binary-parser - npm Package Compare versions

Comparing version 0.0.4 to 0.0.5

lib/binary_parser.js

@@ -28,5 +28,14 @@ //========================================================================================
     'Choice'   : null,
-    'Nest'     : null
+    'Nest'     : null,
+    'Bit'      : null
 };
 
+var BIT_RANGE = [];
+(function() {
+    var i;
+    for (i = 1; i <= 32; i++) {
+        BIT_RANGE.push(i);
+    }
+})();
+
 // Converts Parser's method names to internal type names
@@ -73,2 +82,12 @@ var NAME_MAP = {};
 
+BIT_RANGE.forEach(function(i) {
+    Parser.prototype['bit' + i.toString()] = function(varName, options) {
+        if (!options) {
+            options = {};
+        }
+        options.length = i;
+        return this.setNextParser('bit', varName, options);
+    };
+});
+
 Parser.prototype.skip = function(length, options) {
@@ -171,3 +190,3 @@ if (options && options.assert) {
     ctx.pushCode('var vars = {};');
-    ctx.pushCode('var iterator = 0;');
+    ctx.pushCode('var offset = 0;');
     ctx.pushCode('if (!Buffer.isBuffer(buffer)) {');
@@ -303,10 +322,50 @@ ctx.generateError('"argument buffer is not a Buffer object"');
     Parser.prototype['generate' + type] = function(ctx) {
-        ctx.pushCode('{0} = buffer.read{1}(iterator);', ctx.generateVariable(this.varName), type);
-        ctx.pushCode('iterator += {0};', PRIMITIVE_TYPES[type]);
+        ctx.pushCode('{0} = buffer.read{1}(offset);', ctx.generateVariable(this.varName), type);
+        ctx.pushCode('offset += {0};', PRIMITIVE_TYPES[type]);
     };
 });
 
+Parser.prototype.generateBit = function(ctx) {
+    ctx.bitFields.push(this);
+
+    if (!this.next || (this.next && !this.next.type.match('Bit'))) {
+        var sum = 0;
+        ctx.bitFields.forEach(function(parser) {
+            sum += parser.options.length;
+        });
+
+        var val = ctx.generateTmpVariable();
+
+        if (sum <= 8) {
+            ctx.pushCode('var {0} = buffer.readUInt8(offset);', val);
+            sum = 8;
+        } else if (sum <= 16) {
+            ctx.pushCode('var {0} = buffer.readUInt16BE(offset);', val);
+            sum = 16;
+        } else if (sum <= 32) {
+            ctx.pushCode('var {0} = buffer.readUInt32BE(offset);', val);
+            sum = 32;
+        } else {
+            throw new Error('Currently, bit field sequence longer than 4-bytes is not supported.');
+        }
+        ctx.pushCode('offset += {0};', sum / 8);
+
+        var bitOffset = 0;
+        ctx.bitFields.forEach(function(parser) {
+            ctx.pushCode('{0} = {1} >> {2} & {3};',
+                ctx.generateVariable(parser.varName),
+                val,
+                sum - bitOffset - parser.options.length,
+                (1 << parser.options.length) - 1
+            );
+            bitOffset += parser.options.length;
+        });
+
+        ctx.bitFields = [];
+    }
+};
+
 Parser.prototype.generateSkip = function(ctx) {
     var length = ctx.generateOption(this.options.length);
-    ctx.pushCode('iterator += {0};', length);
+    ctx.pushCode('offset += {0};', length);
 };
@@ -316,10 +375,14 @@
     if (this.options.zeroTerminated) {
-        ctx.pushCode('{0} = (function() {', ctx.generateVariable(this.varName));
-        ctx.pushCode('var start = iterator;');
-        ctx.pushCode('while(buffer.readUInt8(iterator++) !== 0);');
-        ctx.pushCode('return buffer.toString(\'{0}\', start, iterator - 1);', this.options.encoding);
-        ctx.pushCode('})();');
+        var start = ctx.generateTmpVariable();
+
+        ctx.pushCode('var {0} = offset;', start);
+        ctx.pushCode('while(buffer.readUInt8(offset++) !== 0);');
+        ctx.pushCode('{0} = buffer.toString(\'{1}\', {2}, offset - 1);',
+            ctx.generateVariable(this.varName),
+            this.options.encoding,
+            start
+        );
     }
      else {
-        ctx.pushCode('{0} = buffer.toString(\'{1}\', iterator, iterator + {2});',
+        ctx.pushCode('{0} = buffer.toString(\'{1}\', offset, offset + {2});',
                             ctx.generateVariable(this.varName),
@@ -329,3 +392,3 @@ this.options.encoding,
                         );
-        ctx.pushCode('iterator += {0};', ctx.generateOption(this.options.length));
+        ctx.pushCode('offset += {0};', ctx.generateOption(this.options.length));
      }
@@ -336,17 +399,19 @@ };
     if (this.options.readUntil === 'eof') {
-        ctx.pushCode('{0} = buffer.slice(iterator, buffer.length - 1);',
+        ctx.pushCode('{0} = buffer.slice(offset, buffer.length - 1);',
             ctx.generateVariable(this.varName)
             );
     } else {
-        ctx.pushCode('{0} = buffer.slice(iterator, iterator + {1});',
+        ctx.pushCode('{0} = buffer.slice(offset, offset + {1});',
             ctx.generateVariable(this.varName),
             ctx.generateOption(this.options.length)
             );
-        ctx.pushCode('iterator += {0};', ctx.generateOption(this.options.length));
+        ctx.pushCode('offset += {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)
-            );
+        var buf = ctx.generateTmpVariable();
+
+        ctx.pushCode('var {0} = new Buffer({1}.length);', buf, ctx.generateVariable(this.varName));
+        ctx.pushCode('{0}.copy({1});', ctx.generateVariable(this.varName), buf);
+        ctx.pushCode('{0} = {1}', ctx.generateVariable(this.varName), buf);
     }
@@ -358,3 +423,3 @@ };
     var type = this.options.type;
-    var counter = 'i' + ctx.scopes.length.toString();
+    var counter = ctx.generateTmpVariable();
     var lhs = ctx.generateVariable(this.varName);
@@ -364,3 +429,3 @@
     if (this.options.readUntil === 'eof') {
-        ctx.pushCode('for (var {0} = 0; iterator < buffer.length; {0}++) {', counter);
+        ctx.pushCode('for (var {0} = 0; offset < buffer.length; {0}++) {', counter);
     } else {
@@ -371,4 +436,4 @@ ctx.pushCode('for (var {0} = 0; {0} < {1}; {0}++) {', counter, length);
     if (typeof type === 'string') {
-        ctx.pushCode('{0}.push(buffer.read{1}(iterator));', lhs, NAME_MAP[type]);
-        ctx.pushCode('iterator += {0};', PRIMITIVE_TYPES[NAME_MAP[type]]);
+        ctx.pushCode('{0}.push(buffer.read{1}(offset));', lhs, NAME_MAP[type]);
+        ctx.pushCode('offset += {0};', PRIMITIVE_TYPES[NAME_MAP[type]]);
     } else if (type instanceof Parser) {
@@ -386,4 +451,4 @@ ctx.pushCode('{0}.push({});', lhs);
     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]]);
+        ctx.pushCode('{0} = buffer.read{1}(offset);', ctx.generateVariable(this.varName), NAME_MAP[type]);
+        ctx.pushCode('offset += {0};', PRIMITIVE_TYPES[NAME_MAP[type]]);
     } else if (type instanceof Parser) {
@@ -436,2 +501,4 @@ ctx.scopes.push(varName);
     this.isAsync = false;
+    this.bitFields = [];
+    this.tmpVariableCount = 0;
 };
@@ -474,2 +541,6 @@
 
+Context.prototype.generateTmpVariable = function() {
+    return 'tmp' + (this.tmpVariableCount++);
+};
+
 Context.prototype.pushCode = function() {
@@ -476,0 +547,0 @@ var args = Array.prototype.slice.call(arguments);

package.json

 {
   "name": "binary-parser",
   "version": "0.0.4",
+  "version": "0.0.5",
   "description": "Blazing-fast binary parser builder",
@@ -18,3 +19,4 @@ "main": "lib/binary_parser.js",
     "struct",
-    "buffer"
+    "buffer",
+    "bit"
   ],
@@ -21,0 +23,0 @@ "author": {

README.md

@@ -8,3 +8,4 @@ # Binary-parser
 It supports all common data types required to parse a structured binary data,
-such as integers, floating point numbers, strings, arrays (both fixed length and variable length), etc.
+such as integers, bit fields, floating point numbers, strings, arrays 
+(both fixed length and variable length), etc.
 Binary-parser dynamically generates and compiles the parser code on-the-fly.
@@ -76,2 +77,6 @@
 
+### bit\[1-32\](name [,options])
+Parse bytes as a bit field and store it in variable `name`. There are 32 methods from
+`bit1` to `bit32` each corresponding to 1-bit-length to 32-bits-length bit field.
+
 ### {float, double}{le, be}(name [,options])
@@ -235,3 +240,3 @@ Parse bytes as an floating-point value and store it in a variable
 
-Copyright (c) 2013 Keichi Takahashi
+Copyright (c) 2013 Keichi Takahashi <[e-mail]>
 
@@ -238,0 +243,0 @@ Permission is hereby granted, free of charge, to any person obtaining a copy

test/test.js

@@ -45,2 +45,49 @@ var assert = require('assert');
 
+    describe('Bit field parsers', function() {
+        it('should parse 1-byte-length bit field sequence', function() {
+            var parser = new Parser()
+                .bit1('a')
+                .bit2('b')
+                .bit4('c')
+                .bit1('d');
+
+            var buf = new Buffer([parseInt('11010100', 2)]);
+            assert.deepEqual(parser.parse(buf), {
+                a: 1,
+                b: 2,
+                c: 10,
+                d: 0
+            });
+        });
+        it('should parse 2-byte-length bit field sequence', function() {
+            var parser = new Parser()
+                .bit3('a')
+                .bit9('b')
+                .bit4('c');
+
+            var buf = new Buffer([parseInt('10111100', 2), parseInt('01110101', 2)]);
+            assert.deepEqual(parser.parse(buf), {
+                a: 5,
+                b: 455,
+                c: 5
+            });
+        });
+        it('should parse 4-byte-length bit field sequence', function() {
+            var parser = new Parser()
+                .bit1('a')
+                .bit24('b')
+                .bit4('c')
+                .bit2('d')
+                .bit1('e');
+            var buf = new Buffer([parseInt('11010101', 2), parseInt('01010101', 2), parseInt('01010101', 2), parseInt('01111011', 2)]);
+            assert.deepEqual(parser.parse(buf), {
+                a: 1,
+                b: 11184810,
+                c: 15,
+                d: 1,
+                e: 1
+            });
+        });
+    });
+
     describe('String parser', function() {
@@ -47,0 +94,0 @@ it('should parse ASCII encoded string', function(){

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Improved metrics

Total package byte prevSize

104291

increased by4.99%

Number of package files

14

increased by7.69%

Lines of code

1246

increased by13.17%

Number of lines in readme file

257

increased by1.98%

No dependency changes