astoi.c
上传用户:xiejiait
上传日期:2007-01-06
资源大小:881k
文件大小:2k
- /* @(#)astoi.c 1.5 96/05/09 Copyright 1985 J. Schilling */
- /*
- * astoi() converts a string to int
- * astol() converts a string to long
- *
- * Leading tabs and spaces are ignored.
- * Both return pointer to the first char that has not been used.
- * Caller must check if this means a bad conversion.
- *
- * leading "+" is ignored
- * leading "0" makes conversion octal (base 8)
- * leading "0x" makes conversion hex (base 16)
- *
- * Copyright (c) 1985 J. Schilling
- */
- /* This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; see the file COPYING. If not, write to
- * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
- */
- #include <standard.h>
- #define is_space(c) ((c) == ' ' || (c) == 't')
- #define is_digit(c) ((c) >= '0' && (c) <= '9')
- #define is_hex(c) (((c) >= 'a' && (c) <= 'f') ||
- ((c) >= 'A' && (c) <= 'F'))
- #define to_lower(c) (((c) >= 'A' && (c) <= 'Z') ? (c) - 'A'+'a' : (c))
- #ifdef notdef
- int atoi(s)
- char *s;
- {
- long l;
- (void)astol(s, &l);
- return (int) l;
- }
- long atol(s)
- char *s;
- {
- long l;
- (void)astol(s, &l);
- return l;
- }
- #endif
- char *astoi(s, i)
- const char *s;
- int *i;
- {
- long l;
- char *ret;
- ret = astol(s, &l);
- *i = l;
- return(ret);
- }
- char *astol(s, l)
- register const char *s;
- long *l;
- {
- int neg = 0;
- register long ret = 0L;
- register int base = 10;
- register int digit;
- register char c;
-
- while (is_space(*s))
- s++;
- if (*s == '+') {
- s++;
- } else if (*s == '-') {
- s++;
- neg++;
- }
- if (*s == '0') {
- base = 8;
- s++;
- if (*s == 'x' || *s == 'X') {
- s++;
- base = 16;
- }
- }
- for (;(c = *s) != 0; s++) {
- if (is_digit(c)) {
- digit = c - '0';
- } else if (is_hex(c)) {
- digit = to_lower(c) - 'a' + 10;
- } else {
- break;
- }
- if (digit < base) {
- ret *= base;
- ret += digit;
- } else {
- break;
- }
- }
- if (neg)
- ret = -ret;
- *l = ret;
- return ((char *)s);
- }