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/*
* strtoul.c --
*
* Source code for the "strtoul" library procedure.
*
* Copyright 1988 Regents of the University of California
* Permission to use, copy, modify, and distribute this
* software and its documentation for any purpose and without
* fee is hereby granted, provided that the above copyright
* notice appear in all copies. The University of California
* makes no representations about the suitability of this
* software for any purpose. It is provided "as is" without
* express or implied warranty.
*/
#include <ctype.h>
/*
* The table below is used to convert from ASCII digits to a
* numerical equivalent. It maps from '0' through 'z' to integers
* (100 for non-digit characters).
*/
static const char cvtIn[] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, /* '0' - '9' */
100, 100, 100, 100, 100, 100, 100, /* punctuation */
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, /* 'A' - 'Z' */
20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
30, 31, 32, 33, 34, 35,
100, 100, 100, 100, 100, 100, /* punctuation */
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, /* 'a' - 'z' */
20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
30, 31, 32, 33, 34, 35};
/*
*----------------------------------------------------------------------
*
* strtoul --
*
* Convert an ASCII string into an integer.
*
* Results:
* The return value is the integer equivalent of string. If endPtr
* is non-NULL, then *endPtr is filled in with the character
* after the last one that was part of the integer. If string
* doesn't contain a valid integer value, then zero is returned
* and *endPtr is set to string.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
unsigned long int
strtoul(
const char *string, /* String of ASCII digits, possibly
* preceded by white space. For bases
* greater than 10, either lower- or
* upper-case digits may be used.
*/
char **endPtr, /* Where to store address of terminating
* character, or NULL. */
int base) /* Base for conversion. Must be less
* than 37. If 0, then the base is chosen
* from the leading characters of string:
* "0x" means hex, "0" means octal, anything
* else means decimal.
*/
{
register const char *p;
register unsigned long int result = 0;
register unsigned digit;
int anyDigits = 0;
/*
* Skip any leading blanks.
*/
p = string;
while (isspace(*p)) {
p += 1;
}
/*
* If no base was provided, pick one from the leading characters
* of the string.
*/
if (base == 0)
{
if (*p == '0') {
p += 1;
if (*p == 'x') {
p += 1;
base = 16;
} else {
/*
* Must set anyDigits here, otherwise "0" produces a
* "no digits" error.
*/
anyDigits = 1;
base = 8;
}
}
else base = 10;
} else if (base == 16) {
/*
* Skip a leading "0x" from hex numbers.
*/
if ((p[0] == '0') && (p[1] == 'x')) {
p += 2;
}
}
/*
* Sorry this code is so messy, but speed seems important. Do
* different things for base 8, 10, 16, and other.
*/
if (base == 8) {
for ( ; ; p += 1) {
digit = *p - '0';
if (digit > 7) {
break;
}
result = (result << 3) + digit;
anyDigits = 1;
}
} else if (base == 10) {
for ( ; ; p += 1) {
digit = *p - '0';
if (digit > 9) {
break;
}
result = (10*result) + digit;
anyDigits = 1;
}
} else if (base == 16) {
for ( ; ; p += 1) {
digit = *p - '0';
if (digit > ('z' - '0')) {
break;
}
digit = cvtIn[digit];
if (digit > 15) {
break;
}
result = (result << 4) + digit;
anyDigits = 1;
}
} else {
for ( ; ; p += 1) {
digit = *p - '0';
if (digit > ('z' - '0')) {
break;
}
digit = cvtIn[digit];
if (digit >= base) {
break;
}
result = result*base + digit;
anyDigits = 1;
}
}
/*
* See if there were any digits at all.
*/
if (!anyDigits) {
p = string;
}
if (endPtr != 0) {
*endPtr = (char *)p;
}
return result;
}
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