fix support for hdlist compressed with !gzip

we were always defaulting to gzip format, whatever is the decompressor
specified in the archive
bug introduced in commit 18723d2d47f9e069667753703c12ba5139661957

2 files changed, 6 insertions, 4 deletions

diff --git a/NEWS b/NEWS
index 68c542f..8a3f311 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,5 @@
+- fix support for hdlist compressed with !gzip
+
 Version 5.23.2 - 30 December 2019
 
 - restore compatibility with rpm build w/o support for zstd
diff --git a/URPM.xs b/URPM.xs
index 83ab837..efdacbd 100644
--- a/URPM.xs
+++ b/URPM.xs
@@ -993,13 +993,13 @@ open_archive(char *filename, int *empty_archive) {
     } else {
       /* this is an archive, prepare for reading with uncompress defined inside */
       rfd = Fopen(filename, "r.fdio");
-      if (strcmp(buf.uncompress, "gzip"))
+      if (!strncmp(buf.uncompress, "gzip", 4))
            rfd = Fdopen(rfd, "r.gzip");
-      else if (strcmp(buf.uncompress, "bzip"))
+      else if (!strncmp(buf.uncompress, "bzip2", 4))
            rfd = Fdopen(rfd, "r.bzip2");
-      else if (strcmp(buf.uncompress, "xz") || strcmp(buf.uncompress, "lzma"))
+      else if (!strncmp(buf.uncompress, "xz", 2) || !strncmp(buf.uncompress, "lzma", 4))
            rfd = Fdopen(rfd, "r.xz");
-      else if (strcmp(buf.uncompress, "zstd"))
+      else if (!strncmp(buf.uncompress, "zstd", 4))
            rfd = Fdopen(rfd, "r.zstd");
       else {
            free(rfd);