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
8Copyright 1991, 1993, 1994, 1996, 1998, 2000, 2001, 2002, 2003 Free Software
9Foundation, Inc.
10
11This file is part of the GNU MP Library.
12
13The GNU MP Library is free software; you can redistribute it and/or modify
14it under the terms of the GNU Lesser General Public License as published by
15the Free Software Foundation; either version 3 of the License, or (at your
16option) any later version.
17
18The GNU MP Library is distributed in the hope that it will be useful, but
19WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
20or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
21License for more details.
22
23You should have received a copy of the GNU Lesser General Public License
24along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
25
26#include <stdio.h>
27#include <ctype.h>
28#include "gmp.h"
29#include "gmp-impl.h"
30
31extern const unsigned char __gmp_digit_value_tab[];
32#define digit_value_tab __gmp_digit_value_tab
33
34size_t
35mpz_inp_str (mpz_ptr x, FILE *stream, int base)
36{
37  int c;
38  size_t nread;
39
40  if (stream == 0)
41    stream = stdin;
42
43  nread = 0;
44
45  /* Skip whitespace.  */
46  do
47    {
48      c = getc (stream);
49      nread++;
50    }
51  while (isspace (c));
52
53  return mpz_inp_str_nowhite (x, stream, base, c, nread);
54}
55
56/* shared by mpq_inp_str */
57size_t
58mpz_inp_str_nowhite (mpz_ptr x, FILE *stream, int base, int c, size_t nread)
59{
60  char *str;
61  size_t alloc_size, str_size;
62  int negative;
63  mp_size_t xsize;
64  const unsigned char *digit_value;
65
66  ASSERT_ALWAYS (EOF == -1);	/* FIXME: handle this by adding explicit */
67				/* comparisons of c and EOF before each  */
68				/* read of digit_value[].  */
69
70  digit_value = digit_value_tab;
71  if (base > 36)
72    {
73      /* For bases > 36, use the collating sequence
74	 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz.  */
75      digit_value += 224;
76      if (base > 62)
77	return 0;		/* too large base */
78    }
79
80  negative = 0;
81  if (c == '-')
82    {
83      negative = 1;
84      c = getc (stream);
85      nread++;
86    }
87
88  if (c == EOF || digit_value[c] >= (base == 0 ? 10 : base))
89    return 0;			/* error if no digits */
90
91  /* If BASE is 0, try to find out the base by looking at the initial
92     characters.  */
93  if (base == 0)
94    {
95      base = 10;
96      if (c == '0')
97	{
98	  base = 8;
99	  c = getc (stream);
100	  nread++;
101	  if (c == 'x' || c == 'X')
102	    {
103	      base = 16;
104	      c = getc (stream);
105	      nread++;
106	    }
107	  else if (c == 'b' || c == 'B')
108	    {
109	      base = 2;
110	      c = getc (stream);
111	      nread++;
112	    }
113	}
114    }
115
116  /* Skip leading zeros.  */
117  while (c == '0')
118    {
119      c = getc (stream);
120      nread++;
121    }
122
123  alloc_size = 100;
124  str = (char *) (*__gmp_allocate_func) (alloc_size);
125  str_size = 0;
126
127  while (c != EOF)
128    {
129      int dig;
130      dig = digit_value[c];
131      if (dig >= base)
132	break;
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 *) (*__gmp_reallocate_func) (str, old_alloc_size, alloc_size);
138	}
139      str[str_size++] = dig;
140      c = getc (stream);
141    }
142  nread += str_size;
143
144  ungetc (c, stream);
145  nread--;
146
147  /* Make sure the string is not empty, mpn_set_str would fail.  */
148  if (str_size == 0)
149    {
150      x->_mp_size = 0;
151    }
152  else
153    {
154      xsize = 2 + (mp_size_t)
155	(str_size / (GMP_NUMB_BITS * mp_bases[base].chars_per_bit_exactly));
156      MPZ_REALLOC (x, xsize);
157
158      /* Convert the byte array in base BASE to our bignum format.  */
159      xsize = mpn_set_str (x->_mp_d, (unsigned char *) str, str_size, base);
160      x->_mp_size = negative ? -xsize : xsize;
161    }
162  (*__gmp_free_func) (str, alloc_size);
163  return nread;
164}
165