From cdca53e4deabcb8534969143055b7cf450c2be00 Mon Sep 17 00:00:00 2001
From: "Emil J. Tywoniak" <emil@tywoniak.eu>
Date: Thu, 19 Dec 2024 20:49:17 +0100
Subject: [PATCH] gzipping istream

---
 kernel/gzip.cc | 9 +++++----
 kernel/gzip.h  | 9 +++++++--
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/kernel/gzip.cc b/kernel/gzip.cc
index d69d5764edb..52c9e413a99 100644
--- a/kernel/gzip.cc
+++ b/kernel/gzip.cc
@@ -92,10 +92,11 @@ 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;
-		std::stringstream *df = new std::stringstream();
-		decompress_gzip(filename, *df);
-		return df;
+		delete f;
+		// std::stringstream *df = new std::stringstream();
+		// decompress_gzip(filename, *df);
+		gzip_istream* s = new gzip_istream();
+		return s->open(filename.c_str()) ? s : nullptr;
 #else
 		log_cmd_error("File `%s' is a gzip file, but Yosys is compiled without zlib.\n", filename.c_str());
 #endif // YOSYS_ENABLE_ZLIB
diff --git a/kernel/gzip.h b/kernel/gzip.h
index 61558590142..a00ac66a6b5 100644
--- a/kernel/gzip.h
+++ b/kernel/gzip.h
@@ -84,10 +84,15 @@ class gzip_istream final : public std::istream {
             if (bytes_read <= 0) {
                 // An error occurred during reading
                 int err;
+				if (Zlib::gzeof(gzf))
+					return traits_type::eof();
+
                 const char* error_msg = Zlib::gzerror(gzf, &err);
-				if (err != Z_STREAM_END)
+				if (err != Z_OK)
 					log_error("%s", error_msg);
-                return traits_type::eof();
+				else
+					log_error("Decompression logic failure: "\
+							  "read <=0 bytes but neither EOF nor error\n");
             }
 
             // Reset buffer pointers