yetangitu/bitjs
1
0
Fork 0
mirror of https://github.com/codedread/bitjs synced 2025-10-03 17:49:16 +02:00
Code Issues Releases Wiki Activity

Add a BitBuffer to the io package and a few tests

Browse source
This commit is contained in:
Jeff Schiller 2021-12-20 20:35:59 -08:00
parent 596a859bdc
commit 24b1603968
12 changed files with 747 additions and 25 deletions
Download patch file Download diff file Expand all files Collapse all files

15
io/bitstream.js
View file

@ -24,12 +24,13 @@ export const BitStream =
class BitStream {
/**
* @param {ArrayBuffer} ab An ArrayBuffer object or a Uint8Array.
* @param {boolean} rtl Whether the stream reads bits from the byte starting
* from bit 7 to 0 (true) or bit 0 to 7 (false).
* @param {boolean} mtl Whether the stream reads bits from the byte starting with the
* most-significant-bit (bit 7) to least-significant (bit 0). False means the direciton is
* from least-significant-bit (bit 0) to most-significant (bit 7).
* @param {Number} opt_offset The offset into the ArrayBuffer
* @param {Number} opt_length The length of this BitStream
*/
constructor(ab, rtl, opt_offset, opt_length) {
constructor(ab, mtl, opt_offset, opt_length) {
if (!(ab instanceof ArrayBuffer)) {
throw 'Error! BitArray constructed with an invalid ArrayBuffer object';
}
@ -65,7 +66,7 @@ export const BitStream =
*/
this.bitsRead_ = 0;
this.peekBits = rtl ? this.peekBits_rtl : this.peekBits_ltr;
this.peekBits = mtl ? this.peekBits_mtl : this.peekBits_ltm;
}
/**
@ -87,13 +88,13 @@ export const BitStream =
* byte0 byte1 byte2 byte3
* 7......0 | 7......0 | 7......0 | 7......0
*
* The bit pointer starts at bit0 of byte0 and moves left until it reaches
* The bit pointer starts at least-significant bit (0) of byte0 and moves left until it reaches
* bit7 of byte0, then jumps to bit0 of byte1, etc.
* @param {number} n The number of bits to peek, must be a positive integer.
* @param {boolean=} movePointers Whether to move the pointer, defaults false.
* @return {number} The peeked bits, as an unsigned number.
*/
peekBits_ltr(n, opt_movePointers) {
peekBits_ltm(n, opt_movePointers) {
const NUM = parseInt(n, 10);
let num = NUM;
if (n !== num || num <= 0) {
@ -151,7 +152,7 @@ export const BitStream =
* @param {boolean=} movePointers Whether to move the pointer, defaults false.
* @return {number} The peeked bits, as an unsigned number.
*/
peekBits_rtl(n, opt_movePointers) {
peekBits_mtl(n, opt_movePointers) {
const NUM = parseInt(n, 10);
let num = NUM;
if (n !== num || num <= 0) {