1 /*- 2 * Copyright (c) 1992, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #if defined(LIBC_SCCS) && !defined(lint) 9 static char sccsid[] = "@(#)strtoq.c 8.1 (Berkeley) 06/04/93"; 10 #endif /* LIBC_SCCS and not lint */ 11 12 #include <sys/types.h> 13 14 #include <limits.h> 15 #include <errno.h> 16 #include <ctype.h> 17 #include <stdlib.h> 18 19 /* 20 * Convert a string to a quad integer. 21 * 22 * Ignores `locale' stuff. Assumes that the upper and lower case 23 * alphabets and digits are each contiguous. 24 */ 25 quad_t 26 strtoq(nptr, endptr, base) 27 const char *nptr; 28 char **endptr; 29 register int base; 30 { 31 register const char *s; 32 register u_quad_t acc; 33 register int c; 34 register u_quad_t qbase, cutoff; 35 register int neg, any, cutlim; 36 37 /* 38 * Skip white space and pick up leading +/- sign if any. 39 * If base is 0, allow 0x for hex and 0 for octal, else 40 * assume decimal; if base is already 16, allow 0x. 41 */ 42 s = nptr; 43 do { 44 c = *s++; 45 } while (isspace(c)); 46 if (c == '-') { 47 neg = 1; 48 c = *s++; 49 } else { 50 neg = 0; 51 if (c == '+') 52 c = *s++; 53 } 54 if ((base == 0 || base == 16) && 55 c == '0' && (*s == 'x' || *s == 'X')) { 56 c = s[1]; 57 s += 2; 58 base = 16; 59 } 60 if (base == 0) 61 base = c == '0' ? 8 : 10; 62 63 /* 64 * Compute the cutoff value between legal numbers and illegal 65 * numbers. That is the largest legal value, divided by the 66 * base. An input number that is greater than this value, if 67 * followed by a legal input character, is too big. One that 68 * is equal to this value may be valid or not; the limit 69 * between valid and invalid numbers is then based on the last 70 * digit. For instance, if the range for quads is 71 * [-9223372036854775808..9223372036854775807] and the input base 72 * is 10, cutoff will be set to 922337203685477580 and cutlim to 73 * either 7 (neg==0) or 8 (neg==1), meaning that if we have 74 * accumulated a value > 922337203685477580, or equal but the 75 * next digit is > 7 (or 8), the number is too big, and we will 76 * return a range error. 77 * 78 * Set any if any `digits' consumed; make it negative to indicate 79 * overflow. 80 */ 81 qbase = (unsigned)base; 82 cutoff = neg ? -(u_quad_t)QUAD_MIN : QUAD_MAX; 83 cutlim = cutoff % qbase; 84 cutoff /= qbase; 85 for (acc = 0, any = 0;; c = *s++) { 86 if (isdigit(c)) 87 c -= '0'; 88 else if (isalpha(c)) 89 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 90 else 91 break; 92 if (c >= base) 93 break; 94 if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim) 95 any = -1; 96 else { 97 any = 1; 98 acc *= qbase; 99 acc += c; 100 } 101 } 102 if (any < 0) { 103 acc = neg ? QUAD_MIN : QUAD_MAX; 104 errno = ERANGE; 105 } else if (neg) 106 acc = -acc; 107 if (endptr != 0) 108 *endptr = (char *)(any ? s - 1 : nptr); 109 return (acc); 110 } 111