Fix parse fields after bit[17-24] call.

For bits with length in range of [17, 24], should only read 3 bytes for processing.
iwinks · Apr 17, 2015 · 7b8c53a · 7b8c53a
1 parent e2cc40b
commit 7b8c53a
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diff --git a/lib/binary_parser.js b/lib/binary_parser.js
@@ -361,6 +361,13 @@ Parser.prototype.generateBit = function(ctx) {
         } else if (sum <= 16) {
             ctx.pushCode('var {0} = buffer.readUInt16BE(offset);', val);
             sum = 16;
+        } else if (sum <= 24) {
+            var val1 = ctx.generateTmpVariable();
+            var val2 = ctx.generateTmpVariable();
+            ctx.pushCode('var {0} = buffer.readUInt16BE(offset);', val1);
+            ctx.pushCode('var {0} = buffer.readUInt8(offset + 2);', val2);
+            ctx.pushCode('var {2} = ({0} << 8) | {1};', val1, val2, val);
+            sum = 24;
         } else if (sum <= 32) {
             ctx.pushCode('var {0} = buffer.readUInt32BE(offset);', val);
             sum = 32;

diff --git a/test/composite_parser.js b/test/composite_parser.js
@@ -387,4 +387,19 @@ describe('Composite parser', function(){
 
         });
     });
+
+    describe('Parse other fields after bit', function() {
+        it('Parse uint8', function() {
+            var buffer = new Buffer([0, 1, 0, 4]);
+            for (var i = 17; i <= 24; i++) {
+                var parser =
+                    Parser.start()['bit' + i]('a').uint8('b');
+
+                assert.deepEqual(parser.parse(buffer), {
+                    a: 1 << (i - 16),
+                    b: 4,
+                });
+            }
+        });
+    });
 });