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source:
trunk/third/gmp/mpz/inp_str.c
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15294

Revision 15294, 3.6 KB checked in by ghudson, 24 years ago (diff) |
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1 | /* mpz_inp_str(dest_integer, stream, base) -- Input a number in base |

2 | BASE from stdio stream STREAM and store the result in DEST_INTEGER. |

3 | |

4 | Copyright (C) 1991, 1993, 1994, 1996, 1998, 2000 Free Software Foundation, Inc. |

5 | |

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

7 | |

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

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

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

11 | option) any later version. |

12 | |

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

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

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

16 | License for more details. |

17 | |

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

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

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

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

22 | |

23 | #include <stdio.h> |

24 | #include <ctype.h> |

25 | #include "gmp.h" |

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

27 | |

28 | static int |

29 | #if __STDC__ |

30 | digit_value_in_base (int c, int base) |

31 | #else |

32 | digit_value_in_base (c, base) |

33 | int c; |

34 | int base; |

35 | #endif |

36 | { |

37 | int digit; |

38 | |

39 | if (isdigit (c)) |

40 | digit = c - '0'; |

41 | else if (islower (c)) |

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

43 | else if (isupper (c)) |

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

45 | else |

46 | return -1; |

47 | |

48 | if (digit < base) |

49 | return digit; |

50 | return -1; |

51 | } |

52 | |

53 | size_t |

54 | #if __STDC__ |

55 | mpz_inp_str (mpz_ptr x, FILE *stream, int base) |

56 | #else |

57 | mpz_inp_str (x, stream, base) |

58 | mpz_ptr x; |

59 | FILE *stream; |

60 | int base; |

61 | #endif |

62 | { |

63 | char *str; |

64 | size_t alloc_size, str_size; |

65 | int c; |

66 | int negative; |

67 | mp_size_t xsize; |

68 | size_t nread; |

69 | |

70 | if (stream == 0) |

71 | stream = stdin; |

72 | |

73 | nread = 0; |

74 | |

75 | /* Skip whitespace. */ |

76 | do |

77 | { |

78 | c = getc (stream); |

79 | nread++; |

80 | } |

81 | while (isspace (c)); |

82 | |

83 | negative = 0; |

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

85 | { |

86 | negative = 1; |

87 | c = getc (stream); |

88 | nread++; |

89 | } |

90 | |

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

92 | return 0; /* error if no digits */ |

93 | |

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

95 | characters. */ |

96 | if (base == 0) |

97 | { |

98 | base = 10; |

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

100 | { |

101 | base = 8; |

102 | c = getc (stream); |

103 | nread++; |

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

105 | { |

106 | base = 16; |

107 | c = getc (stream); |

108 | nread++; |

109 | } |

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

111 | { |

112 | base = 2; |

113 | c = getc (stream); |

114 | nread++; |

115 | } |

116 | } |

117 | } |

118 | |

119 | /* Skip leading zeros. */ |

120 | while (c == '0') |

121 | { |

122 | c = getc (stream); |

123 | nread++; |

124 | } |

125 | |

126 | alloc_size = 100; |

127 | str = (char *) (*_mp_allocate_func) (alloc_size); |

128 | str_size = 0; |

129 | |

130 | for (;;) |

131 | { |

132 | int dig; |

133 | if (str_size >= alloc_size) |

134 | { |

135 | size_t old_alloc_size = alloc_size; |

136 | alloc_size = alloc_size * 3 / 2; |

137 | str = (char *) (*_mp_reallocate_func) (str, old_alloc_size, alloc_size); |

138 | } |

139 | dig = digit_value_in_base (c, base); |

140 | if (dig < 0) |

141 | break; |

142 | str[str_size++] = dig; |

143 | c = getc (stream); |

144 | } |

145 | |

146 | ungetc (c, stream); |

147 | |

148 | /* Make sure the string is not empty, mpn_set_str would fail. */ |

149 | if (str_size == 0) |

150 | { |

151 | x->_mp_size = 0; |

152 | (*_mp_free_func) (str, alloc_size); |

153 | return nread; |

154 | } |

155 | |

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

157 | / BITS_PER_MP_LIMB + 2); |

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

159 | _mpz_realloc (x, xsize); |

160 | |

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

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

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

164 | |

165 | (*_mp_free_func) (str, alloc_size); |

166 | return str_size + nread; |

167 | } |

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