PC8 / CP437 character set with filereader in Chrome

问题

anyone knows if it is possible to get the FileReader API in chrome to read a file with the CP437 character set? Is there a place where I can list the available encodings? Currently, my workaround is to read it with CP1251 reader.readAsText(file, 'CP1251') and manually replace special characters, which is not cool! Is there other browsers which support this character set? Or do you have any better idea at a workaround?

Edit: The file is parsed only in the browser, there is no backend available.

regards Oskar

回答1:

I had the same problem. CP437 isn't implemented (in Chrome and Firefox at least).

Work around to convert to UTF-8 that requires ArrayBuffer support in the browser:

var Cp437Helper = function () {
    var cp437map = [
        '\u0000', '\u0001', '\u0002', '\u0003', '\u0004', '\u0005', '\u0006',
        '\u0007', '\u0008', '\u0009', '\u000A', '\u000B', '\u000C', '\u000D', 
        '\u000E', '\u000F', '\u0010', '\u0011', '\u0012', '\u0013', '\u0014', 
        '\u0015', '\u0016', '\u0017', '\u0018', '\u0019', '\u001A', '\u001B', 
        '\u001C', '\u001D', '\u001E', '\u001F', '\u0020', '\u0021', '\u0022', 
        '\u0023', '\u0024', '\u0025', '\u0026', '\u0027', '\u0028', '\u0029', 
        '\u002A', '\u002B', '\u002C', '\u002D', '\u002E', '\u002F', '\u0030', 
        '\u0031', '\u0032', '\u0033', '\u0034', '\u0035', '\u0036', '\u0037', 
        '\u0038', '\u0039', '\u003A', '\u003B', '\u003C', '\u003D', '\u003E', 
        '\u003F', '\u0040', '\u0041', '\u0042', '\u0043', '\u0044', '\u0045', 
        '\u0046', '\u0047', '\u0048', '\u0049', '\u004A', '\u004B', '\u004C', 
        '\u004D', '\u004E', '\u004F', '\u0050', '\u0051', '\u0052', '\u0053',
        '\u0054', '\u0055', '\u0056', '\u0057', '\u0058', '\u0059', '\u005A', 
        '\u005B', '\u005C', '\u005D', '\u005E', '\u005F', '\u0060', '\u0061', 
        '\u0062', '\u0063', '\u0064', '\u0065', '\u0066', '\u0067', '\u0068', 
        '\u0069', '\u006A', '\u006B', '\u006C', '\u006D', '\u006E', '\u006F', 
        '\u0070', '\u0071', '\u0072', '\u0073', '\u0074', '\u0075', '\u0076', 
        '\u0077', '\u0078', '\u0079', '\u007A', '\u007B', '\u007C', '\u007D', 
        '\u007E', '\u007F', '\u00C7', '\u00FC', '\u00E9', '\u00E2', '\u00E4', 
        '\u00E0', '\u00E5', '\u00E7', '\u00EA', '\u00EB', '\u00E8', '\u00EF', 
        '\u00EE', '\u00EC', '\u00C4', '\u00C5', '\u00C9', '\u00E6', '\u00C6', 
        '\u00F4', '\u00F6', '\u00F2', '\u00FB', '\u00F9', '\u00FF', '\u00D6', 
        '\u00DC', '\u00A2', '\u00A3', '\u00A5', '\u20A7', '\u0192', '\u00E1', 
        '\u00ED', '\u00F3', '\u00FA', '\u00F1', '\u00D1', '\u00AA', '\u00BA',
        '\u00BF', '\u2310', '\u00AC', '\u00BD', '\u00BC', '\u00A1', '\u00AB', 
        '\u00BB', '\u2591', '\u2592', '\u2593', '\u2502', '\u2524', '\u2561', 
        '\u2562', '\u2556', '\u2555', '\u2563', '\u2551', '\u2557', '\u255D', 
        '\u255C', '\u255B', '\u2510', '\u2514', '\u2534', '\u252C', '\u251C', 
        '\u2500', '\u253C', '\u255E', '\u255F', '\u255A', '\u2554', '\u2569', 
        '\u2566', '\u2560', '\u2550', '\u256C', '\u2567', '\u2568', '\u2564', 
        '\u2565', '\u2559', '\u2558', '\u2552', '\u2553', '\u256B', '\u256A', 
        '\u2518', '\u250C', '\u2588', '\u2584', '\u258C', '\u2590', '\u2580', 
        '\u03B1', '\u00DF', '\u0393', '\u03C0', '\u03A3', '\u03C3', '\u00B5', 
        '\u03C4', '\u03A6', '\u0398', '\u03A9', '\u03B4', '\u221E', '\u03C6', 
        '\u03B5', '\u2229', '\u2261', '\u00B1', '\u2265', '\u2264', '\u2320', 
        '\u2321', '\u00F7', '\u2248', '\u00B0', '\u2219', '\u00B7', '\u221A',
        '\u207F', '\u00B2', '\u25A0', '\u00A0'
    ];

    this.convertToUTF8 = function (buffer) {
        var out = '';
        var view = new DataView(buffer);

        var i ;
        var n = view.byteLength;
        for (i  = 0; i  < n; i ++) {
            var uint = view.getUint8(i);
            if (cp437map[ uint ] == undefined) {
                out += '/' + uint + '/';
            } else {
                out += cp437map[ uint ];
            }
        }
        return out;
    };

    if ( Cp437Helper.prototype._instance == undefined ) {
      Cp437Helper.prototype._instance = this;
    }
    return Cp437Helper.prototype._instance;
};

Use the above:

var getTextFromCP437File = function ( file ) {
    var reader = new FileReader();
    reader.onload = function(e) {
        var text = Cp437Helper().convertToUTF8(reader.result);
        // do something...
    };
    //reader.readAsText(file, 'cp437');
    reader.readAsArrayBuffer(file);
};

来源：https://stackoverflow.com/questions/17815444/pc8-cp437-character-set-with-filereader-in-chrome

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javascript

html

google-chrome

character-encoding

filereader