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libpsyc/include/psyc/parse.h

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#ifndef PSYC_PARSE_H
/**
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* @file psyc/parse.h
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* @brief Interface for PSYC packet parsing.
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*
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* All parsing functions and the definitions they use are defined here.
*/
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/**
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* @defgroup parse Parsing Functions
*
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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
*
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* This simple example does not consider some more complex cases when you
* receive incomplete packets but still want to access the data. This code would
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* simply reject incomplete packets as error. A more detailed tutorial for
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* incomplete packets will follow. In the mean time, have look at the return
* codes in psycParseRC and their explanations. @see psycParseRC
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*/
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/** @{ */ // begin of parser group
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#include <stdint.h>
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#include <string.h>
#include <psyc.h>
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typedef enum
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{
/// Parse only the header
PSYC_PARSE_ROUTING_ONLY = 1,
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/// Parse only the content.
/// Parsing starts at the content and the content must be complete.
PSYC_PARSE_START_AT_CONTENT = 2,
} psycParseFlag;
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/**
* The return value definitions for the packet parsing function.
* @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.
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PSYC_PARSE_ERROR_END = -8,
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/// 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.
/// 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.
/// Operator & name are complete, value is incomplete.
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PSYC_PARSE_ENTITY_START = 3,
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/// Continuation of an incomplete entity modifier.
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PSYC_PARSE_ENTITY_CONT = 4,
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/// End of an incomplete entity modifier.
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PSYC_PARSE_ENTITY_END = 5,
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/// Entity modifier parsing done in one go.
/// Operator, name & value contains the respective parts.
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PSYC_PARSE_ENTITY = 6,
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/// Start of an incomplete body.
/// Name contains method, value contains part of the body.
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PSYC_PARSE_BODY_START = 7,
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/// Continuation of an incomplete body.
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PSYC_PARSE_BODY_CONT = 8,
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/// End of an incomplete body.
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PSYC_PARSE_BODY_END = 9,
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/// Body parsing done in one go, name contains method, value contains body.
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PSYC_PARSE_BODY = 10,
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/// Start of an incomplete content, value contains part of content.
/// Used when PSYC_PARSE_ROUTING_ONLY is set.
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PSYC_PARSE_CONTENT_START = 7,
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/// Continuation of an incomplete body.
/// Used when PSYC_PARSE_ROUTING_ONLY is set.
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PSYC_PARSE_CONTENT_CONT = 8,
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/// End of an incomplete body.
/// Used when PSYC_PARSE_ROUTING_ONLY is set.
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PSYC_PARSE_CONTENT_END = 9,
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/// Content parsing done in one go, value contains the whole content.
/// Used when PSYC_PARSE_ROUTING_ONLY is set.
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PSYC_PARSE_CONTENT = 10,
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/// Finished parsing packet.
PSYC_PARSE_COMPLETE = 11,
} psycParseRC;
/**
* The return value definitions for the list parsing function.
* @see psyc_parseList()
*/
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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,
} 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.
size_t startc; ///< Position where the parsing would be resumed.
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.
size_t contentParsed; ///< Number of bytes parsed from the content so far.
size_t contentLength; ///< Expected length of the content.
psycBool contentLengthFound; ///< Is there a length given for this packet?
size_t valueParsed; ///< Number of bytes parsed from the value so far.
size_t valueLength; ///< Expected length of the value.
psycBool valueLengthFound; ///< Is there a length given for this modifier?
} 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.
psycString buffer; ///< Buffer with data to be parsed.
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.
} 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
void psyc_initParseState (psycParseState *state)
{
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.
* @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
void psyc_initParseState2 (psycParseState *state, uint8_t flags)
{
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.
*
* This function does NOT copy the buffer. It will parse whatever is
* at the memory pointed to by buffer.
*
* @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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static inline
void psyc_setParseBuffer (psycParseState *state, psycString buffer)
{
state->buffer = buffer;
state->cursor = 0;
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.
*
* This function does NOT copy the buffer. It will parse whatever is
* at the memory pointed to by buffer.
*
* @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
void psyc_setParseBuffer2 (psycParseState *state, char *buffer, size_t length)
{
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psycString buf = {length, buffer};
psyc_setParseBuffer(state, buf);
}
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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
void psyc_initParseListState (psycParseListState *state)
{
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
void psyc_setParseListBuffer (psycParseListState *state, psycString buffer)
{
state->buffer = buffer;
state->cursor = 0;
}
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static inline
void psyc_setParseListBuffer2 (psycParseListState *state, char *buffer, size_t length)
{
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psycString buf = {length, buffer};
psyc_setParseListBuffer(state, buf);
}
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static inline
size_t psyc_getParseContentLength (psycParseState *state)
{
return state->contentLength;
}
static inline
psycBool psyc_isParseContentLengthFound (psycParseState *state)
{
return state->contentLengthFound;
}
static inline
size_t psyc_getParseValueLength (psycParseState *state)
{
return state->valueLength;
}
static inline
psycBool psyc_isParseValueLengthFound (psycParseState *state)
{
return state->valueLengthFound;
}
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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/**
* Parse PSYC packets.
*
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* Generalized line-based packet parser.
*
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* This function never allocates heap memory.
*
* @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
* @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
* @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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*/
psycParseRC psyc_parse (psycParseState *state, char *oper,
psycString *name, psycString *value);
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/**
* List value parser.
*/
psycParseListRC psyc_parseList (psycParseListState *state, psycString *name,
psycString *value, psycString *elem);
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/** @} */ // end of parse group
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#define PSYC_PARSE_H
#endif