/******************************************************************************
*
*
*
*
* Copyright (C) 1997-2015 by Dimitri van Heesch.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation under the terms of the GNU General Public License is hereby
* granted. No representations are made about the suitability of this software
* for any purpose. It is provided "as is" without express or implied warranty.
* See the GNU General Public License for more details.
*
* Documents produced by Doxygen are derivative works derived from the
* input used in their production; they are not affected by this license.
*
*/
#include "store.h"
#include "portable.h"
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#define BLOCK_SIZE 512 // should be >8 and a power of 2
#define BLOCK_POINTER_SIZE sizeof(portable_off_t)
#define ASSERTS_ENABLED
#ifdef ASSERTS_ENABLED
#define STORE_ASSERT(x) assert(x)
#else
#define STORE_ASSERT(x)
#endif
// Decide to use ftell or keep track of the current file pointer ourselves.
// Since valgrind shows that calling ftell has the unwanted side-effect of
// writing some uninitialized bytes (!) it might be better (and faster) to keep track
// of the current pointer ourselves.
#define USE_FTELL 0
//------------------------------------------------------------------------------------
Store::Store()
{
m_file = 0;
m_front = 0;
m_cur = 0;
m_head = 0;
m_state = Init;
m_reads = 0;
m_writes = 0;
}
Store::~Store()
{
if (m_file) fclose(m_file);
// clean up free list
while (m_head)
{
Node *node = m_head;
m_head = node->next;
delete node;
}
}
int Store::open(const char *name)
{
int i;
STORE_ASSERT(m_state==Init);
if (m_file) return 0; // already open
m_file = portable_fopen(name,"w+b");
if (m_file==0) return -1;
// first block serves as header, so offset=0 can be used as the end of the list.
for (i=0;i<BLOCK_SIZE/8;i++)
{
fputc('D',m_file);
fputc('O',m_file);
fputc('X',m_file);
fputc('Y',m_file);
fputc('G',m_file);
fputc('E',m_file);
fputc('N',m_file);
fputc(0,m_file);
}
m_front = BLOCK_SIZE;
m_cur = BLOCK_SIZE;
m_head = 0;
m_state = Reading;
return 0;
}
void Store::close()
{
if (m_file) fclose(m_file);
m_file=0;
m_state = Init;
}
portable_off_t Store::alloc()
{
STORE_ASSERT(m_state==Reading);
m_state=Writing;
portable_off_t pos;
if (m_head==0) // allocate new block
{
//printf("alloc: new block, pos=%lld\n",(long long)m_front);
if (portable_fseek(m_file,0,SEEK_END)==-1) // go to end of the file
{
fprintf(stderr,"Store::alloc: Error seeking to end of file: %s\n",strerror(errno));
exit(1);
}
#if USE_FTELL
pos = portable_ftell(m_file);
STORE_ASSERT( (pos & (BLOCK_SIZE-1))==0 );
m_front = pos + BLOCK_SIZE; // move front to end of this block
#else
m_cur = m_front;
pos = m_cur;
STORE_ASSERT( (pos & (BLOCK_SIZE-1))==0 );
m_front = pos + BLOCK_SIZE;
#endif
}
else // reuse freed block
{
//printf("alloc: reuse block: pos=%lld\n",(long long)m_head->pos);
Node *node = m_head;
pos = node->pos;
// point head to next free item
m_head = node->next;
delete node;
// move to start of the block
if (portable_fseek(m_file,pos,SEEK_SET)==-1)
{
fprintf(stderr,"Store::alloc: Error seeking to position %d: %s\n",
(int)pos,strerror(errno));
exit(1);
}
m_cur = pos;
STORE_ASSERT( (pos & (BLOCK_SIZE-1))==0 );
}
//printf("%x: Store::alloc\n",(int)pos);
return pos;
}
int Store::write(const char *buf,uint size)
{
STORE_ASSERT(m_state==Writing);
//printf("%x: Store::write\n",(int)portable_ftell(m_file));
do
{
#if USE_FTELL
portable_off_t curPos = portable_ftell(m_file);
#else
portable_off_t curPos = m_cur;
#endif
int bytesInBlock = (int)(BLOCK_SIZE - BLOCK_POINTER_SIZE - (curPos & (BLOCK_SIZE-1)));
int bytesLeft = bytesInBlock<(int)size ? (int)size-bytesInBlock : 0;
int numBytes = size - bytesLeft;
STORE_ASSERT(bytesInBlock>=0);
STORE_ASSERT(numBytes<=(int)(BLOCK_SIZE-BLOCK_POINTER_SIZE));
if (numBytes>0)
{
if ((int)fwrite(buf,1,numBytes,m_file)!=numBytes)
{
fprintf(stderr,"Error writing: %s\n",strerror(errno));
exit(1);
}
m_cur+=numBytes;
m_writes++;
}
if (bytesLeft>0) // still more bytes to write
{
#if USE_FTELL
STORE_ASSERT(((portable_ftell(m_file)+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);
#else
STORE_ASSERT(((m_cur+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);
#endif
// allocate new block
if (m_head==0) // no free blocks to reuse
{
//printf("%x: Store::write: new: pos=%x\n",(int)m_front,(int)portable_ftell(m_file));
// write pointer to next block
if (fwrite(&m_front,BLOCK_POINTER_SIZE,1,m_file)!=1)
{
fprintf(stderr,"Error writing to store: %s\n",strerror(errno));
exit(1);
}
m_cur+=BLOCK_POINTER_SIZE;
#if USE_FTELL
STORE_ASSERT(portable_ftell(m_file)==(curPos&~(BLOCK_SIZE-1))+BLOCK_SIZE);
#else
STORE_ASSERT(m_cur==(curPos&~(BLOCK_SIZE-1))+BLOCK_SIZE);
#endif
// move to next block
if (portable_fseek(m_file,0,SEEK_END)==-1) // go to end of the file
{
fprintf(stderr,"Store::alloc: Error seeking to end of file: %s\n",strerror(errno));
exit(1);
}
m_cur=m_front;
#if USE_FTELL
STORE_ASSERT(portable_ftell(m_file)==m_front);
#else
STORE_ASSERT(m_cur==m_front);
#endif
// move front to the next of the block
m_front+=BLOCK_SIZE;
}
else // reuse block from the free list
{
// write pointer to next block
if (fwrite(&m_head->pos,BLOCK_POINTER_SIZE,1,m_file)!=1)
{
fprintf(stderr,"Error writing to store: %s\n",strerror(errno));
exit(1);
}
Node *node = m_head;
portable_off_t pos = node->pos;
// point head to next free item
m_head = node->next;
delete node;
// move to start of the block
if (portable_fseek(m_file,pos,SEEK_SET)==-1)
{
fprintf(stderr,"Store::write: Error seeking to position %d: %s\n",
(int)pos,strerror(errno));
exit(1);
}
m_cur = pos;
//printf("%x: Store::write: reuse\n",(int)pos);
}
}
size-=numBytes;
buf+=numBytes;
}
while (size>0);
return size;
}
void Store::end()
{
STORE_ASSERT(m_state==Writing);
#if USE_FTELL
portable_off_t curPos = portable_ftell(m_file);
#else
portable_off_t curPos = m_cur;
#endif
int bytesInBlock = (int)(BLOCK_SIZE - (curPos & (BLOCK_SIZE-1)));
//printf("%x: Store::end erasing %x bytes\n",(int)curPos&~(BLOCK_SIZE-1),bytesInBlock);
//printf("end: bytesInBlock=%x\n",bytesInBlock);
// zero out rest of the block
int i;
for (i=0;i<bytesInBlock;i++)
{
fputc(0,m_file);
}
m_state=Reading;
}
void Store::release(portable_off_t pos)
{
STORE_ASSERT(m_state==Reading);
//printf("release: block pos=%lld\n",(long long)pos);
STORE_ASSERT(pos>0 && (pos & (BLOCK_SIZE-1))==0);
// goto end of the block
portable_off_t cur = pos, next;
while (1)
{
// add new node to the free list
Node *node = new Node;
node->next = m_head;
node->pos = cur;
m_head = node;
// goto the end of cur block
if (portable_fseek(m_file,cur+BLOCK_SIZE-BLOCK_POINTER_SIZE,SEEK_SET)==-1)
{
fprintf(stderr,"Store::release: Error seeking to position %d: %s\n",
(int)(cur+BLOCK_SIZE-BLOCK_POINTER_SIZE),strerror(errno));
exit(1);
}
// read pointer to next block
if (fread(&next,BLOCK_POINTER_SIZE,1,m_file)!=1)
{
fprintf(stderr,"Store::release: Error reading from store: %s\n",strerror(errno));
exit(1);
}
m_cur = cur+BLOCK_SIZE;
if (next==0) break; // found end of list -> cur is last element
STORE_ASSERT((next & (BLOCK_SIZE-1))==0);
cur = next;
//printf("%x: Store::release\n",(int)cur);
}
}
void Store::seek(portable_off_t pos)
{
STORE_ASSERT(m_state==Reading);
//printf("%x: Store::seek\n",(int)pos);
if (portable_fseek(m_file,pos,SEEK_SET)==-1)
{
fprintf(stderr,"Store::seek: Error seeking to position %d: %s\n",
(int)pos,strerror(errno));
exit(1);
}
m_cur = pos;
STORE_ASSERT((pos&(BLOCK_SIZE-1))==0);
}
int Store::read(char *buf,uint size)
{
STORE_ASSERT(m_state==Reading);
//printf("%x: Store::read total=%d\n",(int)portable_ftell(m_file),size);
do
{
#if USE_FTELL
portable_off_t curPos = portable_ftell(m_file);
#else
portable_off_t curPos = m_cur;
#endif
int bytesInBlock = (int)(BLOCK_SIZE - BLOCK_POINTER_SIZE - (curPos & (BLOCK_SIZE-1)));
int bytesLeft = bytesInBlock<(int)size ? (int)size-bytesInBlock : 0;
int numBytes = size - bytesLeft;
//printf(" Store::read: pos=%x num=%d left=%d\n",(int)curPos,numBytes,bytesLeft);
if (numBytes>0)
{
//printf("%x: Store::read: %d out of %d bytes\n",(int)portable_ftell(m_file),numBytes,size);
if ((int)fread(buf,1,numBytes,m_file)!=numBytes)
{
fprintf(stderr,"Error reading from store: %s\n",strerror(errno));
exit(1);
}
m_cur+=numBytes;
m_reads++;
}
if (bytesLeft>0)
{
portable_off_t newPos;
// read offset of the next block
#if USE_FTELL
STORE_ASSERT(((portable_ftell(m_file)+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);
#else
STORE_ASSERT(((m_cur+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);
#endif
if (fread((char *)&newPos,BLOCK_POINTER_SIZE,1,m_file)!=1)
{
fprintf(stderr,"Error reading from store: %s\n",strerror(errno));
exit(1);
}
//printf("%x: Store::read: continue in next block, %d bytes to go\n",(int)newPos,bytesLeft);
//printf(" Store::read: next block=%x\n",(int)newPos);
STORE_ASSERT(newPos!=0);
STORE_ASSERT((newPos&(BLOCK_SIZE-1))==0);
curPos = newPos;
// move to next block
if (portable_fseek(m_file,curPos,SEEK_SET)==-1)
{
fprintf(stderr,"Store::read: Error seeking to position %d: %s\n",
(int)curPos,strerror(errno));
exit(1);
}
m_cur = curPos;
}
size-=numBytes;
buf+=numBytes;
}
while (size>0);
return size;
}
void Store::printFreeList()
{
printf("FreeList: ");
while (m_head)
{
portable_off_t pos = m_head->pos;
printf("%x ",(int)pos);
m_head = m_head->next;
}
printf("\n");
}
void Store::printStats()
{
printf("ObjStore: block size %d bytes, total size %ld blocks, wrote %d blocks, read %d blocks\n",
BLOCK_SIZE,(long)(m_front/BLOCK_SIZE),m_reads,m_writes);
}
void Store::dumpBlock(portable_off_t s,portable_off_t e)
{
portable_fseek(m_file,s,SEEK_SET);
int size = (int)(e-s);
uchar *buf = new uchar[size];
if (fread(buf,size,1,m_file)==(size_t)size)
{
int i,j;
for (i=0;i<size;i+=16)
{
printf("%08x: ",(int)s+i);
for (j=i;j<QMIN(size,i+16);j++)
{
printf("%02x ",buf[i+j]);
}
printf(" ");
for (j=i;j<QMIN(size,i+16);j++)
{
printf("%c",(buf[i+j]>=32 && buf[i+j]<128)?buf[i+j]:'.');
}
printf("\n");
}
}
delete[] buf;
portable_fseek(m_file,m_cur,SEEK_SET);
}
#ifdef STORE_TEST
int main()
{
printf("sizeof(portable_off_t)=%d\n",(int)sizeof(portable_off_t));
Store s;
if (s.open("test.db")==0)
{
const char *str1 = "This is a test message... ";
const char *str2 = "Another message. ";
int i,j;
for (j=0;j<5;j++)
{
char buf[100];
portable_off_t handle = s.alloc();
for (i=0;i<1000000000;i++)
{
s.write(str1,strlen(str1)+1);
}
s.end();
portable_off_t handle2 = s.alloc();
for (i=0;i<10;i++)
{
s.write(str2,strlen(str2)+1);
}
s.end();
s.seek(handle);
for (i=0;i<3;i++)
{
s.read(buf,strlen(str1)+1);
printf("i=%d Read: %s\n",i,buf);
}
s.release(handle);
s.seek(handle2);
for (i=0;i<3;i++)
{
s.read(buf,strlen(str2)+1);
printf("i=%d Read: %s\n",i,buf);
}
s.release(handle2);
}
s.close();
}
else
{
printf("Open failed! %s\n",strerror(errno));
}
}
#endif