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- Changed how errors are detected, as returned by Write(), Read() and

Browse Source 
Seek(). Seek() is particularly challenging because the value it
  returns might be a valid file position and not an error.

- Replaced numeric function return codes of 0 and -1 with macros OK,
  SEEK_ERROR/ERROR to clarify the respective purposes.

- Changed how ftell() and fseek() are used, double-checking the return
  value and the errno code.


git-svn-id: file:///Users/olsen/Code/migration-svn-zu-git/logical-line-staging/clib2/trunk@14923 87f5fb63-7c3d-0410-a384-fd976d0f7a62
This commit is contained in:
Olaf Barthel
2005-04-24 09:53:12 +00:00
parent 1d611fefbe
commit 0c553faff1
12 changed files with 135 additions and 57 deletions
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36
library/unistd_ftruncate.c
View File

@@ -1,5 +1,5 @@
/*
* $Id: unistd_ftruncate.c,v 1.11 2005-04-24 08:46:37 obarthel Exp $
* $Id: unistd_ftruncate.c,v 1.12 2005-04-24 09:53:12 obarthel Exp $
*
* :ts=4
*
@@ -47,9 +47,9 @@ ftruncate(int file_descriptor, off_t length)
D_S(struct FileInfoBlock,fib);
int result = ERROR;
struct fd * fd = NULL;
BOOL restore_initial_position = FALSE;
off_t current_file_size;
off_t initial_position = -1;
LONG initial_position = 0;
BOOL initial_position_valid = FALSE;
ENTER();
@@ -113,21 +113,23 @@ ftruncate(int file_descriptor, off_t length)
goto out;
}
current_file_size = fib->fib_Size;
current_file_size = (off_t)fib->fib_Size;
/* Is the file to be made shorter than it is right now? */
if(length < current_file_size)
{
/* Remember where we started. */
if(initial_position < 0)
if(NOT initial_position_valid)
{
initial_position = Seek(fd->fd_DefaultFile,0,OFFSET_CURRENT);
if(initial_position == SEEK_ERROR)
if(initial_position == SEEK_ERROR && IoErr() != OK)
goto out;
initial_position_valid = TRUE;
}
/* Careful: seek to a position where the file can be safely truncated. */
if(Seek(fd->fd_DefaultFile,length,OFFSET_BEGINNING) == SEEK_ERROR)
if(Seek(fd->fd_DefaultFile,length,OFFSET_BEGINNING) == SEEK_ERROR && IoErr() != OK)
{
D(("could not move to file offset %ld",length));
@@ -146,29 +148,29 @@ ftruncate(int file_descriptor, off_t length)
/* If the file is now shorter than the file position, which must
not be changed by a call to ftruncate(), extend the file again,
filling the extension with 0 bytes. */
if(initial_position > length)
if((off_t)initial_position > length)
{
current_file_size = length;
length = initial_position;
length = (off_t)initial_position;
}
restore_initial_position = TRUE;
}
/* Is the size of the file to grow? */
if(length > current_file_size)
{
/* Remember where we started. */
if(initial_position < 0)
if(NOT initial_position_valid)
{
initial_position = Seek(fd->fd_DefaultFile,0,OFFSET_CURRENT);
if(initial_position == SEEK_ERROR)
if(initial_position == SEEK_ERROR && IoErr() != OK)
goto out;
initial_position_valid = TRUE;
}
/* Move to what should be the end of the file. */
if(Seek(fd->fd_DefaultFile,current_file_size,OFFSET_BEGINNING) == SEEK_ERROR)
if(Seek(fd->fd_DefaultFile,current_file_size,OFFSET_BEGINNING) == SEEK_ERROR && IoErr() != OK)
{
D(("could not move to file offset %ld",current_file_size));
@@ -185,15 +187,15 @@ ftruncate(int file_descriptor, off_t length)
__set_errno(__translate_io_error_to_errno(IoErr()));
goto out;
}
restore_initial_position = TRUE;
}
result = OK;
out:
if(restore_initial_position)
/* ftruncate() may change the size of the file, but it may
not change the current file position. */
if(initial_position_valid)
Seek(fd->fd_DefaultFile,initial_position,OFFSET_CURRENT);
__fd_unlock(fd);