From: Tom Gundersen <teg@jklm.no>
Date: Sat, 3 Oct 2015 19:27:25 +0000 (+0200)
Subject: siphash24: move last compression iteration from compression step to finalization... 
X-Git-Tag: v227.2^2~18
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=16a5cb267fa73a03afc91c372ccc2326db61aa71

siphash24: move last compression iteration from compression step to finalization step

The last compression is special as it deals with the length byte, and padding. Move
it to the finalization step in preparation for making compression decomposable.
---

diff --git a/src/basic/siphash24.c b/src/basic/siphash24.c
index 86d4975ff..8f2f1f553 100644
--- a/src/basic/siphash24.c
+++ b/src/basic/siphash24.c
@@ -57,6 +57,8 @@ struct siphash {
   u64 v1;
   u64 v2;
   u64 v3;
+  u64 padding;
+  size_t inlen;
 };
 
 static void siphash_init(struct siphash *state, const uint8_t k[16]) {
@@ -70,26 +72,27 @@ static void siphash_init(struct siphash *state, const uint8_t k[16]) {
   state->v1 = 0x646f72616e646f6dULL ^ k1;
   state->v2 = 0x6c7967656e657261ULL ^ k0;
   state->v3 = 0x7465646279746573ULL ^ k1;
+  state->padding = 0;
+  state->inlen = 0;
 }
 
 static void siphash24_compress(const void *_in, size_t inlen, struct siphash *state) {
-  u64 b;
   u64 m;
   const u8 *in = _in;
   const u8 *end = in + inlen - ( inlen % sizeof( u64 ) );
   const int left = inlen & 7;
 
-  b = ( ( u64 )inlen ) << 56;
+  state->inlen = inlen;
 
   for ( ; in != end; in += 8 )
   {
     m = U8TO64_LE( in );
 #ifdef DEBUG
-    printf( "(%3d) v0 %08x %08x\n", ( int )inlen, ( u32 )( state->v0 >> 32 ), ( u32 )state->v0 );
-    printf( "(%3d) v1 %08x %08x\n", ( int )inlen, ( u32 )( state->v1 >> 32 ), ( u32 )state->v1 );
-    printf( "(%3d) v2 %08x %08x\n", ( int )inlen, ( u32 )( state->v2 >> 32 ), ( u32 )state->v2 );
-    printf( "(%3d) v3 %08x %08x\n", ( int )inlen, ( u32 )( state->v3 >> 32 ), ( u32 )state->v3 );
-    printf( "(%3d) compress %08x %08x\n", ( int )inlen, ( u32 )( m >> 32 ), ( u32 )m );
+    printf( "(%3d) v0 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v0 >> 32 ), ( u32 )state->v0 );
+    printf( "(%3d) v1 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v1 >> 32 ), ( u32 )state->v1 );
+    printf( "(%3d) v2 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v2 >> 32 ), ( u32 )state->v2 );
+    printf( "(%3d) v3 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v3 >> 32 ), ( u32 )state->v3 );
+    printf( "(%3d) compress %08x %08x\n", ( int )state->inlen, ( u32 )( m >> 32 ), ( u32 )m );
 #endif
     state->v3 ^= m;
     SIPROUND(state);
@@ -99,43 +102,46 @@ static void siphash24_compress(const void *_in, size_t inlen, struct siphash *st
 
   switch( left )
   {
-  case 7: b |= ( ( u64 )in[ 6] )  << 48;
+  case 7: state->padding |= ( ( u64 )in[ 6] )  << 48;
 
-  case 6: b |= ( ( u64 )in[ 5] )  << 40;
+  case 6: state->padding |= ( ( u64 )in[ 5] )  << 40;
 
-  case 5: b |= ( ( u64 )in[ 4] )  << 32;
+  case 5: state->padding |= ( ( u64 )in[ 4] )  << 32;
 
-  case 4: b |= ( ( u64 )in[ 3] )  << 24;
+  case 4: state->padding |= ( ( u64 )in[ 3] )  << 24;
 
-  case 3: b |= ( ( u64 )in[ 2] )  << 16;
+  case 3: state->padding |= ( ( u64 )in[ 2] )  << 16;
 
-  case 2: b |= ( ( u64 )in[ 1] )  <<  8;
+  case 2: state->padding |= ( ( u64 )in[ 1] )  <<  8;
 
-  case 1: b |= ( ( u64 )in[ 0] ); break;
+  case 1: state->padding |= ( ( u64 )in[ 0] ); break;
 
   case 0: break;
   }
+}
+
+static u64 siphash24_finalize(struct siphash *state) {
+  u64 b;
 
+  b = state->padding | (( ( u64 )state->inlen ) << 56);
 #ifdef DEBUG
-  printf( "(%3d) v0 %08x %08x\n", ( int )inlen, ( u32 )( state->v0 >> 32 ), ( u32 )state->v0 );
-  printf( "(%3d) v1 %08x %08x\n", ( int )inlen, ( u32 )( state->v1 >> 32 ), ( u32 )state->v1 );
-  printf( "(%3d) v2 %08x %08x\n", ( int )inlen, ( u32 )( state->v2 >> 32 ), ( u32 )state->v2 );
-  printf( "(%3d) v3 %08x %08x\n", ( int )inlen, ( u32 )( state->v3 >> 32 ), ( u32 )state->v3 );
-  printf( "(%3d) padding   %08x %08x\n", ( int )inlen, ( u32 )( b >> 32 ), ( u32 )b );
+  printf( "(%3d) v0 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v0 >> 32 ), ( u32 )state->v0 );
+  printf( "(%3d) v1 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v1 >> 32 ), ( u32 )state->v1 );
+  printf( "(%3d) v2 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v2 >> 32 ), ( u32 )state->v2 );
+  printf( "(%3d) v3 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v3 >> 32 ), ( u32 )state->v3 );
+  printf( "(%3d) padding   %08x %08x\n", ( int )state->inlen, ( u32 )( state->padding >> 32 ), ( u32 )state->padding );
 #endif
   state->v3 ^= b;
   SIPROUND(state);
   SIPROUND(state);
   state->v0 ^= b;
+
 #ifdef DEBUG
-  printf( "(%3d) v0 %08x %08x\n", ( int )inlen, ( u32 )( state->v0 >> 32 ), ( u32 )state->v0 );
-  printf( "(%3d) v1 %08x %08x\n", ( int )inlen, ( u32 )( state->v1 >> 32 ), ( u32 )state->v1 );
-  printf( "(%3d) v2 %08x %08x\n", ( int )inlen, ( u32 )( state->v2 >> 32 ), ( u32 )state->v2 );
-  printf( "(%3d) v3 %08x %08x\n", ( int )inlen, ( u32 )( state->v3 >> 32 ), ( u32 )state->v3 );
+  printf( "(%3d) v0 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v0 >> 32 ), ( u32 )state->v0 );
+  printf( "(%3d) v1 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v1 >> 32 ), ( u32 )state->v1 );
+  printf( "(%3d) v2 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v2 >> 32 ), ( u32 )state->v2 );
+  printf( "(%3d) v3 %08x %08x\n", ( int )state->inlen, ( u32 )( state->v3 >> 32 ), ( u32 )state->v3 );
 #endif
-}
-
-static u64 siphash24_finalize(struct siphash *state) {
   state->v2 ^= 0xff;
   SIPROUND(state);
   SIPROUND(state);