1 #include "os.h"
2 #include <mp.h>
3 #include "dat.h"
4 
5 static struct {
6 	int	inited;
7 
8 	uchar	t64[256];
9 	uchar	t32[256];
10 	uchar	t16[256];
11 	uchar	t10[256];
12 } tab;
13 
14 enum {
15 	INVAL=	255
16 };
17 
18 static char set64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
19 static char set32[] = "23456789abcdefghijkmnpqrstuvwxyz";
20 static char set16[] = "0123456789ABCDEF0123456789abcdef";
21 static char set10[] = "0123456789";
22 
23 static void
24 init(void)
25 {
26 	char *p;
27 
28 	memset(tab.t64, INVAL, sizeof(tab.t64));
29 	memset(tab.t32, INVAL, sizeof(tab.t32));
30 	memset(tab.t16, INVAL, sizeof(tab.t16));
31 	memset(tab.t10, INVAL, sizeof(tab.t10));
32 
33 	for(p = set64; *p; p++)
34 		tab.t64[(uchar)*p] = p-set64;
35 	for(p = set32; *p; p++)
36 		tab.t32[(uchar)*p] = p-set32;
37 	for(p = set16; *p; p++)
38 		tab.t16[(uchar)*p] = (p-set16)%16;
39 	for(p = set10; *p; p++)
40 		tab.t10[(uchar)*p] = (p-set10);
41 
42 	tab.inited = 1;
43 }
44 
45 static char*
46 from16(char *a, mpint *b)
47 {
48 	char *p, *next;
49 	int i;
50 	mpdigit x;
51 
52 	b->top = 0;
53 	for(p = a; *p; p++)
54 		if(tab.t16[*(uchar*)p] == INVAL)
55 			break;
56 	mpbits(b, (p-a)*4);
57 	b->top = 0;
58 	next = p;
59 	while(p > a){
60 		x = 0;
61 		for(i = 0; i < Dbits; i += 4){
62 			if(p <= a)
63 				break;
64 			x |= tab.t16[*(uchar*)--p]<<i;
65 		}
66 		b->p[b->top++] = x;
67 	}
68 	return next;
69 }
70 
71 static ulong mppow10[] = {
72 	1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000
73 };
74 
75 static char*
76 from10(char *a, mpint *b)
77 {
78 	ulong x, y;
79 	mpint *pow, *r;
80 	int i;
81 
82 	pow = mpnew(0);
83 	r = mpnew(0);
84 
85 	b->top = 0;
86 	for(;;){
87 		/* do a billion at a time in native arithmetic */
88 		x = 0;
89 		for(i = 0; i < 9; i++){
90 			y = tab.t10[*(uchar*)a];
91 			if(y == INVAL)
92 				break;
93 			a++;
94 			x *= 10;
95 			x += y;
96 		}
97 		if(i == 0)
98 			break;
99 
100 		/* accumulate into mpint */
101 		uitomp(mppow10[i], pow);
102 		uitomp(x, r);
103 		mpmul(b, pow, b);
104 		mpadd(b, r, b);
105 		if(i != 9)
106 			break;
107 	}
108 	mpfree(pow);
109 	mpfree(r);
110 	return a;
111 }
112 
113 static char*
114 from64(char *a, mpint *b)
115 {
116 	char *buf = a;
117 	uchar *p;
118 	int n, m;
119 
120 	for(; tab.t64[*(uchar*)a] != INVAL; a++)
121 		;
122 	n = a-buf;
123 	mpbits(b, n*6);
124 	p = malloc(n);
125 	if(p == nil)
126 		return a;
127 	m = dec64(p, n, buf, n);
128 	betomp(p, m, b);
129 	free(p);
130 	return a;
131 }
132 
133 static char*
134 from32(char *a, mpint *b)
135 {
136 	char *buf = a;
137 	uchar *p;
138 	int n, m;
139 
140 	for(; tab.t64[*(uchar*)a] != INVAL; a++)
141 		;
142 	n = a-buf;
143 	mpbits(b, n*5);
144 	p = malloc(n);
145 	if(p == nil)
146 		return a;
147 	m = dec32(p, n, buf, n);
148 	betomp(p, m, b);
149 	free(p);
150 	return a;
151 }
152 
153 mpint*
154 strtomp(char *a, char **pp, int base, mpint *b)
155 {
156 	int sign;
157 	char *e;
158 
159 	if(b == nil)
160 		b = mpnew(0);
161 
162 	if(tab.inited == 0)
163 		init();
164 
165 	while(*a==' ' || *a=='\t')
166 		a++;
167 
168 	sign = 1;
169 	for(;; a++){
170 		switch(*a){
171 		case '-':
172 			sign *= -1;
173 			continue;
174 		}
175 		break;
176 	}
177 
178 	switch(base){
179 	case 10:
180 		e = from10(a, b);
181 		break;
182 	default:
183 	case 16:
184 		e = from16(a, b);
185 		break;
186 	case 32:
187 		e = from32(a, b);
188 		break;
189 	case 64:
190 		e = from64(a, b);
191 		break;
192 	}
193 
194 	/* if no characters parsed, there wasn't a number to convert */
195 	if(e == a)
196 		return nil;
197 
198 	mpnorm(b);
199 	b->sign = sign;
200 	if(pp != nil)
201 		*pp = e;
202 
203 	return b;
204 }