mirror of git://git.psyc.eu/libpsyc
512 lines
14 KiB
C
512 lines
14 KiB
C
#ifndef PSYC_PARSE_H
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/**
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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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/**
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* @defgroup parse 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
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*
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* http://about.psyc.eu/Spec:Packet
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*
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* and the according terms are used throughout this documentation and in the
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* return codes. You should be at least
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* vaguely familiar with differences between "body" and "content" as
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* well as "routing variable" and "entity variable".
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*
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*
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* To parse a packet you first have to initialize a state:
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*
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* @code
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* psycParseState state;
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* psyc_parse_state_init(&state, flags);
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* @endcode
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*
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* With the flags parameter you can fine-tune what
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* part of the packet should be parsed. @see psycParseFlag
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*
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* Next, you have to tell the parser what it should parse. Assuming the variable
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* raw_data points to our packet and raw_len contains the length, you can pass
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* it to the parser as follows:
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*
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* @code
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* char* raw_data; // points to our (possibly incomplete) packet
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* size_t raw_len; // how many bytes of data
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*
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* psyc_parse_buffer_set(&state, raw_data, raw_len); // state is our initialized state from before
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* @endcode
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*
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* Now the the variables that will save the output of the parser need to be
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* declared:
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*
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* @code
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* psycString name, // Name of the variable or method
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* value; // Value of the variable or body
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* char oper; // operator of the variable (if any)
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* @endcode
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*
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* They will be passed to the parsing function which will set them to
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* the according positions and lengths.
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*
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* Now the real parsing begins. The parsing function needs to be called
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* repeatedly with various actions in between, depending on the return values.
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*
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* A simplified example follows, see test/testPsyc.c for actual code that
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* handles incomplete packets as well.
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*
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* @code
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*
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* int ret;
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*
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* do // run the parsing in a loop, each time parsing one line
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* {
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* name.length = value.length = oper = 0; // reset the output variables
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*
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* ret = psyc_parse(&state, &oper, &name, &value); // call the parsing function
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*
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* switch (ret) // look at the return value
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* {
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* case PSYC_PARSE_ROUTING: // it is a routing variable
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* case PSYC_PARSE_ENTITY: // it is a entity variable
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* // Name, value and operator of the variable can now be found in the
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* // respective variables:
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* printf("Variable: %.*s Value: %.*s Operator: %c\n",
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* name.length, name.ptr,
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* 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
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* // you want to reuse that buffer for the next packet, you better copy it
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* // before passing it to the parser or you copy each variable now.
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* break;
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* case PSYC_PARSE_BODY: // it is the method and the body of the packet.
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* printf("Method Name: %.*s Body: %.*s\n",
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* 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
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* // PSYC_PARSE_INSUFFICIENT code which means the line is incomplete.
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* continue;
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* default: //
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* perror("Error %i happened :(\n", res);
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* return res;
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* }
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* }
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* while (ret > 0)
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* @endcode
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*
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* This simple example does not consider some more complex cases when you
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* 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
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* 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>
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#include <psyc.h>
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typedef enum {
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/// Default Flag. Parse everything.
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PSYC_PARSE_ALL = 0,
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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.
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/// Parsing starts at the content and the content must be complete.
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PSYC_PARSE_START_AT_CONTENT = 2,
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} psycParseFlag;
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/**
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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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/// 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.
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/// Fill another buffer and concatenate it with the end of the current buffer,
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/// 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,
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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.
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/// Operator, name & value contains the respective parts.
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PSYC_PARSE_ENTITY = 6,
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/// Start of an incomplete body.
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/// Name contains method, value contains part of the body.
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/// Used when packet length is given
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PSYC_PARSE_BODY_START = 7,
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/// Continuation of an incomplete body.
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/// Used when packet length is given
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PSYC_PARSE_BODY_CONT = 8,
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/// End of an incomplete body.
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/// Used when packet length is given
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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.
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/// 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 content.
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/// 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 content.
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/// 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.
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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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/**
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* The return value definitions for the list parsing function.
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* @see psyc_parse_list()
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*/
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typedef enum {
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PSYC_PARSE_LIST_ERROR_DELIM = -4,
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PSYC_PARSE_LIST_ERROR_LEN = -3,
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PSYC_PARSE_LIST_ERROR_TYPE = -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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/**
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* Struct for keeping parser state.
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*/
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typedef struct {
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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.
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uint8_t flags; ///< Flags for the parser, see psycParseFlag.
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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.
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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.
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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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/**
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* Struct for keeping list parser state.
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*/
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typedef struct {
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size_t cursor; ///< Current position in buffer.
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size_t startc; ///< Line start position.
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psycString buffer; ///< Buffer with data to be parsed.
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psycListType type; ///< List type.
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size_t elemParsed; ///< Number of bytes parsed from the elem so far.
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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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* @param flags Flags to be set for the parser, see psycParseFlag.
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* @see psycParseFlag
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*/
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static inline
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void psyc_parse_state_init (psycParseState *state, uint8_t flags)
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{
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memset(state, 0, sizeof(psycParseState));
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state->flags = flags;
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if (flags & PSYC_PARSE_START_AT_CONTENT)
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state->part = PSYC_PART_CONTENT;
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}
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/**
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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
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* at the memory pointed to by buffer.
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*
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* @param state Pointer to the initialized state of the parser
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* @param buffer pointer to the data that should be parsed
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* @param length length of the data in bytes
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* @see psycString
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*/
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static inline
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void psyc_parse_buffer_set (psycParseState *state, char *buffer, size_t length)
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{
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state->buffer = (psycString) {length, buffer};
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state->cursor = 0;
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if (state->flags & PSYC_PARSE_START_AT_CONTENT) {
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state->contentLength = length;
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state->contentLengthFound = PSYC_TRUE;
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}
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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_parse_list_state_init (psycParseListState *state)
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{
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memset(state, 0, sizeof(psycParseListState));
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}
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/**
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* Sets a new buffer in the list parser state struct with data to be parsed.
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*/
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static inline
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void psyc_parse_list_buffer_set (psycParseListState *state, char *buffer, size_t length)
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{
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state->buffer = (psycString) {length, buffer};
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state->cursor = 0;
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}
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static inline
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size_t psyc_parse_content_length (psycParseState *state)
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{
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return state->contentLength;
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}
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static inline
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psycBool psyc_parse_content_length_found (psycParseState *state)
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{
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return state->contentLengthFound;
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}
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static inline
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size_t psyc_parse_value_length (psycParseState *state)
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{
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return state->valueLength;
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}
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static inline
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psycBool psyc_parse_value_length_found (psycParseState *state)
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{
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return state->valueLengthFound;
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}
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static inline
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size_t psyc_parse_cursor (psycParseState *state)
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{
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return state->cursor;
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}
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static inline
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size_t psyc_parse_buffer_length (psycParseState *state)
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{
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return state->buffer.length;
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}
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static inline
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size_t psyc_parse_remaining_length (psycParseState *state)
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{
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return state->buffer.length - state->cursor;
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}
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static inline
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const char * psyc_parse_remaining_buffer (psycParseState *state)
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{
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return state->buffer.ptr + state->cursor;
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}
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/**
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* Parse PSYC packets.
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*
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* This function parses a full or partial PSYC packet while keeping parsing
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* state in a state variable that you have to pass in every time, and returns
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* whenever a modifier or the body is found. See psycParseRC for the possible
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* return codes. When it returns oper, name & value will point to the respective
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* parts of the buffer, no memory allocation is done.
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*
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* @param state An initialized psycParseState.
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* @param oper In case of a modifier it will be set to the operator.
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* @param name In case of a modifier it will point to the name,
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* in case of the body it will point to the method.
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* @param value In case of a modifier it will point to the value,
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* in case of the body it will point to the data.
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*/
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#ifdef __INLINE_PSYC_PARSE
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static inline
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#endif
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psycParseRC psyc_parse (psycParseState *state, char *oper,
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psycString *name, psycString *value);
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/**
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* List parser.
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*
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* This function parses a _list modifier value and returns one element a time
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* while keeping parsing state in a state variable that you have to pass in
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* every time. When it returns elem will point to the next element in value, no
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* memory allocation is done.
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*
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* @param state An initialized psycParseListState.
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* @param elem It will point to the next element in the list.
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*/
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#ifdef __INLINE_PSYC_PARSE
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static inline
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#endif
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psycParseListRC psyc_parse_list (psycParseListState *state, psycString *elem);
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static inline
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psycBool psyc_parse_number (const char *value, size_t len, ssize_t *n)
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{
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size_t c = 0;
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uint8_t neg = 0;
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if (!value)
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return PSYC_FALSE;
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if (value[0] == '-')
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neg = ++c;
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*n = 0;
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while (c < len && value[c] >= '0' && value[c] <= '9')
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*n = 10 * *n + (value[c++] - '0');
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if (c != len)
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return PSYC_FALSE;
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if (neg)
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*n = 0 - *n;
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return PSYC_TRUE;
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}
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static inline
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psycBool psyc_parse_time (const char *value, size_t len, time_t *t)
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{
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return psyc_parse_number(value, len, t);
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}
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static inline
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psycBool psyc_parse_date (const char *value, size_t len, time_t *t)
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{
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if (psyc_parse_number(value, len, t)) {
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*t += PSYC_EPOCH;
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return PSYC_TRUE;
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}
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return PSYC_FALSE;
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}
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/**
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* Determines if the argument is a glyph.
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* Glyphs are: : = + - ? !
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*/
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static inline
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char psyc_is_glyph (uint8_t g)
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{
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switch(g) {
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case ':':
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case '=':
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case '+':
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case '-':
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case '?':
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case '!':
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return 1;
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default:
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return 0;
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}
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}
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/**
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* Determines if the argument is numeric.
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*/
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static inline
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char psyc_is_numeric (uint8_t c)
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{
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return c >= '0' && c <= '9';
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}
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/**
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* Determines if the argument is alphabetic.
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*/
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static inline
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char psyc_is_alpha (uint8_t c)
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{
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return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
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}
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/**
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* Determines if the argument is alphanumeric.
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*/
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static inline
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char psyc_is_alpha_numeric (uint8_t c)
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{
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return psyc_is_alpha(c) || psyc_is_numeric(c);
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}
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/**
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* Determines if the argument is a keyword character.
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* Keyword characters are: alphanumeric and _
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*/
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static inline
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char psyc_is_kw_char (uint8_t c)
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{
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return psyc_is_alpha_numeric(c) || c == '_';
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}
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/**
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* Determines if the argument is a name character.
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* Name characters are: see opaque_part in RFC 2396
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*/
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static inline
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char psyc_is_name_char (uint8_t c)
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{
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return psyc_is_alpha(c) || (c >= '$' && c <= ';') ||
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c == '_' || c == '!' || c == '?' || c == '=' || c == '@' || c == '~';
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}
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/**
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* Determines if the argument is a hostname character.
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* Hostname characters are: alphanumeric and -
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*/
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static inline
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char psyc_is_host_char (uint8_t c)
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{
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return psyc_is_alpha_numeric(c) || c == '.' || c == '-';
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}
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/** @} */ // end of parse group
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#define PSYC_PARSE_H
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#endif
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