dxf-parser
Version:
Parse dxf files into a readable, logical js object.
150 lines (149 loc) • 4.76 kB
JavaScript
/**
* DxfArrayScanner
*
* Based off the AutoCad 2012 DXF Reference
* http://images.autodesk.com/adsk/files/autocad_2012_pdf_dxf-reference_enu.pdf
*
* Reads through an array representing lines of a dxf file. Takes an array and
* provides an easy interface to extract group code and value pairs.
* @param data - an array where each element represents a line in the dxf file
* @constructor
*/
export default class DxfArrayScanner {
constructor(data) {
this._pointer = 0;
this._eof = false;
this._data = data;
}
/**
* Gets the next group (code, value) from the array. A group is two consecutive elements
* in the array. The first is the code, the second is the value.
* @returns {{code: Number}|*}
*/
next() {
if (!this.hasNext()) {
if (!this._eof)
throw new Error('Unexpected end of input: EOF group not read before end of file. Ended on code ' + this._data[this._pointer]);
else
throw new Error('Cannot call \'next\' after EOF group has been read');
}
const group = {
code: parseInt(this._data[this._pointer])
};
this._pointer++;
group.value = parseGroupValue(group.code, this._data[this._pointer].trim());
this._pointer++;
if (group.code === 0 && group.value === 'EOF')
this._eof = true;
this.lastReadGroup = group;
return group;
}
peek() {
if (!this.hasNext()) {
if (!this._eof)
throw new Error('Unexpected end of input: EOF group not read before end of file. Ended on code ' + this._data[this._pointer]);
else
throw new Error('Cannot call \'next\' after EOF group has been read');
}
const group = {
code: parseInt(this._data[this._pointer])
};
group.value = parseGroupValue(group.code, this._data[this._pointer + 1].trim());
return group;
}
rewind(numberOfGroups = 1) {
this._pointer = this._pointer - numberOfGroups * 2;
}
/**
* Returns true if there is another code/value pair (2 elements in the array).
* @returns {boolean}
*/
hasNext() {
// Check if we have read EOF group code
if (this._eof) {
return false;
}
// We need to be sure there are two lines available
if (this._pointer > this._data.length - 2) {
return false;
}
return true;
}
/**
* Returns true if the scanner is at the end of the array
* @returns {boolean}
*/
isEOF() {
return this._eof;
}
}
/**
* Parse a value to its proper type.
* See pages 3 - 10 of the AutoCad DXF 2012 reference given at the top of this file
*
* @param code
* @param value
* @returns {*}
*/
function parseGroupValue(code, value) {
if (code <= 9)
return value;
if (code >= 10 && code <= 59)
return parseFloat(value);
if (code >= 60 && code <= 99)
return parseInt(value);
if (code >= 100 && code <= 109)
return value;
if (code >= 110 && code <= 149)
return parseFloat(value);
if (code >= 160 && code <= 179)
return parseInt(value);
if (code >= 210 && code <= 239)
return parseFloat(value);
if (code >= 270 && code <= 289)
return parseInt(value);
if (code >= 290 && code <= 299)
return parseBoolean(value);
if (code >= 300 && code <= 369)
return value;
if (code >= 370 && code <= 389)
return parseInt(value);
if (code >= 390 && code <= 399)
return value;
if (code >= 400 && code <= 409)
return parseInt(value);
if (code >= 410 && code <= 419)
return value;
if (code >= 420 && code <= 429)
return parseInt(value);
if (code >= 430 && code <= 439)
return value;
if (code >= 440 && code <= 459)
return parseInt(value);
if (code >= 460 && code <= 469)
return parseFloat(value);
if (code >= 470 && code <= 481)
return value;
if (code === 999)
return value;
if (code >= 1000 && code <= 1009)
return value;
if (code >= 1010 && code <= 1059)
return parseFloat(value);
if (code >= 1060 && code <= 1071)
return parseInt(value);
console.log('WARNING: Group code does not have a defined type: %j', { code: code, value: value });
return value;
}
/**
* Parse a boolean according to a 1 or 0 value
* @param str
* @returns {boolean}
*/
function parseBoolean(str) {
if (str === '0')
return false;
if (str === '1')
return true;
throw TypeError('String \'' + str + '\' cannot be cast to Boolean type');
}