diff options
Diffstat (limited to 'private/crt32/stdio/ftell.c')
| -rw-r--r-- | private/crt32/stdio/ftell.c | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/private/crt32/stdio/ftell.c b/private/crt32/stdio/ftell.c new file mode 100644 index 000000000..8f59e648a --- /dev/null +++ b/private/crt32/stdio/ftell.c @@ -0,0 +1,257 @@ +/*** +*ftell.c - get current file position +* +* Copyright (c) 1985-1992, Microsoft Corporation. All rights reserved. +* +*Purpose: +* defines ftell() - find current current position of file pointer +* +*Revision History: +* 09-02-83 RN initial version +* ??-??-?? TC added code to allow variable buffer sizes +* 05-22-86 TC added code to seek to send if last operation was a +* write and append mode specified +* 11-20-86 SKS do not seek to end of file in append mode +* 12-01-86 SKS fix off-by-1 problem in text mode when last byte in +* buffer was a '\r', and it was followed by a '\n'. Since +* the \n was pushed back and the \r was discarded, we +* must adjust the computed position for the \r. +* 02-09-87 JCR Added errno set code (if flag (_IORW not set) +* 09-09-87 JCR Optimized to eliminate two lseek() calls in binary mode. +* 09-28-87 JCR Corrected _iob2 indexing (now uses _iob_index() macro). +* 11-04-87 JCR Multi-thread version +* 12-11-87 JCR Added "_LOAD_DS" to declaration +* 01-13-88 JCR Removed unnecessary calls to mthread fileno/feof/ferror +* 05-27-88 PHG Merged DLL and normal versions +* 06-06-88 JCR Use _iob2_ macro instead of _iob_index +* 06-15-88 JCR Near reference to _iob[] entries; improve REG variables +* 07-27-88 JCR Changed some variables from int to unsigned (bug fix) +* 08-25-88 GJF Don't use FP_OFF() macro for the 386 +* 12-05-88 JCR Added _IOCTRLZ support (fixes bug pertaining to ^Z at +* eof) +* 08-17-89 GJF Cleanup, now specific to OS/2 2.0 (i.e., 386 flat +* model), also fixed copyright +* 02-15-90 GJF _iob[], _iob2[] merge. Also, fixed copyright and +* indents. +* 03-19-90 GJF Made calling type _CALLTYPE1, added #include +* <cruntime.h> and removed #include <register.h>. +* 07-23-90 SBM Replaced <assertm.h> by <assert.h> +* 10-02-90 GJF New-style function declarators. +* 01-21-91 GJF ANSI naming. +* 03-27-92 DJM POSIX support. +* 08-26-92 GJF Include unistd.h for POSIX build. +* 09-01-92 GJF Fixed POSIX support (was returning -1 for all except +* read-write streams). +* +*******************************************************************************/ + +#include <cruntime.h> +#include <stdio.h> +#include <file2.h> +#include <assert.h> +#include <errno.h> +#ifdef _POSIX_ +#include <unistd.h> +#else +#include <msdos.h> +#endif +#include <stddef.h> +#include <io.h> +#include <internal.h> +#ifndef _POSIX_ +#include <os2dll.h> +#endif + +/*** +*long ftell(stream) - query stream file pointer +* +*Purpose: +* Find out what stream's position is. coordinate with buffering; adjust +* backward for read-ahead and forward for write-behind. This is NOT +* equivalent to fseek(stream,0L,1), because fseek will remove an ungetc, +* may flush buffers, etc. +* +*Entry: +* FILE *stream - stream to query for position +* +*Exit: +* return present file position if succeeds +* returns -1L and sets errno if fails +* +*Exceptions: +* +*******************************************************************************/ + +#ifdef MTHREAD /* multi-thread; define both ftell() and _lk_ftell() */ + +long _CALLTYPE1 ftell ( + FILE *stream + ) +{ + long retval; +#ifdef MTHREAD + int index; +#endif + + assert(stream != NULL); + +#ifdef MTHREAD + index = _iob_index(stream); +#endif + + _lock_str(index); + + retval = _ftell_lk (stream); + + _unlock_str(index); + + return(retval); +} + + +/*** +*_ftell_lk() - Ftell() core routine (assumes stream is locked). +* +*Purpose: +* Core ftell() routine; assumes caller has aquired stream lock). +* +* [See ftell() above for more info.] +* +*Entry: [See ftell()] +* +*Exit: [See ftell()] +* +*Exceptions: +* +*******************************************************************************/ + +long _CALLTYPE1 _ftell_lk ( + +#else /* non multi-thread; define only ftell() */ + +long _CALLTYPE1 ftell ( + +#endif /* rejoin common code */ + + FILE *str + ) +{ + REG1 FILE *stream; + unsigned int offset; + long filepos; +#ifndef _POSIX_ + REG2 char *p; + char *max; +#endif + int fd; + unsigned int rdcnt; + + assert(str != NULL); + + /* Init stream pointer and file descriptor */ + stream = str; +#ifdef _POSIX_ + fd = fileno(stream); +#else + fd = _fileno(stream); +#endif + + if (stream->_cnt < 0) + stream->_cnt = 0; + +#ifdef _POSIX_ + if ((filepos = lseek(fd, 0L, SEEK_CUR)) < 0L) +#else + if ((filepos = _lseek(fd, 0L, SEEK_CUR)) < 0L) +#endif + return(-1L); + + if (!bigbuf(stream)) /* _IONBF or no buffering designated */ + return(filepos - stream->_cnt); + + offset = stream->_ptr - stream->_base; + +#ifndef _POSIX_ + if (stream->_flag & (_IOWRT|_IOREAD)) { + if (_osfile[fd] & FTEXT) + for (p = stream->_base; p < stream->_ptr; p++) + if (*p == '\n') /* adjust for '\r' */ + offset++; + } + else if (!(stream->_flag & _IORW)) { + errno=EINVAL; + return(-1L); + } +#endif + + if (filepos == 0L) + return((long)offset); + + if (stream->_flag & _IOREAD) /* go to preceding sector */ + + if (stream->_cnt == 0) /* filepos holds correct location */ + offset = 0; + + else { + + /* Subtract out the number of unread bytes left in the + buffer. [We can't simply use _iob[]._bufsiz because + the last read may have hit EOF and, thus, the buffer + was not completely filled.] */ + + rdcnt = stream->_cnt + (stream->_ptr - stream->_base); + +#ifndef _POSIX_ + /* If text mode, adjust for the cr/lf substitution. If + binary mode, we're outta here. */ + if (_osfile[fd] & FTEXT) { + /* (1) If we're not at eof, simply copy _bufsiz + onto rdcnt to get the # of untranslated + chars read. (2) If we're at eof, we must + look through the buffer expanding the '\n' + chars one at a time. */ + + /* [NOTE: Performance issue -- it is faster to + do the two _lseek() calls than to blindly go + through and expand the '\n' chars regardless + of whether we're at eof or not.] */ + + if (_lseek(fd, 0L, 2) == filepos) { + + max = stream->_base + rdcnt; + for (p = stream->_base; p < max; p++) + if (*p == '\n') + /* adjust for '\r' */ + rdcnt++; + + /* If last byte was ^Z, the lowio read + didn't tell us about it. Check flag + and bump count, if necessary. */ + + if (stream->_flag & _IOCTRLZ) + ++rdcnt; + } + + else { + + _lseek(fd, filepos, 0); + rdcnt = stream->_bufsiz; + + /* If first byte in untranslated buffer + was a '\n', assume it was preceeded + by a '\r' which was discarded by the + previous read operation and count + the '\n'. */ + if (_osfile[fd] & FCRLF) + ++rdcnt; + } + + } /* end if FTEXT */ +#endif /* !_POSIX_ */ + + filepos -= (long)rdcnt; + + } /* end else stream->_cnt != 0 */ + + return(filepos + (long)offset); +} |