mirror of https://github.com/cc65/cc65.git
58 lines
1.4 KiB
C
58 lines
1.4 KiB
C
/*
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** fseek.c
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**
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** Christian Groessler, 2000-08-07
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** Ullrich von Bassewitz, 2004-05-12
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*/
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#include <stdio.h>
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#include <errno.h>
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#include <unistd.h>
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#include "_file.h"
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/*****************************************************************************/
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/* Code */
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/*****************************************************************************/
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int __fastcall__ fseek (register FILE* f, long offset, int whence)
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{
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long res;
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/* Is the file open? */
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if ((f->f_flags & _FOPEN) == 0) {
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_seterrno (EINVAL); /* File not open */
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return -1;
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}
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/* If we have a pushed back character, and whence is relative to the
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** current position, correct the offset.
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*/
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if ((f->f_flags & _FPUSHBACK) && whence == SEEK_CUR) {
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--offset;
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}
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/* Do the seek */
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res = lseek(f->f_fd, offset, whence);
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/* If the seek was successful. Discard any effects of the ungetc function,
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** and clear the end-of-file indicator. Otherwise set the error indicator
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** on the stream, and return -1. We will check for >= 0 here, because that
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** saves some code, and we don't have files with 2 gigabytes in size
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** anyway:-)
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*/
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if (res >= 0) {
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f->f_flags &= ~(_FEOF | _FPUSHBACK);
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return 0;
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} else {
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f->f_flags |= _FERROR;
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return -1;
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}
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}
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