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authorSiddhesh Poyarekar <siddhesh@redhat.com>2012-09-28 18:20:40 +0530
committerSiddhesh Poyarekar <siddhesh@redhat.com>2012-09-28 18:21:39 +0530
commit4573c6b09884a93fffa3a754678ef881cadebfb3 (patch)
tree89734fdb5480204f4bf4ad5c0977c39a5265ec2f /libio/wfileops.c
parent784421e72b926d027398ee93c6c2f1ddad549c6a (diff)
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Adjust wide data buffer pointers during fseek and ftell
[BZ #14543] Set the internal buffer state correctly whenever the external buffer state is modified by fseek by either computing the current _IO_read_ptr/end for the internal buffer based on the new _IO_read_ptr in the external buffer or converting the content read into the external buffer, up to the extent of the requested fseek offset.
Diffstat (limited to 'libio/wfileops.c')
-rw-r--r--libio/wfileops.c59
1 files changed, 59 insertions, 0 deletions
diff --git a/libio/wfileops.c b/libio/wfileops.c
index b790029ffc..d3f46b2ed1 100644
--- a/libio/wfileops.c
+++ b/libio/wfileops.c
@@ -545,6 +545,57 @@ _IO_wfile_sync (fp)
}
libc_hidden_def (_IO_wfile_sync)
+/* Adjust the internal buffer pointers to reflect the state in the external
+ buffer. The content between fp->_IO_read_base and fp->_IO_read_ptr is
+ assumed to be converted and available in the range
+ fp->_wide_data->_IO_read_base and fp->_wide_data->_IO_read_end.
+
+ Returns 0 on success and -1 on error with the _IO_ERR_SEEN flag set. */
+static inline int
+adjust_wide_data (_IO_FILE *fp, bool do_convert)
+{
+ struct _IO_codecvt *cv = fp->_codecvt;
+
+ int clen = (*cv->__codecvt_do_encoding) (cv);
+
+ /* Take the easy way out for constant length encodings if we don't need to
+ convert. */
+ if (!do_convert && clen > 0)
+ {
+ fp->_wide_data->_IO_read_end += ((fp->_IO_read_ptr - fp->_IO_read_base)
+ / clen);
+ goto done;
+ }
+
+ enum __codecvt_result status;
+ const char *read_stop = (const char *) fp->_IO_read_base;
+ do
+ {
+
+ fp->_wide_data->_IO_last_state = fp->_wide_data->_IO_state;
+ status = (*cv->__codecvt_do_in) (cv, &fp->_wide_data->_IO_state,
+ fp->_IO_read_base, fp->_IO_read_ptr,
+ &read_stop,
+ fp->_wide_data->_IO_read_base,
+ fp->_wide_data->_IO_buf_end,
+ &fp->_wide_data->_IO_read_end);
+
+ /* Should we return EILSEQ? */
+ if (__builtin_expect (status == __codecvt_error, 0))
+ {
+ fp->_flags |= _IO_ERR_SEEN;
+ return -1;
+ }
+ }
+ while (__builtin_expect (status == __codecvt_partial, 0));
+
+done:
+ /* Now seek to _IO_read_end to behave as if we have read it all in. */
+ fp->_wide_data->_IO_read_ptr = fp->_wide_data->_IO_read_end;
+
+ return 0;
+}
+
_IO_off64_t
_IO_wfile_seekoff (fp, offset, dir, mode)
_IO_FILE *fp;
@@ -693,6 +744,10 @@ _IO_wfile_seekoff (fp, offset, dir, mode)
fp->_wide_data->_IO_buf_base);
_IO_wsetp (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base);
+
+ if (adjust_wide_data (fp, false))
+ goto dumb;
+
_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
goto resync;
}
@@ -733,6 +788,10 @@ _IO_wfile_seekoff (fp, offset, dir, mode)
_IO_wsetg (fp, fp->_wide_data->_IO_buf_base,
fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base);
_IO_wsetp (fp, fp->_wide_data->_IO_buf_base, fp->_wide_data->_IO_buf_base);
+
+ if (adjust_wide_data (fp, true))
+ goto dumb;
+
fp->_offset = result + count;
_IO_mask_flags (fp, 0, _IO_EOF_SEEN);
return offset;