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authorRoland McGrath <roland@gnu.org>1995-12-21 10:00:22 +0000
committerRoland McGrath <roland@gnu.org>1995-12-21 10:00:22 +0000
commit8ef76445e88079b80d9684e8069e06d1378bcc68 (patch)
tree2af48fbd43dee5136f9ad577be24119f3e2e9023 /stdio/internals.c
parentf94a3574d523335c0158ee3445731077a1c872ef (diff)
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Wed Dec 20 18:23:10 1995 Roland McGrath <roland@churchy.gnu.ai.mit.edu>
* stdio/internals.c (flushbuf): If the target is -1, always discard the buffer of read data. Only set TWIDDLED flag in !ALIGNED case. Never increment target or offset when old value is -1.
Diffstat (limited to 'stdio/internals.c')
-rw-r--r--stdio/internals.c40
1 files changed, 24 insertions, 16 deletions
diff --git a/stdio/internals.c b/stdio/internals.c
index c238bf39f9..acdf97783a 100644
--- a/stdio/internals.c
+++ b/stdio/internals.c
@@ -199,9 +199,14 @@ DEFUN(flushbuf, (fp, c),
size_t buffer_offset = 0;
- /* If the user has read some of the buffer, the target position
- is incremented for each character he has read. */
- fp->__target += fp->__bufp - fp->__buffer;
+ if (fp->__target == -1)
+ /* For an unseekable object, data recently read bears no relation
+ to data we will write later. Discard the buffer. */
+ fp->__get_limit = fp->__buffer;
+ else
+ /* If the user has read some of the buffer, the target position
+ is incremented for each character he has read. */
+ fp->__target += fp->__bufp - fp->__buffer;
if (fp->__mode.__read && fp->__room_funcs.__input != NULL &&
!fp->__mode.__append)
@@ -231,12 +236,12 @@ DEFUN(flushbuf, (fp, c),
/* Start bufp as far into the buffer as we were into
this block before we read it. */
buffer_offset = o;
- }
- /* The target position is now set to where the beginning of the
- buffer maps to; and the get_limit was set by the input-room
- function. */
- twiddled = 1;
+ /* The target position is now set to where the beginning of the
+ buffer maps to; and the get_limit was set by the input-room
+ function. */
+ twiddled = 1;
+ }
}
if (fp->__buffer != NULL)
@@ -289,7 +294,8 @@ DEFUN(flushbuf, (fp, c),
call with nothing in the buffer, so just say the buffer's
been flushed, increment the file offset, and return. */
fp->__bufp = fp->__buffer;
- fp->__offset += to_write;
+ if (fp->__offset != -1)
+ fp->__offset += to_write;
goto end;
}
@@ -315,7 +321,7 @@ DEFUN(flushbuf, (fp, c),
bother to find the current position; we can get it
later if we need it. */
fp->__offset = fp->__target = -1;
- else
+ else if (fp->__offset != -1)
/* Record that we've moved forward in the file. */
fp->__offset += wrote;
}
@@ -339,7 +345,7 @@ DEFUN(flushbuf, (fp, c),
char cc = (unsigned char) c;
if ((*fp->__io_funcs.__write)(fp->__cookie, &cc, 1) < 1)
fp->__error = 1;
- else
+ else if (fp->__offset != -1)
{
/* Record that we've moved forward in the file. */
++fp->__offset;
@@ -355,9 +361,10 @@ DEFUN(flushbuf, (fp, c),
if (!twiddled)
{
- /* The new target position moves up as
- much as the user wrote into the buffer. */
- fp->__target += buffer_written;
+ if (fp->__target != -1)
+ /* The new target position moves up as
+ much as the user wrote into the buffer. */
+ fp->__target += buffer_written;
/* Set the reading limit to the beginning of the buffer,
so the next `getc' will call __fillbf. */
@@ -433,8 +440,9 @@ DEFUN(fillbuf, (fp), register FILE *fp)
buffer += count;
nread += count;
to_read -= count;
- /* Record that we've moved forward in the file. */
- fp->__offset += count;
+ if (fp->__offset != -1)
+ /* Record that we've moved forward in the file. */
+ fp->__offset += count;
}
}