186 lines
4.0 KiB
C
186 lines
4.0 KiB
C
/*
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* strtoul.c --
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*
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* Source code for the "strtoul" library procedure.
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*
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* Copyright (c) 1988 The Regents of the University of California.
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* Copyright (c) 1994 Sun Microsystems, Inc.
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*
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* See the file "license.terms" for information on usage and redistribution
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* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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*/
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#ifndef lint
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static char sccsid[] = "@(#) strtoul.c 1.4 94/12/17 16:26:26";
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#endif /* not lint */
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#include <ctype.h>
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/*
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* The table below is used to convert from ASCII digits to a
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* numerical equivalent. It maps from '0' through 'z' to integers
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* (100 for non-digit characters).
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*/
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static char cvtIn[] = {
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, /* '0' - '9' */
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100, 100, 100, 100, 100, 100, 100, /* punctuation */
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10, 11, 12, 13, 14, 15, 16, 17, 18, 19, /* 'A' - 'Z' */
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20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
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30, 31, 32, 33, 34, 35,
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100, 100, 100, 100, 100, 100, /* punctuation */
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10, 11, 12, 13, 14, 15, 16, 17, 18, 19, /* 'a' - 'z' */
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20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
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30, 31, 32, 33, 34, 35};
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/*
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*----------------------------------------------------------------------
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*
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* strtoul --
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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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unsigned long int
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strtoul(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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register unsigned long int result = 0;
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register unsigned digit;
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int anyDigits = 0;
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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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* If no base was provided, pick one from the leading characters
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* of the string.
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*/
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if (base == 0)
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{
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if (*p == '0') {
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p += 1;
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if (*p == 'x') {
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p += 1;
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base = 16;
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} else {
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/*
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* Must set anyDigits here, otherwise "0" produces a
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* "no digits" error.
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*/
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anyDigits = 1;
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base = 8;
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}
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}
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else base = 10;
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} else if (base == 16) {
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/*
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* Skip a leading "0x" from hex numbers.
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*/
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if ((p[0] == '0') && (p[1] == 'x')) {
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p += 2;
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}
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}
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/*
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* Sorry this code is so messy, but speed seems important. Do
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* different things for base 8, 10, 16, and other.
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*/
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if (base == 8) {
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for ( ; ; p += 1) {
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digit = *p - '0';
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if (digit > 7) {
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break;
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}
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result = (result << 3) + digit;
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anyDigits = 1;
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}
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} else if (base == 10) {
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for ( ; ; p += 1) {
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digit = *p - '0';
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if (digit > 9) {
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break;
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}
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result = (10*result) + digit;
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anyDigits = 1;
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}
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} else if (base == 16) {
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for ( ; ; p += 1) {
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digit = *p - '0';
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if (digit > ('z' - '0')) {
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break;
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}
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digit = cvtIn[digit];
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if (digit > 15) {
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break;
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}
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result = (result << 4) + digit;
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anyDigits = 1;
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}
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} else {
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for ( ; ; p += 1) {
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digit = *p - '0';
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if (digit > ('z' - '0')) {
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break;
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}
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digit = cvtIn[digit];
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if (digit >= base) {
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break;
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}
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result = result*base + digit;
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anyDigits = 1;
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}
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}
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/*
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* See if there were any digits at all.
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*/
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if (!anyDigits) {
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p = string;
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}
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if (endPtr != 0) {
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*endPtr = p;
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}
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return result;
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}
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