128 lines
3.2 KiB
C
128 lines
3.2 KiB
C
#include <u.h>
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#include <libc.h>
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enum {
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INVAL= 255
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};
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static uchar t64d[256] = {
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INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL, 62,INVAL,INVAL,INVAL, 63,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
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41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,
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INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL,INVAL
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};
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static char t64e[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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int
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dec64(uchar *out, int lim, char *in, int n)
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{
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ulong b24;
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uchar *start = out;
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uchar *e = out + lim;
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int i, c;
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b24 = 0;
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i = 0;
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while(n-- > 0){
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c = t64d[*(uchar*)in++];
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if(c == INVAL)
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continue;
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switch(i){
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case 0:
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b24 = c<<18;
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break;
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case 1:
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b24 |= c<<12;
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break;
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case 2:
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b24 |= c<<6;
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break;
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case 3:
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if(out + 3 > e)
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goto exhausted;
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b24 |= c;
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*out++ = b24>>16;
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*out++ = b24>>8;
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*out++ = b24;
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i = -1;
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break;
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}
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i++;
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}
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switch(i){
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case 2:
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if(out + 1 > e)
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goto exhausted;
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*out++ = b24>>16;
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break;
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case 3:
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if(out + 2 > e)
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goto exhausted;
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*out++ = b24>>16;
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*out++ = b24>>8;
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break;
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}
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exhausted:
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return out - start;
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}
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int
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enc64(char *out, int lim, uchar *in, int n)
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{
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int i;
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ulong b24;
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char *start = out;
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char *e = out + lim;
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for(i = n/3; i > 0; i--){
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b24 = (*in++)<<16;
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b24 |= (*in++)<<8;
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b24 |= *in++;
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if(out + 4 >= e)
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goto exhausted;
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*out++ = t64e[(b24>>18)];
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*out++ = t64e[(b24>>12)&0x3f];
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*out++ = t64e[(b24>>6)&0x3f];
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*out++ = t64e[(b24)&0x3f];
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}
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switch(n%3){
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case 2:
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b24 = (*in++)<<16;
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b24 |= (*in)<<8;
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if(out + 4 >= e)
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goto exhausted;
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*out++ = t64e[(b24>>18)];
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*out++ = t64e[(b24>>12)&0x3f];
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*out++ = t64e[(b24>>6)&0x3f];
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*out++ = '=';
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break;
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case 1:
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b24 = (*in)<<16;
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if(out + 4 >= e)
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goto exhausted;
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*out++ = t64e[(b24>>18)];
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*out++ = t64e[(b24>>12)&0x3f];
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*out++ = '=';
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*out++ = '=';
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break;
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}
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exhausted:
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*out = 0;
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return out - start;
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}
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