gzip: simplify uncompressed interface

kernel/gzip.cc

@@ -96,15 +96,17 @@ gzip_istream::ibuf::~ibuf() {
 
 // Takes a successfully opened ifstream. If it's gzipped, returns an istream. Otherwise,
 // returns the original ifstream, rewound to the start.
-std::istream* uncompressed(std::ifstream* f, const std::string filename) {
-	if (!f)
-		return nullptr;
+std::istream& uncompressed(const std::string filename, std::ios_base::openmode mode) {
+	std::ifstream& f = *new std::ifstream();
+	f.open(filename, mode);
+	if (f.fail())
+		return f;
 	// Check for gzip magic
 	unsigned char magic[3];
 	int n = 0;
 	while (n < 3)
 	{
-		int c = f->get();
+		int c = f.get();
 		if (c != EOF) {
 			magic[n] = (unsigned char) c;
 		}
@@ -116,15 +118,16 @@ std::istream* uncompressed(std::ifstream* f, const std::string filename) {
 		if (magic[2] != 8)
 			log_cmd_error("gzip file `%s' uses unsupported compression type %02x\n",
 				filename.c_str(), unsigned(magic[2]));
-		delete f;
-		gzip_istream* s = new gzip_istream();
-		return s->open(filename.c_str()) ? s : nullptr;
+		gzip_istream& s = *new gzip_istream();
+		delete &f;
+		s.open(filename.c_str());
+		return s;
 #else
 		log_cmd_error("File `%s' is a gzip file, but Yosys is compiled without zlib.\n", filename.c_str());
 #endif // YOSYS_ENABLE_ZLIB
 	} else {
-		f->clear();
-		f->seekg(0, std::ios::beg);
+		f.clear();
+		f.seekg(0, std::ios::beg);
 		return f;
 	}
 }

kernel/gzip.h

@@ -72,7 +72,7 @@ private:
 
 #endif // YOSYS_ENABLE_ZLIB
 
-std::istream* uncompressed(std::ifstream* f, const std::string filename);
+std::istream& uncompressed(const std::string filename, std::ios_base::openmode mode = std::ios_base::in);
 
 YOSYS_NAMESPACE_END
 

kernel/register.cc

@@ -469,14 +469,8 @@ void Frontend::extra_args(std::istream *&f, std::string &filename, std::vector<s
 				next_args.insert(next_args.end(), args.begin(), args.begin()+argidx);
 				next_args.insert(next_args.end(), filenames.begin()+1, filenames.end());
 			}
-			std::ifstream *ff = new std::ifstream;
-			ff->open(filename.c_str(), bin_input ? std::ifstream::binary : std::ifstream::in);
 			yosys_input_files.insert(filename);
-			if (ff->fail()) {
-				delete ff;
-				ff = nullptr;
-			}
-			f = uncompressed(ff, filename);
+			f = &uncompressed(filename, bin_input ? std::ifstream::binary : std::ifstream::in);
 		}
 		if (f == NULL)
 			log_cmd_error("Can't open input file `%s' for reading: %s\n", filename.c_str(), strerror(errno));

passes/techmap/dfflibmap.cc

@@ -631,14 +631,12 @@ struct DfflibmapPass : public Pass {
 
 		LibertyMergedCells merged;
 		for (auto path : liberty_files) {
-			std::ifstream f;
-			f.open(path.c_str());
-			std::istream* ff = uncompressed(&f, path);
-			if (ff->fail())
+			std::istream& f = uncompressed(path);
+			if (f.fail())
 				log_cmd_error("Can't open liberty file `%s': %s\n", path.c_str(), strerror(errno));
-			LibertyParser p(*ff);
+			LibertyParser p(f);
 			merged.merge(p);
-			delete ff;
+			delete &f;
 		}
 
 		find_cell(merged.cells, ID($_DFF_N_), false, false, false, false, false, false, dont_use_cells);