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Diffstat (limited to 'include/pdp_type.h_old')
| -rw-r--r-- | include/pdp_type.h_old | 180 |
1 files changed, 0 insertions, 180 deletions
diff --git a/include/pdp_type.h_old b/include/pdp_type.h_old deleted file mode 100644 index d588e7f..0000000 --- a/include/pdp_type.h_old +++ /dev/null @@ -1,180 +0,0 @@ -/* - * Pure Data Packet system implementation. Type handling interface - * Copyright (c) by Tom Schouten <pdp@zzz.kotnet.org> - * - * This program 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. - * - * This program 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 this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - * - */ - - -/* COMMENTS - -Since version 0.11 all packets have an (optional) high level type description. -This can be thought of as their mime type. It has several uses: - -* automatic type conversion -* better reuse strategy for non pure packets -* debugging - -The description is text-encoded, in the following form: - -type/subtype/subsubtype/.. - -This is implemented using t_pdp_symbol. - -Type descriptors can have wildcards. This is to give some freedom to a desired -type conversion. The following are all compatible: - -*/ - -// image/grey/320x240 -// image/*/320x240 -// image/*/* - -/* - -From a user pov, the type conversion is centralized. A single object (pdp_convert) -can do most of the conversions. - -Type conversion implementation has to be done decentralized. It is subdivided into -two steps: inter-type and intra-type conversions. - -Intra-type is the full responsability of each type implementation and can be handled -in a decentralized way (at linkage the type central intra-converter is registered -at the pdp framework. - -Inter-type conversion is harder to do decentralized, therefore each new type should -provide some conversions to the basic built in types. (internal image, bitmap or matrix -types. - -The point of this whole business is to - -* enable automatic conversion from anything to a desired type for operators that combine objects. - i.e. pdp_add but receive incompatible objects. -* enable manual anything to anything conversion using a pdp_convert object, i.e. have a consistent - package conversion api for users. - - -The solution is type conversion programs. A program's behaviour is specified as follows: - -* the program is registered with a source and destination (result) template -* it is passed a packet and a destination template -* it can assume the source packet complies to the program's registerd source template -* it should convert the packet to a packet that will comply to it's registered destination template -* if for some reason a conversion fails, an invalid packet (handle == -1) should be returned - -about type templates: - -* they are hierarchical, with subtypes separated by a '/' character -* they can contain a wildcard '*', meaning that a certain level in the type hierarchy is: - - a don't care value, when the wildcard is used - -> as a destination template in a requested conversion - -> as a source template in a conversion program's specification - - uspecified, when the wildcard is used - -> as a destination template in a conversion program's specification - - - -NOTE: - - a wildcard can't be used in a source template for a conversion request - this assymetry requires there be 2 kinds of template matching mechanisms: - - - source type description (without wildcards) to conversion program source template matching - - destination type description (with wildcards) to conversion program destination template matching - - since a packet's type description cannot have wildcards, a symmetric matching (both sides have - wildcards) can be used for matching. - -*/ - - - -/* - -implementation: - -there are 2 lists with conversion progams: -* the global list, containing all registered programs. -* the cached list, containing all recently used registered programs, or combinations thereof - -if there is no cached, perfectly matching rule, a new one will be created, and added to -the head of the conversion list. - -all conversion methods should keep their hand's off the source packet. it is treated as readonly. -this is to ensure a more flexible operation (i.e. be able to put the conversion at the register_ro -level) this will need a bit more logic in running the conversion program though.. - - -*/ - -#ifndef PDP_TYPE_H -#define PDP_TYPE_H - -/* the conversion method accepts a packet (which is freed) and a destination wildcard - and produces a new packet, or the invalid packet if the conversion failed */ -typedef int (*t_pdp_conversion_method)(int, t_pdp_symbol *); - -/* a conversion program is alist of conversion methods */ -typedef struct _pdp_conversion_program -{ - t_pdp_conversion_method method; // conversion method - struct _pdp_conversion_program *next; // next method in program -} t_pdp_conversion_program; - -/* a conversion has source and dest wildcards, and a conversion program */ -typedef struct _pdp_conversion -{ - t_pdp_symbol *src_pattern; // source type pattern - t_pdp_symbol *dst_pattern; // destination type pattern - t_pdp_conversion_program *program; // the conversion program for this conversion - struct _pdp_conversion *next; // next conversion program record -} t_pdp_conversion; - -/* all symbols are C style */ -#ifdef __cplusplus -extern "C" -{ -#endif - -/* pdp_packet methods */ -t_pdp_symbol *pdp_packet_get_description(int packet); -int pdp_packet_convert_ro(int packet, t_pdp_symbol *dest_pattern); -int pdp_packet_convert_rw(int packet, t_pdp_symbol *dest_pattern); - - -/* pdp_conversion_program methods */ -void pdp_conversion_program_free(t_pdp_conversion_program *program); -t_pdp_conversion_program *pdp_conversion_program_new(t_pdp_conversion_method method, ...); -t_pdp_conversion_program *pdp_conversion_program_copy(t_pdp_conversion_program *program); -void pdp_conversion_program_add(t_pdp_conversion_program *program, t_pdp_conversion_program *tail); - -/* pdp_type (central type object) methods */ -int pdp_type_description_match(t_pdp_symbol *description, t_pdp_symbol *pattern); -void pdp_type_register_conversion (t_pdp_symbol *src_pattern, t_pdp_symbol *dst_pattern, t_pdp_conversion_program *program); -void pdp_type_register_cached_conversion (t_pdp_symbol *src_pattern, t_pdp_symbol *dst_pattern, t_pdp_conversion_program *program); - - //t_pdp_symbol *pdp_type_gendesc(char *desc); //generate a type description (with description list attached) -t_pdp_list *pdp_type_to_list(t_pdp_symbol *type); - -/* pdp's (threadsafe) symbol */ -t_pdp_symbol *pdp_gensym(char *s); - - -#ifdef __cplusplus -} -#endif - -#endif |