parsetools.h

/* Copyright (C) 2011 Circuits At Home, LTD. All rights reserved.

This software may be distributed and modified under the terms of the GNU
General Public License version 2 (GPL2) as published by the Free Software
Foundation and appearing in the file GPL2.TXT included in the packaging of
this file. Please note that GPL2 Section 2[b] requires that all works based
on this software must also be made publicly available under the terms of
the GPL2 ("Copyleft").

Contact information
-------------------

Circuits At Home, LTD
Web      :  http://www.circuitsathome.com
e-mail   :  support@circuitsathome.com
 */

#if !defined(_usb_h_) || defined(__PARSETOOLS_H__)
#error "Never include parsetools.h directly; include Usb.h instead"
#else
#define __PARSETOOLS_H__

struct MultiValueBuffer {
        uint8_t valueSize;
        void *pValue;
} __attribute__((packed));

class MultiByteValueParser {
        uint8_t * pBuf;
        uint8_t countDown;
        uint8_t valueSize;

public:

        MultiByteValueParser() : pBuf(NULL), countDown(0), valueSize(0) {
        };

        const uint8_t* GetBuffer() {
                return pBuf;
        };

        void Initialize(MultiValueBuffer * const pbuf) {
                pBuf = (uint8_t*)pbuf->pValue;
                countDown = valueSize = pbuf->valueSize;
        };

        bool Parse(uint8_t **pp, uint16_t *pcntdn);
};

class ByteSkipper {
        uint8_t *pBuf;
        uint8_t nStage;
        uint16_t countDown;

public:

        ByteSkipper() : pBuf(NULL), nStage(0), countDown(0) {
        };

        void Initialize(MultiValueBuffer *pbuf) {
                pBuf = (uint8_t*)pbuf->pValue;
                countDown = 0;
        };

        bool Skip(uint8_t **pp, uint16_t *pcntdn, uint16_t bytes_to_skip) {
                switch(nStage) {
                        case 0:
                                countDown = bytes_to_skip;
                                nStage++;
                        case 1:
                                for(; countDown && (*pcntdn); countDown--, (*pp)++, (*pcntdn)--);

                                if(!countDown)
                                        nStage = 0;
                };
                return (!countDown);
        };
};

// Pointer to a callback function triggered for each element of PTP array when used with PTPArrayParser
typedef void (*PTP_ARRAY_EL_FUNC)(const MultiValueBuffer * const p, uint32_t count, const void *me);

class PTPListParser {
public:

        enum ParseMode {
                modeArray, modeRange/*, modeEnum*/
        };

private:
        uint8_t nStage;
        uint8_t enStage;

        uint32_t arLen;
        uint32_t arLenCntdn;

        uint8_t lenSize; // size of the array length field in bytes
        uint8_t valSize; // size of the array element in bytes

        MultiValueBuffer *pBuf;

        // The only parser for both size and array element parsing
        MultiByteValueParser theParser;

        uint8_t /*ParseMode*/ prsMode;

public:

        PTPListParser() :
        nStage(0),
        enStage(0),
        arLen(0),
        arLenCntdn(0),
        lenSize(0),
        valSize(0),
        pBuf(NULL),
        prsMode(modeArray) {
        };

        void Initialize(const uint8_t len_size, const uint8_t val_size, MultiValueBuffer * const p, const uint8_t mode = modeArray) {
                pBuf = p;
                lenSize = len_size;
                valSize = val_size;
                prsMode = mode;

                if(prsMode == modeRange) {
                        arLenCntdn = arLen = 3;
                        nStage = 2;
                } else {
                        arLenCntdn = arLen = 0;
                        nStage = 0;
                }
                enStage = 0;
                theParser.Initialize(p);
        };

        bool Parse(uint8_t **pp, uint16_t *pcntdn, PTP_ARRAY_EL_FUNC pf, const void *me = NULL);
};

#endif // __PARSETOOLS_H__