haiku.git

//----------------------------------------------------------------------
//  This software is part of the OpenBeOS distribution and is covered 
//  by the MIT License.
//---------------------------------------------------------------------
/*!
	\file Rule.cpp
	MIME sniffer rule implementation
*/

#include <sniffer/Err.h>
#include <sniffer/DisjList.h>
#include <sniffer/Rule.h>
#include <DataIO.h>
#include <stdio.h>

using namespace BPrivate::Storage::Sniffer;

/*! \brief Creates an unitialized Sniffer::Rule object. To initialize it, you
	must pass a pointer to the object to Sniffer::parse().
*/
Rule::Rule()
	: fPriority(0.0)
	, fConjList(NULL)
{
}

Rule::~Rule() {
	Unset();	
}

status_t
Rule::InitCheck() const {
	return fConjList ? B_OK : B_NO_INIT;
}

//! Returns the priority of the rule. 0.0 <= priority <= 1.0.
double
Rule::Priority() const {
	return fPriority;
}

//! Sniffs the given data stream. Returns true if the rule matches, false if not.
bool
Rule::Sniff(BPositionIO *data) const {
	if (InitCheck() != B_OK)
		return false;
	else {
		bool result = true;
		std::vector<DisjList*>::const_iterator i;
		for (i = fConjList->begin(); i != fConjList->end(); i++) {
			if (*i)
				result &= (*i)->Sniff(data);		
		}
		return result;
	}
}

/*! \brief Returns the number of bytes needed for this rule to perform a complete sniff,
	or an error code if something goes wrong.
*/
ssize_t
Rule::BytesNeeded() const
{
	ssize_t result = InitCheck();
	
	// Tally up the BytesNeeded() values for all the DisjLists and return the largest.
	if (result == B_OK) {
		result = 0; // Just to be safe...
		std::vector<DisjList*>::const_iterator i;
		for (i = fConjList->begin(); i != fConjList->end(); i++) {
			if (*i) {
				ssize_t bytes = (*i)->BytesNeeded();
				if (bytes >= 0) {
					if (bytes > result)
						result = bytes;
				} else {
					result = bytes;
					break;
				}
			}
		}
	}	
	return result;
}


void
Rule::Unset() {
 	if (fConjList){
		delete fConjList;
		fConjList = NULL;
	}
}

//! Called by Parser::Parse() after successfully parsing a sniffer rule.
void
Rule::SetTo(double priority, std::vector<DisjList*>* list) {
	Unset();
	if (0.0 <= priority && priority <= 1.0)
		fPriority = priority;
	else
		throw new Err("Sniffer pattern error: invalid priority", -1);
	fConjList = list;
}