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Diffstat (limited to 'newlib/libc/stdio64/ftello64.c')
-rw-r--r-- | newlib/libc/stdio64/ftello64.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/newlib/libc/stdio64/ftello64.c b/newlib/libc/stdio64/ftello64.c new file mode 100644 index 000000000..c6b888cf4 --- /dev/null +++ b/newlib/libc/stdio64/ftello64.c @@ -0,0 +1,138 @@ +#ifdef __LARGE64_FILES + +/* + * Copyright (c) 1990 The Regents of the University of California. + * All rights reserved. + * + * Redistribution and use in source and binary forms are permitted + * provided that the above copyright notice and this paragraph are + * duplicated in all such forms and that any documentation, + * advertising materials, and other materials related to such + * distribution and use acknowledge that the software was developed + * by the University of California, Berkeley. The name of the + * University may not be used to endorse or promote products derived + * from this software without specific prior written permission. + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. + */ + +/* +FUNCTION +<<ftello64>>---return position in a stream or file + +INDEX + ftello64 + +ANSI_SYNOPSIS + #include <stdio.h> + _off64_t ftello64(FILE *<[fp]>); + +TRAD_SYNOPSIS + #include <stdio.h> + _off64_t ftello64(<[fp]>) + FILE *<[fp]>; + +DESCRIPTION +Objects of type <<FILE>> can have a ``position'' that records how much +of the file your program has already read. Many of the <<stdio>> functions +depend on this position, and many change it as a side effect. + +The result of <<ftello64>> is the current position for a large file +identified by <[fp]>. If you record this result, you can later +use it with <<fseeko64>> to return the file to this +position. The difference between <<ftello>> and <<ftello64>> is that +<<ftello>> returns <<off_t>> and <<ftello64>> is designed to work +for large files (>2GB) and returns <<_off64_t>>. + +In the current implementation, <<ftello64>> simply uses a character +count to represent the file position; this is the same number that +would be recorded by <<fgetpos64>>. + +The function exists only if the __LARGE64_FILES flag is defined. +An error occurs if the <[fp]> was not opened via <<fopen64>>. + +RETURNS +<<ftello64>> returns the file position, if possible. If it cannot do +this, it returns <<-1>>. Failure occurs on streams that do not support +positioning or not opened via <<fopen64>>; the global <<errno>> indicates +this condition with the value <<ESPIPE>>. + +PORTABILITY +<<ftello64>> is a glibc extension. + +No supporting OS subroutines are required. +*/ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "%W% (Berkeley) %G%"; +#endif /* LIBC_SCCS and not lint */ + +/* + * ftello64: return current offset. + */ + +#include <stdio.h> +#include <errno.h> + +#include "local64.h" + +_off64_t +_DEFUN (ftello64, (fp), + register FILE * fp) +{ + _fpos64_t pos; + + _flockfile(fp); + + /* Ensure stdio is set up. */ + + CHECK_INIT (fp); + + if (fp->_seek64 == NULL) + { + fp->_data->_errno = ESPIPE; + _funlockfile(fp); + return -1L; + } + + /* Find offset of underlying I/O object, then + adjust for buffered bytes. */ + fflush(fp); /* may adjust seek offset on append stream */ + if (fp->_flags & __SOFF) + pos = fp->_offset; + else + { + pos = (*fp->_seek64) (fp->_cookie, (_fpos64_t) 0, SEEK_CUR); + if (pos == -1L) + { + _funlockfile(fp); + return pos; + } + } + if (fp->_flags & __SRD) + { + /* + * Reading. Any unread characters (including + * those from ungetc) cause the position to be + * smaller than that in the underlying object. + */ + pos -= fp->_r; + if (HASUB (fp)) + pos -= fp->_ur; + } + else if (fp->_flags & __SWR && fp->_p != NULL) + { + /* + * Writing. Any buffered characters cause the + * position to be greater than that in the + * underlying object. + */ + pos += fp->_p - fp->_bf._base; + } + + _funlockfile(fp); + return pos; +} + +#endif /* __LARGE64_FILES */ |