Standard Libraries for EDK II.

[mirror_edk2.git] / StdLib / LibC / Stdio / fseeko.c

/*  $NetBSD: fseeko.c,v 1.5 2005/03/04 16:04:58 dsl Exp $ */\r
\r
/*-\r
 * Copyright (c) 1990, 1993\r
 *  The Regents of the University of California.  All rights reserved.\r
 *\r
 * This code is derived from software contributed to Berkeley by\r
 * Chris Torek.\r
 *\r
 * Redistribution and use in source and binary forms, with or without\r
 * modification, are permitted provided that the following conditions\r
 * are met:\r
 * 1. Redistributions of source code must retain the above copyright\r
 *    notice, this list of conditions and the following disclaimer.\r
 * 2. Redistributions in binary form must reproduce the above copyright\r
 *    notice, this list of conditions and the following disclaimer in the\r
 *    documentation and/or other materials provided with the distribution.\r
 * 3. Neither the name of the University nor the names of its contributors\r
 *    may be used to endorse or promote products derived from this software\r
 *    without specific prior written permission.\r
 *\r
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND\r
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE\r
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE\r
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE\r
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL\r
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS\r
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)\r
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT\r
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY\r
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF\r
 * SUCH DAMAGE.\r
 */\r
//#include <Uefi.h>               // REMOVE, For DEBUG only\r
//#include <Library/UefiLib.h>    // REMOVE, For DEBUG only\r
\r
#include  <LibConfig.h>\r
#include <sys/EfiCdefs.h>\r
#if defined(LIBC_SCCS) && !defined(lint)\r
__RCSID("$NetBSD: fseeko.c,v 1.5 2005/03/04 16:04:58 dsl Exp $");\r
#endif /* LIBC_SCCS and not lint */\r
\r
#include "namespace.h"\r
#include <sys/types.h>\r
#include <sys/stat.h>\r
\r
#include <assert.h>\r
#include <errno.h>\r
#include <fcntl.h>\r
#include <stdio.h>\r
#include <stdlib.h>\r
#include "reentrant.h"\r
#include "local.h"\r
\r
#ifdef __weak_alias\r
__weak_alias(fseeko, _fseeko)\r
#endif\r
\r
#define POS_ERR (-(fpos_t)1)\r
\r
/*\r
 * Seek the given file to the given offset.\r
 * `Whence' must be one of the three SEEK_* macros.\r
 */\r
int\r
fseeko(FILE *fp, off_t offset, int whence)\r
{\r
  fpos_t (*seekfn)(void *, fpos_t, int);\r
  fpos_t target, curoff;\r
  size_t n;\r
  struct stat st;\r
  int havepos;\r
\r
  _DIAGASSERT(fp != NULL);\r
\r
#ifdef __GNUC__\r
  /* This outrageous construct just to shut up a GCC warning. */\r
  (void) &curoff;\r
#endif\r
\r
  /* make sure stdio is set up */\r
  if (!__sdidinit)\r
    __sinit();\r
\r
//Print(L"%a( %d, %Ld, %d)\n", __func__, fp->_file, offset, whence);\r
  FLOCKFILE(fp);\r
\r
  /*\r
   * Have to be able to seek.\r
   */\r
  if ((seekfn = fp->_seek) == NULL) {\r
    errno = ESPIPE;     /* historic practice */\r
    FUNLOCKFILE(fp);\r
//Print(L"%a: %d\n", __func__, __LINE__);\r
    return (-1);\r
  }\r
\r
  /*\r
   * Change any SEEK_CUR to SEEK_SET, and check `whence' argument.\r
   * After this, whence is either SEEK_SET or SEEK_END.\r
   */\r
  switch (whence) {\r
\r
  case SEEK_CUR:\r
    /*\r
     * In order to seek relative to the current stream offset,\r
     * we have to first find the current stream offset a la\r
     * ftell (see ftell for details).\r
     */\r
    __sflush(fp); /* may adjust seek offset on append stream */\r
    if (fp->_flags & __SOFF)\r
      curoff = fp->_offset;\r
    else {\r
      curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);\r
      if (curoff == POS_ERR) {\r
        FUNLOCKFILE(fp);\r
//Print(L"%a: %d\n", __func__, __LINE__);\r
        return (-1);\r
      }\r
    }\r
    if (fp->_flags & __SRD) {\r
      curoff -= fp->_r;\r
      if (HASUB(fp))\r
        curoff -= fp->_ur;\r
    } else if (fp->_flags & __SWR && fp->_p != NULL)\r
      curoff += fp->_p - fp->_bf._base;\r
\r
    offset += curoff;\r
    whence = SEEK_SET;\r
    havepos = 1;\r
    break;\r
\r
  case SEEK_SET:\r
  case SEEK_END:\r
    curoff = 0;   /* XXX just to keep gcc quiet */\r
    havepos = 0;\r
    break;\r
\r
  default:\r
    errno = EINVAL;\r
    FUNLOCKFILE(fp);\r
//Print(L"%a: %d\n", __func__, __LINE__);\r
    return (-1);\r
  }\r
\r
  /*\r
   * Can only optimise if:\r
   *  reading (and not reading-and-writing);\r
   *  not unbuffered; and\r
   *  this is a `regular' Unix file (and hence seekfn==__sseek).\r
   * We must check __NBF first, because it is possible to have __NBF\r
   * and __SOPT both set.\r
   */\r
  if (fp->_bf._base == NULL)\r
    __smakebuf(fp);\r
  if (fp->_flags & (__SWR | __SRW | __SNBF | __SNPT))\r
    goto dumb;\r
  if ((fp->_flags & __SOPT) == 0) {\r
    if (seekfn != __sseek ||\r
        fp->_file < 0 || fstat(fp->_file, &st) ||\r
        !S_ISREG(st.st_mode)) {\r
      fp->_flags |= __SNPT;\r
      goto dumb;\r
    }\r
    fp->_blksize = st.st_blksize;\r
    fp->_flags |= __SOPT;\r
  }\r
\r
  /*\r
   * We are reading; we can try to optimise.\r
   * Figure out where we are going and where we are now.\r
   */\r
  if (whence == SEEK_SET)\r
    target = offset;\r
  else {\r
    if (fstat(fp->_file, &st))\r
    {\r
//Print(L"%a: %d\n", __func__, __LINE__);\r
      goto dumb;\r
    }\r
    target = st.st_size + offset;\r
  }\r
\r
  if (!havepos) {\r
    if (fp->_flags & __SOFF)\r
      curoff = fp->_offset;\r
    else {\r
      curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);\r
      if (curoff == POS_ERR)\r
      {\r
//Print(L"%a: %d\n", __func__, __LINE__);\r
        goto dumb;\r
      }\r
    }\r
    curoff -= fp->_r;\r
    if (HASUB(fp))\r
      curoff -= fp->_ur;\r
  }\r
\r
  /*\r
   * Compute the number of bytes in the input buffer (pretending\r
   * that any ungetc() input has been discarded).  Adjust current\r
   * offset backwards by this count so that it represents the\r
   * file offset for the first byte in the current input buffer.\r
   */\r
  if (HASUB(fp)) {\r
    curoff += fp->_r; /* kill off ungetc */\r
    n = fp->_up - fp->_bf._base;\r
    curoff -= n;\r
    n += fp->_ur;\r
  } else {\r
    n = fp->_p - fp->_bf._base;\r
    curoff -= n;\r
    n += fp->_r;\r
  }\r
\r
  /*\r
   * If the target offset is within the current buffer,\r
   * simply adjust the pointers, clear EOF, undo ungetc(),\r
   * and return.  (If the buffer was modified, we have to\r
   * skip this; see fgetln.c.)\r
   */\r
  if ((fp->_flags & __SMOD) == 0 &&\r
      target >= curoff && target < (fpos_t)(curoff + n)) {\r
    int o = (int)(target - curoff);\r
\r
    fp->_p = fp->_bf._base + o;\r
    fp->_r = (int)(n - o);\r
    if (HASUB(fp))\r
      FREEUB(fp);\r
    fp->_flags &= ~__SEOF;\r
    FUNLOCKFILE(fp);\r
    return (0);\r
  }\r
\r
  /*\r
   * The place we want to get to is not within the current buffer,\r
   * but we can still be kind to the kernel copyout mechanism.\r
   * By aligning the file offset to a block boundary, we can let\r
   * the kernel use the VM hardware to map pages instead of\r
   * copying bytes laboriously.  Using a block boundary also\r
   * ensures that we only read one block, rather than two.\r
   */\r
  curoff = target & ~(fp->_blksize - 1);\r
  if ((*seekfn)(fp->_cookie, curoff, SEEK_SET) == POS_ERR)\r
  {\r
//Print(L"%a: %d\n", __func__, __LINE__);\r
    goto dumb;\r
  }\r
  fp->_r = 0;\r
  fp->_p = fp->_bf._base;\r
  if (HASUB(fp))\r
    FREEUB(fp);\r
  fp->_flags &= ~__SEOF;\r
  n = (int)(target - curoff);\r
  if (n) {\r
    if (__srefill(fp) || fp->_r < (int)n)\r
    {\r
//Print(L"%a: %d\n", __func__, __LINE__);\r
      goto dumb;\r
    }\r
    fp->_p += n;\r
    fp->_r -= (int)n;\r
  }\r
  FUNLOCKFILE(fp);\r
  return (0);\r
\r
  /*\r
   * We get here if we cannot optimise the seek ... just\r
   * do it.  Allow the seek function to change fp->_bf._base.\r
   */\r
dumb:\r
//Print(L"%a: %d\n", __func__, __LINE__);\r
  if (__sflush(fp) ||\r
      (*seekfn)(fp->_cookie, (fpos_t)offset, whence) == POS_ERR) {\r
    FUNLOCKFILE(fp);\r
//Print(L"%a: %d\n", __func__, __LINE__);\r
    return (-1);\r
  }\r
  /* success: clear EOF indicator and discard ungetc() data */\r
  if (HASUB(fp))\r
    FREEUB(fp);\r
  fp->_p = fp->_bf._base;\r
  fp->_r = 0;\r
  /* fp->_w = 0; */ /* unnecessary (I think...) */\r
  fp->_flags &= ~__SEOF;\r
  FUNLOCKFILE(fp);\r
//Print(L"%a: %d\n", __func__, __LINE__);\r
  return (0);\r
}\r