = zlib.Z_FINISH;
}
return engine._processChunk(buffer, flushFlag);
}
function inflateSync(buffer, opts) {
return zlibBufferSync(new Inflate(opts), buffer);
}
module.exports = exports = inflateSync;
exports.Inflate = Inflate;
exports.createInflate = createInflate;
exports.inflateSync = inflateSync;