diff options
Diffstat (limited to 'include/freetype/cache/ftlru.h')
| -rw-r--r-- | include/freetype/cache/ftlru.h | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/include/freetype/cache/ftlru.h b/include/freetype/cache/ftlru.h new file mode 100644 index 00000000..9e4507ef --- /dev/null +++ b/include/freetype/cache/ftlru.h @@ -0,0 +1,202 @@ +/***************************************************************************/ +/* */ +/* ftlru.h */ +/* */ +/* Simple LRU list-cache (specification). */ +/* */ +/* Copyright 2000-2001 by */ +/* David Turner, Robert Wilhelm, and Werner Lemberg. */ +/* */ +/* This file is part of the FreeType project, and may only be used, */ +/* modified, and distributed under the terms of the FreeType project */ +/* license, LICENSE.TXT. By continuing to use, modify, or distribute */ +/* this file you indicate that you have read the license and */ +/* understand and accept it fully. */ +/* */ +/***************************************************************************/ + + + /*************************************************************************/ + /* */ + /* An LRU is a list that cannot hold more than a certain number of */ + /* elements (`max_elements'). All elements in the list are sorted in */ + /* least-recently-used order, i.e., the `oldest' element is at the tail */ + /* of the list. */ + /* */ + /* When doing a lookup (either through `Lookup()' or `Lookup_Node()'), */ + /* the list is searched for an element with the corresponding key. If */ + /* it is found, the element is moved to the head of the list and is */ + /* returned. */ + /* */ + /* If no corresponding element is found, the lookup routine will try to */ + /* obtain a new element with the relevant key. If the list is already */ + /* full, the oldest element from the list is discarded and replaced by a */ + /* new one; a new element is added to the list otherwise. */ + /* */ + /* Note that it is possible to pre-allocate the element list nodes. */ + /* This is handy if `max_elements' is sufficiently small, as it saves */ + /* allocations/releases during the lookup process. */ + /* */ + /*************************************************************************/ + + + /*************************************************************************/ + /*************************************************************************/ + /*************************************************************************/ + /*************************************************************************/ + /*************************************************************************/ + /********* *********/ + /********* WARNING, THIS IS BETA CODE. *********/ + /********* *********/ + /*************************************************************************/ + /*************************************************************************/ + /*************************************************************************/ + /*************************************************************************/ + /*************************************************************************/ + + +#ifndef __FTLRU_H__ +#define __FTLRU_H__ + + +#include <ft2build.h> +#include FT_FREETYPE_H + + +FT_BEGIN_HEADER + + + /* generic list key type */ + typedef FT_Pointer FT_LruKey; + + /* a list list handle */ + typedef struct FT_LruListRec_* FT_LruList; + + /* a list class handle */ + typedef const struct FT_LruList_ClassRec_* FT_LruList_Class; + + /* a list node handle */ + typedef struct FT_LruNodeRec_* FT_LruNode; + + /* the list node structure */ + typedef struct FT_LruNodeRec_ + { + FT_LruNode next; + FT_LruKey key; + + } FT_LruNodeRec; + + + /* the list structure */ + typedef struct FT_LruListRec_ + { + FT_Memory memory; + FT_LruList_Class clazz; + FT_LruNode nodes; + FT_UInt max_nodes; + FT_UInt num_nodes; + FT_Pointer data; + + } FT_LruListRec; + + + /* initialize a list list */ + typedef FT_Error + (*FT_LruList_InitFunc)( FT_LruList list ); + + /* finalize a list list */ + typedef void + (*FT_LruList_DoneFunc)( FT_LruList list ); + + /* this method is used to initialize a new list element node */ + typedef FT_Error + (*FT_LruNode_InitFunc)( FT_LruNode node, + FT_LruKey key, + FT_Pointer data ); + + /* this method is used to finalize a given list element node */ + typedef void + (*FT_LruNode_DoneFunc)( FT_LruNode node, + FT_Pointer data ); + + /* If defined, this method is called when the list if full */ + /* during the lookup process -- it is used to change the contents */ + /* of a list element node instead of calling `done_element()', */ + /* then `init_element()'. Set it to 0 for default behaviour. */ + typedef FT_Error + (*FT_LruNode_FlushFunc)( FT_LruNode node, + FT_LruKey new_key, + FT_Pointer data ); + + /* If defined, this method is used to compare a list element node */ + /* with a given key during a lookup. If set to 0, the `key' */ + /* fields will be directly compared instead. */ + typedef FT_Bool + (*FT_LruNode_CompareFunc)( FT_LruNode node, + FT_LruKey key, + FT_Pointer data ); + + /* A selector is used to indicate whether a given list element node */ + /* is part of a selection for FT_LruList_Remove_Selection(). The */ + /* functrion must return true (i.e., non-null) to indicate that the */ + /* node is part of it. */ + typedef FT_Bool + (*FT_LruNode_SelectFunc)( FT_LruNode node, + FT_Pointer data, + FT_Pointer list_data ); + + /* LRU class */ + typedef struct FT_LruList_ClassRec_ + { + FT_UInt list_size; + FT_LruList_InitFunc list_init; /* optional */ + FT_LruList_DoneFunc list_done; /* optional */ + + FT_UInt node_size; + FT_LruNode_InitFunc node_init; /* MANDATORY */ + FT_LruNode_DoneFunc node_done; /* optional */ + FT_LruNode_FlushFunc node_flush; /* optional */ + FT_LruNode_CompareFunc node_compare; /* optional */ + + } FT_LruList_ClassRec; + + + /* The following functions must be exported in the case where */ + /* applications would want to write their own cache classes. */ + + FT_EXPORT( FT_Error ) + FT_LruList_New( FT_LruList_Class clazz, + FT_UInt max_elements, + FT_Pointer user_data, + FT_Memory memory, + FT_LruList *alist ); + + FT_EXPORT( void ) + FT_LruList_Reset( FT_LruList list ); + + FT_EXPORT( void ) + FT_LruList_Destroy ( FT_LruList list ); + + FT_EXPORT( FT_Error ) + FT_LruList_Lookup( FT_LruList list, + FT_LruKey key, + FT_LruNode *anode ); + + FT_EXPORT( void ) + FT_LruList_Remove( FT_LruList list, + FT_LruNode node ); + + FT_EXPORT( void ) + FT_LruList_Remove_Selection( FT_LruList list, + FT_LruNode_SelectFunc select_func, + FT_Pointer select_data ); + + /* */ + +FT_END_HEADER + + +#endif /* __FTLRU_H__ */ + + +/* END */ |