mem.c File Reference

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "mem.h"

Go to the source code of this file.

Data Structures
struct	Mem_Fixed_t_
	DECLARATIONS ///. More...
struct	Mem_Flex_t_
struct	Mem_Step_t_

Functions
Mem_Fixed_t *	Mem_FixedStart (int nEntrySize)
	FUNCTION DEFINITIONS ///. More...
void	Mem_FixedStop (Mem_Fixed_t *p, int fVerbose)
char *	Mem_FixedEntryFetch (Mem_Fixed_t *p)
void	Mem_FixedEntryRecycle (Mem_Fixed_t *p, char *pEntry)
void	Mem_FixedRestart (Mem_Fixed_t *p)
int	Mem_FixedReadMemUsage (Mem_Fixed_t *p)
int	Mem_FixedReadMaxEntriesUsed (Mem_Fixed_t *p)
Mem_Flex_t *	Mem_FlexStart ()
void	Mem_FlexStop (Mem_Flex_t *p, int fVerbose)
char *	Mem_FlexEntryFetch (Mem_Flex_t *p, int nBytes)
void	Mem_FlexRestart (Mem_Flex_t *p)
int	Mem_FlexReadMemUsage (Mem_Flex_t *p)
Mem_Step_t *	Mem_StepStart (int nSteps)
void	Mem_StepStop (Mem_Step_t *p, int fVerbose)
char *	Mem_StepEntryFetch (Mem_Step_t *p, int nBytes)
void	Mem_StepEntryRecycle (Mem_Step_t *p, char *pEntry, int nBytes)
int	Mem_StepReadMemUsage (Mem_Step_t *p)

Function Documentation

char* Mem_FixedEntryFetch

(

Mem_Fixed_t *

p

)

Function*************************************************************

Synopsis []

Description []

SideEffects []

SeeAlso []

Definition at line 168 of file mem.c.

{
    char * pTemp;
    int i;

    // check if there are still free entries
    if ( p->nEntriesUsed == p->nEntriesAlloc )
    { // need to allocate more entries
        assert( p->pEntriesFree == NULL );
        if ( p->nChunks == p->nChunksAlloc )
        {
            p->nChunksAlloc *= 2;
            p->pChunks = ABC_REALLOC( char *, p->pChunks, p->nChunksAlloc ); 
        }
        p->pEntriesFree = ABC_ALLOC( char, p->nEntrySize * p->nChunkSize );
        p->nMemoryAlloc += p->nEntrySize * p->nChunkSize;
        // transform these entries into a linked list
        pTemp = p->pEntriesFree;
        for ( i = 1; i < p->nChunkSize; i++ )
        {
            *((char **)pTemp) = pTemp + p->nEntrySize;
            pTemp += p->nEntrySize;
        }
        // set the last link
        *((char **)pTemp) = NULL;
        // add the chunk to the chunk storage
        p->pChunks[ p->nChunks++ ] = p->pEntriesFree;
        // add to the number of entries allocated
        p->nEntriesAlloc += p->nChunkSize;
    }
    // incrememt the counter of used entries
    p->nEntriesUsed++;
    if ( p->nEntriesMax < p->nEntriesUsed )
        p->nEntriesMax = p->nEntriesUsed;
    // return the first entry in the free entry list
    pTemp = p->pEntriesFree;
    p->pEntriesFree = *((char **)pTemp);
    return pTemp;
}

void Mem_FixedEntryRecycle	(	Mem_Fixed_t *	p,
		char *	pEntry
	)

Function*************************************************************

Synopsis []

Description []

SideEffects []

SeeAlso []

Definition at line 219 of file mem.c.

{
    // decrement the counter of used entries
    p->nEntriesUsed--;
    // add the entry to the linked list of free entries
    *((char **)pEntry) = p->pEntriesFree;
    p->pEntriesFree = pEntry;
}

int Mem_FixedReadMaxEntriesUsed

(

Mem_Fixed_t *

p

)

Function*************************************************************

Synopsis []

Description []

SideEffects []

SeeAlso []

Definition at line 293 of file mem.c.

{
    return p->nEntriesMax;
}

int Mem_FixedReadMemUsage

(

Mem_Fixed_t *

p

)

Function*************************************************************

Synopsis []

Description []

SideEffects []

SeeAlso []

Definition at line 277 of file mem.c.

{
    return p->nMemoryAlloc;
}

void Mem_FixedRestart

(

Mem_Fixed_t *

p

)

Function*************************************************************

Synopsis []

Description [Relocates all the memory except the first chunk.]

SideEffects []

SeeAlso []

Definition at line 239 of file mem.c.

{
    int i;
    char * pTemp;

    // deallocate all chunks except the first one
    for ( i = 1; i < p->nChunks; i++ )
        ABC_FREE( p->pChunks[i] );
    p->nChunks = 1;
    // transform these entries into a linked list
    pTemp = p->pChunks[0];
    for ( i = 1; i < p->nChunkSize; i++ )
    {
        *((char **)pTemp) = pTemp + p->nEntrySize;
        pTemp += p->nEntrySize;
    }
    // set the last link
    *((char **)pTemp) = NULL;
    // set the free entry list
    p->pEntriesFree  = p->pChunks[0];
    // set the correct statistics
    p->nMemoryAlloc  = p->nEntrySize * p->nChunkSize;
    p->nMemoryUsed   = 0;
    p->nEntriesAlloc = p->nChunkSize;
    p->nEntriesUsed  = 0;
}

Mem_Fixed_t* Mem_FixedStart

(

int

nEntrySize

)

FUNCTION DEFINITIONS ///.

Function*************************************************************

Synopsis [Allocates memory pieces of fixed size.]

Description [The size of the chunk is computed as the minimum of 1024 entries and 64K. Can only work with entry size at least 4 byte long.]

SideEffects []

SeeAlso []

Definition at line 100 of file mem.c.

{
    Mem_Fixed_t * p;

    p = ABC_ALLOC( Mem_Fixed_t, 1 );
    memset( p, 0, sizeof(Mem_Fixed_t) );

    p->nEntrySize    = nEntrySize;
    p->nEntriesAlloc = 0;
    p->nEntriesUsed  = 0;
    p->pEntriesFree  = NULL;

    if ( nEntrySize * (1 << 10) < (1<<16) )
        p->nChunkSize = (1 << 10);
    else
        p->nChunkSize = (1<<16) / nEntrySize;
    if ( p->nChunkSize < 8 )
        p->nChunkSize = 8;

    p->nChunksAlloc  = 64;
    p->nChunks       = 0;
    p->pChunks       = ABC_ALLOC( char *, p->nChunksAlloc );

    p->nMemoryUsed   = 0;
    p->nMemoryAlloc  = 0;
    return p;
}

void Mem_FixedStop	(	Mem_Fixed_t *	p,
		int	fVerbose
	)

Function*************************************************************

Synopsis []

Description []

SideEffects []

SeeAlso []

Definition at line 139 of file mem.c.

{
    int i;
    if ( p == NULL )
        return;
    if ( fVerbose )
    {
        printf( "Fixed memory manager: Entry = %5d. Chunk = %5d. Chunks used = %5d.\n",
            p->nEntrySize, p->nChunkSize, p->nChunks );
        printf( "   Entries used = %8d. Entries peak = %8d. Memory used = %8d. Memory alloc = %8d.\n",
            p->nEntriesUsed, p->nEntriesMax, p->nEntrySize * p->nEntriesUsed, p->nMemoryAlloc );
    }
    for ( i = 0; i < p->nChunks; i++ )
        ABC_FREE( p->pChunks[i] );
    ABC_FREE( p->pChunks );
    ABC_FREE( p );
}

char* Mem_FlexEntryFetch	(	Mem_Flex_t *	p,
		int	nBytes
	)

Function*************************************************************

Synopsis []

Description []

SideEffects []

SeeAlso []

Definition at line 372 of file mem.c.

{
    char * pTemp;
    // check if there are still free entries
    if ( p->pCurrent == NULL || p->pCurrent + nBytes > p->pEnd )
    { // need to allocate more entries
        if ( p->nChunks == p->nChunksAlloc )
        {
            p->nChunksAlloc *= 2;
            p->pChunks = ABC_REALLOC( char *, p->pChunks, p->nChunksAlloc ); 
        }
        if ( nBytes > p->nChunkSize )
        {
            // resize the chunk size if more memory is requested than it can give
            // (ideally, this should never happen)
            p->nChunkSize = 2 * nBytes;
        }
        p->pCurrent = ABC_ALLOC( char, p->nChunkSize );
        p->pEnd     = p->pCurrent + p->nChunkSize;
        p->nMemoryAlloc += p->nChunkSize;
        // add the chunk to the chunk storage
        p->pChunks[ p->nChunks++ ] = p->pCurrent;
    }
    assert( p->pCurrent + nBytes <= p->pEnd );
    // increment the counter of used entries
    p->nEntriesUsed++;
    // keep track of the memory used
    p->nMemoryUsed += nBytes;
    // return the next entry
    pTemp = p->pCurrent;
    p->pCurrent += nBytes;
    return pTemp;
}

int Mem_FlexReadMemUsage

(

Mem_Flex_t *

p

)

Function*************************************************************

Synopsis []

Description []

SideEffects []

SeeAlso []

Definition at line 445 of file mem.c.

{
    return p->nMemoryUsed;
}

void Mem_FlexRestart

(

Mem_Flex_t *

p

)

Function*************************************************************

Synopsis []

Description [Relocates all the memory except the first chunk.]

SideEffects []

SeeAlso []

Definition at line 417 of file mem.c.

{
    int i;
    if ( p->nChunks == 0 )
        return;
    // deallocate all chunks except the first one
    for ( i = 1; i < p->nChunks; i++ )
        ABC_FREE( p->pChunks[i] );
    p->nChunks  = 1;
    p->nMemoryAlloc = p->nChunkSize;
    // transform these entries into a linked list
    p->pCurrent = p->pChunks[0];
    p->pEnd     = p->pCurrent + p->nChunkSize;
    p->nEntriesUsed = 0;
    p->nMemoryUsed = 0;
}

Mem_Flex_t* Mem_FlexStart

(

)

Function*************************************************************

Synopsis [Allocates entries of flexible size.]

Description [Can only work with entry size at least 4 byte long.]

SideEffects []

SeeAlso []

Definition at line 311 of file mem.c.

{
    Mem_Flex_t * p;

    p = ABC_ALLOC( Mem_Flex_t, 1 );
    memset( p, 0, sizeof(Mem_Flex_t) );

    p->nEntriesUsed  = 0;
    p->pCurrent      = NULL;
    p->pEnd          = NULL;

    p->nChunkSize    = (1 << 12);
    p->nChunksAlloc  = 64;
    p->nChunks       = 0;
    p->pChunks       = ABC_ALLOC( char *, p->nChunksAlloc );

    p->nMemoryUsed   = 0;
    p->nMemoryAlloc  = 0;
    return p;
}

void Mem_FlexStop	(	Mem_Flex_t *	p,
		int	fVerbose
	)

Function*************************************************************

Synopsis []

Description []

SideEffects []

SeeAlso []

Definition at line 343 of file mem.c.

{
    int i;
    if ( p == NULL )
        return;
    if ( fVerbose )
    {
        printf( "Flexible memory manager: Chunk size = %d. Chunks used = %d.\n",
            p->nChunkSize, p->nChunks );
        printf( "   Entries used = %d. Memory used = %d. Memory alloc = %d.\n",
            p->nEntriesUsed, p->nMemoryUsed, p->nMemoryAlloc );
    }
    for ( i = 0; i < p->nChunks; i++ )
        ABC_FREE( p->pChunks[i] );
    ABC_FREE( p->pChunks );
    ABC_FREE( p );
}

char* Mem_StepEntryFetch	(	Mem_Step_t *	p,
		int	nBytes
	)

Function*************************************************************

Synopsis [Creates the entry.]

Description []

SideEffects []

SeeAlso []

Definition at line 537 of file mem.c.

{
    if ( nBytes == 0 )
        return NULL;
    if ( nBytes > p->nMapSize )
    {
//        printf( "Allocating %d bytes.\n", nBytes );
//        return ABC_ALLOC( char, nBytes );
        if ( p->nLargeChunks == p->nLargeChunksAlloc )
        {
            if ( p->nLargeChunksAlloc == 0 )
                p->nLargeChunksAlloc = 32;
            p->nLargeChunksAlloc *= 2;
            p->pLargeChunks = (void **)ABC_REALLOC( char *, p->pLargeChunks, p->nLargeChunksAlloc ); 
        }
        p->pLargeChunks[ p->nLargeChunks++ ] = ABC_ALLOC( char, nBytes );
        return (char *)p->pLargeChunks[ p->nLargeChunks - 1 ];
    }
    return Mem_FixedEntryFetch( p->pMap[nBytes] );
}

void Mem_StepEntryRecycle	(	Mem_Step_t *	p,
		char *	pEntry,
		int	nBytes
	)

Function*************************************************************

Synopsis [Recycles the entry.]

Description []

SideEffects []

SeeAlso []

Definition at line 570 of file mem.c.

{
    if ( nBytes == 0 )
        return;
    if ( nBytes > p->nMapSize )
    {
//        ABC_FREE( pEntry );
        return;
    }
    Mem_FixedEntryRecycle( p->pMap[nBytes], pEntry );
}

int Mem_StepReadMemUsage

(

Mem_Step_t *

p

)

Function*************************************************************

Synopsis []

Description []

SideEffects []

SeeAlso []

Definition at line 593 of file mem.c.

{
    int i, nMemTotal = 0;
    for ( i = 0; i < p->nMems; i++ )
        nMemTotal += p->pMems[i]->nMemoryAlloc;
    return nMemTotal;
}

Mem_Step_t* Mem_StepStart

(

int

nSteps

)

Function*************************************************************

Synopsis [Starts the hierarchical memory manager.]

Description [This manager can allocate entries of any size. Iternally they are mapped into the entries with the number of bytes equal to the power of 2. The smallest entry size is 8 bytes. The next one is 16 bytes etc. So, if the user requests 6 bytes, he gets 8 byte entry. If we asks for 25 bytes, he gets 32 byte entry etc. The input parameters "nSteps" says how many fixed memory managers are employed internally. Calling this procedure with nSteps equal to 10 results in 10 hierarchically arranged internal memory managers, which can allocate up to 4096 (1Kb) entries. Requests for larger entries are handed over to malloc() and then ABC_FREE()ed.]

SideEffects []

SeeAlso []

Definition at line 474 of file mem.c.

{
    Mem_Step_t * p;
    int i, k;
    p = ABC_ALLOC( Mem_Step_t, 1 );
    memset( p, 0, sizeof(Mem_Step_t) );
    p->nMems = nSteps;
    // start the fixed memory managers
    p->pMems = ABC_ALLOC( Mem_Fixed_t *, p->nMems );
    for ( i = 0; i < p->nMems; i++ )
        p->pMems[i] = Mem_FixedStart( (8<<i) );
    // set up the mapping of the required memory size into the corresponding manager
    p->nMapSize = (4<<p->nMems);
    p->pMap = ABC_ALLOC( Mem_Fixed_t *, p->nMapSize+1 );
    p->pMap[0] = NULL;
    for ( k = 1; k <= 4; k++ )
        p->pMap[k] = p->pMems[0];
    for ( i = 0; i < p->nMems; i++ )
        for ( k = (4<<i)+1; k <= (8<<i); k++ )
            p->pMap[k] = p->pMems[i];
//for ( i = 1; i < 100; i ++ )
//printf( "%10d: size = %10d\n", i, p->pMap[i]->nEntrySize );
    return p;
}

void Mem_StepStop	(	Mem_Step_t *	p,
		int	fVerbose
	)

Function*************************************************************

Synopsis [Stops the memory manager.]

Description []

SideEffects []

SeeAlso []

Definition at line 510 of file mem.c.

{
    int i;
    for ( i = 0; i < p->nMems; i++ )
        Mem_FixedStop( p->pMems[i], fVerbose );
    if ( p->pLargeChunks ) 
    {
        for ( i = 0; i < p->nLargeChunks; i++ )
            ABC_FREE( p->pLargeChunks[i] );
        ABC_FREE( p->pLargeChunks );
    }
    ABC_FREE( p->pMems );
    ABC_FREE( p->pMap );
    ABC_FREE( p );
}