ec7dfb1890
* Remove "probe" type from db_field_log * Supply probe when registering plugin chains * Minor refactoring (rename) in dbfl_type and chFilter
281 lines
9.6 KiB
C
281 lines
9.6 KiB
C
/*************************************************************************\
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* Copyright (c) 2010 Brookhaven National Laboratory.
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* Copyright (c) 2010 Helmholtz-Zentrum Berlin
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* fuer Materialien und Energie GmbH.
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* EPICS BASE is distributed subject to a Software License Agreement found
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* in file LICENSE that is included with this distribution.
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\*************************************************************************/
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#ifndef CHFPLUGIN_H
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#define CHFPLUGIN_H
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#include <shareLib.h>
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#include <dbDefs.h>
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#include <epicsTypes.h>
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#include <dbChannel.h>
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struct db_field_log;
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/* Based on the linkoptions utility by Michael Davidsaver (BNL) */
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/** @file chfPlugin.h
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* @brief Channel filter simplified plugins.
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*
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* Utility layer to allow an easier (reduced) interface for
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* channel filter plugins.
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*
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* Parsing the configuration arguments of a channel filter plugin
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* is done according to an argument description table provided by the plugin.
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* The parser stores the results directly into a user supplied structure
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* after appropriate type conversion.
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*
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* To specify the arguments, a chfPluginArgDef table must be defined
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* for the user structure. This table has to be specified when the plugin registers.
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*
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* The plugin is responsible to register an init function using
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* epicsExportRegistrar() and the accompanying registrar() directive in the dbd,
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* and call chfPluginRegister() from within the init function.
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*
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* For example:
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*
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* typedef struct myStruct {
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* ... other stuff
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* epicsUInt32 ival;
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* double dval;
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* epicsUInt32 ival2;
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* int enumval;
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* char strval[20];
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* } myStruct;
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*
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* static const
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* chfPluginEnumType colorEnum[] = { {"Red",1}, {"Green",2}, {"Blue",3}, {NULL,0} };
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*
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* static const
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* chfPluginDef myStructDef[] = {
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* chfInt32 (myStruct, ival, "Integer" , 0, 0),
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* chfInt32 (myStruct, ival2, "Second" , 1, 0),
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* chfDouble(myStruct, dval, "Double" , 1, 0),
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* chfString(myStruct, strval , "String" , 1, 0),
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* chfEnum (myStruct, enumval, "Color" , 1, 0, colorEnum),
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* chfPluginEnd
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* };
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*
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* Note: The 4th argument specifies the parameter to be required (1) or optional (0),
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* the 5th whether converting to the required type is allowed (1), or
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* type mismatches are an error (0).
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*
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** @brief Channel filter simplified plugin interface.
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*
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* The routines in this structure must be implemented by each filter plugin.
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*/
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typedef struct chfPluginIf {
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/* Memory management */
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/** @brief Allocate private resources.
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*
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* <em>Called before parsing starts.</em>
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* The plugin should allocate its per-instance structures,
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* returning a pointer to them or NULL requesting an abort of the operation.
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*
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* allocPvt may be set to NULL, if no resource allocation is needed.
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*
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* @return Pointer to private structure, NULL if operation is to be aborted.
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*/
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void * (* allocPvt) (void);
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/** @brief Free private resources.
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*
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* <em>Called as part of abort or shutdown.</em>
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* The plugin should release any resources allocated for this filter;
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* no further calls through this interface will be made.
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*
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* freePvt may be set to NULL, if no resources need to be released.
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*
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* @param pvt Pointer to private structure.
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*/
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void (* freePvt) (void *pvt);
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/* Parameter parsing results */
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/** @brief A parsing error occurred.
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*
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* <em>Called after parsing failed with an error.</em>
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*/
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void (* parse_error) (void);
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/** @brief Configuration has been parsed successfully.
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*
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* <em>Called after parsing has finished ok.</em>
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* The plugin may check the validity of the parsed data,
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* returning -1 to request an abort of the operation.
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*
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* @param pvt Pointer to private structure.
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* @return 0 for success, -1 if operation is to be aborted.
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*/
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int (* parse_ok) (void *pvt);
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/* Channel operations */
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/** @brief Open channel.
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*
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* <em>Called as part of the channel connection setup.</em>
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*
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* @param chan dbChannel for which the connection is being made.
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* @param pvt Pointer to private structure.
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* @return 0 for success, -1 if operation is to be aborted.
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*/
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long (* channel_open) (dbChannel *chan, void *pvt);
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/** @brief Register callbacks for pre-event-queue operation.
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*
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* <em>Called as part of the channel connection setup.</em>
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*
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* This function is called to establish the stack of plugins that an event
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* is passed through between the database and the event queue.
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*
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* The plugin must set pe_out to point to its own post-event callback in order
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* to be called when a data update is sent from the database towards the
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* event queue.
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*
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* The plugin may find out the type of data it will receive by looking at 'probe'.
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* If the plugin will change the data type and/or size, it must update 'probe'
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* accordingly.
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*
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* @param chan dbChannel for which the connection is being made.
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* @param pvt Pointer to private structure.
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* @param cb_out Pointer to this plugin's post-event callback (NULL to bypass
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* this plugin).
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* @param arg_out Argument that must be supplied when calling
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* this plugin's post-event callback.
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*/
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void (* channelRegisterPre) (dbChannel *chan, void *pvt,
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chPostEventFunc **cb_out, void **arg_out,
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db_field_log *probe);
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/** @brief Register callbacks for post-event-queue operation.
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*
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* <em>Called as part of the channel connection setup.</em>
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*
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* This function is called to establish the stack of plugins that an event
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* is passed through between the event queue and the final user (CA server or
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* database access).
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*
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* The plugin must set pe_out to point to its own post-event callback in order
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* to be called when a data update is sent from the event queue towards the
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* final user.
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*
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* The plugin may find out the type of data it will receive by looking at 'probe'.
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* If the plugin will change the data type and/or size, it must update 'probe'
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* accordingly.
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*
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* @param chan dbChannel for which the connection is being made.
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* @param pvt Pointer to private structure.
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* @param cb_out Pointer to this plugin's post-event callback (NULL to bypass
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* this plugin).
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* @param arg_out Argument that must be supplied when calling
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* this plugin's post-event callback.
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*/
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void (* channelRegisterPost) (dbChannel *chan, void *pvt,
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chPostEventFunc **cb_out, void **arg_out,
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db_field_log *probe);
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/** @brief Channel report request.
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*
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* <em>Called as part of show... routines.</em>
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*
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* @param chan dbChannel for which the report is requested.
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* @param pvt Pointer to private structure.
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* @param intro Line header string to be printed at the beginning of each line.
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* @param level Interest level.
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*/
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void (* channel_report) (dbChannel *chan, void *pvt, const char *intro, int level);
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/* FIXME: More filter routines here ... */
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/** @brief Channel close request.
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*
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* <em>Called as part of connection shutdown.</em>
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* @param chan dbChannel for which the connection is being shut down.
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* @param pvt Pointer to private structure.
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*/
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void (* channel_close) (dbChannel *chan, void *pvt);
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} chfPluginIf;
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typedef enum chfPluginArg {
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chfPluginArgInvalid=0,
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chfPluginArgBoolean,
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chfPluginArgInt32,
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chfPluginArgDouble,
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chfPluginArgString,
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chfPluginArgEnum
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} chfPluginArg;
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typedef struct chfPluginEnumType {
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const char *name;
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const int value;
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} chfPluginEnumType;
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typedef struct chfPluginArgDef {
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const char * name;
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chfPluginArg optType;
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int required:1;
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int convert:1;
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epicsUInt32 offset;
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epicsUInt32 size;
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const chfPluginEnumType *enums;
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} chfPluginArgDef;
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#define chfInt32(Struct, Member, Name, Req, Conv) \
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{Name, chfPluginArgInt32, Req, Conv, OFFSET(Struct, Member), sizeof( ((Struct*)0)->Member ), NULL}
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#define chfBoolean(Struct, Member, Name, Req, Conv) \
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{Name, chfPluginArgBoolean, Req, Conv, OFFSET(Struct, Member), sizeof( ((Struct*)0)->Member ), NULL}
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#define chfDouble(Struct, Member, Name, Req, Conv) \
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{Name, chfPluginArgDouble, Req, Conv, OFFSET(Struct, Member), sizeof( ((Struct*)0)->Member ), NULL}
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#define chfString(Struct, Member, Name, Req, Conv) \
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{Name, chfPluginArgString, Req, Conv, OFFSET(Struct, Member), sizeof( ((Struct*)0)->Member ), NULL}
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#define chfEnum(Struct, Member, Name, Req, Conv, Enums) \
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{Name, chfPluginArgEnum, Req, Conv, OFFSET(Struct, Member), sizeof( ((Struct*)0)->Member ), Enums}
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#define chfPluginArgEnd {0}
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/* Extra output when parsing and converting */
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#define CHFPLUGINDEBUG 1
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/** @brief Return the string associated with Enum index 'i'.
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*
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* @param Enums A null-terminated array of string/integer pairs.
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* @param i An Enum index.
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* @param def String to be returned when 'i' isn't a valid Enum index.
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* @return The string associated with 'i'.
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*/
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epicsShareFunc
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const char*
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epicsShareAPI
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chfPluginEnumString(const chfPluginEnumType *Enums, int i, const char* def);
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/** @brief Register a plugin.
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*
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* @param key The plugin name key that clients will use.
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* @param pif Pointer to the plugin's interface.
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* @param opts Pointer to the configuration argument description table.
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*/
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epicsShareFunc
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int
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epicsShareAPI
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chfPluginRegister(const char* key, const chfPluginIf *pif, const chfPluginArgDef* opts);
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#ifdef __cplusplus
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}
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#endif
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#endif // CHFPLUGIN_H
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