From 43847d7ff8da1876975edf741f889342a816e216 Mon Sep 17 00:00:00 2001
From: Rob Wu <gwnRob@gmail.com>
Date: Sat, 7 Dec 2013 23:19:50 +0100
Subject: [PATCH] Set eof to true at the end of a FlateStream

At the initialization of `Lexer_getObj` (in `parser.js`), there's a loop
that skips whitespace and breaks out whenever EOF is encountered.
(https://github.com/mozilla/pdf.js/blob/88ec2bd1a/src/core/parser.js#L586-L599)

Whenever the current character is not a whitespace character,
`ch = this.nextChar();` is used to find the next character
(using `return this.currentChar = this.stream.getByte())`).

The aforementioned `getByte` method retrieves the next byte using
(https://github.com/mozilla/pdf.js/blob/88ec2bd1a/src/core/stream.js#L122-L128)

      var pos = this.pos;
      while (this.bufferLength <= pos) {
        if (this.eof)
          return -1;
        this.readBlock();
      }
      return this.buffer[this.pos++];

This piece of code relies on this.eof to detect whether the last character
has been read. When the stream is a `FlateStream`, and the end of the stream
has been reached, then **`this.eof` is not set to `true`**, because this check
is done inside a loop that does not occur when the read block size is zero:
(https://github.com/mozilla/pdf.js/blob/88ec2bd1ac/src/core/stream.js#L511-L517)

      for (var n = bufferLength; n < end; ++n) {
        if (typeof (b = bytes[bytesPos++]) == 'undefined') {
          this.eof = true;
          break;
        }
        buffer[n] = b;
      }

This commit fixes the issue by setting this.eof to true whenever the loop is not
going to run (i.e. when bufferLength === end, i.e. blockLen === 0).
---
 src/core/stream.js | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/core/stream.js b/src/core/stream.js
index 61f1af544..6e25b36c2 100644
--- a/src/core/stream.js
+++ b/src/core/stream.js
@@ -508,12 +508,18 @@ var FlateStream = (function FlateStreamClosure() {
       var buffer = this.ensureBuffer(bufferLength + blockLen);
       var end = bufferLength + blockLen;
       this.bufferLength = end;
-      for (var n = bufferLength; n < end; ++n) {
-        if (typeof (b = bytes[bytesPos++]) == 'undefined') {
+      if (blockLen === 0) {
+        if (typeof bytes[bytesPos] == 'undefined') {
           this.eof = true;
-          break;
         }
-        buffer[n] = b;
+      } else {
+        for (var n = bufferLength; n < end; ++n) {
+          if (typeof (b = bytes[bytesPos++]) == 'undefined') {
+            this.eof = true;
+            break;
+          }
+          buffer[n] = b;
+        }
       }
       this.bytesPos = bytesPos;
       return;