gzip: support the --rsyncable option

* deflate.c: Include verify.h.
(RSYNC_WIN, RSYNC_SUM_MATCH): Define.
(rsync_sum, rsync_chunk_end): Declare file-scoped globals.
(lm_init): Initialize globals.
(fill_window): Update rsync_chunk_end.
(rsync_roll): New function.
(RSYNC_ROLL): New macro.
(FLUSH_BLOCK): Update for new "pad" parameter.
(deflate_fast): Use RSYNC_ROLL and flush/pad.
(deflate): Likewise.
* trees.c (flush_block): Add "pad" parameter.
* gzip.c (rsync): New global.
(RSYNCABLE_OPTION, longopts, help): Add the option.
(main): Set the new global.
* gzip.h (rsync): Declare new global.
(flush_block): Update prototype.
* doc/gzip.texi: Document it.
* gzip.1: Likewise.
* bootstrap.conf: Use verify module.
* NEWS (New feature): Mention it.
* Makefile.am (check-local): Add tests and use AM_V__* command-
hiding opions. Reported against Debian here:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=118118

1 files changed, 6 insertions, 1 deletions

diff --git a/trees.c b/trees.c
index f314e57..025d5ba 100644
--- a/trees.c
+++ b/trees.c
@@ -856,9 +856,10 @@ local void send_all_trees(lcodes, dcodes, blcodes)
  * trees or store, and output the encoded block to the zip file. This function
  * returns the total compressed length for the file so far.
  */
-off_t flush_block(buf, stored_len, eof)
+off_t flush_block(buf, stored_len, pad, eof)
     char *buf;        /* input block, or NULL if too old */
     ulg stored_len;   /* length of input block */
+    int pad;          /* pad output to byte boundary */
     int eof;          /* true if this is the last block for a file */
 {
     ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
@@ -951,6 +952,10 @@ off_t flush_block(buf, stored_len, eof)
         Assert (input_len == bytes_in, "bad input size");
         bi_windup();
         compressed_len += 7;  /* align on byte boundary */
+    } else if (pad && (compressed_len % 8) != 0) {
+        send_bits((STORED_BLOCK<<1)+eof, 3);  /* send block type */
+        compressed_len = (compressed_len + 3 + 7) & ~7L;
+        copy_block(buf, 0, 1); /* with header */
     }
 
     return compressed_len >> 3;