/**
* PCBoard BBS display file decoder.
*
* Handles the .BBS display format used by PCBoard and compatible BBS software.
* Color codes are written as @XY@ where XY is a two-digit hex CGA attribute
* byte (high nibble = background 0-7, low nibble = foreground 0-F).
* Control macros (@CLS@, @NOSTOP@, @NOPAUSE@, etc.) are also handled.
* Text body is CP437-encoded.
*
* Public API (attached to window):
* renderPCBoardBuffer(input) ? string | Uint8Array ? HTML string
* hasPCBoardCodes(text) ? string ? boolean (auto-detection)
* pcbCp437ToString(bytes) ? Uint8Array ? string (CP437 ? Unicode)
*/
// ??? CP437 ? Unicode map ??????????????????????????????????????????????????????
/* eslint-disable */
const _PCB_CP437 = [
// 0x00-0x0F (control codes have visible CP437 glyphs)
'\u0000','\u263A','\u263B','\u2665','\u2666','\u2663','\u2660','\u2022',
'\u25D8','\u25CB','\u25D9','\u2642','\u2640','\u266A','\u266B','\u263C',
// 0x10-0x1F
'\u25BA','\u25C4','\u2195','\u203C','\u00B6','\u00A7','\u25AC','\u21A8',
'\u2191','\u2193','\u2192','\u2190','\u221F','\u2194','\u25B2','\u25BC',
// 0x20-0x7E (standard printable ASCII)
' ','!','"','#','$','%','&',"'",'(',')','*','+',',','-','.','/','0','1',
'2','3','4','5','6','7','8','9',':',';','<','=','>','?','@','A','B','C',
'D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U',
'V','W','X','Y','Z','[','\\',']','^','_','`','a','b','c','d','e','f','g',
'h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y',
'z','{','|','}','~',
// 0x7F
'\u2302',
// 0x80-0x8F
'\u00C7','\u00FC','\u00E9','\u00E2','\u00E4','\u00E0','\u00E5','\u00E7',
'\u00EA','\u00EB','\u00E8','\u00EF','\u00EE','\u00EC','\u00C4','\u00C5',
// 0x90-0x9F
'\u00C9','\u00E6','\u00C6','\u00F4','\u00F6','\u00F2','\u00FB','\u00F9',
'\u00FF','\u00D6','\u00DC','\u00A2','\u00A3','\u00A5','\u20A7','\u0192',
// 0xA0-0xAF
'\u00E1','\u00ED','\u00F3','\u00FA','\u00F1','\u00D1','\u00AA','\u00BA',
'\u00BF','\u2310','\u00AC','\u00BD','\u00BC','\u00A1','\u00AB','\u00BB',
// 0xB0-0xBF (box-drawing, shade blocks)
'\u2591','\u2592','\u2593','\u2502','\u2524','\u2561','\u2562','\u2556',
'\u2555','\u2563','\u2551','\u2557','\u255D','\u255C','\u255B','\u2510',
// 0xC0-0xCF
'\u2514','\u2534','\u252C','\u251C','\u2500','\u253C','\u255E','\u255F',
'\u255A','\u2554','\u2569','\u2566','\u2560','\u2550','\u256C','\u2567',
// 0xD0-0xDF
'\u2568','\u2564','\u2565','\u2559','\u2558','\u2552','\u2553','\u256B',
'\u256A','\u2518','\u250C','\u2588','\u2584','\u258C','\u2590','\u2580',
// 0xE0-0xEF (Greek and math)
'\u03B1','\u00DF','\u0393','\u03C0','\u03A3','\u03C3','\u00B5','\u03C4',
'\u03A6','\u0398','\u03A9','\u03B4','\u221E','\u03C6','\u03B5','\u2229',
// 0xF0-0xFF
'\u2261','\u00B1','\u2265','\u2264','\u2320','\u2321','\u00F7','\u2248',
'\u00B0','\u2219','\u00B7','\u221A','\u207F','\u00B2','\u25A0','\u00A0',
];
/* eslint-enable */
/** CGA 16-colour palette (attribute nibble ? CSS colour) */
const _PCB_CGA = [
'#000000','#0000AA','#00AA00','#00AAAA',
'#AA0000','#AA00AA','#AA5500','#AAAAAA',
'#555555','#5555FF','#55FF55','#55FFFF',
'#FF5555','#FF55FF','#FFFF55','#FFFFFF',
];
/** PCBoard control macros that carry no visible output ? skip them entirely. */
const _PCB_SKIP = new Set([
'NOSTOP','NOPAUSE','MORE','PAUSE','BEEP','EOL','POS',
'TIME','DATE','TIMELEFT','MINLEFT','INAME','RNAME',
'FIRST','LAST','ALIAS','CITY','BAUD','WHO',
'BOARDNAME','SYSOP','OPTEXT','TEMPTYPE',
]);
// ??? Public API ???????????????????????????????????????????????????????????????
/**
* Decode a CP437 byte array to a Unicode string.
* @param {Uint8Array} bytes
* @returns {string}
*/
function pcbCp437ToString(bytes) {
let s = '';
for (let i = 0; i < bytes.length; i++) s += _PCB_CP437[bytes[i]];
return s;
}
/**
* Heuristic check ? returns true if the string contains PCBoard @ codes.
* @param {string} text
* @returns {boolean}
*/
function hasPCBoardCodes(text) {
return /@[0-9A-Fa-f]{2}@/.test(text) ||
/@CLS@/i.test(text) ||
/@NOSTOP@/i.test(text);
}
/**
* Render a PCBoard display file to an HTML string suitable for a <pre>.
*
* @param {string|Uint8Array} input String (message body) or raw bytes (file).
* @returns {string} HTML fragment.
*/
function renderPCBoardBuffer(input) {
// Decode bytes if needed
const text = (input instanceof Uint8Array) ? pcbCp437ToString(input) : input;
// Strip trailing SAUCE metadata record (starts with "SAUCE", within last 200 chars)
let src = text;
const sauceIdx = src.lastIndexOf('SAUCE');
if (sauceIdx !== -1 && src.length - sauceIdx <= 200) {
src = src.substring(0, sauceIdx);
}
let out = '';
let fgIdx = 7; // default light gray
let bgIdx = 0; // default black
let spanOpen = false;
let i = 0;
function esc(s) {
return s.replace(/&/g, '&').replace(/</g, '<').replace(/>/g, '>');
}
function openSpan() {
out += `<span style="color:${_PCB_CGA[fgIdx]};background-color:${_PCB_CGA[bgIdx]}">`;
spanOpen = true;
}
function closeSpan() {
if (spanOpen) { out += '</span>'; spanOpen = false; }
}
function setAttr(attr) {
closeSpan();
fgIdx = attr & 0x0F;
bgIdx = (attr >> 4) & 0x07;
openSpan();
}
openSpan();
while (i < src.length) {
const ch = src[i];
if (ch === '@') {
// Search for closing @ within a reasonable distance
const end = src.indexOf('@', i + 1);
if (end > i && end - i <= 24) {
const code = src.substring(i + 1, end);
const upper = code.toUpperCase();
// Two-character hex color attribute: @XY@ ? CGA attribute byte
if (/^[0-9A-Fa-f]{2}$/.test(code)) {
setAttr(parseInt(code, 16));
i = end + 1;
continue;
}
// Clear screen ? discard all previous output
if (upper === 'CLS') {
closeSpan();
out = '';
openSpan();
i = end + 1;
continue;
}
// Known display-control macros with no visible output
if (_PCB_SKIP.has(upper)) {
i = end + 1;
continue;
}
// Unrecognised @WORD@ that looks like a macro ? skip silently
if (/^[A-Za-z][A-Za-z0-9_]{0,23}$/.test(code)) {
i = end + 1;
continue;
}
}
// Not a valid code ? emit the literal @ character
out += '@';
i++;
} else if (ch === '\r') {
// Normalise CR/CRLF to LF
i++;
if (i < src.length && src[i] === '\n') i++;
out += '\n';
} else {
out += esc(ch);
i++;
}
}
closeSpan();
return out;
}
// ??? Attach to window ?????????????????????????????????????????????????????????
if (typeof window !== 'undefined') {
window.renderPCBoardBuffer = renderPCBoardBuffer;
window.hasPCBoardCodes = hasPCBoardCodes;
window.pcbCp437ToString = pcbCp437ToString;
}
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