binary-parser - npm Package Compare versions

Comparing version 0.0.1 to 0.0.2

lib/binary_parser.js

 //========================================================================================
 // Globals
 //========================================================================================
-var util = require('util');
 
-var Parser = function() {
-    this.varName = '';
-    this.type = '';
-    this.options = {};
-    this.next = null;
-    this.head = null;
-    this.compiled = null;
-};
-
 var PRIMITIVE_TYPES = {
@@ -34,2 +24,3 @@ 'UInt8'    : 1,
     'String'   : null,
+    'Buffer'   : null,
     'Array'    : null,
@@ -49,24 +40,24 @@ 'Skip'     : null,
 //========================================================================================
-// Parser builder functions
+// class Parser
 //========================================================================================
 
-Parser.start = function() {
-    return new Parser();
+//----------------------------------------------------------------------------------------
+// constructor
+//----------------------------------------------------------------------------------------
+
+var Parser = function() {
+    this.varName = '';
+    this.type = '';
+    this.options = {};
+    this.next = null;
+    this.head = null;
+    this.compiled = null;
 };
 
-Parser.prototype.setNextParser = function(type, varName, options) {
-    var parser = new Parser();
-    
-    parser.type = NAME_MAP[type];
-    parser.varName = varName;
-    parser.options = options || parser.options;
-    
-    if (this.head) {
-        this.head.next = parser;
-    } else {
-        this.next = parser;
-    }
-    this.head = parser;
+//----------------------------------------------------------------------------------------
+// public methods
+//----------------------------------------------------------------------------------------
 
-    return this;
+Parser.start = function() {
+    return new Parser();
 };
@@ -98,2 +89,10 @@
 
+Parser.prototype.buffer = function(varName, options) {
+    if (!options.length && !options.readUntil) {
+        throw new Error('Length nor readUntil is defined in buffer parser');
+    }
+
+    return this.setNextParser('buffer', varName, options);
+};
+
 Parser.prototype.array = function(varName, options) {
@@ -153,68 +152,84 @@ if (!options.readUntil && !options.length) {
 
-//========================================================================================
-// Parser
-//========================================================================================
+Parser.prototype.getCode = function() {
+    var ctx = new Context();
 
-// Follow the parser chain till the root and start parsing from there
-Parser.prototype.parse = function(buffer) {
-    if (!Buffer.isBuffer(buffer)) {
-        throw new Error('argument "buffer" is not a Buffer object');
-    }
+    ctx.pushCode('var vars = {};');
+    ctx.pushCode('var iterator = 0;');
+    this.generate(ctx);
+    ctx.pushCode('return vars;');
 
-    if (!this.compiled) {
-        this.compile();
-    }
-
-    return this.compiled(buffer);
+    return ctx.code;
 };
 
-var Context = function() {
-    this.code = '';
-    this.scopes = [];
+Parser.prototype.compile = function() {
+    this.compiled = new Function('buffer', this.getCode());
 };
 
-Context.prototype.generateVariable = function(name) {
-    var arr = ['vars'];
-    Array.prototype.push.apply(arr, this.scopes);
-    if (name) {
-        arr.push(name);
+Parser.prototype.sizeOf = function() {
+    var size = NaN;
+
+    if (Object.keys(PRIMITIVE_TYPES).indexOf(this.type) >= 0) {
+        size = PRIMITIVE_TYPES[this.type];
+    
+    // if this is a fixed length string
+    } else if (this.type === 'String' && typeof this.options.length === 'number') {
+        size = this.options.length;
+    
+    // if this is a fixed length array
+    } else if (this.type === 'Array' && typeof this.options.length === 'number') {
+        var elementSize = NaN;
+        if (typeof this.options.type === 'string'){
+            elementSize = PRIMITIVE_TYPES[NAME_MAP[this.options.type]];
+        } else if (this.options.type instanceof Parser) {
+            elementSize = this.options.type.sizeOf();
+        }
+        size = this.options.length * elementSize;
+    
+    // if this a skip
+    } else if (this.type === 'Skip') {
+        size = this.options.length;
+
+    } else if (!this.type) {
+        size = 0;
     }
 
-    return arr.join('.');
+    if (this.next) {
+        size += this.next.sizeOf();
+    }
+
+    return size;
 };
 
-Context.prototype.generateOption = function(val) {
-    if (typeof val === 'number') {
-        return val.toString();
-    } else if (typeof val === 'string') {
-        return this.generateVariable(val);
-    } else if (typeof val === 'function') {
-        return util.format('(%s).call(%s)', val, this.generateVariable());
+// Follow the parser chain till the root and start parsing from there
+Parser.prototype.parse = function(buffer) {
+    if (!Buffer.isBuffer(buffer)) {
+        throw new Error('argument "buffer" is not a Buffer object');
     }
-};
 
-Context.prototype.pushCode = function(code) {
-    var re = /{\d+}/g;
-    var matches = code.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);
-            code = code.replace(match, params[index].toString());
-        });
+    if (!this.compiled) {
+        this.compile();
     }
 
-    this.code += code + '\n';
+    return this.compiled(buffer);
 };
 
-Parser.prototype.compile = function() {
-    var ctx = new Context();
+//----------------------------------------------------------------------------------------
+// private methods
+//----------------------------------------------------------------------------------------
 
-    ctx.pushCode('var vars = {};');
-    ctx.pushCode('var iterator = 0;');
-    this.generate(ctx);
-    ctx.pushCode('return vars;');
+Parser.prototype.setNextParser = function(type, varName, options) {
+    var parser = new Parser();
+    
+    parser.type = NAME_MAP[type];
+    parser.varName = varName;
+    parser.options = options || parser.options;
+    
+    if (this.head) {
+        this.head.next = parser;
+    } else {
+        this.next = parser;
+    }
+    this.head = parser;
 
-    this.compiled = new Function('buffer', ctx.code);
+    return this;
 };
@@ -283,2 +298,22 @@
 
+Parser.prototype.generateBuffer = function(ctx) {
+    if (this.options.readUntil === 'eof') {
+        ctx.pushCode('{0} = buffer.slice(iterator, buffer.length - 1);',
+            ctx.generateVariable(this.varName)
+            );
+    } else {
+        ctx.pushCode('{0} = buffer.slice(iterator, iterator + {1});',
+            ctx.generateVariable(this.varName),
+            ctx.generateOption(this.options.length)
+            );
+        ctx.pushCode('iterator += {0};', ctx.generateOption(this.options.length));
+    }
+
+    if (this.options.clone) {
+        ctx.pushCode('{0} = (function() { var buf = new Buffer({0}.length); {0}.copy(buf); return buf; })();',
+            ctx.generateVariable(this.varName)
+            );
+    }
+};
+
 Parser.prototype.generateArray = function(ctx) {
@@ -321,13 +356,2 @@ var length = ctx.generateOption(this.options.length);
 
-Parser.prototype.generateChoiceCase = function(ctx, varName, type) {
-    if (typeof type === 'string') {
-        ctx.pushCode('{0} = buffer.read{1}(iterator);', ctx.generateVariable(this.varName), NAME_MAP[type]);
-        ctx.pushCode('iterator += {0};', PRIMITIVE_TYPES[NAME_MAP[type]]);
-    } else if (type instanceof Parser) {
-        ctx.scopes.push(varName);
-        type.generate(ctx);
-        ctx.scopes.pop();
-    }
-};
-
 Parser.prototype.generateChoice = function(ctx) {
@@ -358,35 +382,48 @@ var tag = ctx.generateOption(this.options.tag);
 
-Parser.prototype.sizeOf = function() {
-    var size = NaN;
+//----------------------------------------------------------------------------------------
+// constructor
+//----------------------------------------------------------------------------------------
 
-    if (Object.keys(PRIMITIVE_TYPES).indexOf(this.type) >= 0) {
-        size = PRIMITIVE_TYPES[this.type];
-    
-    // if this is a fixed length string
-    } else if (this.type === 'String' && typeof this.options.length === 'number') {
-        size = this.options.length;
-    
-    // if this is a fixed length array
-    } else if (this.type === 'Array' && typeof this.options.length === 'number') {
-        var elementSize = NaN;
-        if (typeof this.options.type === 'string'){
-            elementSize = PRIMITIVE_TYPES[NAME_MAP[this.options.type]];
-        } else if (this.options.type instanceof Parser) {
-            elementSize = this.options.type.sizeOf();
-        }
-        size = this.options.length * elementSize;
-    
-    // if this a skip
-    } else if (this.type === 'Skip') {
-        size = this.options.length;
+var Context = function() {
+    this.code = '';
+    this.scopes = [];
+};
 
-    } else if (!this.type) {
-        size = 0;
+//----------------------------------------------------------------------------------------
+// public methods
+//----------------------------------------------------------------------------------------
+
+Context.prototype.generateVariable = function(name) {
+    var arr = ['vars'];
+    Array.prototype.push.apply(arr, this.scopes);
+    if (name) {
+        arr.push(name);
     }
 
-    if (this.next) {
-        size += this.next.sizeOf();
+    return arr.join('.');
+};
+
+Context.prototype.generateOption = function(val) {
+    if (typeof val === 'number') {
+        return val.toString();
+    } else if (typeof val === 'string') {
+        return this.generateVariable(val);
+    } else if (typeof val === 'function') {
+        return '(' + val + ').call(' + this.generateVariable() + ')';
     }
+};
 
-    return size;
+Context.prototype.pushCode = function(code) {
+    var re = /{\d+}/g;
+    var matches = code.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);
+            code = code.replace(match, params[index].toString());
+        });
+    }
+
+    this.code += code + '\n';
 };
@@ -393,0 +430,0 @@

package.json

 {
   "name": "binary-parser",
-  "version": "0.0.1",
+  "version": "0.0.2",
   "description": "Blazing-fast binary parser builder",
@@ -5,0 +5,0 @@ "main": "lib/binary_parser.js",

README.md

@@ -82,3 +82,3 @@ # Binary-parser
 	are valid. See [`Buffer.toString`](http://nodejs.org/api/buffer.html#buffer_buf_tostring_encoding_start_end) for more info.
-- `length `- (Required) Length of the string. Can be a number, string or a function.
+- `length ` - (Required) Length of the string. Can be a number, string or a function.
 	Use number for statically sized arrays, string to reference another variable and
@@ -88,2 +88,16 @@ function to do some calculation.
 
+### buffer(name [,options])
+Parse bytes as a string. `name` should consist only of alpha numeric characters and start
+with an alphabet. `options` is an object; following options are available: 
+
+- `clone` - (Optional, defaults to `false`) By default, `buffer(name [,options])` returns a new buffer which references
+    the same memory as the parser input, but offset and cropped by a certain range. If this option is true, input buffer
+    will be cloned and a new buffer referncing another memory is returned.
+- `length ` - (either `length` or `readUntil` is required) Length of the buffer. Can be a number, string or a function.
+    Use number for statically sized buffers, string to reference another variable and
+    function to do some calculation.
+- `readUntil` - (either `length` or `readUntil` is required) If `'eof'`, then this parser
+    will read till it reaches end of the `Buffer` object.
+
+
 ### array(name [,options])
@@ -177,2 +191,6 @@ Parse bytes as an array. `options` is an object; following options are available:
 
+### getCode()
+Dynamically generates the code for this parser and returns it as a string.
+Usually used for debugging.
+
 ### Assertion
@@ -179,0 +197,0 @@ You can do assertions during the parsing (useful for checking magic numbers and so on).

test/test.js

@@ -83,2 +83,31 @@ var assert = require('assert');
 
+    describe('Buffer parser', function() {
+        it('should parse as buffer', function() {
+            var parser = new Parser()
+                .uint8('len')
+                .buffer('raw', {
+                    length: 'len'
+                });
+
+            var buf = new Buffer('deadbeefdeadbeef', 'hex');
+            var result = parser.parse(Buffer.concat([new Buffer([8]), buf]));
+
+            assert.deepEqual(result.raw, buf);
+        });
+
+        it('should clone buffer if options.clone is true', function() {
+            var parser = new Parser()
+                .buffer('raw', {
+                    length: 8,
+                    clone: true
+                });
+
+            var buf = new Buffer('deadbeefdeadbeef', 'hex');
+            var result = parser.parse(buf);
+            assert.deepEqual(result.raw, buf);
+            result.raw[0] = 0xff;
+            assert.notDeepEqual(result.raw, buf);
+        });
+    });
+
     describe('Array parser', function() {
@@ -85,0 +114,0 @@ it('should parse array of primitive types', function(){

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Uses eval

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Improved metrics

Total package byte prevSize

271396

increased by1.26%

Lines of code

924

increased by6.08%

Number of lines in readme file

232

increased by8.41%

Number of medium supply chain risk alerts

0

decreased by-100%

No dependency changes