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change file trans.{c,h} to encode.{c,h}

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This commit is contained in:
Eric 2025-05-26 23:12:16 +02:00
parent 221a8588c0
commit 28fcd5ed7a
4 changed files with 7 additions and 7 deletions
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94
trans.c
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@ -1,94 +0,0 @@
#include "trans.h"
#define PADDING '='
unsigned char b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
"abcdefghijklmnopqrstuvwxyz" \
"0123456789" \
"+/";
int
encode(unsigned char *op, int olen, unsigned char *sp)
{
int n;
unsigned char *sb;
sb = sp;
switch (olen) {
case 3:
*sp++ = b64[(*op & ~3) >> 2];
n = (*op++ & 3) << 4;
*sp++ = b64[n + ((*op & ~15) >> 4)];
n = (*op++ & 15) << 2;
*sp++ = b64[n + ((*op & 192) >> 6)];
*sp = b64[*op & ~192];
break;
case 2:
*sp++ = b64[(*op & ~3) >> 2];
n = (*op++ & 3) << 4;
*sp++ = b64[n + ((*op & ~15) >> 4)];
*sp++ = b64[(*op & 15) << 2];
*sp = PADDING;
break;
case 1:
*sp++ = b64[(*op & ~3) >> 2];
*sp++ = b64[(*op & 3) << 4];
*sp++ = PADDING;
*sp = PADDING;
break;
}
return sp-sb+1;
}
int
decode(unsigned char *sp, int slen, unsigned char *op)
{
int n, b, atob(int c);
unsigned char *ob;
ob = op;
switch (slen) {
case 4:
n = atob(*sp++) << 2;
b = atob(*sp++);
*op++ = n + ((b & ~15) >> 4);
n = (b & 15) << 4;
b = atob(*sp++);
*op++ = n + ((b & ~3) >> 2);
*op = ((b & 3) << 6) + atob(*sp);
break;
case 3:
n = atob(*sp++) << 2;
b = atob(*sp++);
*op++ = n + ((b & ~15) >> 4);
n = (b & 15) << 4;
*op = n + ((atob(*sp) & ~3) >> 2);
break;
case 2:
n = atob(*sp++) << 2;
*op = n + ((atob(*sp) & ~15) >> 4);
break;
}
return op-ob+1;
}
int atob(int c)
{
if (c >= 'A' && c <= 'Z')
c -= 'A';
else if (c >= 'a' && c <= 'z')
c = c - 'a' + 26;
else if (c >= '0' && c <= '9')
c = c - '0' + 26 * 2;
else if (c == '+')
c = 62;
else
c = 63;
return c;
}