What on earth happened to platform.h?

[Denys Vlasenko]

On Sunday 24 October 2010 11:02, Rob Landley wrote:
> Attached is the sha1sum.c I wrote for toybox a few years back.  (Never did 
> quite get around to cleaning it up, extending it to support the various other 
> shaXXXsum sizes, or implementing md5sum.  My todo list runneth over.)  But 
> what I was going for was _simple_, and I confirmed it produced the right output 
> on all the data I threw at it.  It's 185 lines including the actual applet 
> implementation and help text and everything.  The busybox one is 900 lines for 
> the engine.

Patch: -19 bytes on x86, sums 300 mbytes in 4 seconds instead of 5.4:

-- 
vda

--- sha1sum.c.orig
+++ sha1sum.c
@@ -58,34 +58,33 @@
 {
 	int i, j, k, count;
 	uint32_t *block = this->buffer.i;
-	uint32_t *rot[5], *temp;
+	uint32_t rot[5], temp;
 
 	// Copy context->state[] to working vars
 	for (i=0; i<5; i++) {
-		this->oldstate[i] = this->state[i];
-		rot[i] = this->state + i;
+		rot[i] = this->state[i];
 	}
 	// 4 rounds of 20 operations each.
 	for (i=count=0; i<4; i++) {
 		for (j=0; j<20; j++) {
 			uint32_t work;
 
-			work = *rot[2] ^ *rot[3];
-			if (!i) work = (work & *rot[1]) ^ *rot[3];
+			work = rot[2] ^ rot[3];
+			if (!i) work = (work & rot[1]) ^ rot[3];
 			else {
 				if (i==2)
-					work = ((*rot[1]|*rot[2])&*rot[3])|(*rot[1]&*rot[2]);
-				else work ^= *rot[1];
+					work = ((rot[1]|rot[2])&rot[3])|(rot[1]&rot[2]);
+				else work ^= rot[1];
 			}
 			if (!i && j<16) work += blk0(count);
 			else work += blk(count);
-			*rot[4] += work + rol(*rot[0],5) + rconsts[i];
-			*rot[1] = rol(*rot[1],30);
+			rot[4] += work + rol(rot[0],5) + rconsts[i];
+			rot[1] = rol(rot[1],30);
 
 			// Rotate by one for next time.
 			temp = rot[4];
 			for (k=4; k; k--) rot[k] = rot[k-1];
-			*rot = temp;
+			rot[0] = temp;
 			count++;
 		}
 	}