Merge pull request #232 from theqabalist/fix/bit-seq-wrong

Fix issue where entire (very long) input is passed to bitSeq.
jneen · Mar 22, 2018 · 1821f52 · 1821f52
2 parents c1e28fb + 8eb1966
commit 1821f52
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Showing 2 changed files with 15 additions and 3 deletions.
diff --git a/src/parsimmon.js b/src/parsimmon.js
@@ -129,11 +129,12 @@ function bitSeq(alignments) {
   }
 
   return new Parsimmon(function(input, i) {
-    if (bytes + i > input.length) {
+    var newPos = bytes + i;
+    if (newPos > input.length) {
       return makeFailure(i, bytes.toString() + " bytes");
     }
     return makeSuccess(
-      i + bytes,
+      newPos,
       reduce(
         function(acc, bits) {
           var state = consumeBitsFromBuffer(bits, acc.buf);
@@ -142,7 +143,7 @@ function bitSeq(alignments) {
             buf: state.buf
           };
         },
-        { coll: [], buf: input },
+        { coll: [], buf: input.slice(i, newPos) },
         alignments
       ).coll
     );

diff --git a/test/core/bitSeq.test.js b/test/core/bitSeq.test.js
@@ -42,4 +42,15 @@ describe("bitSeq", function() {
       }, /buffer global/i);
     });
   });
+
+  context("We are bitSeq'ing not at the beginning.", function() {
+    it("Should still work.", function() {
+      var b = Buffer.from([0x10, 0xff, 0xff]);
+      var p = Parsimmon.seqObj(Parsimmon.any, [
+        "data",
+        Parsimmon.Binary.bitSeq([3, 5, 5, 3])
+      ]);
+      assert.deepEqual(p.parse(b).value.data, [7, 31, 31, 7]);
+    });
+  });
 });