63 lines
1.6 KiB
C
63 lines
1.6 KiB
C
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/***
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*atox.c - atoi and atol conversion
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*
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* Copyright (c) 1989-1997, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* Converts a character string into an int or long.
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*
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*******************************************************************************/
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#include <cruntime.h>
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#include <stdlib.h>
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#include <ctype.h>
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/***
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*long atol(char *nptr) - Convert string to long
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*
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*Purpose:
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* Converts ASCII string pointed to by nptr to binary.
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* Overflow is not detected.
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*
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*Entry:
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* nptr = ptr to string to convert
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*
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*Exit:
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* return long int value of the string
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*
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*Exceptions:
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* None - overflow is not detected.
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*
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*******************************************************************************/
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long __cdecl atol(
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const char *nptr
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)
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{
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int c; /* current char */
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long total; /* current total */
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int sign; /* if '-', then negative, otherwise positive */
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/* skip whitespace */
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while ( isspace((int)(unsigned char)*nptr) )
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++nptr;
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c = (int)(unsigned char)*nptr++;
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sign = c; /* save sign indication */
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if (c == '-' || c == '+')
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c = (int)(unsigned char)*nptr++; /* skip sign */
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total = 0;
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while (isdigit(c)) {
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total = 10 * total + (c - '0'); /* accumulate digit */
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c = (int)(unsigned char)*nptr++; /* get next char */
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}
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if (sign == '-')
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return -total;
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else
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return total; /* return result, negated if necessary */
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}
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