prompto.reader.CSVReader.js Maven / Gradle / Ivy

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/* we can't use Papa or other js csv libs, because they either load everything in memory or require a continuation */
/* ideally we would use generators, but support with browsers is poor so far */
/* so we use our own stuff until ES6 becomes widespread */


function csvIterate(text, columns, separator, encloser) {
    return new CSVIterator(text, columns, separator, encloser);
}

function csvRead(text, columns, separator, encloser) {
    var list = new intrinsic.List();
    var iter = new CSVIterator(text, columns, separator, encloser);
    while(iter.hasNext())
        list.push(iter.next());
    return list;
}


function csvReadHeaders(text, separator, encloser) {
    var iter = new CSVIterator(text, null, separator, encloser);
    var headers = iter.readHeaders();
    return new intrinsic.List(false, headers);
}


function CSVIterator(text, columns, separator, encloser) {
    this.text = text || null;
    this.index = 0;
    this.columns = columns;
    this.separator = (separator || ',').charCodeAt(0);
    this.encloser = (encloser || '"').charCodeAt(0);
    this.headers = null;
    this.peekedChar = null;
    this.nextChar = 0;
    return this;
}

var DQ = '"'.charCodeAt(0);
var CR = '\r'.charCodeAt(0);
var LF = '\n'.charCodeAt(0);
var ESC = '\\'.charCodeAt(0);


CSVIterator.prototype.iterator = function() {
    return this;
};


CSVIterator.prototype.readHeaders = function() {
    if(this.nextChar==0)
        this.fetchChar(true);
    return this.parseHeaders();
};


CSVIterator.prototype.hasNext = function() {
    if(this.nextChar==0)
        this.fetchChar(true);
    if(this.headers==null)
        this.headers = this.parseHeaders();
    return this.nextChar>0;
};



CSVIterator.prototype.next = function() {
    if(!this.hasNext()) // will parse headers
        return null;
    var values = this.parseLine();
    var doc = new intrinsic.Document();
    for(var i=0;i0) {
                chars = chars.map(function(c) {
                    return String.fromCharCode(c);
                });
                list.push(chars.join(""));
            }
            return;
        }
    }
};


CSVIterator.prototype.handleOtherChar = function(chars, _endChar, _list) {
    chars.push(this.nextChar);
    this.fetchChar();
    return false;
};


CSVIterator.prototype.handleEscape = function(chars, _endChar, _list) {
    if(this.peekChar()!=-1) {
        chars.push(this.peekChar());
        this.fetchChar();
    }
    this.fetchChar();
    return false;
};


CSVIterator.prototype.handleEOF = function(_chars, _endChar, _list) {
    return true;
}

CSVIterator.prototype.handleEndChar = function(chars, endChar, _list) {
    if(endChar==DQ && this.peekChar()==endChar) {
        chars.push(this.nextChar);
        this.fetchChar();
        this.fetchChar();
        return false;
    } else {
        this.fetchChar();
        return true;
    }
};


CSVIterator.prototype.handleNewLine = function(chars, endChar, _list) {
    if(endChar==DQ) {
        chars.push(this.nextChar);
        this.fetchChar();
        return false;
    } else {
        return true;
    }
}


exports.csvIterate = csvIterate;
exports.csvRead = csvRead;
exports.csvReadHeaders = csvReadHeaders;