bintzwing/js/zlib-1.2.11.js
2019-05-11 10:38:14 +02:00

146 lines
5.1 KiB
JavaScript

'use strict';
(function() {
let ret;
async function initialize() {
if (ret) return ret;
const COMPRESSION_LEVEL = 7;
const NO_ZLIB_HEADER = -1;
const CHUNK_SIZE = 32 * 1024;
const map = {};
const memory = new WebAssembly.Memory({
initial: 1,
maximum: 1024, // 64MB
});
const env = {
memory,
writeToJs(ptr, size) {
const o = map[ptr];
o.onData(new Uint8Array(memory.buffer, dstPtr, size));
},
_abort: errno => { console.error(`Error: ${errno}`) },
_grow: () => { },
};
let buff;
if (typeof fetch === 'undefined') {
buff = fs.readFileSync('zlib-1.2.11.wasm');
} else {
const resp = await fetch('js/zlib-1.2.11.wasm');
buff = await resp.arrayBuffer();
}
const module = await WebAssembly.compile(buff);
const ins = await WebAssembly.instantiate(module, { env });
const srcPtr = ins.exports._malloc(CHUNK_SIZE);
const dstPtr = ins.exports._malloc(CHUNK_SIZE);
class RawDef {
constructor() {
this.zstreamPtr = ins.exports._createDeflateContext(COMPRESSION_LEVEL, NO_ZLIB_HEADER);
map[this.zstreamPtr] = this;
this.offset = 0;
this.buff = new Uint8Array(CHUNK_SIZE);
}
deflate(chunk, flush) {
const src = new Uint8Array(memory.buffer, srcPtr, chunk.length);
src.set(chunk);
ins.exports._deflate(this.zstreamPtr, srcPtr, dstPtr, chunk.length, CHUNK_SIZE, flush);
}
onData(chunk) {
if (this.buff.length < this.offset + chunk.length) {
const buff = this.buff;
this.buff = new Uint8Array(this.buff.length * 2);
this.buff.set(buff);
}
this.buff.set(chunk, this.offset);
this.offset += chunk.length;
}
destroy() {
ins.exports._freeDeflateContext(this.zstreamPtr);
delete map[this.zstreamPtr];
this.buff = null;
}
getBuffer() {
const res = new Uint8Array(this.offset);
for (let i = 0; i < this.offset; ++i) {
res[i] = this.buff[i];
}
return res;
}
}
class RawInf {
constructor() {
this.zstreamPtr = ins.exports._createInflateContext(NO_ZLIB_HEADER);
map[this.zstreamPtr] = this;
this.offset = 0;
this.buff = new Uint8Array(CHUNK_SIZE);
}
inflate(chunk) {
const src = new Uint8Array(memory.buffer, srcPtr, chunk.length);
src.set(chunk);
ins.exports._inflate(this.zstreamPtr, srcPtr, dstPtr, chunk.length, CHUNK_SIZE);
}
onData(chunk) {
if (this.buff.length < this.offset + chunk.length) {
const buff = this.buff;
this.buff = new Uint8Array(this.buff.length * 2);
this.buff.set(buff);
}
this.buff.set(chunk, this.offset);
this.offset += chunk.length;
}
destroy() {
ins.exports._freeInflateContext(this.zstreamPtr);
delete map[this.zstreamPtr];
this.buff = null;
}
getBuffer() {
const res = new Uint8Array(this.offset);
for (let i = 0; i < this.offset; ++i) {
res[i] = this.buff[i];
}
return res;
}
}
ret = {
inflate(rawDeflateBuffer) {
const rawInf = new RawInf();
for (let offset = 0; offset < rawDeflateBuffer.length; offset += CHUNK_SIZE) {
const end = Math.min(offset + CHUNK_SIZE, rawDeflateBuffer.length);
const chunk = rawDeflateBuffer.subarray(offset, end);
rawInf.inflate(chunk);
}
const ret = rawInf.getBuffer();
rawInf.destroy();
return ret;
},
deflate(rawInflateBuffer) {
const rawDef = new RawDef();
for (let offset = 0; offset < rawInflateBuffer.length; offset += CHUNK_SIZE) {
const end = Math.min(offset + CHUNK_SIZE, rawInflateBuffer.length);
const chunk = rawInflateBuffer.subarray(offset, end);
rawDef.deflate(chunk, rawInflateBuffer.length <= offset + CHUNK_SIZE);
}
const ret = rawDef.getBuffer();
rawDef.destroy();
return ret;
},
}
return ret;
}
this.zlib = initialize();
}).call(this);