Make read/write gzip files on macos works, fixes #1357

diff --git a/kernel/register.cc b/kernel/register.cc
index 1fd1bad1dd3e92704ac6299439cbcdc7e774eeaa..8131fa279ca5565582fe8a0b2a0b1950dadef367 100644 (file)
--- a/kernel/register.cc
+++ b/kernel/register.cc
@@ -48,7 +48,7 @@ using zlib to write gzip-compressed data every time the stream is flushed.
 */
 class gzip_ostream : public std::ostream  {
 public:
-       gzip_ostream()
+       gzip_ostream() : std::ostream(nullptr)
        {
                rdbuf(&outbuf);
        }
@@ -71,7 +71,7 @@ private:
                        str("");
                        return 0;
                }
-               ~gzip_streambuf()
+               virtual ~gzip_streambuf()
                {
                        sync();
                        gzclose(gzf);
@@ -498,7 +498,15 @@ void Frontend::extra_args(std::istream *&f, std::string &filename, std::vector<s
                        if (f != NULL) {
                                // Check for gzip magic
                                unsigned char magic[3];
-                               int n = readsome(*ff, reinterpret_cast<char*>(magic), 3);
+                               int n = 0;
+                               while (n < 3)
+                               {
+                                       int c = ff->get();
+                                       if (c != EOF) {
+                                               magic[n] = (unsigned char) c;
+                                       }
+                                       n++;
+                               }
                                if (n == 3 && magic[0] == 0x1f && magic[1] == 0x8b) {
        #ifdef YOSYS_ENABLE_ZLIB
                                        log("Found gzip magic in file `%s', decompressing using zlib.\n", filename.c_str());