1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
const int gifsize;
void captcha(unsigned char im[70*200], unsigned char l[6]);
void makegif(unsigned char im[70*200], unsigned char gif[gifsize]);
#include <unistd.h>
#include <stdint.h>
#include <fcntl.h>
#include <string.h>
static int8_t *lt[];
const int gifsize=17646;
void makegif(unsigned char im[70*200], unsigned char gif[gifsize]) {
// tag ; widthxheight ; GCT:0:0:7 ; bgcolor + aspect // GCT
// Image Separator // left x top // widthxheight // Flags
// LZW code size
memcpy(gif,"GIF89a" "\xc8\0\x46\0" "\x83" "\0\0"
"\x00\x00\x00"
"\x10\x10\x10"
"\x20\x20\x20"
"\x30\x30\x30"
"\x40\x40\x40"
"\x50\x50\x50"
"\x60\x60\x60"
"\x70\x70\x70"
"\x80\x80\x80"
"\x90\x90\x90"
"\xa0\xa0\xa0"
"\xb0\xb0\xb0"
"\xc0\xc0\xc0"
"\xd0\xd0\xd0"
"\xe0\xe0\xe0"
"\xff\xff\xff"
"," "\0\0\0\0" "\xc8\0\x46\0" "\0" "\x04",13+48+10+1);
int x,y;
unsigned char *i=im;
unsigned char *p=gif+13+48+10+1;
for(y=0;y<70;y++) {
*p++=250; // Data length 5*50=250
for(x=0;x<50;x++)
{
unsigned char a=i[0]>>4,b=i[1]>>4,c=i[2]>>4,d=i[3]>>4;
p[0]=16|(a<<5); // bbb10000
p[1]=(a>>3)|64|(b<<7); // b10000xb
p[2]=b>>1; // 0000xbbb
p[3]=1|(c<<1); // 00xbbbb1
p[4]=4|(d<<3); // xbbbb100
i+=4;
p+=5;
}
}
// Data length // End of LZW (b10001) // Terminator // GIF End
memcpy(gif+gifsize-4,"\x01" "\x11" "\x00" ";",4);
}
static const int8_t sw[200]={0, 4, 8, 12, 16, 20, 23, 27, 31, 35, 39, 43, 47, 50, 54, 58, 61, 65, 68, 71, 75, 78, 81, 84, 87, 90, 93, 96, 98, 101, 103, 105, 108, 110, 112, 114, 115, 117, 119, 120, 121, 122, 123, 124, 125, 126, 126, 127, 127, 127, 127, 127, 127, 127, 126, 126, 125, 124, 123, 122, 121, 120, 119, 117, 115, 114, 112, 110, 108, 105, 103, 101, 98, 96, 93, 90, 87, 84, 81, 78, 75, 71, 68, 65, 61, 58, 54, 50, 47, 43, 39, 35, 31, 27, 23, 20, 16, 12, 8, 4, 0, -4, -8, -12, -16, -20, -23, -27, -31, -35, -39, -43, -47, -50, -54, -58, -61, -65, -68, -71, -75, -78, -81, -84, -87, -90, -93, -96, -98, -101, -103, -105, -108, -110, -112, -114, -115, -117, -119, -120, -121, -122, -123, -124, -125, -126, -126, -127, -127, -127, -127, -127, -127, -127, -126, -126, -125, -124, -123, -122, -121, -120, -119, -117, -115, -114, -112, -110, -108, -105, -103, -101, -98, -96, -93, -90, -87, -84, -81, -78, -75, -71, -68, -65, -61, -58, -54, -50, -47, -43, -39, -35, -31, -27, -23, -20, -16, -12, -8, -4};
#define MAX(x,y) ((x>y)?(x):(y))
static int letter(int n, int pos, unsigned char im[70*200], unsigned char swr[200], uint8_t s1, uint8_t s2) {
int8_t *p=lt[n];
unsigned char *r=im+200*16+pos;
unsigned char *i=r;
int sk1=s1+pos;
int sk2=s2+pos;
int mpos=pos;
int row=0;
for(;*p!=-101;p++) {
if(*p<0) {
if(*p==-100) { r+=200; i=r; sk1=s1+pos; row++; continue; }
i+=-*p;
continue;
}
if(sk1>=200) sk1=sk1%200;
int skew=sw[sk1]/16;
sk1+=(swr[pos+i-r]&0x1)+1;
if(sk2>=200) sk2=sk2%200;
int skewh=sw[sk2]/70;
sk2+=(swr[row]&0x1);
unsigned char *x=i+skew*200+skewh;
mpos=MAX(mpos,pos+i-r);
if((x-im)<70*200) *x=(*p)<<4;
i++;
}
return mpos;
}
#define NDOTS 100
uint32_t dr[NDOTS];
static void line(unsigned char im[70*200], unsigned char swr[200], uint8_t s1) {
int x;
int sk1=s1;
for(x=0;x<199;x++) {
if(sk1>=200) sk1=sk1%200;
int skew=sw[sk1]/16;
sk1+=swr[x]&0x3+1;
unsigned char *i= im+(200*(45+skew)+x);
i[0]=0; i[1]=0; i[200]=0; i[201]=0;
}
}
static void dots(unsigned char im[70*200]) {
int n;
for(n=0;n<NDOTS;n++) {
uint32_t v=dr[n];
unsigned char *i=im+v%(200*67);
i[0]=0xff;
i[1]=0xff;
i[2]=0xff;
i[200]=0xff;
i[201]=0xff;
i[202]=0xff;
}
}
static void blur(unsigned char im[70*200]) {
unsigned char *i=im;
int x,y;
for(y=0;y<68;y++) {
for(x=0;x<198;x++) {
unsigned int c11=*i,c12=i[1],c21=i[200],c22=i[201];
*i++=((c11+c12+c21+c22)/4);
}
}
}
static void filter(unsigned char im[70*200]) {
unsigned char om[70*200];
unsigned char *i=im;
unsigned char *o=om;
memset(om,0xff,sizeof(om));
int x,y;
for(y=0;y<70;y++) {
for(x=4;x<200-4;x++) {
if(i[0]>0xf0 && i[1]<0xf0) { o[0]=0; o[1]=0; }
else if(i[0]<0xf0 && i[1]>0xf0) { o[0]=0; o[1]=0; }
i++;
o++;
}
}
memmove(im,om,sizeof(om));
}
static const char *letters="abcdafahijklmnopqrstuvwxyz";
void captcha(unsigned char im[70*200], unsigned char l[6]) {
unsigned char swr[200];
uint8_t s1,s2;
int f=open("/dev/urandom",O_RDONLY);
read(f,l,5); read(f,swr,200); read(f,dr,sizeof(dr)); read(f,&s1,1); read(f,&s2,1);
close(f);
memset(im,0xff,200*70); s1=s1&0x7f; s2=s2&0x3f; l[0]%=25; l[1]%=25; l[2]%=25; l[3]%=25; l[4]%=25; l[5]=0;
int p=30; p=letter(l[0],p,im,swr,s1,s2); p=letter(l[1],p,im,swr,s1,s2); p=letter(l[2],p,im,swr,s1,s2); p=letter(l[3],p,im,swr,s1,s2); letter(l[4],p,im,swr,s1,s2);
dots(im); blur(im); filter(im); line(im,swr,s1);
l[0]=letters[l[0]]; l[1]=letters[l[1]]; l[2]=letters[l[2]]; l[3]=letters[l[3]]; l[4]=letters[l[4]];
}
#ifdef CAPTCHA
int main() {
char l[6];
unsigned char im[70*200];
unsigned char gif[gifsize];
captcha(im,l);
makegif(im,gif);
write(1,gif,gifsize);
write(2,l,5);
return 0;
}
#endif
#include "f.h"
|
