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Diffstat (limited to 'src/game/bg_alloc.c')
| -rw-r--r-- | src/game/bg_alloc.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/src/game/bg_alloc.c b/src/game/bg_alloc.c new file mode 100644 index 00000000..080bf83a --- /dev/null +++ b/src/game/bg_alloc.c @@ -0,0 +1,204 @@ +/* +=========================================================================== +Copyright (C) 1999-2005 Id Software, Inc. +Copyright (C) 2000-2006 Tim Angus + +This file is part of Tremulous. + +Tremulous 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 Foundation; either version 2 of the License, +or (at your option) any later version. + +Tremulous 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 Tremulous; if not, write to the Free Software +Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +=========================================================================== +*/ + +#include "../qcommon/q_shared.h" +#include "bg_public.h" + +#ifdef GAME +# define POOLSIZE ( 1024 * 1024 ) +#else +# define POOLSIZE ( 256 * 1024 ) +#endif + +#define FREEMEMCOOKIE ((int)0xDEADBE3F) // Any unlikely to be used value +#define ROUNDBITS 31 // Round to 32 bytes + +typedef struct freeMemNode_s +{ + // Size of ROUNDBITS + int cookie, size; // Size includes node (obviously) + struct freeMemNode_s *prev, *next; +} freeMemNode_t; + +static char memoryPool[POOLSIZE]; +static freeMemNode_t *freeHead; +static int freeMem; + +void *BG_Alloc( int size ) +{ + // Find a free block and allocate. + // Does two passes, attempts to fill same-sized free slot first. + + freeMemNode_t *fmn, *prev, *next, *smallest; + int allocsize, smallestsize; + char *endptr; + int *ptr; + + allocsize = ( size + sizeof(int) + ROUNDBITS ) & ~ROUNDBITS; // Round to 32-byte boundary + ptr = NULL; + + smallest = NULL; + smallestsize = POOLSIZE + 1; // Guaranteed not to miss any slots :) + for( fmn = freeHead; fmn; fmn = fmn->next ) + { + if( fmn->cookie != FREEMEMCOOKIE ) + Com_Error( ERR_DROP, "BG_Alloc: Memory corruption detected!\n" ); + + if( fmn->size >= allocsize ) + { + // We've got a block + if( fmn->size == allocsize ) + { + // Same size, just remove + + prev = fmn->prev; + next = fmn->next; + if( prev ) + prev->next = next; // Point previous node to next + if( next ) + next->prev = prev; // Point next node to previous + if( fmn == freeHead ) + freeHead = next; // Set head pointer to next + ptr = (int *) fmn; + break; // Stop the loop, this is fine + } + else + { + // Keep track of the smallest free slot + if( fmn->size < smallestsize ) + { + smallest = fmn; + smallestsize = fmn->size; + } + } + } + } + + if( !ptr && smallest ) + { + // We found a slot big enough + smallest->size -= allocsize; + endptr = (char *) smallest + smallest->size; + ptr = (int *) endptr; + } + + if( ptr ) + { + freeMem -= allocsize; + memset( ptr, 0, allocsize ); + *ptr++ = allocsize; // Store a copy of size for deallocation + return( (void *) ptr ); + } + + Com_Error( ERR_DROP, "BG_Alloc: failed on allocation of %i bytes\n", size ); + return( NULL ); +} + +void BG_Free( void *ptr ) +{ + // Release allocated memory, add it to the free list. + + freeMemNode_t *fmn; + char *freeend; + int *freeptr; + + freeptr = ptr; + freeptr--; + + freeMem += *freeptr; + + for( fmn = freeHead; fmn; fmn = fmn->next ) + { + freeend = ((char *) fmn) + fmn->size; + if( freeend == (char *) freeptr ) + { + // Released block can be merged to an existing node + + fmn->size += *freeptr; // Add size of node. + return; + } + } + // No merging, add to head of list + + fmn = (freeMemNode_t *) freeptr; + fmn->size = *freeptr; // Set this first to avoid corrupting *freeptr + fmn->cookie = FREEMEMCOOKIE; + fmn->prev = NULL; + fmn->next = freeHead; + freeHead->prev = fmn; + freeHead = fmn; +} + +void BG_InitMemory( void ) +{ + // Set up the initial node + + freeHead = (freeMemNode_t *)memoryPool; + freeHead->cookie = FREEMEMCOOKIE; + freeHead->size = POOLSIZE; + freeHead->next = NULL; + freeHead->prev = NULL; + freeMem = sizeof( memoryPool ); +} + +void BG_DefragmentMemory( void ) +{ + // If there's a frenzy of deallocation and we want to + // allocate something big, this is useful. Otherwise... + // not much use. + + freeMemNode_t *startfmn, *endfmn, *fmn; + + for( startfmn = freeHead; startfmn; ) + { + endfmn = (freeMemNode_t *)(((char *) startfmn) + startfmn->size); + for( fmn = freeHead; fmn; ) + { + if( fmn->cookie != FREEMEMCOOKIE ) + Com_Error( ERR_DROP, "BG_DefragmentMemory: Memory corruption detected!\n" ); + + if( fmn == endfmn ) + { + // We can add fmn onto startfmn. + + if( fmn->prev ) + fmn->prev->next = fmn->next; + if( fmn->next ) + { + if( !(fmn->next->prev = fmn->prev) ) + freeHead = fmn->next; // We're removing the head node + } + startfmn->size += fmn->size; + memset( fmn, 0, sizeof(freeMemNode_t) ); // A redundant call, really. + + startfmn = freeHead; + endfmn = fmn = NULL; // Break out of current loop + } + else + fmn = fmn->next; + } + + if( endfmn ) + startfmn = startfmn->next; // endfmn acts as a 'restart' flag here + } +} |