Added a peek function for the igzfstream. Wish this wasn't needed, but some of our line oriented reading requires checking for eof to avoid reading an empty line. This is included in the istream so we are doing the same here. If this were put into the getline function it might cause slowdown because I'm not sure about the gaurantees on speed of ugzungetc

Author: andrewdavidsmith

zlib_wrapper.cpp

@@ -19,11 +19,19 @@
 
 using std::string;
 
+char
+igzfstream::peek() {
+  const char c = gzgetc(fileobj);
+  if (!gzeof(fileobj))
+    gzungetc(c, fileobj);
+  return c;
+}
+
 igzfstream&
 getline(igzfstream &in, string &line) {
   if (gzgets(in.fileobj, &in.buf[0], in.chunk_size)) {
-      auto eol = std::find(begin(in.buf), end(in.buf), '\n');
-      line = string(begin(in.buf), eol);
+    auto eol = std::find(begin(in.buf), end(in.buf), '\n');
+    line = string(begin(in.buf), eol);
   }
   return in;
 }

zlib_wrapper.hpp

@@ -32,6 +32,7 @@ struct igzfstream {
     }
   ~igzfstream() {gzclose_r(fileobj);}
   operator bool() const {return !gzeof(fileobj);}
+  char peek();
 
   size_t chunk_size;
   std::vector<char> buf;