184 lines
3.9 KiB
C
184 lines
3.9 KiB
C
/*
|
||
* strtoul.c --
|
||
*
|
||
* Source code for the "strtoul" library procedure.
|
||
*
|
||
* Copyright (c) 1988 The Regents of the University of California.
|
||
* Copyright (c) 1994 Sun Microsystems, Inc.
|
||
*
|
||
* See the file "license.terms" for information on usage and redistribution
|
||
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
|
||
*
|
||
* SCCS: @(#) strtoul.c 1.5 96/02/15 12:08:24
|
||
*/
|
||
|
||
#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 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(string, endPtr, base)
|
||
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 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 = p;
|
||
}
|
||
|
||
return result;
|
||
}
|