stdlib.c (3609B)
1 /* 2 * libc/stdlib.c 3 * 4 * Copyright (C) 2009 stateless 5 */ 6 7 #include <stdlib.h> 8 #include <ctype.h> 9 #include <errno.h> 10 11 void 12 itoa(long int num, char *buffer, int base) 13 { 14 static char hex[] = "0123456789abcdef"; 15 char *ptr = buffer, tmp, *beg = buffer; 16 int rem; 17 unsigned int uns; 18 19 if (base == 'x') { 20 unsigned long n = num; 21 do { 22 rem = n % 16; 23 *ptr++ = hex[rem]; 24 n /= 16; 25 } while (n); *ptr = '\0'; --ptr; 26 } else { 27 if (base == 'd' && num < 0) { 28 *ptr++ = '-'; num = -num; 29 ++beg; 30 } 31 uns = (unsigned int)num; 32 do { 33 rem = uns % 10; 34 *ptr++ = rem + '0'; 35 uns /= 10; 36 } while (uns); *ptr = '\0'; --ptr; 37 } 38 while (ptr >= beg) { 39 tmp = *beg; 40 *beg = *ptr; 41 *ptr = tmp; 42 --ptr; 43 ++beg; 44 } 45 } 46 47 /* 48 * Copyright (c) 1990 Regents of the University of California. 49 * All rights reserved. 50 * 51 * Redistribution and use in source and binary forms, with or without 52 * modification, are permitted provided that the following conditions 53 * are met: 54 * 1. Redistributions of source code must retain the above copyright 55 * notice, this list of conditions and the following disclaimer. 56 * 2. Redistributions in binary form must reproduce the above copyright 57 * notice, this list of conditions and the following disclaimer in the 58 * documentation and/or other materials provided with the distribution. 59 * 3. Neither the name of the University nor the names of its contributors 60 * may be used to endorse or promote products derived from this software 61 * without specific prior written permission. 62 * 63 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 64 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 65 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 66 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 67 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 68 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 69 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 70 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 71 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 72 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 73 * SUCH DAMAGE. 74 */ 75 76 /* 77 * Convert a string to an unsigned long integer. 78 * 79 * Ignores `locale' stuff. Assumes that the upper and lower case 80 * alphabets and digits are each contiguous. 81 */ 82 unsigned long 83 strtoul(const char *nptr, char **endptr, int base) 84 { 85 const char *s; 86 unsigned long acc, cutoff; 87 int c; 88 int neg, any, cutlim; 89 90 /* 91 * See strtol for comments as to the logic used. 92 */ 93 s = nptr; 94 do { 95 c = (unsigned char) * s++; 96 } while (isspace(c)); 97 if (c == '-') { 98 neg = 1; 99 c = *s++; 100 } else { 101 neg = 0; 102 if (c == '+') 103 c = *s++; 104 } 105 if ((base == 0 || base == 16) && 106 c == '0' && (*s == 'x' || *s == 'X')) { 107 c = s[1]; 108 s += 2; 109 base = 16; 110 } 111 if (base == 0) 112 base = c == '0' ? 8 : 10; 113 114 cutoff = 0xffffffff / (unsigned long)base; 115 cutlim = 0xffffffff % (unsigned long)base; 116 for (acc = 0, any = 0;; c = (unsigned char) * s++) { 117 if (isdigit(c)) 118 c -= '0'; 119 else if (isalpha(c)) 120 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 121 else 122 break; 123 if (c >= base) 124 break; 125 if (any < 0) 126 continue; 127 if (acc > cutoff || (acc == cutoff && c > cutlim)) { 128 any = -1; 129 acc = 0xffffffff; 130 errno = ERANGE; 131 } else { 132 any = 1; 133 acc *= (unsigned long)base; 134 acc += c; 135 } 136 } 137 if (neg && any > 0) 138 acc = -acc; 139 if (endptr != 0) 140 *endptr = (char *) (any ? s - 1 : nptr); 141 return (acc); 142 } 143