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And undo, due to coding style and changed interface.

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This commit is contained in:
Alcaro 2014-02-22 19:21:55 +01:00
parent f055060878
commit 1748442199
1 changed files with 269 additions and 339 deletions
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608
rewind.c
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@ -1,5 +1,25 @@
#include "minir.h"
/* RetroArch - A frontend for libretro.
* Copyright (C) 2010-2014 - Hans-Kristian Arntzen
*
* RetroArch is free software: you can redistribute it and/or modify it under the terms
* of the GNU General Public License as published by the Free Software Found-
* ation, either version 3 of the License, or (at your option) any later version.
*
* RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with RetroArch.
* If not, see <http://www.gnu.org/licenses/>.
*/
#define __STDC_LIMIT_MACROS
#include "rewind.h"
#include <stdlib.h>
#include "msvc/msvc-stdint/stdint.h"
//#define NO_UNALIGNED_MEM
//Uncomment the above if alignment is enforced.
//Format per frame:
//size nextstart;
@ -23,7 +43,7 @@
//Each size value is stored native endian if alignment is not enforced; if it is, they're little endian.
//The start of the buffer contains a size pointing to the end of the buffer; the end points to its start.
//Wrapping is handled by returning to the start of the buffer if the compressed data could potentially hit the edge;
//if the compressed data could potentially overwrite the tail pointer, the tail retreats until it can no longer collide.
// if the compressed data could potentially overwrite the tail pointer, the tail retreats until it can no longer collide.
//This means that on average, ~2*maxcompsize is unused at any given moment.
#if SIZE_MAX == 0xFFFFFFFF
@ -41,29 +61,29 @@ extern char double_check_sizeof_size_t[(sizeof(size_t)==8)?1:-1];
#ifdef USE_64BIT
static inline void write_size_t(uint16_t* ptr, size_t val)
{
ptr[0]=val>>0;
ptr[1]=val>>16;
ptr[2]=val>>32;
ptr[3]=val>>48;
ptr[0] = val>>0;
ptr[1] = val>>16;
ptr[2] = val>>32;
ptr[3] = val>>48;
}
static inline size_t read_size_t(uint16_t* ptr)
{
return ((size_t)ptr[0]<<0 |
(size_t)ptr[1]<<16 |
(size_t)ptr[2]<<32 |
(size_t)ptr[3]<<48);
return ((size_t)ptr[0]<<0 |
(size_t)ptr[1]<<16 |
(size_t)ptr[2]<<32 |
(size_t)ptr[3]<<48);
}
#else
static inline void write_size_t(uint16_t* ptr, size_t val)
{
ptr[0]=val;
ptr[1]=val>>16;
ptr[0] = val;
ptr[1] = val>>16;
}
static inline size_t read_size_t(uint16_t* ptr)
{
return (ptr[0] | (size_t)ptr[1]<<16);
return (ptr[0] | (size_t)ptr[1]<<16);
}
#endif
@ -72,95 +92,163 @@ static inline size_t read_size_t(uint16_t* ptr)
#define write_size_t(ptr, val) (*(size_t*)(ptr) = (val))
#endif
struct rewindstack_impl {
struct rewindstack i;
char * data;
size_t capacity;
char * head;//Reading and writing is done here.
char * tail;//If head comes close to this, discard a frame.
char * thisblock;
char * nextblock;
bool thisblock_valid;
size_t blocksize;//This one is runded up from reset::blocksize.
size_t maxcompsize;//size_t+(blocksize+131071)/131072*(blocksize+u16+u16)+u16+u32+size_t (yes, the math is a bit ugly)
unsigned int entries;
struct state_manager {
char *data;
size_t capacity;
char *head;//Reading and writing is done here.
char *tail;//If head comes close to this, discard a frame.
char *thisblock;
char *nextblock;
bool thisblock_valid;
size_t blocksize;//This one is runded up from reset::blocksize.
size_t maxcompsize;//size_t+(blocksize+131071)/131072*(blocksize+u16+u16)+u16+u32+size_t (yes, the math is a bit ugly)
unsigned int entries;
};
static void reset(struct rewindstack * this_, size_t blocksize, size_t capacity)
state_manager_t *state_manager_new(size_t state_size, size_t buffer_size)
{
struct rewindstack_impl * this=(struct rewindstack_impl*)this_;
int newblocksize=((blocksize-1)|(sizeof(uint16_t)-1))+1;
if (this->blocksize!=newblocksize)
{
this->blocksize=newblocksize;
const int maxcblkcover=UINT16_MAX*sizeof(uint16_t);
const int maxcblks=(this->blocksize+maxcblkcover-1)/maxcblkcover;
this->maxcompsize=this->blocksize + maxcblks*sizeof(uint16_t)*2 + sizeof(uint16_t)+sizeof(uint32_t) + sizeof(size_t)*2;
free(this->thisblock);
free(this->nextblock);
this->thisblock=calloc(this->blocksize+sizeof(uint16_t)*4+16, 1);
this->nextblock=calloc(this->blocksize+sizeof(uint16_t)*4+16, 1);
//Force in a different byte at the end, so we don't need to check bounds in the innermost loop (it's expensive).
//There is also a large amount of data that's the same, to stop the other scan
//There is also some padding at the end. This is so we don't read outside the buffer end if we're reading in large blocks;
// it doesn't make any difference to us, but sacrificing 16 bytes to get Valgrind happy is worth it.
*(uint16_t*)(this->thisblock+this->blocksize+sizeof(uint16_t)*3)=0xFFFF;
*(uint16_t*)(this->nextblock+this->blocksize+sizeof(uint16_t)*3)=0x0000;
}
if (capacity!=this->capacity)
{
free(this->data);
this->data=malloc(capacity);
this->capacity=capacity;
}
this->head=this->data+sizeof(size_t);
this->tail=this->data+sizeof(size_t);
this->thisblock_valid=false;
this->entries=0;
state_manager_t *state = (state_manager_t*)malloc(sizeof(*state));
state->capacity = 0;
state->blocksize = 0;
int newblocksize = ((state_size-1)|(sizeof(uint16_t)-1))+1;
state->blocksize = newblocksize;
const int maxcblkcover = UINT16_MAX*sizeof(uint16_t);
const int maxcblks = (state->blocksize+maxcblkcover-1)/maxcblkcover;
state->maxcompsize = state->blocksize + maxcblks*sizeof(uint16_t)*2 + sizeof(uint16_t)+sizeof(uint32_t) + sizeof(size_t)*2;
state->data = (char*)malloc(buffer_size);
state->thisblock = (char*)calloc(state->blocksize+sizeof(uint16_t)*4+16, 1);
state->nextblock = (char*)calloc(state->blocksize+sizeof(uint16_t)*4+16, 1);
if (!state->data || !state->thisblock || !state->nextblock)
{
free(state->data);
free(state->thisblock);
free(state->nextblock);
free(state);
return NULL;
}
//Force in a different byte at the end, so we don't need to check bounds in the innermost loop (it's expensive).
//There is also a large amount of data that's the same, to stop the other scan
//There is also some padding at the end. This is so we don't read outside the buffer end if we're reading in large blocks;
// it doesn't make any difference to us, but sacrificing 16 bytes to get Valgrind happy is worth it.
*(uint16_t*)(state->thisblock+state->blocksize+sizeof(uint16_t)*3) = 0xFFFF;
*(uint16_t*)(state->nextblock+state->blocksize+sizeof(uint16_t)*3) = 0x0000;
state->capacity=buffer_size;
state->head = state->data+sizeof(size_t);
state->tail = state->data+sizeof(size_t);
state->thisblock_valid = false;
state->entries = 0;
return state;
}
static void * push_begin(struct rewindstack * this_)
void state_manager_free(state_manager_t *state)
{
struct rewindstack_impl * this=(struct rewindstack_impl*)this_;
//We need to ensure we have an uncompressed copy of the last pushed state, or we could
// end up applying a 'patch' to wrong savestate, and that'd blow up rather quickly.
if (!this->thisblock_valid)
{
if (this_->pull(this_))
{
this->thisblock_valid=true;
this->entries++;
}
}
return this->nextblock;
free(state->data);
free(state->thisblock);
free(state->nextblock);
free(state);
}
bool state_manager_pop(state_manager_t *state, const void **data)
{
*data = NULL;
if (state->thisblock_valid)
{
state->thisblock_valid = false;
state->entries--;
*data = state->thisblock;
return true;
}
if (state->head == state->tail) return false;
size_t start = read_size_t((uint16_t*)(state->head - sizeof(size_t)));
state->head = state->data+start;
const char *compressed = state->data+start+sizeof(size_t);
char *out = state->thisblock;
//Begin decompression code
//out is the last pushed (or returned) state
const uint16_t *compressed16 = (const uint16_t*)compressed;
uint16_t *out16 = (uint16_t*)out;
while (true)
{
uint16_t numchanged = *(compressed16++);
if (numchanged)
{
out16 += *(compressed16++);
//We could do memcpy, but it seems that memcpy has a constant-per-call overhead that actually shows up.
//Our average size in here seems to be 8 or something.
//Therefore, we do something with lower overhead.
for (int i=0;i<numchanged;i++) out16[i] = compressed16[i];
compressed16 += numchanged;
out16 += numchanged;
}
else
{
uint32_t numunchanged = compressed16[0] | compressed16[1]<<16;
if (!numunchanged) break;
compressed16 += 2;
out16 += numunchanged;
}
}
//End decompression code
state->entries--;
*data = state->thisblock;
return true;
}
void state_manager_push_where(state_manager_t *state, void **data)
{
//We need to ensure we have an uncompressed copy of the last pushed state, or we could
// end up applying a 'patch' to wrong savestate, and that'd blow up rather quickly.
if (!state->thisblock_valid)
{
const void *ignored;
if (state_manager_pop(state, &ignored))
{
state->thisblock_valid = true;
state->entries++;
}
}
*data=state->nextblock;
}
#if __SSE2__
#if defined(__GNUC__)
static inline int compat_ctz(unsigned int x)
{
return __builtin_ctz(x);
return __builtin_ctz(x);
}
#else
// Only checks at nibble granularity, because that's what we need.
static inline int compat_ctz(unsigned int x)
{
if (x&0x000f) return 0;
if (x&0x00f0) return 4;
if (x&0x0f00) return 8;
if (x&0xf000) return 12;
return 16;
if (x & 0x000f)
return 0;
if (x & 0x00f0)
return 4;
if (x & 0x0f00)
return 8;
if (x & 0xf000)
return 12;
return 16;
}
#endif
@ -220,11 +308,11 @@ static inline size_t find_change(const uint16_t * a, const uint16_t * b)
}
#endif
#if __SSE2__x
#if __SSE2__x // this is not a typo - do not fix unless you can show evidence that this version is faster
//This one can give different answers than the C version in some cases. However, the compression ratio remains unaffected.
//It also appears to be slower. Probably due to the low average duration of this loop.
static inline size_t find_same(const uint16_t * a, const uint16_t * b)
{gfgf
{
if (a[0]==b[0] && a[1]==b[1]) return 0;
if (a[1]==b[1] && a[2]==b[2]) return 1;
if (a[2]==b[2] && a[3]==b[3]) return 2;
@ -249,8 +337,6 @@ static inline size_t find_same(const uint16_t * a, const uint16_t * b)
}
}
#else
//desired comp ratio: 4.074198%
//*
static inline size_t find_same(const uint16_t * a, const uint16_t * b)
{
const uint16_t * a_org=a;
@ -285,261 +371,105 @@ static inline size_t find_same(const uint16_t * a, const uint16_t * b)
}
return a-a_org;
}
/*/
static inline size_t find_same(const uint16_t * a, const uint16_t * b)
{
const uint16_t * a_org=a;
//Comparing two or three words makes no real difference.
//With two, the smaller blocks are less likely to be chopped up elsewhere due to 64KB;
// with three, we get larger blocks which should be a minuscle bit faster to decompress,
// but probably a little slower to compress. Since compression is more bottleneck than decompression is, we favor that.
while (a[0]!=b[0] || a[1]!=b[1])
{
a++;
b++;
//Optimize this by only checking one at the time for as long as possible.
while (*a!=*b)
{
a++;
b++;
}
}
return a-a_org;
}
//*/
#endif
#include<stdio.h>
static void push_end(struct rewindstack * this_)
void state_manager_push_do(state_manager_t *state)
{
struct rewindstack_impl * this=(struct rewindstack_impl*)this_;
if (this->thisblock_valid)
{
/*
if(1)
{
static FILE * out=NULL;
bool q=0;
if(!out)out=fopen("diff.bin", "wb"),q=1;
int p=0;
while (p<this->blocksize)
{
int pp=p;
while(this->thisblock[p]==this->nextblock[p]) p++;
unsigned int o2=p-pp;
while(o2>0xFFFF)
{
unsigned short l=0;
unsigned short h=0xFFFF;
fwrite(&h, 2,1, out);
fwrite(&l, 2,1, out);
o2-=0xFFFF;
}
unsigned short o=o2;
fwrite(&o, 2,1, out);
pp=p;
while(this->thisblock[p]!=this->nextblock[p]) p++;
o2=p-pp;
while(o2>0xFFFF)
{
unsigned short l=0;
unsigned short h=0xFFFF;
fwrite(&l, 2,1, out);
fwrite(&h, 2,1, out);
o2-=0xFFFF;
}
o=o2;
fwrite(&o, 2,1, out);
}
fflush(out);
if(q)printf("[%i %zu]\n",p,this->blocksize);
}
// */
if (this->capacity<sizeof(size_t)+this->maxcompsize) return;
recheckcapacity:;
size_t headpos=(this->head-this->data);
size_t tailpos=(this->tail-this->data);
size_t remaining=(tailpos+this->capacity-sizeof(size_t)-headpos-1)%this->capacity + 1;
if (remaining<=this->maxcompsize)
{
this->tail=this->data + read_size_t((uint16_t*)this->tail);
this->entries--;
goto recheckcapacity;
}
const char* old=this->thisblock;
const char* new=this->nextblock;
char* compressed=this->head+sizeof(size_t);
//Begin compression code; 'compressed' will point to the end of the compressed data (excluding the prev pointer).
const uint16_t * old16=(const uint16_t*)old;
const uint16_t * new16=(const uint16_t*)new;
uint16_t * compressed16=(uint16_t*)compressed;
size_t num16s=this->blocksize/sizeof(uint16_t);
while (num16s)
{
size_t skip=find_change(old16, new16);
//size_t skip=find_change_b(old16, new16);
//if (skip!=skip2) abort();
if (skip>=num16s) break;
old16+=skip;
new16+=skip;
num16s-=skip;
if (skip>UINT16_MAX)
{
if (skip>UINT32_MAX)
{
//This will make it scan the entire thing again, but it only hits on 8GB unchanged
//data anyways, and if you're doing that, you've got bigger problems.
skip=UINT32_MAX;
}
*(compressed16++)=0;
*(compressed16++)=skip;
*(compressed16++)=skip>>16;
skip=0;
continue;
}
size_t changed=find_same(old16, new16);
if (changed>UINT16_MAX) changed=UINT16_MAX;
*(compressed16++)=changed;
*(compressed16++)=skip;
for (int i=0;i<changed;i++) compressed16[i]=old16[i];
old16+=changed;
new16+=changed;
compressed16+=changed;
num16s-=changed;
}
compressed16[0]=0;
compressed16[1]=0;
compressed16[2]=0;
compressed=(char*)(compressed16+3);
//End compression code.
if (compressed-this->data+this->maxcompsize > this->capacity)
{
compressed=this->data;
if (this->tail==this->data+sizeof(size_t)) this->tail=this->data + *(size_t*)this->tail;
}
write_size_t((uint16_t*)compressed, this->head-this->data);
compressed+=sizeof(size_t);
write_size_t((uint16_t*)this->head, compressed-this->data);
this->head=compressed;
}
else
{
this->thisblock_valid=true;
}
char * swap=this->thisblock;
this->thisblock=this->nextblock;
this->nextblock=swap;
this->entries++;
if (state->thisblock_valid)
{
if (state->capacity<sizeof(size_t)+state->maxcompsize) return;
recheckcapacity:;
size_t headpos = (state->head-state->data);
size_t tailpos = (state->tail-state->data);
size_t remaining = (tailpos+state->capacity-sizeof(size_t)-headpos-1)%state->capacity + 1;
if (remaining <= state->maxcompsize)
{
state->tail = state->data + read_size_t((uint16_t*)state->tail);
state->entries--;
goto recheckcapacity;
}
const char *oldb = state->thisblock;
const char *newb = state->nextblock;
char *compressed = state->head+sizeof(size_t);
//Begin compression code; 'compressed' will point to the end of the compressed data (excluding the prev pointer).
const uint16_t *old16 = (const uint16_t*)oldb;
const uint16_t *new16 = (const uint16_t*)newb;
uint16_t *compressed16 = (uint16_t*)compressed;
size_t num16s = state->blocksize/sizeof(uint16_t);
while (num16s)
{
size_t skip = find_change(old16, new16);
if (skip >= num16s) break;
old16+=skip;
new16+=skip;
num16s-=skip;
if (skip > UINT16_MAX)
{
if (skip > UINT32_MAX)
{
//This will make it scan the entire thing again, but it only hits on 8GB unchanged
//data anyways, and if you're doing that, you've got bigger problems.
skip = UINT32_MAX;
}
*(compressed16++) = 0;
*(compressed16++) = skip;
*(compressed16++) = skip>>16;
skip = 0;
continue;
}
size_t changed=find_same(old16, new16);
if (changed>UINT16_MAX) changed=UINT16_MAX;
*(compressed16++)=changed;
*(compressed16++)=skip;
for (int i=0;i<changed;i++) compressed16[i]=old16[i];
old16+=changed;
new16+=changed;
compressed16+=changed;
num16s-=changed;
}
compressed16[0] = 0;
compressed16[1] = 0;
compressed16[2] = 0;
compressed = (char*)(compressed16+3);
//End compression code.
if (compressed - state->data + state->maxcompsize > state->capacity)
{
compressed = state->data;
if (state->tail == state->data+sizeof(size_t)) state->tail = state->data + *(size_t*)state->tail;
}
write_size_t((uint16_t*)compressed, state->head-state->data);
compressed += sizeof(size_t);
write_size_t((uint16_t*)state->head, compressed-state->data);
state->head = compressed;
}
else
{
state->thisblock_valid = true;
}
char *swap = state->thisblock;
state->thisblock = state->nextblock;
state->nextblock = swap;
state->entries++;
return;
}
static void push_cancel(struct rewindstack * this_)
void state_manager_capacity(state_manager_t *state, unsigned int * entries, size_t * bytes, bool * full)
{
//struct rewindstack_impl * this=(struct rewindstack_impl*)this_;
//We ignore this. push_begin just returns a pointer anyways.
}
size_t headpos = (state->head-state->data);
size_t tailpos = (state->tail-state->data);
size_t remaining = (tailpos+state->capacity-sizeof(size_t)-headpos-1)%state->capacity + 1;
static const void * pull(struct rewindstack * this_)
{
struct rewindstack_impl * this=(struct rewindstack_impl*)this_;
if (this->thisblock_valid)
{
this->thisblock_valid=false;
this->entries--;
return this->thisblock;
}
if (this->head==this->tail) return NULL;
size_t start=read_size_t((uint16_t*)(this->head - sizeof(size_t)));
this->head=this->data+start;
const char * compressed=this->data+start+sizeof(size_t);
char * out=this->thisblock;
//Begin decompression code
//out is the last pushed (or returned) state
const uint16_t * compressed16=(const uint16_t*)compressed;
uint16_t * out16=(uint16_t*)out;
while (true)
{
uint16_t numchanged=*(compressed16++);
if (numchanged)
{
out16+=*(compressed16++);
//We could do memcpy, but it seems that memcpy has a constant-per-call overhead that actually shows up.
//Our average size in here seems to be 8 or something.
//Therefore, we do something with lower overhead.
for (int i=0;i<numchanged;i++) out16[i]=compressed16[i];
compressed16+=numchanged;
out16+=numchanged;
}
else
{
uint32_t numunchanged=compressed16[0] | compressed16[1]<<16;
if (!numunchanged) break;
compressed16+=2;
out16+=numunchanged;
}
}
//End decompression code
this->entries--;
return this->thisblock;
}
static void capacity_f(struct rewindstack * this_, unsigned int * entries, size_t * bytes, bool * full)
{
struct rewindstack_impl * this=(struct rewindstack_impl*)this_;
size_t headpos=(this->head-this->data);
size_t tailpos=(this->tail-this->data);
size_t remaining=(tailpos+this->capacity-sizeof(size_t)-headpos-1)%this->capacity + 1;
if (entries) *entries=this->entries;
if (bytes) *bytes=(this->capacity-remaining);
if (full) *full=(remaining<=this->maxcompsize*2);
}
static void free_(struct rewindstack * this_)
{
struct rewindstack_impl * this=(struct rewindstack_impl*)this_;
free(this->data);
free(this->thisblock);
free(this->nextblock);
free(this);
}
struct rewindstack * rewindstack_create(size_t blocksize, size_t capacity)
{
struct rewindstack_impl * this=malloc(sizeof(struct rewindstack_impl));
this->i.reset=reset;
this->i.push_begin=push_begin;
this->i.push_end=push_end;
this->i.push_cancel=push_cancel;
this->i.pull=pull;
this->i.capacity=capacity_f;
this->i.free=free_;
this->data=NULL;
this->thisblock=NULL;
this->nextblock=NULL;
this->capacity=0;
this->blocksize=0;
reset((struct rewindstack*)this, blocksize, capacity);
return (struct rewindstack*)this;
if (entries) *entries = state->entries;
if (bytes) *bytes = (state->capacity-remaining);
if (full) *full = (remaining<=state->maxcompsize*2);
}