172 lines
6.3 KiB
C
172 lines
6.3 KiB
C
/*
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defspace.h
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management of data segments
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Copyright (C) 2011 Bill Currie <bill@taniwha.org>
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Author: Bill Currie <bill@taniwha.org>
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Date: 2011/01/16
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to:
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Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307, USA
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*/
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#ifndef __defspace_h
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#define __defspace_h
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#include "QF/pr_comp.h"
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#include "QF/pr_debug.h"
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/** \defgroup qfcc_defspace Defspace handling
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\ingroup qfcc
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*/
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///@{
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typedef enum {
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ds_backed, ///< data space is globally addressable (near/far/type) and
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///< has backing store
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ds_virtual, ///< data space has no backing store (local vars, entity
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///< fields)
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} ds_type_t;
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/** Represent a block of memory in the progs data space.
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*/
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typedef struct defspace_s {
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struct defspace_s *next; ///< for ALLOC
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ds_type_t type; ///< basic type of defspace
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struct locref_s *free_locs; ///< list of free blocks in this space
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struct def_s *defs; ///< list of defs using this space
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struct def_s **def_tail; ///< for appending to \a defs
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pr_type_t *data; ///< backing memory for this space
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int size; ///< current high-water mark for alloced data
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int max_size; ///< size of backing memory
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/** Grow the backing memory of the defspace.
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This function is called when more memory is needed for the space.
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The default \a grow function for ds_backed defspaces expands the
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backing memory by 1024 pr_type_t words and initializes them to 0.
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Other defspace types do not actually allocate backing memory as it
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is not needed. If null, more space cannot be allocated and an
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internal error will be generated.
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\param space This defspace.
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\return 1 for success, 0 for failure. On failure, an internal
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error will be generated.
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\note Setting to null forces failure and thus an internal error.
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*/
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int (*grow) (struct defspace_s *space);
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int qfo_space; ///< index to space in qfo spaces
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} defspace_t;
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/** Create an empty defspace.
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No backing memory is allocated, but the defspace_t::grow function is
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initialized to the default grow function so the backing memory may be
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accessed after space has been allocated via defspace_alloc_loc().
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\param type The type of defspace to create. Affects only the default
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defspace_t::grow function: ds_backed uses a grow function
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that allocates backing memory, while ds_virtual uses a
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grow function that only increases defspace_t::max_size
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\return The new, empty defspace.
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*/
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defspace_t *defspace_new (ds_type_t type);
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/** Allocate space from the defspace's backing memory.
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If the memory is fragmented, then the first available location at least
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as large as \a size is returned. This means that freeing a location then
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allocating the same amount of space may return a different location.
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If memory cannot be allocated (there is no free space in the currently
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available memory and defspace_t::grow is null), then an internal error
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will be generated.
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\param space The space from which to allocate data.
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\param size The amount of pr_type_t words to allocated. int and float
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need 1 word, vector 3 words, and quaternion 4.
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\return The offset of the first word of the freshly allocated
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space. May be 0 if the allocated space is at the beginning
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of the defspace.
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*/
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int defspace_alloc_loc (defspace_t *space, int size);
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/** Allocate space from the defspace's backing memory.
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If the memory is fragmented, then the first available location at least
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as large as \a size plus padding for alignment is returned. This means
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that freeing a location then allocating the same amount of space may
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return a different location.
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If memory cannot be allocated (there is no free space in the currently
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available memory and defspace_t::grow is null), then an internal error
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will be generated.
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\param space The space from which to allocate data.
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\param size The amount of pr_type_t words to allocated. int and float
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need 1 word, vector 3 words, and quaternion 4.
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\param alignment The alignment of the allocated space.
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\return The offset of the first word of the freshly allocated
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space. May be 0 if the allocated space is at the beginning
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of the defspace.
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*/
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int defspace_alloc_aligned_loc (defspace_t *space, int size, int alignment);
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/** Free a block of contiguous words, returning them to the defspace.
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The block to be freed is specified by \a ofs indicating the offset of the
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first word of the block and \a size indicating the number of words in the
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block.
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If the block to be freed has 0 words, or if the block is partly or fully
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outside the defspace (as defined by defspace_t::size), or if the block
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overlaps any unallocated space in the defspace, then an internal error
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will be generated. However, it is perfectly valid to allocate a large
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block and subsequently free a small block from anywhere within the larger
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block. This is because when memory is not fragmented, there is no
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difference between allocating one large block and allocating several
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smaller blocks when allocating the same amount of memory.
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\param space The space to which the freed block will be returned.
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\param ofs The first word of the block to be freed.
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\param size The number of words in the block to be freed.
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*/
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void defspace_free_loc (defspace_t *space, int ofs, int size);
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/** Copy a block of data into a defspace.
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Space for the data is allocated from the defspace via
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defspace_alloc_loc().
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If \a data is null, then the copying stage is skipped and this function
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becomes a synonym for defspace_alloc_loc().
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\param space The space to which the data will be added.
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\param data The data to be copied into the space.
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\param size The number of words of data to be copied.
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\return The offset of the block allocated for the data.
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*/
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int defspace_add_data (defspace_t *space, pr_type_t *data, int size);
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///@}
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#endif//__defspace_h
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