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84 lines
2.1 KiB
C
84 lines
2.1 KiB
C
/*
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* strtol.c --
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*
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* Source code for the "strtol" library procedure.
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*
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* Copyright 1988 Regents of the University of California
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* Permission to use, copy, modify, and distribute this
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* software and its documentation for any purpose and without
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* fee is hereby granted, provided that the above copyright
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* notice appear in all copies. The University of California
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* makes no representations about the suitability of this
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* software for any purpose. It is provided "as is" without
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* express or implied warranty.
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*/
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#include <ctype.h>
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/*
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*----------------------------------------------------------------------
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*
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* strtol --
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*
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* Convert an ASCII string into an integer.
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*
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* Results:
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* The return value is the integer equivalent of string. If endPtr
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* is non-NULL, then *endPtr is filled in with the character
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* after the last one that was part of the integer. If string
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* doesn't contain a valid integer value, then zero is returned
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* and *endPtr is set to string.
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*
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* Side effects:
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* None.
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*
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*----------------------------------------------------------------------
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*/
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long int
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strtol(string, endPtr, base)
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char *string; /* String of ASCII digits, possibly
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* preceded by white space. For bases
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* greater than 10, either lower- or
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* upper-case digits may be used.
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*/
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char **endPtr; /* Where to store address of terminating
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* character, or NULL. */
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int base; /* Base for conversion. Must be less
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* than 37. If 0, then the base is chosen
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* from the leading characters of string:
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* "0x" means hex, "0" means octal, anything
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* else means decimal.
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*/
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{
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register char *p;
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int result;
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/*
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* Skip any leading blanks.
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*/
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p = string;
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while (isspace(*p)) {
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p += 1;
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}
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/*
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* Check for a sign.
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*/
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if (*p == '-') {
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p += 1;
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result = -(strtoul(p, endPtr, base));
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} else {
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if (*p == '+') {
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p += 1;
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}
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result = strtoul(p, endPtr, base);
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}
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if ((result == 0) && (endPtr != 0) && (*endPtr == p)) {
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*endPtr = string;
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}
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return result;
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}
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