74 lines
1.5 KiB
TypeScript
74 lines
1.5 KiB
TypeScript
export default class PrimitiveReader {
|
|
/** pointer for curent position in the buffer */
|
|
protected p: number = 0;
|
|
|
|
constructor(protected buf: Uint8Array = new Uint8Array(0)) {}
|
|
|
|
append(buf: Uint8Array) {
|
|
const newBuf = new Uint8Array(this.buf.length + buf.length);
|
|
newBuf.set(this.buf);
|
|
newBuf.set(buf, this.buf.length);
|
|
this.buf = newBuf;
|
|
}
|
|
|
|
hasNextByte(): boolean {
|
|
return this.p < this.buf.length;
|
|
}
|
|
|
|
readUint(): number | null {
|
|
let { p } = this;
|
|
let r = 0;
|
|
let s = 1;
|
|
let b;
|
|
do {
|
|
if (p >= this.buf.length) {
|
|
return null;
|
|
}
|
|
b = this.buf[p++];
|
|
r += (b & 0x7F) * s;
|
|
s *= 128;
|
|
} while (b >= 0x80);
|
|
this.p = p;
|
|
return r;
|
|
}
|
|
|
|
readCustomIndex(input: Uint8Array) {
|
|
let p = 0; let r = 0; let s = 1; let
|
|
b;
|
|
do {
|
|
if (p > 8) {
|
|
return null;
|
|
}
|
|
b = input[p++];
|
|
r += (b & 0x7F) * s;
|
|
s *= 128;
|
|
} while (b >= 0x80);
|
|
return r;
|
|
}
|
|
|
|
readInt(): number | null {
|
|
let u = this.readUint();
|
|
if (u === null) { return u; }
|
|
if (u % 2) {
|
|
u = (u + 1) / -2;
|
|
} else {
|
|
u /= 2;
|
|
}
|
|
return u;
|
|
}
|
|
|
|
readString(): string | null {
|
|
const l = this.readUint();
|
|
if (l === null || this.p + l > this.buf.length) { return null; }
|
|
return new TextDecoder().decode(this.buf.subarray(this.p, this.p += l));
|
|
}
|
|
|
|
readBoolean(): boolean | null {
|
|
if (this.p >= this.buf.length) { return null; }
|
|
return !!this.buf[this.p++];
|
|
}
|
|
|
|
skip(n: number) {
|
|
this.p += n;
|
|
}
|
|
}
|