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source:
trunk/third/gmp/mpz/set_str.c
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18191

Revision 18191, 3.4 KB checked in by ghudson, 22 years ago (diff) |
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1 | /* mpz_set_str(mp_dest, string, base) -- Convert the \0-terminated |

2 | string STRING in base BASE to multiple precision integer in |

3 | MP_DEST. Allow white space in the string. If BASE == 0 determine |

4 | the base in the C standard way, i.e. 0xhh...h means base 16, |

5 | 0oo...o means base 8, otherwise assume base 10. |

6 | |

7 | Copyright 1991, 1993, 1994, 1996, 1997, 1998, 2000, 2001, 2002 Free Software |

8 | Foundation, Inc. |

9 | |

10 | This file is part of the GNU MP Library. |

11 | |

12 | The GNU MP Library is free software; you can redistribute it and/or modify |

13 | it under the terms of the GNU Lesser General Public License as published by |

14 | the Free Software Foundation; either version 2.1 of the License, or (at your |

15 | option) any later version. |

16 | |

17 | The GNU MP Library is distributed in the hope that it will be useful, but |

18 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |

19 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |

20 | License for more details. |

21 | |

22 | You should have received a copy of the GNU Lesser General Public License |

23 | along with the GNU MP Library; see the file COPYING.LIB. If not, write to |

24 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |

25 | MA 02111-1307, USA. */ |

26 | |

27 | #include <string.h> |

28 | #include <ctype.h> |

29 | #include "gmp.h" |

30 | #include "gmp-impl.h" |

31 | #include "longlong.h" |

32 | |

33 | static int |

34 | digit_value_in_base (int c, int base) |

35 | { |

36 | int digit; |

37 | |

38 | if (isdigit (c)) |

39 | digit = c - '0'; |

40 | else if (islower (c)) |

41 | digit = c - 'a' + 10; |

42 | else if (isupper (c)) |

43 | digit = c - 'A' + 10; |

44 | else |

45 | return -1; |

46 | |

47 | if (digit < base) |

48 | return digit; |

49 | return -1; |

50 | } |

51 | |

52 | int |

53 | mpz_set_str (mpz_ptr x, const char *str, int base) |

54 | { |

55 | size_t str_size; |

56 | char *s, *begs; |

57 | size_t i; |

58 | mp_size_t xsize; |

59 | int c; |

60 | int negative; |

61 | TMP_DECL (marker); |

62 | |

63 | /* Skip whitespace. */ |

64 | do |

65 | c = *str++; |

66 | while (isspace (c)); |

67 | |

68 | negative = 0; |

69 | if (c == '-') |

70 | { |

71 | negative = 1; |

72 | c = *str++; |

73 | } |

74 | |

75 | if (digit_value_in_base (c, base == 0 ? 10 : base) < 0) |

76 | return -1; /* error if no digits */ |

77 | |

78 | /* If BASE is 0, try to find out the base by looking at the initial |

79 | characters. */ |

80 | if (base == 0) |

81 | { |

82 | base = 10; |

83 | if (c == '0') |

84 | { |

85 | base = 8; |

86 | c = *str++; |

87 | if (c == 'x' || c == 'X') |

88 | { |

89 | base = 16; |

90 | c = *str++; |

91 | } |

92 | else if (c == 'b' || c == 'B') |

93 | { |

94 | base = 2; |

95 | c = *str++; |

96 | } |

97 | } |

98 | } |

99 | |

100 | /* Skip leading zeros and white space. */ |

101 | while (c == '0' || isspace (c)) |

102 | c = *str++; |

103 | /* Make sure the string does not become empty, mpn_set_str would fail. */ |

104 | if (c == 0) |

105 | { |

106 | x->_mp_size = 0; |

107 | return 0; |

108 | } |

109 | |

110 | TMP_MARK (marker); |

111 | str_size = strlen (str - 1); |

112 | s = begs = (char *) TMP_ALLOC (str_size + 1); |

113 | |

114 | /* Remove spaces from the string and convert the result from ASCII to a |

115 | byte array. */ |

116 | for (i = 0; i < str_size; i++) |

117 | { |

118 | if (!isspace (c)) |

119 | { |

120 | int dig = digit_value_in_base (c, base); |

121 | if (dig < 0) |

122 | { |

123 | TMP_FREE (marker); |

124 | return -1; |

125 | } |

126 | *s++ = dig; |

127 | } |

128 | c = *str++; |

129 | } |

130 | |

131 | str_size = s - begs; |

132 | |

133 | xsize = (((mp_size_t) (str_size / __mp_bases[base].chars_per_bit_exactly)) |

134 | / GMP_NUMB_BITS + 2); |

135 | if (x->_mp_alloc < xsize) |

136 | _mpz_realloc (x, xsize); |

137 | |

138 | /* Convert the byte array in base BASE to our bignum format. */ |

139 | xsize = mpn_set_str (x->_mp_d, (unsigned char *) begs, str_size, base); |

140 | x->_mp_size = negative ? -xsize : xsize; |

141 | |

142 | TMP_FREE (marker); |

143 | return 0; |

144 | } |

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