42 lines
899 B
C
42 lines
899 B
C
/*
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* This version reads directly from the buffer rather than looping on getc.
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* Ptr args aren't checked for NULL because the program would be a
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* catastrophic mess anyway. Better to abort than just to return NULL.
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*/
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#include <stdio.h>
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#include "stdiom.h"
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#define MIN(x, y) (x < y ? x : y)
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extern int _filbuf();
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extern _bufsync();
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extern char *memcpy();
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int
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fread(ptr, size, count, iop)
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char *ptr;
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int size, count;
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register FILE *iop;
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{
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register unsigned nleft;
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register int n;
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if (size <= 0 || count <= 0)
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return (0);
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for (nleft = count * size; ; ) {
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if (iop->_cnt <= 0) { /* empty buffer */
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if (_filbuf(iop) == EOF)
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return (count - (nleft + size - 1)/size);
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iop->_ptr--;
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iop->_cnt++;
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}
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n = MIN(nleft, iop->_cnt);
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ptr = memcpy(ptr, (char *) iop->_ptr, n) + n;
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iop->_cnt -= n;
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iop->_ptr += n;
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_BUFSYNC(iop);
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if ((nleft -= n) == 0)
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return (count);
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}
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}
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