opensistemas-parser/lib/context.js

Parser for binaries in Javascript based in the binary-parser module from npm

//========================================================================================
// class Context
//========================================================================================

//----------------------------------------------------------------------------------------
// constructor
//----------------------------------------------------------------------------------------

var Context = function() {
    this.code = '';
    this.scopes = [['vars']];
    this.isAsync = false;
    this.bitFields = [];
    this.tmpVariableCount = 0;
    this.references = {};
};

//----------------------------------------------------------------------------------------
// public methods
//----------------------------------------------------------------------------------------

Context.prototype.generateVariable = function(name) {
    var arr = [];

    Array.prototype.push.apply(arr, this.scopes[this.scopes.length - 1]);
    if (name) {
        arr.push(name);
    }

    return arr.join('.');
};

Context.prototype.generateOption = function(val) {
    switch(typeof val) {
        case 'number':
            return val.toString();
        case 'string':
            return this.generateVariable(val);
        case 'function':
            return '(' + val + ').call(' + this.generateVariable() + ', vars)';
    }
};

Context.prototype.generateError = function() {
    var args = Array.prototype.slice.call(arguments);
    var err = Context.interpolate.apply(this, args);

    if (this.isAsync) {
        this.pushCode('return process.nextTick(function() { callback(new Error(' + err + '), vars); });');
    } else {
        this.pushCode('throw new Error(' + err + ');');
    }
};

Context.prototype.generateTmpVariable = function() {
    return '$tmp' + (this.tmpVariableCount++);
};

Context.prototype.pushCode = function() {
    var args = Array.prototype.slice.call(arguments);

    this.code += Context.interpolate.apply(this, args) + '\n';
};

Context.prototype.pushPath = function(name) {
    if (name)
    {
    	this.scopes[this.scopes.length - 1].push(name);
    }
};

Context.prototype.popPath = function(name) {
    if (name)
   { 
   	this.scopes[this.scopes.length - 1].pop();
   }
};

Context.prototype.pushScope = function(name) {
    this.scopes.push([name]);
};

Context.prototype.popScope = function() {
    this.scopes.pop();
};

Context.prototype.addReference = function(alias) {
    if (this.references[alias]) return;
    this.references[alias] = { resolved: false, requested: false };
};

Context.prototype.markResolved = function(alias) {
    this.references[alias].resolved = true;
};

Context.prototype.markRequested = function(aliasList) {
    aliasList.forEach(function(alias) {
        this.references[alias].requested = true;
    }.bind(this));
};

Context.prototype.getUnresolvedReferences = function() {
    var references = this.references;
    return Object.keys(this.references).filter(function(alias) {
        return !references[alias].resolved && !references[alias].requested;
    });
};

//----------------------------------------------------------------------------------------
// private methods
//----------------------------------------------------------------------------------------

Context.interpolate = function(s) {
    var re = /{\d+}/g;
    var matches = s.match(re);
    var params = Array.prototype.slice.call(arguments, 1);

    if (matches) {
        matches.forEach(function(match) {
            var index = parseInt(match.substr(1, match.length - 2), 10);
            s = s.replace(match, params[index].toString());
        });
    }

    return s;
};

exports.Context = Context;