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    OF THE FUNCTIONS IN THIS FILE, ONLY mpz_inp_str IS FOR EXTERNAL USE, THE
5    REST ARE INTERNALS AND ARE ALMOST CERTAIN TO BE SUBJECT TO INCOMPATIBLE
6    CHANGES OR DISAPPEAR COMPLETELY IN FUTURE GNU MP RELEASES.
7 
8 Copyright 1991, 1993, 1994, 1996, 1998, 2000-2003, 2011-2013 Free Software
9 Foundation, Inc.
10 
11 This file is part of the GNU MP Library.
12 
13 The GNU MP Library is free software; you can redistribute it and/or modify
14 it under the terms of either:
15 
16   * the GNU Lesser General Public License as published by the Free
17     Software Foundation; either version 3 of the License, or (at your
18     option) any later version.
19 
20 or
21 
22   * the GNU General Public License as published by the Free Software
23     Foundation; either version 2 of the License, or (at your option) any
24     later version.
25 
26 or both in parallel, as here.
27 
28 The GNU MP Library is distributed in the hope that it will be useful, but
29 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
30 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
31 for more details.
32 
33 You should have received copies of the GNU General Public License and the
34 GNU Lesser General Public License along with the GNU MP Library.  If not,
35 see https://www.gnu.org/licenses/.  */
36 
37 #include <stdio.h>
38 #include <ctype.h>
39 #include "gmp-impl.h"
40 #include "longlong.h"
41 
42 #define digit_value_tab __gmp_digit_value_tab
43 
44 size_t
mpz_inp_str(mpz_ptr x,FILE * stream,int base)45 mpz_inp_str (mpz_ptr x, FILE *stream, int base)
46 {
47   int c;
48   size_t nread;
49 
50   if (stream == 0)
51     stream = stdin;
52 
53   nread = 0;
54 
55   /* Skip whitespace.  */
56   do
57     {
58       c = getc (stream);
59       nread++;
60     }
61   while (isspace (c));
62 
63   return mpz_inp_str_nowhite (x, stream, base, c, nread);
64 }
65 
66 /* shared by mpq_inp_str */
67 size_t
mpz_inp_str_nowhite(mpz_ptr x,FILE * stream,int base,int c,size_t nread)68 mpz_inp_str_nowhite (mpz_ptr x, FILE *stream, int base, int c, size_t nread)
69 {
70   char *str;
71   size_t alloc_size, str_size;
72   int negative;
73   mp_size_t xsize;
74   const unsigned char *digit_value;
75 
76   ASSERT_ALWAYS (EOF == -1);  /* FIXME: handle this by adding explicit */
77                                         /* comparisons of c and EOF before each  */
78                                         /* read of digit_value[].  */
79 
80   digit_value = digit_value_tab;
81   if (base > 36)
82     {
83       /* For bases > 36, use the collating sequence
84            0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz.  */
85       digit_value += 208;
86       if (UNLIKELY (base > 62))
87           return 0;           /* too large base */
88     }
89 
90   negative = 0;
91   if (c == '-')
92     {
93       negative = 1;
94       c = getc (stream);
95       nread++;
96     }
97 
98   if (c == EOF || digit_value[c] >= (base == 0 ? 10 : base))
99     return 0;                           /* error if no digits */
100 
101   /* If BASE is 0, try to find out the base by looking at the initial
102      characters.  */
103   if (base == 0)
104     {
105       base = 10;
106       if (c == '0')
107           {
108             base = 8;
109             c = getc (stream);
110             nread++;
111             if (c == 'x' || c == 'X')
112               {
113                 base = 16;
114                 c = getc (stream);
115                 nread++;
116               }
117             else if (c == 'b' || c == 'B')
118               {
119                 base = 2;
120                 c = getc (stream);
121                 nread++;
122               }
123           }
124     }
125 
126   /* Skip leading zeros.  */
127   while (c == '0')
128     {
129       c = getc (stream);
130       nread++;
131     }
132 
133   alloc_size = 100;
134   str = __GMP_ALLOCATE_FUNC_TYPE (alloc_size, char);
135   str_size = 0;
136 
137   while (c != EOF)
138     {
139       int dig;
140       dig = digit_value[c];
141       if (dig >= base)
142           break;
143       if (str_size >= alloc_size)
144           {
145             size_t old_alloc_size = alloc_size;
146             alloc_size = alloc_size * 3 / 2;
147             str = __GMP_REALLOCATE_FUNC_TYPE (str, old_alloc_size, alloc_size, char);
148           }
149       str[str_size++] = dig;
150       c = getc (stream);
151     }
152   nread += str_size;
153 
154   ungetc (c, stream);
155   nread--;
156 
157   /* Make sure the string is not empty, mpn_set_str would fail.  */
158   if (str_size == 0)
159     {
160       SIZ (x) = 0;
161     }
162   else
163     {
164       LIMBS_PER_DIGIT_IN_BASE (xsize, str_size, base);
165       MPZ_NEWALLOC (x, xsize);
166 
167       /* Convert the byte array in base BASE to our bignum format.  */
168       xsize = mpn_set_str (PTR (x), (unsigned char *) str, str_size, base);
169       SIZ (x) = negative ? -xsize : xsize;
170     }
171   (*__gmp_free_func) (str, alloc_size);
172   return nread;
173 }
174