Mark Adler wrote:
>> A test case will be forthcoming (I need to create a case that delicately
>> crosses a buffer boundary). Once I get a test case working, you can push it.
>
> Jim,
>
> It turns out that is no condition in which the lack of the patch to the patch
> causes a problem. So I have no test case for it. I will leave the patch to
> the patch in nevertheless, since otherwise it still looks like a bug.
I may have encountered this already
when I was trying to create a compressed file
of size one smaller than gzip's internal buffer size.
It appeared to be impossible.
Here's the output of "git format-patch --stdout -1"
for that patch. I'll push it today.
>From 1204630c96e0c368b4325f95cbaef95c3f9c482a Mon Sep 17 00:00:00 2001
From: Mark Adler <mad...@alumni.caltech.edu>
Date: Wed, 3 Feb 2010 10:11:33 +0100
Subject: [PATCH] gzip -cdf now handles concatenation of gzip'd and uncompressed
data
* util.c (copy): Change semantics so as to honor a decremented inptr.
* gzip.c (get_method): When needed (-cdf), decrement inptr rather
than clearing it -- and output the first magic byte.
---
gnulib | 2 +-
gzip.c | 12 ++++++++++--
util.c | 22 +++++++++++++---------
3 files changed, 24 insertions(+), 12 deletions(-)
diff --git a/gnulib b/gnulib
index a5b5500..9d0ad65 160000
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit a5b5500500ba4d6aaa9a1b3bb214f6917dc1ac3c
+Subproject commit 9d0ad652de159d08e5f679842f8a2a5658196361
diff --git a/gzip.c b/gzip.c
index f523be7..141397e 100644
--- a/gzip.c
+++ b/gzip.c
@@ -1239,6 +1239,7 @@ local int get_method(in)
{
uch flags; /* compression flags */
char magic[2]; /* magic header */
+ int imagic0; /* first magic byte or EOF */
int imagic1; /* like magic[1], but can represent EOF */
ulg stamp; /* time stamp */
@@ -1246,12 +1247,14 @@ local int get_method(in)
* premature end of file: use try_byte instead of get_byte.
*/
if (force && to_stdout) {
- magic[0] = (char)try_byte();
+ imagic0 = try_byte();
+ magic[0] = (char) imagic0;
imagic1 = try_byte ();
magic[1] = (char) imagic1;
/* If try_byte returned EOF, magic[1] == (char) EOF. */
} else {
magic[0] = (char)get_byte();
+ imagic0 = 0;
if (magic[0]) {
magic[1] = (char)get_byte();
imagic1 = 0; /* avoid lint warning */
@@ -1395,8 +1398,13 @@ local int get_method(in)
} else if (force && to_stdout && !list) { /* pass input unchanged */
method = STORED;
work = copy;
- inptr = 0;
+ if (imagic1 != EOF)
+ inptr--;
last_member = 1;
+ if (imagic0 != EOF) {
+ write_buf(fileno(stdout), magic, 1);
+ bytes_out++;
+ }
}
if (method >= 0) return method;
diff --git a/util.c b/util.c
index 1de2701..80b1075 100644
--- a/util.c
+++ b/util.c
@@ -44,21 +44,25 @@ extern ulg crc_32_tab[]; /* crc table, defined below */
/* ===========================================================================
* Copy input to output unchanged: zcat == cat with --force.
- * IN assertion: insize bytes have already been read in inbuf.
+ * IN assertion: insize bytes have already been read in inbuf and inptr bytes
+ * already processed or copied.
*/
int copy(in, out)
int in, out; /* input and output file descriptors */
{
+ int got;
+
errno = 0;
- while (insize != 0 && (int)insize != -1) {
- write_buf(out, (char*)inbuf, insize);
- bytes_out += insize;
- insize = read_buffer (in, (char *) inbuf, INBUFSIZ);
- }
- if ((int)insize == -1) {
- read_error();
+ while (insize > inptr) {
+ write_buf(out, (char*)inbuf + inptr, insize - inptr);
+ bytes_out += insize - inptr;
+ got = read_buffer (in, (char *) inbuf, INBUFSIZ);
+ if (got == -1)
+ read_error();
+ bytes_in += got;
+ insize = (unsigned)got;
+ inptr = 0;
}
- bytes_in = bytes_out;
return OK;
}
--
1.7.0.rc1.193.ge8618
