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lzpf: this doesn't fix anything but doesn't break it more either :)

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- renamed some functions
- fixed some param documentation
- added ConvertToBuffer function
This commit is contained in:
zefie
2021-08-08 16:05:02 -04:00
parent cc88570466
commit 1949ccb01a
1 changed files with 37 additions and 23 deletions
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60
zefie_wtvp_minisrv/WTVLzpf.js
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@@ -21,7 +21,7 @@ class WTVLzpf {
checksum = 0; checksum = 0;
flag_table = new Uint16Array(0x1000) flag_table = new Uint16Array(0x1000)
ring_buffer = new Uint8Array(0x2000) ring_buffer = new Uint8Array(0x2000)
compressed_data = []; encoded_data = [];
nomatchEncode = [ nomatchEncode = [
[0x0000, 0x10], [0x0001, 0x10], [0x0002, 0x10], [0x0000, 0x10], [0x0001, 0x10], [0x0002, 0x10],
@@ -289,7 +289,7 @@ class WTVLzpf {
this.checksum = 0; this.checksum = 0;
this.ring_buffer.fill(0x00, 0, 0x2000) this.ring_buffer.fill(0x00, 0, 0x2000)
this.flag_table.fill(0xFFFF, 0, 0x1000); this.flag_table.fill(0xFFFF, 0, 0x1000);
this.compressed_data = []; this.encoded_data = [];
} }
/** /**
@@ -300,7 +300,7 @@ class WTVLzpf {
* @returns {undefined} * @returns {undefined}
*/ */
AddByte(byte) { AddByte(byte) {
this.compressed_data.push(byte); this.encoded_data.push(byte);
} }
/** /**
@@ -335,23 +335,16 @@ class WTVLzpf {
} }
/** /**
* Compress a block of data. Used for streamed chunks. * Encode a block of data. Used for streamed chunks.
* *
* @param uncompressed_data {String} data to compress * @param unencoded_data {Buffer} data to encode
* @param compress_data {Boolean} compress data
* *
* @returns {Buffer} Lzpf compression data * @returns {Buffer} Lzpf encoded data
*/ */
CompressBlock(uncompressed_data) { EncodeBlock(unencoded_data, compress_data) {
this.compressed_data = []; this.encoded_data = [];
var uncompressed_len = unencoded_data.byteLength;
if (uncompressed_data.words) {
uncompressed_data = new Buffer.from(wtvsec.wordArrayToUint8Array(uncompressed_data));
} else if (!uncompressed_data.byteLength) {
// otherwise if its not already a Buffer, convert it to one
uncompressed_data = new Buffer.from(uncompressed_data);
}
var uncompressed_len = uncompressed_data.length;
var i = 0; var i = 0;
var flags_index = 0; var flags_index = 0;
@@ -359,7 +352,7 @@ class WTVLzpf {
var code_length = -1; var code_length = -1;
var code = -1; var code = -1;
var byte = uncompressed_data.readUInt8(i); var byte = unencoded_data.readUInt8(i);
this.ring_buffer[i & 0x1FFF] = byte; this.ring_buffer[i & 0x1FFF] = byte;
if (this.match_index > 0) { if (this.match_index > 0) {
@@ -389,7 +382,7 @@ class WTVLzpf {
if (this.flag == 0xFFFF) { if (this.flag == 0xFFFF) {
code_length = this.nomatchEncode[byte][1]; code_length = this.nomatchEncode[byte][1];
code = this.nomatchEncode[byte][0] << 0x10; code = this.nomatchEncode[byte][0] << 0x10;
} else if (byte == this.ring_buffer[this.flag]) { } else if (byte == this.ring_buffer[this.flag] && compress_data) {
this.match_index = 1; this.match_index = 1;
this.flag = (this.flag + 1) & 0x1FFF; this.flag = (this.flag + 1) & 0x1FFF;
this.type_index = 4; this.type_index = 4;
@@ -408,7 +401,7 @@ class WTVLzpf {
} }
} }
return Buffer.from(this.compressed_data); return Buffer.from(this.encoded_data);
} }
/** /**
@@ -454,16 +447,37 @@ class WTVLzpf {
/** /**
* Compress data using WebTV's Lzpf compression algorithm and adds the footer to the end. * Compress data using WebTV's Lzpf compression algorithm and adds the footer to the end.
* *
* @param uncompressed_data {String} data to compress * @param data {String|Buffer|CryptoJS.lib.WordArray} data to convert
*
* @returns {Buffer} Javascript Buffer object
*/
ConvertToBuffer(data) {
if (data.words) {
var WTVSec = require("./WTVSec.js");
wtvsec = new WTVSec(1);
data = new Buffer.from(wtvsec.wordArrayToUint8Array(data));
WTVSec, wtvsec = null;
} else if (!data.byteLength) {
// otherwise if its not already a Buffer, convert it to one
data = new Buffer.from(data);
}
return data;
}
/**
* Compress data using WebTV's Lzpf compression algorithm and adds the footer to the end.
*
* @param uncompressed_data {String|Buffer|CryptoJS.lib.WordArray} data to compress
* *
* @returns {Buffer} Lzpf compression data * @returns {Buffer} Lzpf compression data
*/ */
Compress(uncompressed_data) { Compress(uncompressed_data) {
uncompressed_data = this.ConvertToBuffer(uncompressed_data);
this.Begin(); this.Begin();
this.CompressBlock(uncompressed_data) this.EncodeBlock(uncompressed_data, true);
this.Finish(); this.Finish();
return Buffer.from(this.compressed_data); return Buffer.from(this.encoded_data);
} }
} }