fix windows?

src/Image.cc

@@ -773,9 +773,7 @@ class BufferReader : public Image::Reader {
   bool hasBytes(unsigned n) const override { return (_idx + n - 1 < _len); }
 
   uint8_t getNext() override {
-    if (_idx < _len) {
-      return _buf[_idx++];
-    }
+    return _buf[_idx++];
   }
 
   void skipBytes(unsigned n) override { _idx += n; }
@@ -789,9 +787,9 @@ class BufferReader : public Image::Reader {
 class StreamReader : public Image::Reader {
 public:
   StreamReader(FILE *stream) : _stream(stream), _len(0), _idx(0) {
-    fseeko(_stream, 0, SEEK_END);
-    _len = ftello(_stream);
-    fseeko(_stream, 0, SEEK_SET);
+    fseek(_stream, 0, SEEK_END);
+    _len = ftell(_stream);
+    fseek(_stream, 0, SEEK_SET);
   }
 
   bool hasBytes(unsigned n) const override { return (_idx + n - 1 < _len); }
@@ -803,13 +801,13 @@ class StreamReader : public Image::Reader {
 
   void skipBytes(unsigned n) override {
     _idx += n;
-    fseeko(_stream, _idx, SEEK_SET);
+    fseek(_stream, _idx, SEEK_SET);
   }
 
 private:
   FILE* _stream;
-  off_t _len;
-  off_t _idx;
+  unsigned _len;
+  unsigned _idx;
 };
 
 void Image::jpegToARGB(jpeg_decompress_struct* args, uint8_t* data, uint8_t* src, JPEGDecodeL decode) {