diff options
Diffstat (limited to 'libio/fileops.c')
| -rw-r--r-- | libio/fileops.c | 738 |
1 files changed, 738 insertions, 0 deletions
diff --git a/libio/fileops.c b/libio/fileops.c new file mode 100644 index 0000000..89381ec --- /dev/null +++ b/libio/fileops.c @@ -0,0 +1,738 @@ +/* +Copyright (C) 1993, 1995 Free Software Foundation + +This file is part of the GNU IO Library. This library is free +software; you can redistribute it and/or modify it under the +terms of the GNU General Public License as published by the +Free Software Foundation; either version 2, or (at your option) +any later version. + +This library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this library; see the file COPYING. If not, write to the Free +Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + +As a special exception, if you link this library with files +compiled with a GNU compiler to produce an executable, this does not cause +the resulting executable to be covered by the GNU General Public License. +This exception does not however invalidate any other reasons why +the executable file might be covered by the GNU General Public License. */ + +/* written by Per Bothner (bothner@cygnus.com) */ + +#define _POSIX_SOURCE +#include "libioP.h" +#include <fcntl.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <string.h> +#include <errno.h> +#ifndef errno +extern int errno; +#endif + +/* An fstream can be in at most one of put mode, get mode, or putback mode. + Putback mode is a variant of get mode. + + In a filebuf, there is only one current position, instead of two + separate get and put pointers. In get mode, the current posistion + is that of gptr(); in put mode that of pptr(). + + The position in the buffer that corresponds to the position + in external file system is file_ptr(). + This is normally _IO_read_end, except in putback mode, + when it is _IO_save_end. + If the field _fb._offset is >= 0, it gives the offset in + the file as a whole corresponding to eGptr(). (?) + + PUT MODE: + If a filebuf is in put mode, pbase() is non-NULL and equal to base(). + Also, epptr() == ebuf(). + Also, eback() == gptr() && gptr() == egptr(). + The un-flushed character are those between pbase() and pptr(). + GET MODE: + If a filebuf is in get or putback mode, eback() != egptr(). + In get mode, the unread characters are between gptr() and egptr(). + The OS file position corresponds to that of egptr(). + PUTBACK MODE: + Putback mode is used to remember "excess" characters that have + been sputbackc'd in a separate putback buffer. + In putback mode, the get buffer points to the special putback buffer. + The unread characters are the characters between gptr() and egptr() + in the putback buffer, as well as the area between save_gptr() + and save_egptr(), which point into the original reserve buffer. + (The pointers save_gptr() and save_egptr() are the values + of gptr() and egptr() at the time putback mode was entered.) + The OS position corresponds to that of save_egptr(). + + LINE BUFFERED OUTPUT: + During line buffered output, pbase()==base() && epptr()==base(). + However, ptr() may be anywhere between base() and ebuf(). + This forces a call to filebuf::overflow(int C) on every put. + If there is more space in the buffer, and C is not a '\n', + then C is inserted, and pptr() incremented. + + UNBUFFERED STREAMS: + If a filebuf is unbuffered(), the _shortbuf[1] is used as the buffer. +*/ + +#define CLOSED_FILEBUF_FLAGS \ + (_IO_IS_FILEBUF+_IO_NO_READS+_IO_NO_WRITES+_IO_TIED_PUT_GET) + + +void +DEFUN(_IO_file_init, (fp), + register _IO_FILE *fp) +{ + /* POSIX.1 allows another file handle to be used to change the position + of our file descriptor. Hence we actually don't know the actual + position before we do the first fseek (and until a following fflush). */ + fp->_offset = _IO_pos_BAD; + fp->_IO_file_flags |= CLOSED_FILEBUF_FLAGS; + + _IO_link_in(fp); + fp->_fileno = -1; +} + +int +DEFUN(_IO_file_close_it, (fp), + register _IO_FILE* fp) +{ + int sync_status, close_status; + if (!_IO_file_is_open(fp)) + return EOF; + + sync_status = _IO_file_sync (fp); + + _IO_unsave_markers(fp); + + close_status = _IO_SYSCLOSE (fp); + + /* Free buffer. */ + _IO_setb(fp, NULL, NULL, 0); + _IO_setg(fp, NULL, NULL, NULL); + _IO_setp(fp, NULL, NULL); + + _IO_un_link(fp); + fp->_flags = _IO_MAGIC|CLOSED_FILEBUF_FLAGS; + fp->_fileno = EOF; + fp->_offset = _IO_pos_BAD; + + return close_status ? close_status : sync_status; +} + +void +DEFUN(_IO_file_finish, (fp), + register _IO_FILE* fp) +{ + if (_IO_file_is_open(fp)) + { + _IO_do_flush (fp); + if (!(fp->_flags & _IO_DELETE_DONT_CLOSE)) + _IO_SYSCLOSE (fp); + } + _IO_default_finish(fp); +} + +_IO_FILE * +DEFUN(_IO_file_fopen, (fp, filename, mode), + register _IO_FILE *fp AND const char *filename AND const char *mode) +{ + int oflags = 0, omode; + int read_write, fdesc; + int oprot = 0666; + if (_IO_file_is_open (fp)) + return 0; + switch (*mode++) { + case 'r': + omode = O_RDONLY; + read_write = _IO_NO_WRITES; + break; + case 'w': + omode = O_WRONLY; + oflags = O_CREAT|O_TRUNC; + read_write = _IO_NO_READS; + break; + case 'a': + omode = O_WRONLY; + oflags = O_CREAT|O_APPEND; + read_write = _IO_NO_READS|_IO_IS_APPENDING; + break; + default: + errno = EINVAL; + return NULL; + } + if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+')) { + omode = O_RDWR; + read_write &= _IO_IS_APPENDING; + } + fdesc = open(filename, omode|oflags, oprot); + if (fdesc < 0) + return NULL; + fp->_fileno = fdesc; + _IO_mask_flags(fp, read_write,_IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING); + if (read_write & _IO_IS_APPENDING) + if (_IO_SEEKOFF (fp, (_IO_off_t)0, _IO_seek_end, _IOS_INPUT|_IOS_OUTPUT) + == _IO_pos_BAD) + return NULL; + _IO_link_in(fp); + return fp; +} + +_IO_FILE* +DEFUN(_IO_file_attach, (fp, fd), + _IO_FILE *fp AND int fd) +{ + if (_IO_file_is_open(fp)) + return NULL; + fp->_fileno = fd; + fp->_flags &= ~(_IO_NO_READS+_IO_NO_WRITES); + fp->_flags |= _IO_DELETE_DONT_CLOSE; + fp->_offset = _IO_pos_BAD; + return fp; +} + +_IO_FILE* +DEFUN(_IO_file_setbuf, (fp, p, len), + register _IO_FILE *fp AND char* p AND _IO_ssize_t len) +{ + if (_IO_default_setbuf(fp, p, len) == NULL) + return NULL; + + fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_write_end + = fp->_IO_buf_base; + _IO_setg(fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base); + + return fp; +} + +/* Write TO_DO bytes from DATA to FP. + Then mark FP has having empty buffers. */ + +int +DEFUN(_IO_do_write, (fp, data, to_do), + register _IO_FILE *fp AND const char* data AND _IO_size_t to_do) +{ + _IO_size_t count; + if (to_do == 0) + return 0; + if (fp->_flags & _IO_IS_APPENDING) + /* On a system without a proper O_APPEND implementation, + you would need to sys_seek(0, SEEK_END) here, but is + is not needed nor desirable for Unix- or Posix-like systems. + Instead, just indicate that offset (before and after) is + unpredictable. */ + fp->_offset = _IO_pos_BAD; + else if (fp->_IO_read_end != fp->_IO_write_base) + { + _IO_pos_t new_pos + = _IO_SYSSEEK(fp, fp->_IO_write_base - fp->_IO_read_end, 1); + if (new_pos == _IO_pos_BAD) + return EOF; + fp->_offset = new_pos; + } + count = _IO_SYSWRITE (fp, data, to_do); + if (fp->_cur_column) + fp->_cur_column = _IO_adjust_column(fp->_cur_column - 1, data, to_do) + 1; + _IO_setg(fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base); + fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_buf_base; + fp->_IO_write_end = (fp->_flags & (_IO_LINE_BUF+_IO_UNBUFFERED)) ? fp->_IO_buf_base + : fp->_IO_buf_end; + return count != to_do ? EOF : 0; +} + +int +DEFUN(_IO_file_underflow, (fp), + register _IO_FILE *fp) +{ + _IO_ssize_t count; +#if 0 + /* SysV does not make this test; take it out for compatibility */ + if (fp->_flags & _IO_EOF_SEEN) + return (EOF); +#endif + + if (fp->_flags & _IO_NO_READS) + return EOF; + if (fp->_IO_read_ptr < fp->_IO_read_end) + return *(unsigned char*)fp->_IO_read_ptr; + + if (fp->_IO_buf_base == NULL) + _IO_doallocbuf(fp); + + /* Flush all line buffered files before reading. */ + /* FIXME This can/should be moved to genops ?? */ + if (fp->_flags & (_IO_LINE_BUF|_IO_UNBUFFERED)) + _IO_flush_all_linebuffered(); + + _IO_switch_to_get_mode(fp); + + count = _IO_SYSREAD (fp, fp->_IO_buf_base, + fp->_IO_buf_end - fp->_IO_buf_base); + if (count <= 0) + { + if (count == 0) + fp->_flags |= _IO_EOF_SEEN; + else + fp->_flags |= _IO_ERR_SEEN, count = 0; + } + fp->_IO_read_base = fp->_IO_read_ptr = fp->_IO_buf_base; + fp->_IO_read_end = fp->_IO_buf_base + count; + fp->_IO_write_base = fp->_IO_write_ptr = fp->_IO_write_end + = fp->_IO_buf_base; + if (count == 0) + return EOF; + if (fp->_offset != _IO_pos_BAD) + _IO_pos_adjust(fp->_offset, count); + return *(unsigned char*)fp->_IO_read_ptr; +} + +int +DEFUN(_IO_file_overflow, (f, ch), + register _IO_FILE* f AND int ch) +{ + if (f->_flags & _IO_NO_WRITES) /* SET ERROR */ + return EOF; + /* If currently reading or no buffer allocated. */ + if ((f->_flags & _IO_CURRENTLY_PUTTING) == 0) + { + /* Allocate a buffer if needed. */ + if (f->_IO_write_base == 0) + { + _IO_doallocbuf(f); + _IO_setg (f, f->_IO_buf_base, f->_IO_buf_base, f->_IO_buf_base); + } + /* Otherwise must be currently reading. */ + f->_IO_write_ptr = f->_IO_read_ptr; + f->_IO_write_base = f->_IO_write_ptr; + f->_IO_write_end = f->_IO_buf_end; + f->_IO_read_base = f->_IO_read_ptr = f->_IO_read_end; + + if (f->_flags & (_IO_LINE_BUF+_IO_UNBUFFERED)) + f->_IO_write_end = f->_IO_write_ptr; + f->_flags |= _IO_CURRENTLY_PUTTING; + } + if (ch == EOF) + return _IO_do_flush(f); + if (f->_IO_write_ptr == f->_IO_buf_end ) /* Buffer is really full */ + if (_IO_do_flush(f) == EOF) + return EOF; + *f->_IO_write_ptr++ = ch; + if ((f->_flags & _IO_UNBUFFERED) + || ((f->_flags & _IO_LINE_BUF) && ch == '\n')) + if (_IO_do_flush(f) == EOF) + return EOF; + return (unsigned char)ch; +} + +int +DEFUN(_IO_file_sync, (fp), + register _IO_FILE* fp) +{ + _IO_size_t delta; + /* char* ptr = cur_ptr(); */ + if (fp->_IO_write_ptr > fp->_IO_write_base) + if (_IO_do_flush(fp)) return EOF; + delta = fp->_IO_read_ptr - fp->_IO_read_end; + if (delta != 0) + { +#ifdef TODO + if (_IO_in_backup(fp)) + delta -= eGptr() - Gbase(); +#endif + _IO_off_t new_pos = _IO_SYSSEEK (fp, delta, 1); + if (new_pos != (_IO_off_t)EOF) + fp->_IO_read_end = fp->_IO_read_ptr; +#ifdef ESPIPE + else if (errno == ESPIPE) + ; /* Ignore error from unseekable devices. */ +#endif + else + return EOF; + } + fp->_offset = _IO_pos_BAD; + /* FIXME: Cleanup - can this be shared? */ + /* setg(base(), ptr, ptr); */ + return 0; +} + +_IO_pos_t +DEFUN(_IO_file_seekoff, (fp, offset, dir, mode), + register _IO_FILE *fp AND _IO_off_t offset AND int dir AND int mode) +{ + _IO_pos_t result; + _IO_off_t delta, new_offset; + long count; + + if (mode == 0) + dir = _IO_seek_cur, offset = 0; /* Don't move any pointers. */ + + /* Flush unwritten characters. + (This may do an unneeded write if we seek within the buffer. + But to be able to switch to reading, we would need to set + egptr to ptr. That can't be done in the current design, + which assumes file_ptr() is eGptr. Anyway, since we probably + end up flushing when we close(), it doesn't make much difference.) + FIXME: simulate mem-papped files. */ + + if (fp->_IO_write_ptr > fp->_IO_write_base || _IO_in_put_mode(fp)) + if (_IO_switch_to_get_mode(fp)) return EOF; + + if (fp->_IO_buf_base == NULL) + { + _IO_doallocbuf(fp); + _IO_setp(fp, fp->_IO_buf_base, fp->_IO_buf_base); + _IO_setg(fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base); + } + + switch (dir) + { + case _IO_seek_cur: + /* Adjust for read-ahead (bytes is buffer). */ + offset -= fp->_IO_read_end - fp->_IO_read_ptr; + if (fp->_offset == _IO_pos_BAD) + goto dumb; + /* Make offset absolute, assuming current pointer is file_ptr(). */ + offset += _IO_pos_as_off(fp->_offset); + + dir = _IO_seek_set; + break; + case _IO_seek_set: + break; + case _IO_seek_end: + { + struct stat st; + if (_IO_SYSSTAT (fp, &st) == 0 && S_ISREG(st.st_mode)) + { + offset += st.st_size; + dir = _IO_seek_set; + } + else + goto dumb; + } + } + /* At this point, dir==_IO_seek_set. */ + + /* If destination is within current buffer, optimize: */ + if (fp->_offset != _IO_pos_BAD && fp->_IO_read_base != NULL + && !_IO_in_backup (fp)) + { + /* Offset relative to start of main get area. */ + _IO_pos_t rel_offset = offset - fp->_offset + + (fp->_IO_read_end - fp->_IO_read_base); + if (rel_offset >= 0) + { +#if 0 + if (_IO_in_backup(fp)) + _IO_switch_to_main_get_area(fp); +#endif + if (rel_offset <= fp->_IO_read_end - fp->_IO_read_base) + { + _IO_setg(fp, fp->_IO_buf_base, fp->_IO_buf_base + rel_offset, + fp->_IO_read_end); + _IO_setp(fp, fp->_IO_buf_base, fp->_IO_buf_base); + return offset; + } +#ifdef TODO + /* If we have streammarkers, seek forward by reading ahead. */ + if (_IO_have_markers(fp)) + { + int to_skip = rel_offset + - (fp->_IO_read_ptr - fp->_IO_read_base); + if (ignore(to_skip) != to_skip) + goto dumb; + return offset; + } +#endif + } +#ifdef TODO + if (rel_offset < 0 && rel_offset >= Bbase() - Bptr()) + { + if (!_IO_in_backup(fp)) + _IO_switch_to_backup_area(fp); + gbump(fp->_IO_read_end + rel_offset - fp->_IO_read_ptr); + return offset; + } +#endif + } + +#ifdef TODO + _IO_unsave_markers(fp); +#endif + + if (fp->_flags & _IO_NO_READS) + goto dumb; + + /* Try to seek to a block boundary, to improve kernel page management. */ + new_offset = offset & ~(fp->_IO_buf_end - fp->_IO_buf_base - 1); + delta = offset - new_offset; + if (delta > fp->_IO_buf_end - fp->_IO_buf_base) + { + new_offset = offset; + delta = 0; + } + result = _IO_SYSSEEK (fp, new_offset, 0); + if (result < 0) + return EOF; + if (delta == 0) + count = 0; + else + { + count = _IO_SYSREAD (fp, fp->_IO_buf_base, + fp->_IO_buf_end - fp->_IO_buf_base); + if (count < delta) + { + /* We weren't allowed to read, but try to seek the remainder. */ + offset = count == EOF ? delta : delta-count; + dir = _IO_seek_cur; + goto dumb; + } + } + _IO_setg(fp, fp->_IO_buf_base, fp->_IO_buf_base+delta, fp->_IO_buf_base+count); + _IO_setp(fp, fp->_IO_buf_base, fp->_IO_buf_base); + fp->_offset = result + count; + _IO_mask_flags(fp, 0, _IO_EOF_SEEN); + return offset; + dumb: + + _IO_unsave_markers(fp); + result = _IO_SYSSEEK (fp, offset, dir); + if (result != EOF) + _IO_mask_flags(fp, 0, _IO_EOF_SEEN); + fp->_offset = result; + _IO_setg(fp, fp->_IO_buf_base, fp->_IO_buf_base, fp->_IO_buf_base); + _IO_setp(fp, fp->_IO_buf_base, fp->_IO_buf_base); + return result; +} + +_IO_ssize_t +DEFUN(_IO_file_read, (fp, buf, size), + register _IO_FILE* fp AND void* buf AND _IO_ssize_t size) +{ + for (;;) + { + _IO_ssize_t count = _IO_read(fp->_fileno, buf, size); +#ifdef EINTR + if (count == -1 && errno == EINTR) + continue; +#endif + return count; + } +} + +_IO_pos_t +DEFUN(_IO_file_seek, (fp, offset, dir), + _IO_FILE *fp AND _IO_off_t offset AND int dir) +{ + return _IO_lseek(fp->_fileno, offset, dir); +} + +int +DEFUN(_IO_file_stat, (fp, st), + _IO_FILE *fp AND void* st) +{ + return _IO_fstat(fp->_fileno, (struct stat*)st); +} + +int +DEFUN(_IO_file_close, (fp), + _IO_FILE* fp) +{ + return _IO_close(fp->_fileno); +} + +_IO_ssize_t +DEFUN(_IO_file_write, (f, data, n), + register _IO_FILE* f AND const void* data AND _IO_ssize_t n) +{ + _IO_ssize_t to_do = n; + while (to_do > 0) + { + _IO_ssize_t count = _IO_write(f->_fileno, data, to_do); + if (count == EOF) + { +#ifdef EINTR + if (errno == EINTR) + continue; + else +#endif + { + f->_flags |= _IO_ERR_SEEN; + break; + } + } + to_do -= count; + data = (void*)((char*)data + count); + } + n -= to_do; + if (f->_offset >= 0) + f->_offset += n; + return n; +} + +_IO_size_t +DEFUN(_IO_file_xsputn, (f, data, n), + _IO_FILE *f AND const void *data AND _IO_size_t n) +{ + register const char *s = (char*) data; + _IO_size_t to_do = n; + int must_flush = 0; + _IO_size_t count; + + if (n <= 0) + return 0; + /* This is an optimized implementation. + If the amount to be written straddles a block boundary + (or the filebuf is unbuffered), use sys_write directly. */ + + /* First figure out how much space is available in the buffer. */ + count = f->_IO_write_end - f->_IO_write_ptr; /* Space available. */ + if ((f->_flags & _IO_LINE_BUF) && (f->_flags & _IO_CURRENTLY_PUTTING)) + { + count = f->_IO_buf_end - f->_IO_write_ptr; + if (count >= n) + { register const char *p; + for (p = s + n; p > s; ) + { + if (*--p == '\n') { + count = p - s + 1; + must_flush = 1; + break; + } + } + } + } + /* Then fill the buffer. */ + if (count > 0) + { + if (count > to_do) + count = to_do; + if (count > 20) { + memcpy(f->_IO_write_ptr, s, count); + s += count; + } + else + { + register char *p = f->_IO_write_ptr; + register int i = (int)count; + while (--i >= 0) *p++ = *s++; + } + f->_IO_write_ptr += count; + to_do -= count; + } + if (to_do + must_flush > 0) + { _IO_size_t block_size, dont_write; + /* Next flush the (full) buffer. */ + if (__overflow(f, EOF) == EOF) + return n - to_do; + + /* Try to maintain alignment: write a whole number of blocks. + dont_write is what gets left over. */ + block_size = f->_IO_buf_end - f->_IO_buf_base; + dont_write = block_size >= 128 ? to_do % block_size : 0; + + count = to_do - dont_write; + if (_IO_do_write(f, s, count) == EOF) + return n - to_do; + to_do = dont_write; + + /* Now write out the remainder. Normally, this will fit in the + buffer, but it's somewhat messier for line-buffered files, + so we let _IO_default_xsputn handle the general case. */ + if (dont_write) + to_do -= _IO_default_xsputn(f, s+count, dont_write); + } + return n - to_do; +} + +#if 0 +/* Work in progress */ +_IO_size_t +DEFUN(_IO_file_xsgetn, (fp, data, n), + _IO_FILE *fp AND void *data AND _IO_size_t n) +{ + register _IO_size_t more = n; + register char *s = data; + for (;;) + { + _IO_ssize_t count = fp->_IO_read_end - fp->_IO_read_ptr; /* Data available. */ + if (count > 0) + { + if (count > more) + count = more; + if (count > 20) + { + memcpy(s, fp->_IO_read_ptr, count); + s += count; + fp->_IO_read_ptr += count; + } + else if (count <= 0) + count = 0; + else + { + register char *p = fp->_IO_read_ptr; + register int i = (int)count; + while (--i >= 0) *s++ = *p++; + fp->_IO_read_ptr = p; + } + more -= count; + } +#if 0 + if (! _IO_in put_mode (fp) + && ! _IO_have_markers (fp) && ! IO_have_backup (fp)) + { + /* This is an optimization of _IO_file_underflow */ + if (fp->_flags & _IO_NO_READS) + break; + /* If we're reading a lot of data, don't bother allocating + a buffer. But if we're only reading a bit, perhaps we should ??*/ + if (count <= 512 && fp->_IO_buf_base == NULL) + _IO_doallocbuf(fp); + if (fp->_flags & (_IO_LINE_BUF|_IO_UNBUFFERED)) + _IO_flush_all_linebuffered(); + + _IO_switch_to_get_mode(fp); ???; + count = _IO_SYSREAD (fp, s, more); + if (count <= 0) + { + if (count == 0) + fp->_flags |= _IO_EOF_SEEN; + else + fp->_flags |= _IO_ERR_SEEN, count = 0; + } + + s += count; + more -= count; + } +#endif + if (more == 0 || __underflow(fp) == EOF) + break; + } + return n - more; +} +#endif + +struct _IO_jump_t _IO_file_jumps = { + JUMP_INIT_DUMMY, + JUMP_INIT(finish, _IO_file_finish), + JUMP_INIT(overflow, _IO_file_overflow), + JUMP_INIT(underflow, _IO_file_underflow), + JUMP_INIT(uflow, _IO_default_uflow), + JUMP_INIT(pbackfail, _IO_default_pbackfail), + JUMP_INIT(xsputn, _IO_file_xsputn), + JUMP_INIT(xsgetn, _IO_default_xsgetn), + JUMP_INIT(seekoff, _IO_file_seekoff), + JUMP_INIT(seekpos, _IO_default_seekpos), + JUMP_INIT(setbuf, _IO_file_setbuf), + JUMP_INIT(sync, _IO_file_sync), + JUMP_INIT(doallocate, _IO_file_doallocate), + JUMP_INIT(read, _IO_file_read), + JUMP_INIT(write, _IO_file_write), + JUMP_INIT(seek, _IO_file_seek), + JUMP_INIT(close, _IO_file_close), + JUMP_INIT(stat, _IO_file_stat) +}; |