-# define RC4_STEP ( \
- x=(x+1) &0xff, \
- tx=d[x], \
- y=(tx+y)&0xff, \
- ty=d[y], \
- d[y]=tx, \
- d[x]=ty, \
- (RC4_CHUNK)d[(tx+ty)&0xff]\
- )
-
- if ( ( ((size_t)indata & (sizeof(RC4_CHUNK)-1)) |
- ((size_t)outdata & (sizeof(RC4_CHUNK)-1)) ) == 0 )
- {
- RC4_CHUNK ichunk,otp;
- const union { long one; char little; } is_endian = {1};
-
- /*
- * I reckon we can afford to implement both endian
- * cases and to decide which way to take at run-time
- * because the machine code appears to be very compact
- * and redundant 1-2KB is perfectly tolerable (i.e.
- * in case the compiler fails to eliminate it:-). By
- * suggestion from Terrel Larson <terr@terralogic.net>
- * who also stands for the is_endian union:-)
- *
- * Special notes.
- *
- * - is_endian is declared automatic as doing otherwise
- * (declaring static) prevents gcc from eliminating
- * the redundant code;
- * - compilers (those I've tried) don't seem to have
- * problems eliminating either the operators guarded
- * by "if (sizeof(RC4_CHUNK)==8)" or the condition
- * expressions themselves so I've got 'em to replace
- * corresponding #ifdefs from the previous version;
- * - I chose to let the redundant switch cases when
- * sizeof(RC4_CHUNK)!=8 be (were also #ifdefed
- * before);
- * - in case you wonder "&(sizeof(RC4_CHUNK)*8-1)" in
- * [LB]ESHFT guards against "shift is out of range"
- * warnings when sizeof(RC4_CHUNK)!=8
- *
- * <appro@fy.chalmers.se>
- */
- if (!is_endian.little)
- { /* BIG-ENDIAN CASE */
-# define BESHFT(c) (((sizeof(RC4_CHUNK)-(c)-1)*8)&(sizeof(RC4_CHUNK)*8-1))
- for (;len&(0-sizeof(RC4_CHUNK));len-=sizeof(RC4_CHUNK))
- {
- ichunk = *(RC4_CHUNK *)indata;
- otp = RC4_STEP<<BESHFT(0);
- otp |= RC4_STEP<<BESHFT(1);
- otp |= RC4_STEP<<BESHFT(2);
- otp |= RC4_STEP<<BESHFT(3);
- if (sizeof(RC4_CHUNK)==8)
- {
- otp |= RC4_STEP<<BESHFT(4);
- otp |= RC4_STEP<<BESHFT(5);
- otp |= RC4_STEP<<BESHFT(6);
- otp |= RC4_STEP<<BESHFT(7);
- }
- *(RC4_CHUNK *)outdata = otp^ichunk;
- indata += sizeof(RC4_CHUNK);
- outdata += sizeof(RC4_CHUNK);
- }
- if (len)
- {
- RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk;
-
- ichunk = *(RC4_CHUNK *)indata;
- ochunk = *(RC4_CHUNK *)outdata;
- otp = 0;
- i = BESHFT(0);
- mask <<= (sizeof(RC4_CHUNK)-len)<<3;
- switch (len&(sizeof(RC4_CHUNK)-1))
- {
- case 7: otp = RC4_STEP<<i, i-=8;
- case 6: otp |= RC4_STEP<<i, i-=8;
- case 5: otp |= RC4_STEP<<i, i-=8;
- case 4: otp |= RC4_STEP<<i, i-=8;
- case 3: otp |= RC4_STEP<<i, i-=8;
- case 2: otp |= RC4_STEP<<i, i-=8;
- case 1: otp |= RC4_STEP<<i, i-=8;
- case 0: ; /*
- * it's never the case,
- * but it has to be here
- * for ultrix?
- */
- }
- ochunk &= ~mask;
- ochunk |= (otp^ichunk) & mask;
- *(RC4_CHUNK *)outdata = ochunk;
- }
- key->x=x;
- key->y=y;
- return;
- }
- else
- { /* LITTLE-ENDIAN CASE */
-# define LESHFT(c) (((c)*8)&(sizeof(RC4_CHUNK)*8-1))
- for (;len&(0-sizeof(RC4_CHUNK));len-=sizeof(RC4_CHUNK))
- {
- ichunk = *(RC4_CHUNK *)indata;
- otp = RC4_STEP;
- otp |= RC4_STEP<<8;
- otp |= RC4_STEP<<16;
- otp |= RC4_STEP<<24;
- if (sizeof(RC4_CHUNK)==8)
- {
- otp |= RC4_STEP<<LESHFT(4);
- otp |= RC4_STEP<<LESHFT(5);
- otp |= RC4_STEP<<LESHFT(6);
- otp |= RC4_STEP<<LESHFT(7);
- }
- *(RC4_CHUNK *)outdata = otp^ichunk;
- indata += sizeof(RC4_CHUNK);
- outdata += sizeof(RC4_CHUNK);
- }
- if (len)
- {
- RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk;
-
- ichunk = *(RC4_CHUNK *)indata;
- ochunk = *(RC4_CHUNK *)outdata;
- otp = 0;
- i = 0;
- mask >>= (sizeof(RC4_CHUNK)-len)<<3;
- switch (len&(sizeof(RC4_CHUNK)-1))
- {
- case 7: otp = RC4_STEP, i+=8;
- case 6: otp |= RC4_STEP<<i, i+=8;
- case 5: otp |= RC4_STEP<<i, i+=8;
- case 4: otp |= RC4_STEP<<i, i+=8;
- case 3: otp |= RC4_STEP<<i, i+=8;
- case 2: otp |= RC4_STEP<<i, i+=8;
- case 1: otp |= RC4_STEP<<i, i+=8;
- case 0: ; /*
- * it's never the case,
- * but it has to be here
- * for ultrix?
- */
- }
- ochunk &= ~mask;
- ochunk |= (otp^ichunk) & mask;
- *(RC4_CHUNK *)outdata = ochunk;
- }
- key->x=x;
- key->y=y;
- return;
- }
- }
-#endif