Release-1.4.7-20060910

1 files changed, 392 insertions, 0 deletions

diff --git a/src/store.cpp b/src/store.cpp
new file mode 100644
index 0000000..f1f24cd
--- /dev/null
+++ b/src/store.cpp
@@ -0,0 +1,392 @@
+#include "store.h"
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <assert.h>
+
+#define BLOCK_SIZE         512 // should be >8 and a multiple of 8
+#define BLOCK_POINTER_SIZE sizeof(off_t)
+
+
+#define ASSERTS_ENABLED
+
+#ifdef ASSERTS_ENABLED
+#define STORE_ASSERT(x) assert(x)
+#else
+#define STORE_ASSERT(x)
+#endif
+
+#ifdef _WIN32 // TODO: add 64bit support using _fseeki64 and _ftelli64 (studio 2003+ req)
+#define fseeko fseek
+#define ftello ftell
+#endif
+
+
+//------------------------------------------------------------------------------------
+
+Store::Store() 
+{
+  m_file       = 0;
+  m_front      = 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 = 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_head   = 0;
+  m_state  = Reading;
+  return 0;
+}
+
+void Store::close()
+{
+  if (m_file) fclose(m_file);
+  m_file=0;
+  m_state  = Init;
+}
+     
+off_t Store::alloc()
+{
+  STORE_ASSERT(m_state==Reading);
+  m_state=Writing;
+  off_t pos;
+  if (m_head==0) // allocate new block
+  {
+    //printf("alloc: new block\n");
+    if (fseeko(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);
+    }
+    pos = ftello(m_file);
+    STORE_ASSERT( (pos & (BLOCK_SIZE-1))==0 );
+    m_front = pos + BLOCK_SIZE; // move front to end of this block
+  }
+  else // reuse freed block
+  {
+    //printf("alloc: reuse block: m_head=%d\n",(int)m_head);
+    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 (fseeko(m_file,pos,SEEK_SET)==-1)
+    {
+      fprintf(stderr,"Store::alloc: Error seeking to position %d: %s\n",
+          (int)pos,strerror(errno));
+      exit(1);
+    }
+    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)ftello(m_file));
+  do
+  {
+    off_t curPos     = ftello(m_file);
+    int bytesInBlock = 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_writes++;
+    }
+    if (bytesLeft>0) // still more bytes to write
+    {
+      STORE_ASSERT(((ftello(m_file)+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);
+      // allocate new block
+      if (m_head==0) // no free blocks to reuse
+      {
+        //printf("%x: Store::write: new: pos=%x\n",(int)m_front,(int)ftello(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);
+        }
+        STORE_ASSERT(ftello(m_file)==(curPos&~(BLOCK_SIZE-1))+BLOCK_SIZE);
+
+        // move to next block
+        if (fseeko(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);
+        }
+        STORE_ASSERT(ftello(m_file)==m_front);
+        // 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;
+        off_t pos = node->pos;
+        // point head to next free item
+        m_head = node->next;
+        delete node;
+        // move to start of the block
+        if (fseeko(m_file,pos,SEEK_SET)==-1)
+        {
+          fprintf(stderr,"Store::write: Error seeking to position %d: %s\n",
+              (int)pos,strerror(errno));
+          exit(1);
+        }
+        //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);
+  off_t curPos     = ftello(m_file);
+  int bytesInBlock = 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(off_t pos)
+{
+  STORE_ASSERT(m_state==Reading);
+  //printf("%x: Store::release\n",(int)pos);
+  STORE_ASSERT(pos>0 && (pos & (BLOCK_SIZE-1))==0);
+  // goto end of the block
+  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 (fseeko(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);
+    }
+    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(off_t pos)
+{
+  STORE_ASSERT(m_state==Reading);
+  //printf("%x: Store::seek\n",(int)pos);
+  if (fseeko(m_file,pos,SEEK_SET)==-1)
+  {
+    fprintf(stderr,"Store::seek: Error seeking to position %d: %s\n",
+        (int)pos,strerror(errno));
+    exit(1);
+  }
+  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)ftello(m_file),size);
+  do
+  {
+    off_t curPos     = ftello(m_file);
+    int bytesInBlock = 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)ftello(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_reads++;
+    }
+    if (bytesLeft>0)
+    {
+      off_t newPos;
+      // read offset of the next block
+      STORE_ASSERT(((ftello(m_file)+BLOCK_POINTER_SIZE)&(BLOCK_SIZE-1))==0);
+      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 (fseeko(m_file,curPos,SEEK_SET)==-1)
+      {
+        fprintf(stderr,"Store::read: Error seeking to position %d: %s\n",
+            (int)curPos,strerror(errno));
+        exit(1);
+      }
+    }
+
+    size-=numBytes;
+    buf+=numBytes;
+  }
+  while (size>0);
+  return size;
+}
+
+void Store::printFreeList()
+{
+  printf("FreeList: ");
+  off_t pos = m_head->pos;
+  while (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);
+}
+
+#ifdef  STORE_TEST
+
+int main()
+{
+  printf("sizeof(off_t)=%d\n",(int)sizeof(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];
+
+      off_t handle = s.alloc();
+      for (i=0;i<1000000000;i++)
+      {
+        s.write(str1,strlen(str1)+1);
+      }
+      s.end();
+      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
+