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/**
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* @ file psyc / parser . h
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* @ brief Interface for various PSYC parser functions .
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*
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* All parsing functions and the definitions they use are
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* defined in this file .
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*/
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/**
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* @ defgroup parser Parsing Functions
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*
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* This module contains packet and list parsing functions .
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* The parser adheres to the definition of a packet found at
*
* http : //about.psyc.eu/Spec:Packet
*
* and the according terms are used throughout this documentation and in the
* return codes . You should be at least
* vaguely familiar with what the difference between " body " and " content " as
* well as " routing variable " and " entity variable " is .
*
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*
* To parse a packet you first have to initialize a state :
*
* @ code
* psycParseState state ;
*
* psyc_initParseState ( & state ) ;
* @ endcode
*
* Note that there is also psyc_initParseState2 if you want to fine - tune what
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* part of the packet should be parsed . @ see psycParseFlag
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*
* Next , you have to tell the parser what it should parse . Assuming the variable
* raw_data points to our packet and raw_len contains the length , you can pass
* it to the parser as follows :
*
* @ code
* char * raw_data ; // points to our (possibly incomplete) packet
* size_t raw_len ; // how many bytes of data
*
* psyc_setParseBuffer ( & state , // our initialized state from before
* raw_data ,
* raw_len ) ;
* @ endcode
*
* Now the the variables that will save the output of the parser need to be
* declared :
*
* @ code
* psycString name , // Name of the variable or method
* value ; // Value of the variable or body
* char oper ; // operator of the variable (if any)
* @ endcode
*
* They will be passd to the parsing function which will set them to
* the according positions and lengths .
*
* Now the real parsing begins . The parsing function needs to be called
* repeatedly with various actions in between , depending on the return values :
*
* @ code
*
* int res ;
*
* do // run the parsing in a loop, each time parsing one line
* {
* name . length = value . length = oper = 0 ; // reset the output variables
*
* ret = psyc_parse ( & state , & oper , & name , & value ) ; // call the parsing function
*
* switch ( ret ) // look at the return value
* {
* case PSYC_PARSE_ROUTING : // it is a routing variable
* case PSYC_PARSE_ENTITY : // it is a entity variable
* // Name, value and operator of the variable can now be found in the
* // respective variables:
* printf ( " Variable: %.*s Value: %.*s Operator: %c \n " ,
* name . length , name . ptr ,
* value . length , value . ptr ,
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* oper ) ;
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* // Note that the .ptr member still points at your original buffer. If
* // you want to reuse that buffer for the next packet, you better copy it
* // before passing it to the parser or you copy each variable now.
* break ;
* case PSYC_PARSE_BODY : // it is the method and the body of the packet.
* printf ( " Method Name: %.*s Body: %.*s \n " ,
* name . length , name . ptr , // name of the method
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* value . length , value . ptr ) ; // value of the body
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* break ;
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* case PSYC_PARSE_COMPLETE : // parsing of this packet is complete
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* // You can simply continue parsing till you get the
* // PSYC_PARSE_INSUFFICIENT code which means teh packet is incomplete.
* continue ;
* default : //
* perror ( " Error %i happened :( \n " , res ) ;
* return res ;
* }
* }
* @ endcode
*
* This simple example does not consider some more complex cases for when you
* recieve incomplete packets but still want to access the data . This code would
* simply reject incomplete packets as error . A more detailed tutorial for
* incomplete packets will follow , in the mean time , have look at the return
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* codes in psycParseRC and their explainations . @ see psycParseRC
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*/
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/** @{ */ // begin of parser group
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# ifndef PSYC_PARSER_H
# define PSYC_PARSER_H
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# include <stdint.h>
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# include <string.h>
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# include <psyc.h>
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typedef enum
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{
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/// Parse only the header
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PSYC_PARSE_ROUTING_ONLY = 1 ,
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/// Parse only the content. Parsing starts at the content and the content must be complete. "content" means the definition used in the packet specification.
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PSYC_PARSE_START_AT_CONTENT = 2 ,
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} psycParseFlag ;
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/**
* The return value definitions for the packet parsing function .
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* @ see psyc_parse ( )
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*/
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typedef enum
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{
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/// Error, packet is not ending with a valid delimiter.
PSYC_PARSE_ERROR_END = - 8 ,
/// Error, expected NL after the method.
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PSYC_PARSE_ERROR_METHOD = - 7 ,
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/// Error, expected NL after a modifier.
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PSYC_PARSE_ERROR_MOD_NL = - 6 ,
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/// Error, modifier length is not numeric.
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PSYC_PARSE_ERROR_MOD_LEN = - 5 ,
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/// Error, expected TAB before modifier value.
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PSYC_PARSE_ERROR_MOD_TAB = - 4 ,
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/// Error, modifier name is missing.
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PSYC_PARSE_ERROR_MOD_NAME = - 3 ,
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/// Error, expected NL after the content length.
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PSYC_PARSE_ERROR_LENGTH = - 2 ,
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/// Error in packet.
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PSYC_PARSE_ERROR = - 1 ,
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/// Buffer contains insufficient amount of data.
/// Fill another buffer and concatenate it with the end of the current buffer,
/// from the cursor position to the end.
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PSYC_PARSE_INSUFFICIENT = 1 ,
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/// Routing modifier parsing done.
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/// Operator, name & value contains the respective parts.
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PSYC_PARSE_ROUTING = 2 ,
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/// Start of an incomplete entity modifier.
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/// Operator & name are complete, value is incomplete.
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PSYC_PARSE_ENTITY_START = 3 ,
/// Continuation of an incomplete entity modifier.
PSYC_PARSE_ENTITY_CONT = 4 ,
/// End of an incomplete entity modifier.
PSYC_PARSE_ENTITY_END = 5 ,
/// Entity modifier parsing done in one go.
/// Operator, name & value contains the respective parts.
PSYC_PARSE_ENTITY = 6 ,
/// Start of an incomplete body.
/// Name contains method, value contains part of the body.
PSYC_PARSE_BODY_START = 7 ,
/// Continuation of an incomplete body.
PSYC_PARSE_BODY_CONT = 8 ,
/// End of an incomplete body.
PSYC_PARSE_BODY_END = 9 ,
/// Body parsing done in one go, name contains method, value contains body.
PSYC_PARSE_BODY = 10 ,
/// Start of an incomplete content, value contains part of content.
/// Used when PSYC_PARSE_ROUTING_ONLY is set.
PSYC_PARSE_CONTENT_START = 7 ,
/// Continuation of an incomplete body.
/// Used when PSYC_PARSE_ROUTING_ONLY is set.
PSYC_PARSE_CONTENT_CONT = 8 ,
/// End of an incomplete body.
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/// Used when PSYC_PARSE_ROUTING_ONLY is set.
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PSYC_PARSE_CONTENT_END = 9 ,
/// Content parsing done in one go, value contains the whole content.
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/// Used when PSYC_PARSE_ROUTING_ONLY is set.
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PSYC_PARSE_CONTENT = 10 ,
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/// Finished parsing packet.
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PSYC_PARSE_COMPLETE = 11 ,
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} psycParseRC ;
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/**
* The return value definitions for the list parsing function .
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* @ see psyc_parseList ( )
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*/
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typedef enum
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{
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PSYC_PARSE_LIST_ERROR_DELIM = - 5 ,
PSYC_PARSE_LIST_ERROR_LEN = - 4 ,
PSYC_PARSE_LIST_ERROR_TYPE = - 3 ,
PSYC_PARSE_LIST_ERROR_NAME = - 2 ,
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PSYC_PARSE_LIST_ERROR = - 1 ,
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/// Completed parsing a list element.
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PSYC_PARSE_LIST_ELEM = 1 ,
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/// Reached end of buffer.
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PSYC_PARSE_LIST_END = 2 ,
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/// Binary list is incomplete.
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PSYC_PARSE_LIST_INCOMPLETE = 3 ,
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} psycParseListRC ;
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/**
* Struct for keeping parser state .
*/
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typedef struct
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{
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size_t cursor ; ///< current position in buffer
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size_t startc ; ///< position where the parsing would be resumed
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psycString buffer ; ///< buffer with data to be parsed
uint8_t flags ; ///< flags for the parser, see psycParseFlag
psycPart part ; ///< part of the packet being parsed currently
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size_t routingLength ; ///< length of routing part parsed so far
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size_t contentParsed ; ///< number of bytes parsed from the content so far
size_t contentLength ; ///< expected length of the content
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psycBool contentLengthFound ; ///< is there a length given for this packet?
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size_t valueParsed ; ///< number of bytes parsed from the value so far
size_t valueLength ; ///< expected length of the value
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psycBool valueLengthFound ; ///< is there a length given for this modifier?
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} psycParseState ;
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/**
* Struct for keeping list parser state .
*/
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typedef struct
{
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size_t cursor ; ///< current position in buffer
size_t startc ; ///< line start position
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psycString buffer ;
psycListType type ; ///< list type
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size_t elemParsed ; ///< number of bytes parsed from the elem so far
size_t elemLength ; ///< expected length of the elem
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} psycParseListState ;
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/**
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* Initializes the state struct .
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*
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* @ param state Pointer to the state struct that should be initialized .
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* @ see psyc_initParseState2
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*/
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static inline
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void psyc_initParseState ( psycParseState * state )
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{
memset ( state , 0 , sizeof ( psycParseState ) ) ;
}
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/**
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* Initializes the state struct with flags .
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*
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* @ param state Pointer to the state struct that should be initialized .
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* @ param flags Flags to be set for the parser , see psycParseFlag .
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* @ see psyc_initParseState
* @ see psycParseFlag
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*/
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static inline
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void psyc_initParseState2 ( psycParseState * state , uint8_t flags )
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{
memset ( state , 0 , sizeof ( psycParseState ) ) ;
state - > flags = flags ;
if ( flags & PSYC_PARSE_START_AT_CONTENT )
state - > part = PSYC_PART_CONTENT ;
}
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/**
* Sets a new buffer in the parser state struct with data to be parsed .
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*
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* This function does NOT copy the buffer . It will parse whatever is
* at the memory pointed to by buffer .
*
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* @ param state Pointer to the initialized state of the parser
* @ param buffer the buffer that should be parsed now
* @ see psycString
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*/
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static inline
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void psyc_setParseBuffer ( psycParseState * state , psycString buffer )
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{
state - > buffer = buffer ;
state - > cursor = 0 ;
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if ( state - > flags & PSYC_PARSE_START_AT_CONTENT )
{
state - > contentLength = buffer . length ;
state - > contentLengthFound = PSYC_TRUE ;
}
}
/**
* Sets a new buffer in the parser state struct with data to be parsed .
*
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* This function does NOT copy the buffer . It will parse whatever is
* at the memory pointed to by buffer .
*
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* @ param state Pointer to the initialized state of the parser
* @ param buffer pointer to the data that should be parsed
* @ param length length of the data in bytes
* @ see psycString
*/
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static inline
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void psyc_setParseBuffer2 ( psycParseState * state , char * buffer , size_t length )
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{
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psycString buf = { length , buffer } ;
psyc_setParseBuffer ( state , buf ) ;
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}
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/**
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* Initializes the list state struct .
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*
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* @ param state Pointer to the list state struct that should be initialized .
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*/
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static inline
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void psyc_initParseListState ( psycParseListState * state )
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{
memset ( state , 0 , sizeof ( psycParseListState ) ) ;
}
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/**
* Sets a new buffer in the list parser state struct with data to be parsed .
*/
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static inline
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void psyc_setParseListBuffer ( psycParseListState * state , psycString buffer )
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{
state - > buffer = buffer ;
state - > cursor = 0 ;
}
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static inline
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void psyc_setParseListBuffer2 ( psycParseListState * state , char * buffer , size_t length )
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{
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psycString buf = { length , buffer } ;
psyc_setParseListBuffer ( state , buf ) ;
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}
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static inline
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size_t psyc_getParseContentLength ( psycParseState * state )
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{
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return state - > contentLength ;
}
static inline
psycBool psyc_isParseContentLengthFound ( psycParseState * state )
{
return state - > contentLengthFound ;
}
static inline
size_t psyc_getParseValueLength ( psycParseState * state )
{
return state - > valueLength ;
}
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static inline
psycBool psyc_isParseValueLengthFound ( psycParseState * state )
{
return state - > valueLengthFound ;
}
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static inline
size_t psyc_getParseCursor ( psycParseState * state )
{
return state - > cursor ;
}
static inline
size_t psyc_getParseBufferLength ( psycParseState * state )
{
return state - > buffer . length ;
}
static inline
size_t psyc_getParseRemainingLength ( psycParseState * state )
{
return state - > buffer . length - state - > cursor ;
}
static inline
const char * psyc_getParseRemainingBuffer ( psycParseState * state )
{
return state - > buffer . ptr + state - > cursor ;
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}
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/**
* Parse PSYC packets .
*
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* Generalized line - based packet parser .
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*
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* This function never allocates heap memory .
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*
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* @ param state An initialized psycParseState
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* @ param oper A pointer to a character . In case of a variable , it will
* be set to the operator of that variable
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* @ param name A pointer to a psycString . It will point to the name of
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* the variable or method and its length will be set accordingly
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* @ param value A pointer to a psycString . It will point to the
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* value / body the variable / method and its length will be set accordingly
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*/
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psycParseRC psyc_parse ( psycParseState * state , char * oper ,
psycString * name , psycString * value ) ;
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/**
* List value parser .
*/
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psycParseListRC psyc_parseList ( psycParseListState * state , psycString * name ,
psycString * value , psycString * elem ) ;
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# endif // PSYC_PARSER_H
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/** @} */ // end of parser group