in the attempt to fix 627393, changed IFX_FileRead's readBlock to return the length it reads

testing/libfuzzer/xfa_codec_fuzzer.h

Index: testing/libfuzzer/xfa_codec_fuzzer.h
diff --git a/testing/libfuzzer/xfa_codec_fuzzer.h b/testing/libfuzzer/xfa_codec_fuzzer.h
index 38c4e0ac333f062343d5a7c06cfc9e80d659a3f0..2cc81453ea283050e443fb0de738237622e8d9da 100644
--- a/testing/libfuzzer/xfa_codec_fuzzer.h
+++ b/testing/libfuzzer/xfa_codec_fuzzer.h
@@ -43,22 +43,31 @@ class XFACodecFuzzer {
  private:
   class Reader : public IFX_FileRead {
    public:
-    Reader(const uint8_t* data, size_t size) : m_data(data), m_size(size) {}
+    Reader(const uint8_t* data, size_t size)
+        : m_data(data), m_size(size), m_nCurPos(0) {}
     ~Reader() {}
 
     void Release() override {}
 
-    FX_BOOL ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override {
+    FX_BOOL IsEOF() override {
+      return m_nCurPos >= static_cast<FX_FILESIZE>(m_size);
+    }
+
+    size_t ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override {
+      if (offset > m_size)
+        return 0;
       if (offset + size > m_size)
         size = m_size - offset;
       memcpy(buffer, m_data + offset, size);
-      return TRUE;
+      m_nCurPos = offset + static_cast<FX_FILESIZE>(size);
+      return size;
     }
 
     FX_FILESIZE GetSize() override { return static_cast<FX_FILESIZE>(m_size); }
 
    private:
     const uint8_t* const m_data;
+    FX_FILESIZE m_nCurPos;
     size_t m_size;

[Tom Sepez, 2016/10/19 23:12:48]

this may be cleaner if it were FX_FILESIZE as well.

   };
 };