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984263bc MD |
1 | /*- |

2 | * Copyright (c) 1990, 1993 | |

3 | * The Regents of the University of California. All rights reserved. | |

4 | * | |

5 | * Redistribution and use in source and binary forms, with or without | |

6 | * modification, are permitted provided that the following conditions | |

7 | * are met: | |

8 | * 1. Redistributions of source code must retain the above copyright | |

9 | * notice, this list of conditions and the following disclaimer. | |

10 | * 2. Redistributions in binary form must reproduce the above copyright | |

11 | * notice, this list of conditions and the following disclaimer in the | |

12 | * documentation and/or other materials provided with the distribution. | |

13 | * 3. All advertising materials mentioning features or use of this software | |

14 | * must display the following acknowledgement: | |

15 | * This product includes software developed by the University of | |

16 | * California, Berkeley and its contributors. | |

17 | * 4. Neither the name of the University nor the names of its contributors | |

18 | * may be used to endorse or promote products derived from this software | |

19 | * without specific prior written permission. | |

20 | * | |

21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |

22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |

23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |

24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |

25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |

26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |

27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |

28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |

29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |

30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |

31 | * SUCH DAMAGE. | |

1de703da MD |
32 | * |

33 | * @(#)strtol.c 8.1 (Berkeley) 6/4/93 | |

ff2aef30 | 34 | * $DragonFly: src/lib/libstand/strtol.c,v 1.4 2005/12/11 02:27:26 swildner Exp $ |

984263bc MD |
35 | */ |

36 | ||

984263bc MD |
37 | #include "stand.h" |

38 | #include <limits.h> | |

39 | ||

40 | /* | |

41 | * Convert a string to a long integer. | |

42 | * | |

43 | * Ignores `locale' stuff. Assumes that the upper and lower case | |

44 | * alphabets and digits are each contiguous. | |

45 | */ | |

46 | long | |

ff2aef30 | 47 | strtol(const char *nptr, char **endptr, int base) |

984263bc | 48 | { |

660c873b DR |
49 | const char *s; |

50 | unsigned long acc; | |

51 | unsigned char c; | |

52 | unsigned long cutoff; | |

53 | int neg = 0, any, cutlim; | |

984263bc MD |
54 | |

55 | /* Be sensible about NULL strings */ | |

56 | if (nptr == NULL) | |

57 | nptr = ""; | |

58 | s = nptr; | |

59 | ||

60 | /* | |

61 | * Skip white space and pick up leading +/- sign if any. | |

62 | * If base is 0, allow 0x for hex and 0 for octal, else | |

63 | * assume decimal; if base is already 16, allow 0x. | |

64 | */ | |

65 | do { | |

66 | c = *s++; | |

67 | } while (isspace(c)); | |

68 | if (c == '-') { | |

69 | neg = 1; | |

70 | c = *s++; | |

71 | } else if (c == '+') | |

72 | c = *s++; | |

73 | if ((base == 0 || base == 16) && | |

74 | c == '0' && (*s == 'x' || *s == 'X')) { | |

75 | c = s[1]; | |

76 | s += 2; | |

77 | base = 16; | |

78 | } | |

79 | if (base == 0) | |

80 | base = c == '0' ? 8 : 10; | |

81 | ||

82 | /* | |

83 | * Compute the cutoff value between legal numbers and illegal | |

84 | * numbers. That is the largest legal value, divided by the | |

85 | * base. An input number that is greater than this value, if | |

86 | * followed by a legal input character, is too big. One that | |

87 | * is equal to this value may be valid or not; the limit | |

88 | * between valid and invalid numbers is then based on the last | |

89 | * digit. For instance, if the range for longs is | |

90 | * [-2147483648..2147483647] and the input base is 10, | |

91 | * cutoff will be set to 214748364 and cutlim to either | |

92 | * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated | |

93 | * a value > 214748364, or equal but the next digit is > 7 (or 8), | |

94 | * the number is too big, and we will return a range error. | |

95 | * | |

96 | * Set any if any `digits' consumed; make it negative to indicate | |

97 | * overflow. | |

98 | */ | |

99 | cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX; | |

100 | cutlim = cutoff % (unsigned long)base; | |

101 | cutoff /= (unsigned long)base; | |

102 | for (acc = 0, any = 0;; c = *s++) { | |

103 | if (!isascii(c)) | |

104 | break; | |

105 | if (isdigit(c)) | |

106 | c -= '0'; | |

107 | else if (isalpha(c)) | |

108 | c -= isupper(c) ? 'A' - 10 : 'a' - 10; | |

109 | else | |

110 | break; | |

111 | if (c >= base) | |

112 | break; | |

113 | if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) | |

114 | any = -1; | |

115 | else { | |

116 | any = 1; | |

117 | acc *= base; | |

118 | acc += c; | |

119 | } | |

120 | } | |

121 | if (any < 0) { | |

122 | acc = neg ? LONG_MIN : LONG_MAX; | |

123 | errno = ERANGE; | |

124 | } else if (neg) | |

125 | acc = -acc; | |

126 | if (endptr != 0) | |

127 | *endptr = (char *)(any ? s - 1 : nptr); | |

128 | return (acc); | |

129 | } |