ticlab.js/src/ticparse.js

// import { base64decode, base64encode, base64ToBytes } from './base64.js';
// https://github.com/nesbox/TIC-80/wiki/TIC-File-Format
export const CHUNK_TILES = 1,
      CHUNK_SPRITES = 2,
      CHUNK_COVER = 3,
      CHUNK_MAP = 4,
      CHUNK_CODE = 5,
      CHUNK_FLAGS = 6,
      CHUNK_SAMPLES = 9,
      CHUNK_WAVEFORM = 10,
      CHUNK_PALETTE = 12,
      CHUNK_MUSIC_TRACKS = 14,
      CHUNK_MUSIC_PATTERNS = 15,
      CHUNK_CODE_ZIP = 16,
      LITTLE_ENDIAN = 1;

function pad0(n, p) {
    n = ''+n;
    while (n.length < p) { n = '0'+n; }
    return n;
}

function tohex (a) {
    let ret = '', hh;
    console.log("tohex", a);
    for (var b=0, len=a.byteLength; b<len; b+=1) {
        ret += pad0(a.getUint8(b).toString(16), 2);
    }
    
    return ret;
}

export function parsetic (buffer) {
    var ret = {},
        data = new DataView(buffer),
        i=0,
        bank,
        ctype,
        clen,
        future_use,
        firstbyte;

    ret.chunks = [];
    ret.chunks_by_type = {};
    while (i<data.byteLength) {
        firstbyte = data.getUint8(i, LITTLE_ENDIAN);
        bank = firstbyte >> 5;
        ctype = firstbyte & 0b11111;
        i+=1;
        clen = data.getUint16(i, LITTLE_ENDIAN);
        i+=2;
        future_use = data.getUint8(i, LITTLE_ENDIAN);
        i+=1; // byte reserved for future_use
        var chunk = {bank: bank, ctype: ctype, future_use: future_use};
        chunk.original_length = clen; // can be out of sync with data, only for control purposes
        ret.chunks.push(chunk);
        ret.chunks_by_type[ctype] = chunk;
        var chunk_data = buffer.slice(i, i+clen);
        if (ctype == CHUNK_CODE) {
            ret.code = chunk;
            chunk.text = new TextDecoder().decode(chunk_data);
        } else {
            //chunk.data = new DataView(buf.buffer, i, clen);
            chunk.data = chunk_data;
        }
        i += clen;
//      chunk.data = base64encode(chunk.data);
    }
    ret.tobuffer = function () {
        // dry run for length
        var outputLength = 0;
        ret.chunks.forEach(chunk => {
            outputLength += 4;
            outputLength += (chunk.text) ? new TextEncoder().encode(chunk.text).byteLength : chunk.data.byteLength;
        });
        var outputBuffer = new Uint8Array(outputLength),
            o = 0,
            data = new DataView(outputBuffer.buffer);

        ret.chunks.forEach(chunk => {
            data.setUint8(o++, (chunk.bank << 5) | chunk.ctype);
            var chunk_data = chunk.text ? new TextEncoder().encode(chunk.text) : chunk.data;
            data.setUint16(o, chunk_data.byteLength, 1);
            o += 2;
            data.setUint8(o++, chunk.future_use);
            for (var i=0; i<chunk_data.byteLength; i++) {
                data.setUint8(o++, chunk_data[i]);
            }
        });
        return outputBuffer;
    };
    return ret;
}