[f40a309] | 1 | /*
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| 2 | =============================================================================
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| 3 | ftell.c -- return current file position
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| 4 | Version 7 -- 1987-10-28 -- D.N. Lynx Crowe
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| 5 | =============================================================================
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| 6 | */
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| 7 |
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| 8 | #define DEBUGIT 0
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| 9 |
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| 10 | #include "biosdefs.h"
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| 11 | #include "stdio.h"
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| 12 | #include "io.h"
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| 13 | #include "stddefs.h"
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| 14 |
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| 15 | #if DEBUGIT
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| 16 | extern short fsdebug;
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| 17 | #endif
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| 18 |
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| 19 | extern int _filecl();
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| 20 |
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| 21 | /*
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| 22 | =============================================================================
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| 23 | ftell(fp) -- return the current position of file 'fp'.
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| 24 | =============================================================================
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| 25 | */
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| 26 |
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| 27 | long
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| 28 | ftell(fp)
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| 29 | register FILE *fp;
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| 30 | {
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| 31 | register struct fcb *fcp;
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| 32 | register struct channel *chp;
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| 33 | register long dpos, pos, diff;
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| 34 |
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| 35 | if (fp EQ (FILE *)0L) { /* see if we point at a FILE */
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| 36 |
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| 37 | #if DEBUGIT
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| 38 | if (fsdebug)
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| 39 | printf("ftell($%08.8lX): ERROR - null FILE pointer\n", fp);
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| 40 | #endif
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| 41 |
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| 42 | return(0L);
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| 43 | }
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| 44 |
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| 45 | if (!fp->_flags & _BUSY) { /* see if it's open */
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| 46 |
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| 47 | #if DEBUGIT
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| 48 | if (fsdebug)
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| 49 | printf("ftell($%08.8lX): ERROR - FILE not open\n", fp);
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| 50 | #endif
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| 51 |
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| 52 | return(0L);
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| 53 | }
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| 54 |
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| 55 | chp = &chantab[fp->_unit]; /* point at the channel */
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| 56 |
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| 57 | if (chp->c_close NE _filecl) { /* see if it's seekable */
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| 58 |
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| 59 | #if DEBUGIT
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| 60 | if (fsdebug)
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| 61 | printf("ftell($%08.8lX): ERROR - FILE device not seekable\n",
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| 62 | fp);
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| 63 | #endif
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| 64 |
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| 65 | return(0L);
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| 66 | }
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| 67 |
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| 68 | fcp = chp->c_arg; /* point at the FCB */
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| 69 |
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| 70 | dpos = fcp->offset + (fcp->curlsn << FILESHFT);
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| 71 |
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| 72 | if (fp->_flags & _DIRTY) /* adjust for the buffering */
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| 73 | pos = dpos + (diff = ((long)fp->_bp - (long)fp->_buff));
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| 74 | else if (fp->_bp)
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| 75 | pos = dpos - (diff = ((long)fp->_bend - (long)fp->_bp));
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| 76 | else
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| 77 | pos = dpos;
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| 78 |
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| 79 | #if DEBUGIT
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| 80 | if (fsdebug) {
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| 81 |
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| 82 | printf("ftell($%08.8lX): flags=$%04.4X, buff=$%08.8lX, bp=$%08.8lX, bend=$%08.8lX\n",
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| 83 | fp, fp->_flags, fp->_buff, fp->_bp, fp->_bend);
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| 84 | printf("ftell($%08.8lX): fcp=$%08.8lX, pos=%ld, dpos=%ld, diff=%ld\n",
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| 85 | fp, fcp, pos, dpos, diff);
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| 86 | printf("ftell($%08.8lX): curlsn=%ld, offset=%u\n",
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| 87 | fp, fcp->curlsn, fcp->offset);
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| 88 |
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| 89 | if ((fp->_flags & _DIRTY) AND (fp->_bp EQ NULL))
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| 90 | printf("ftell($%08.8lX): ERROR - file is DIRTY and bp is NULL\n",
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| 91 | fp);
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| 92 | }
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| 93 | #endif
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| 94 |
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| 95 | return(pos);
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| 96 | }
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