u32.c - vx32 - Local 9vx git repository for patches.
(HTM) git clone git://r-36.net/vx32
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u32.c (2413B)
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1 #include "u.h"
2 #include "lib.h"
3
4 int
5 dec32(uchar *dest, int ndest, char *src, int nsrc)
6 {
7 char *s, *tab;
8 uchar *start;
9 int i, u[8];
10
11 if(ndest+1 < (5*nsrc+7)/8)
12 return -1;
13 start = dest;
14 tab = "23456789abcdefghijkmnpqrstuvwxyz";
15 while(nsrc>=8){
16 for(i=0; i<8; i++){
17 s = strchr(tab,(int)src[i]);
18 u[i] = s ? s-tab : 0;
19 }
20 *dest++ = (u[0]<<3) | (0x7 & (u[1]>>2));
21 *dest++ = ((0x3 & u[1])<<6) | (u[2]<<1) | (0x1 & (u[3]>>4));
22 *dest++ = ((0xf & u[3])<<4) | (0xf & (u[4]>>1));
23 *dest++ = ((0x1 & u[4])<<7) | (u[5]<<2) | (0x3 & (u[6]>>3));
24 *dest++ = ((0x7 & u[6])<<5) | u[7];
25 src += 8;
26 nsrc -= 8;
27 }
28 if(nsrc > 0){
29 if(nsrc == 1 || nsrc == 3 || nsrc == 6)
30 return -1;
31 for(i=0; i<nsrc; i++){
32 s = strchr(tab,(int)src[i]);
33 u[i] = s ? s-tab : 0;
34 }
35 *dest++ = (u[0]<<3) | (0x7 & (u[1]>>2));
36 if(nsrc == 2)
37 goto out;
38 *dest++ = ((0x3 & u[1])<<6) | (u[2]<<1) | (0x1 & (u[3]>>4));
39 if(nsrc == 4)
40 goto out;
41 *dest++ = ((0xf & u[3])<<4) | (0xf & (u[4]>>1));
42 if(nsrc == 5)
43 goto out;
44 *dest++ = ((0x1 & u[4])<<7) | (u[5]<<2) | (0x3 & (u[6]>>3));
45 }
46 out:
47 return dest-start;
48 }
49
50 int
51 enc32(char *dest, int ndest, uchar *src, int nsrc)
52 {
53 char *tab, *start;
54 int j;
55
56 if(ndest <= (8*nsrc+4)/5 )
57 return -1;
58 start = dest;
59 tab = "23456789abcdefghijkmnpqrstuvwxyz";
60 while(nsrc>=5){
61 j = (0x1f & (src[0]>>3));
62 *dest++ = tab[j];
63 j = (0x1c & (src[0]<<2)) | (0x03 & (src[1]>>6));
64 *dest++ = tab[j];
65 j = (0x1f & (src[1]>>1));
66 *dest++ = tab[j];
67 j = (0x10 & (src[1]<<4)) | (0x0f & (src[2]>>4));
68 *dest++ = tab[j];
69 j = (0x1e & (src[2]<<1)) | (0x01 & (src[3]>>7));
70 *dest++ = tab[j];
71 j = (0x1f & (src[3]>>2));
72 *dest++ = tab[j];
73 j = (0x18 & (src[3]<<3)) | (0x07 & (src[4]>>5));
74 *dest++ = tab[j];
75 j = (0x1f & (src[4]));
76 *dest++ = tab[j];
77 src += 5;
78 nsrc -= 5;
79 }
80 if(nsrc){
81 j = (0x1f & (src[0]>>3));
82 *dest++ = tab[j];
83 j = (0x1c & (src[0]<<2));
84 if(nsrc == 1)
85 goto out;
86 j |= (0x03 & (src[1]>>6));
87 *dest++ = tab[j];
88 j = (0x1f & (src[1]>>1));
89 if(nsrc == 2)
90 goto out;
91 *dest++ = tab[j];
92 j = (0x10 & (src[1]<<4));
93 if(nsrc == 3)
94 goto out;
95 j |= (0x0f & (src[2]>>4));
96 *dest++ = tab[j];
97 j = (0x1e & (src[2]<<1));
98 if(nsrc == 4)
99 goto out;
100 j |= (0x01 & (src[3]>>7));
101 *dest++ = tab[j];
102 j = (0x1f & (src[3]>>2));
103 *dest++ = tab[j];
104 j = (0x18 & (src[3]<<3));
105 out:
106 *dest++ = tab[j];
107 }
108 *dest = 0;
109 return dest-start;
110 }