Miroirs/xwords
1
0
Fork 0
mirror of git://xwords.git.sourceforge.net/gitroot/xwords/xwords synced 2024-12-27 09:58:45 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

first attempt, commented out, to hash the stream directly rather than

Browse source 
its exploded contents.  Does't work once there's been some undo
activity as I don't have a way to get the length of the stack below
the undo/redo line.  Looks promising though.
This commit is contained in:
Eric House 2012-05-05 10:47:28 -07:00
parent eb2f5ff6eb
commit 058cbc4e1b
1 changed files with 52 additions and 16 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

68
xwords4/common/movestak.c
View file

@ -26,6 +26,15 @@
#include "memstream.h"
#include "strutils.h"
/* HASH_STREAM: It should be possible to hash the move stack by simply hashing
the stream from the beginning to the top of the undo stack (excluding
what's in the redo area), avoiding iterating over it and doing a ton of
bitwise operations to read it into entries. But I don't currently seem to
have a XWStreamPos that corresponds to the undo-top and so I can't figure
out the length. Hashing that includes the redo part of the stack doesn't
work once there's been undo activity. (Not sure why...) */
// #define HASH_STREAM
#ifdef CPLUS
extern "C" {
#endif
@ -58,8 +67,22 @@ stack_init( StackCtxt* stack )
} /* stack_init */
#ifdef STREAM_VERS_BIGBOARD
#ifdef HASH_STREAM
static XP_U16
figureStackSize( const StackCtxt* stack )
{
XWStreamCtxt* data = stack->data;
XWStreamPos oldReadPos = stream_setPos( data, POS_READ, START_OF_STREAM );
XWStreamPos oldWritePos = stream_setPos( data, POS_WRITE, stack->cachedPos );
XP_U16 len = stream_getSize( data );
(void)stream_setPos( data, POS_READ, oldReadPos );
(void)stream_setPos( data, POS_WRITE, oldWritePos );
return len;
}
#endif
static XP_U32
augmentHash( XP_U32 hash, XP_U8* ptr, XP_U16 len )
augmentHash( XP_U32 hash, const XP_U8* ptr, XP_U16 len )
{
XP_ASSERT( 0 < len );
// see http://en.wikipedia.org/wiki/Jenkins_hash_function
@ -72,9 +95,11 @@ augmentHash( XP_U32 hash, XP_U8* ptr, XP_U16 len )
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
// XP_LOGF( "%s: hashed %d bytes -> %X", __func__, len, (unsigned int)hash );
return hash;
}
#ifndef HASH_STREAM
static XP_U32
augmentFor( XP_U32 hash, const StackEntry* entry )
{
@ -98,12 +123,20 @@ augmentFor( XP_U32 hash, const StackEntry* entry )
}
return hash;
}
#endif
XP_U32
stack_getHash( StackCtxt* stack )
{
XP_U32 hash = 0L;
XP_U32 hash;
#ifdef HASH_STREAM
XP_U16 len = figureStackSize( stack );
const XP_U8* ptr = stream_getPtr( stack->data );
LOG_HEX( ptr, len, __func__ );
hash = augmentHash( 0L, ptr, len );
#else
XP_U16 nn, nEntries = stack->nEntries;
hash = 0L;
for ( nn = 0; nn < nEntries; ++nn ) {
StackEntry entry;
XP_MEMSET( &entry, 0, sizeof(entry) );
@ -115,6 +148,7 @@ stack_getHash( StackCtxt* stack )
}
XP_ASSERT( 0 != hash );
// LOG_RETURNF( "%.8X", (unsigned int)hash );
#endif
return hash;
}
#endif
@ -214,7 +248,7 @@ stack_copy( const StackCtxt* stack )
static void
pushEntry( StackCtxt* stack, const StackEntry* entry )
{
XP_U16 i, bitsPerTile;
XP_U16 ii, bitsPerTile;
XWStreamPos oldLoc;
XP_U16 nTiles = entry->u.move.moveInfo.nTiles;
XWStreamCtxt* stream = stack->data;
@ -239,12 +273,12 @@ pushEntry( StackCtxt* stack, const StackEntry* entry )
stream_putBits( stream, 1, entry->u.move.moveInfo.isHorizontal );
bitsPerTile = stack->bitsPerTile;
XP_ASSERT( bitsPerTile == 5 || bitsPerTile == 6 );
for ( i = 0; i < nTiles; ++i ) {
for ( ii = 0; ii < nTiles; ++ii ) {
Tile tile;
stream_putBits( stream, 5,
entry->u.move.moveInfo.tiles[i].varCoord );
entry->u.move.moveInfo.tiles[ii].varCoord );
tile = entry->u.move.moveInfo.tiles[i].tile;
tile = entry->u.move.moveInfo.tiles[ii].tile;
stream_putBits( stream, bitsPerTile, tile & TILE_VALUE_MASK );
stream_putBits( stream, 1, (tile & TILE_BLANK_BIT) != 0 );
}
@ -270,6 +304,7 @@ pushEntry( StackCtxt* stack, const StackEntry* entry )
++stack->nEntries;
stack->highWaterMark = stack->nEntries;
stack->top = stream_setPos( stream, POS_WRITE, oldLoc );
// XP_LOGF( "after %s size now %d", __func__, figureStackSize( stack ) );
} /* pushEntry */
static void
@ -380,18 +415,18 @@ stack_addAssign( StackCtxt* stack, XP_U16 turn, const TrayTileSet* tiles )
} /* stack_addAssign */
static XP_Bool
setCacheReadyFor( StackCtxt* stack, XP_U16 n )
setCacheReadyFor( StackCtxt* stack, XP_U16 nn )
{
StackEntry dummy;
XP_U16 i;
XP_U16 ii;
stream_setPos( stack->data, POS_READ, START_OF_STREAM );
for ( i = 0; i < n; ++i ) {
for ( ii = 0; ii < nn; ++ii ) {
StackEntry dummy;
readEntry( stack, &dummy );
}
stack->cacheNext = n;
stack->cachedPos = stream_getPos( stack->data, XP_FALSE );
stack->cacheNext = nn;
stack->cachedPos = stream_getPos( stack->data, POS_READ );
return XP_TRUE;
} /* setCacheReadyFor */
@ -434,14 +469,15 @@ stack_getNthEntry( StackCtxt* stack, XP_U16 nn, StackEntry* entry )
XP_Bool
stack_popEntry( StackCtxt* stack, StackEntry* entry )
{
XP_U16 n = stack->nEntries - 1;
XP_Bool found = stack_getNthEntry( stack, n, entry );
XP_U16 nn = stack->nEntries - 1;
XP_Bool found = stack_getNthEntry( stack, nn, entry );
if ( found ) {
stack->nEntries = n;
stack->nEntries = nn;
setCacheReadyFor( stack, n ); /* set cachedPos by side-effect */
setCacheReadyFor( stack, nn ); /* set cachedPos by side-effect */
stack->top = stack->cachedPos;
}
//XP_LOGF( "after %s size now %d", __func__, figureStackSize( stack ) );
return found;
} /* stack_popEntry */