/******************************************************************************
 * $Id$
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Author:   Even Rouault, <even dot rouault at spatialys.com>
 * Purpose:  Google Protocol Buffer generic handling functions
 *
 ******************************************************************************
 * Copyright (c) 2012, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#ifndef GPB_H_INCLUDED
#define GPB_H_INCLUDED

#include "cpl_port.h"
#include "cpl_error.h"
#include "cpl_string.h"

#include <string>
#include <exception>

#ifndef CHECK_OOB
#define CHECK_OOB 1
#endif

class GPBException : public std::exception
{
    std::string m_osMessage;

  public:
    explicit GPBException(int nLine)
        : m_osMessage(CPLSPrintf("Parsing error occurred at line %d", nLine))
    {
    }

    const char *what() const noexcept override
    {
        return m_osMessage.c_str();
    }
};

#define THROW_GPB_EXCEPTION throw GPBException(__LINE__)

/************************************************************************/
/*                Google Protocol Buffer definitions                    */
/************************************************************************/

// TODO(schwehr): This should be an enum.
constexpr int WT_VARINT = 0;
constexpr int WT_64BIT = 1;
constexpr int WT_DATA = 2;
// constexpr WT_STARTGROUP = 3; // unused
// constexpr WT_ENDGROUP = 4; // unused
constexpr int WT_32BIT = 5;

#define MAKE_KEY(nFieldNumber, nWireType) ((nFieldNumber << 3) | nWireType)
#define GET_WIRETYPE(nKey) (nKey & 0x7)
#define GET_FIELDNUMBER(nKey) (nKey >> 3)

/************************************************************************/
/*                          ReadVarUInt32()                             */
/************************************************************************/

inline int ReadVarUInt32(const GByte **ppabyData)
{
    unsigned int nVal = 0;
    int nShift = 0;
    const GByte *pabyData = *ppabyData;

    while (true)
    {
        int nByte = *pabyData;
        if (!(nByte & 0x80))
        {
            *ppabyData = pabyData + 1;
            return nVal | (static_cast<unsigned>(nByte) << nShift);
        }
        nVal |= (nByte & 0x7f) << nShift;
        pabyData++;
        nShift += 7;
        if (nShift == 28)
        {
            nByte = *pabyData;
            if (!(nByte & 0x80))
            {
                *ppabyData = pabyData + 1;
                return nVal | ((static_cast<unsigned>(nByte) & 0xf) << nShift);
            }
            *ppabyData = pabyData;
            return nVal;
        }
    }
}

#define READ_VARUINT32(pabyData, pabyDataLimit, nVal)                          \
    {                                                                          \
        nVal = ReadVarUInt32(&pabyData);                                       \
        if (CHECK_OOB && pabyData > pabyDataLimit)                             \
            THROW_GPB_EXCEPTION;                                               \
    }

#define READ_SIZE(pabyData, pabyDataLimit, nSize)                              \
    {                                                                          \
        READ_VARUINT32(pabyData, pabyDataLimit, nSize);                        \
        if (CHECK_OOB &&                                                       \
            nSize > static_cast<unsigned int>(pabyDataLimit - pabyData))       \
            THROW_GPB_EXCEPTION;                                               \
    }

/************************************************************************/
/*                          ReadVarUInt64()                             */
/************************************************************************/

inline GUIntBig ReadVarUInt64(const GByte **ppabyData)
{
    GUIntBig nVal = 0;
    int nShift = 0;
    const GByte *pabyData = *ppabyData;

    while (true)
    {
        int nByte = *pabyData;
        if (!(nByte & 0x80))
        {
            *ppabyData = pabyData + 1;
            return nVal | (static_cast<GUIntBig>(nByte) << nShift);
        }
        nVal |= (static_cast<GUIntBig>(nByte & 0x7f)) << nShift;
        pabyData++;
        nShift += 7;
        if (nShift == 63)
        {
            nByte = *pabyData;
            if (!(nByte & 0x80))
            {
                *ppabyData = pabyData + 1;
                return nVal | ((static_cast<GUIntBig>(nByte) & 1) << nShift);
            }
            *ppabyData = pabyData;
            return nVal;
        }
    }
}

#define READ_VARUINT64(pabyData, pabyDataLimit, nVal)                          \
    {                                                                          \
        nVal = ReadVarUInt64(&pabyData);                                       \
        if (CHECK_OOB && pabyData > pabyDataLimit)                             \
            THROW_GPB_EXCEPTION;                                               \
    }

#define READ_SIZE64(pabyData, pabyDataLimit, nSize)                            \
    {                                                                          \
        READ_VARUINT64(pabyData, pabyDataLimit, nSize);                        \
        if (CHECK_OOB &&                                                       \
            nSize > static_cast<unsigned int>(pabyDataLimit - pabyData))       \
            THROW_GPB_EXCEPTION;                                               \
    }

/************************************************************************/
/*                           ReadVarInt64()                             */
/************************************************************************/

inline GIntBig ReadVarInt64(const GByte **ppabyData)
{
    return static_cast<GIntBig>(ReadVarUInt64(ppabyData));
}

#define READ_VARINT64(pabyData, pabyDataLimit, nVal)                           \
    {                                                                          \
        nVal = ReadVarInt64(&pabyData);                                        \
        if (CHECK_OOB && pabyData > pabyDataLimit)                             \
            THROW_GPB_EXCEPTION;                                               \
    }

/************************************************************************/
/*                            DecodeSInt()                              */
/************************************************************************/

inline GIntBig DecodeSInt(GUIntBig nVal)
{
    return ((nVal & 1) == 0) ? static_cast<GIntBig>(nVal >> 1)
                             : -static_cast<GIntBig>(nVal >> 1) - 1;
}

inline GInt32 DecodeSInt(GUInt32 nVal)
{
    return ((nVal & 1) == 0) ? static_cast<GInt32>(nVal >> 1)
                             : -static_cast<GInt32>(nVal >> 1) - 1;
}

/************************************************************************/
/*                            ReadVarSInt64()                           */
/************************************************************************/

inline GIntBig ReadVarSInt64(const GByte **ppabyPtr)
{
    return DecodeSInt(ReadVarUInt64(ppabyPtr));
}

#define READ_VARSINT64(pabyData, pabyDataLimit, nVal)                          \
    {                                                                          \
        nVal = ReadVarSInt64(&pabyData);                                       \
        if (CHECK_OOB && pabyData > pabyDataLimit)                             \
            THROW_GPB_EXCEPTION;                                               \
    }

#define READ_VARSINT64_NOCHECK(pabyData, pabyDataLimit, nVal)                  \
    {                                                                          \
        nVal = ReadVarSInt64(&pabyData);                                       \
    }

/************************************************************************/
/*                           ReadVarInt32()                             */
/************************************************************************/

inline int ReadVarInt32(const GByte **ppabyData)
{
    /*  If you use int32 or int64 as the type for a negative number, */
    /* the resulting varint is always ten bytes long */
    GIntBig nVal = static_cast<GIntBig>(ReadVarUInt64(ppabyData));
    return static_cast<int>(nVal);
}

#define READ_VARINT32(pabyData, pabyDataLimit, nVal)                           \
    {                                                                          \
        nVal = ReadVarInt32(&pabyData);                                        \
        if (CHECK_OOB && pabyData > pabyDataLimit)                             \
            THROW_GPB_EXCEPTION;                                               \
    }

#define READ_VARSINT32(pabyData, pabyDataLimit, nVal)                          \
    {                                                                          \
        nVal = DecodeSInt(static_cast<GUInt32>(ReadVarUInt64(&pabyData)));     \
        if (CHECK_OOB && pabyData > pabyDataLimit)                             \
            THROW_GPB_EXCEPTION;                                               \
    }

/************************************************************************/
/*                            ReadFloat32()                             */
/************************************************************************/

inline float ReadFloat32(const GByte **ppabyData, const GByte *pabyDataLimit)
{
    if (*ppabyData + sizeof(float) > pabyDataLimit)
        THROW_GPB_EXCEPTION;
    float fValue;
    memcpy(&fValue, *ppabyData, sizeof(float));
    CPL_LSBPTR32(&fValue);
    *ppabyData += sizeof(float);
    return fValue;
}

/************************************************************************/
/*                            ReadFloat64()                             */
/************************************************************************/

inline double ReadFloat64(const GByte **ppabyData, const GByte *pabyDataLimit)
{
    if (*ppabyData + sizeof(double) > pabyDataLimit)
        THROW_GPB_EXCEPTION;
    double dfValue;
    memcpy(&dfValue, *ppabyData, sizeof(double));
    CPL_LSBPTR64(&dfValue);
    *ppabyData += sizeof(double);
    return dfValue;
}

/************************************************************************/
/*                            SkipVarInt()                              */
/************************************************************************/

inline void SkipVarInt(const GByte **ppabyData)
{
    const GByte *pabyData = *ppabyData;
    while (true)
    {
        int nByte = *pabyData;
        if (!(nByte & 0x80))
        {
            *ppabyData = pabyData + 1;
            return;
        }
        pabyData++;
    }
}

#define SKIP_VARINT(pabyData, pabyDataLimit)                                   \
    {                                                                          \
        SkipVarInt(&pabyData);                                                 \
        if (CHECK_OOB && pabyData > pabyDataLimit)                             \
            THROW_GPB_EXCEPTION;                                               \
    }

#define READ_FIELD_KEY(nKey) READ_VARINT32(pabyData, pabyDataLimit, nKey)

#define READ_TEXT_WITH_SIZE(pabyData, pabyDataLimit, pszTxt, l_nDataLength)    \
    do                                                                         \
    {                                                                          \
        READ_SIZE(pabyData, pabyDataLimit, l_nDataLength);                     \
        pszTxt = static_cast<char *>(VSI_MALLOC_VERBOSE(l_nDataLength + 1));   \
        if (pszTxt == nullptr)                                                 \
            THROW_GPB_EXCEPTION;                                               \
        memcpy(pszTxt, pabyData, l_nDataLength);                               \
        pszTxt[l_nDataLength] = 0;                                             \
        pabyData += l_nDataLength;                                             \
    } while (0)

#define READ_TEXT(pabyData, pabyDataLimit, pszTxt)                             \
    do                                                                         \
    {                                                                          \
        unsigned int l_nDataLength;                                            \
        READ_TEXT_WITH_SIZE(pabyData, pabyDataLimit, pszTxt, l_nDataLength);   \
    } while (0)

/************************************************************************/
/*                         SkipUnknownField()                           */
/************************************************************************/

#define SKIP_UNKNOWN_FIELD_INLINE(pabyData, pabyDataLimit, verbose)            \
    int nWireType = GET_WIRETYPE(nKey);                                        \
    if (verbose)                                                               \
    {                                                                          \
        int nFieldNumber = GET_FIELDNUMBER(nKey);                              \
        CPLDebug("PBF", "Unhandled case: nFieldNumber = %d, nWireType = %d",   \
                 nFieldNumber, nWireType);                                     \
    }                                                                          \
    switch (nWireType)                                                         \
    {                                                                          \
        case WT_VARINT:                                                        \
        {                                                                      \
            SKIP_VARINT(pabyData, pabyDataLimit);                              \
            break;                                                             \
        }                                                                      \
        case WT_64BIT:                                                         \
        {                                                                      \
            if (CHECK_OOB && pabyDataLimit - pabyData < 8)                     \
                THROW_GPB_EXCEPTION;                                           \
            pabyData += 8;                                                     \
            break;                                                             \
        }                                                                      \
        case WT_DATA:                                                          \
        {                                                                      \
            unsigned int nDataLength;                                          \
            READ_SIZE(pabyData, pabyDataLimit, nDataLength);                   \
            pabyData += nDataLength;                                           \
            break;                                                             \
        }                                                                      \
        case WT_32BIT:                                                         \
        {                                                                      \
            if (CHECK_OOB && pabyDataLimit - pabyData < 4)                     \
                THROW_GPB_EXCEPTION;                                           \
            pabyData += 4;                                                     \
            break;                                                             \
        }                                                                      \
        default:                                                               \
            THROW_GPB_EXCEPTION;                                               \
    }

inline int SkipUnknownField(int nKey, const GByte *pabyData,
                            const GByte *pabyDataLimit, int verbose)
{
    const GByte *pabyDataBefore = pabyData;
    try
    {
        SKIP_UNKNOWN_FIELD_INLINE(pabyData, pabyDataLimit, verbose);
        return static_cast<int>(pabyData - pabyDataBefore);
    }
    catch (const GPBException &e)
    {
        if (verbose)
        {
            CPLError(CE_Failure, CPLE_AppDefined, "%s", e.what());
        }
        return -1;
    }
}

#define SKIP_UNKNOWN_FIELD(pabyData, pabyDataLimit, verbose)                   \
    {                                                                          \
        int _nOffset =                                                         \
            SkipUnknownField(nKey, pabyData, pabyDataLimit, verbose);          \
        if (_nOffset < 0)                                                      \
            THROW_GPB_EXCEPTION;                                               \
        pabyData += _nOffset;                                                  \
    }

/************************************************************************/
/*                          GetVarUIntSize()                            */
/************************************************************************/

inline int GetVarUIntSize(GUIntBig nVal)
{
    int nBytes = 1;
    while (nVal > 127)
    {
        nBytes++;
        nVal >>= 7;
    }
    return nBytes;
}

/************************************************************************/
/*                            EncodeSInt()                              */
/************************************************************************/

inline GUIntBig EncodeSInt(GIntBig nVal)
{
    if (nVal < 0)
        return (static_cast<GUIntBig>(-(nVal + 1)) << 1) | 1;
    else
        return static_cast<GUIntBig>(nVal) << 1;
}

inline GUInt32 EncodeSInt(GInt32 nVal)
{
    if (nVal < 0)
        return (static_cast<GUInt32>(-(nVal + 1)) << 1) | 1;
    else
        return static_cast<GUInt32>(nVal) << 1;
}

/************************************************************************/
/*                          GetVarIntSize()                             */
/************************************************************************/

inline int GetVarIntSize(GIntBig nVal)
{
    return GetVarUIntSize(static_cast<GUIntBig>(nVal));
}

/************************************************************************/
/*                          GetVarSIntSize()                            */
/************************************************************************/

inline int GetVarSIntSize(GIntBig nVal)
{
    return GetVarUIntSize(EncodeSInt(nVal));
}

/************************************************************************/
/*                           WriteVarUInt()                             */
/************************************************************************/

inline void WriteVarUInt(GByte **ppabyData, GUIntBig nVal)
{
    GByte *pabyData = *ppabyData;
    while (nVal > 127)
    {
        *pabyData = static_cast<GByte>((nVal & 0x7f) | 0x80);
        pabyData++;
        nVal >>= 7;
    }
    *pabyData = static_cast<GByte>(nVal);
    pabyData++;
    *ppabyData = pabyData;
}

/************************************************************************/
/*                        WriteVarUIntSingleByte()                      */
/************************************************************************/

inline void WriteVarUIntSingleByte(GByte **ppabyData, GUIntBig nVal)
{
    GByte *pabyData = *ppabyData;
    CPLAssert(nVal < 128);
    *pabyData = static_cast<GByte>(nVal);
    pabyData++;
    *ppabyData = pabyData;
}

/************************************************************************/
/*                           WriteVarInt()                              */
/************************************************************************/

inline void WriteVarInt(GByte **ppabyData, GIntBig nVal)
{
    WriteVarUInt(ppabyData, static_cast<GUIntBig>(nVal));
}

/************************************************************************/
/*                           WriteVarSInt()                             */
/************************************************************************/

inline void WriteVarSInt(GByte **ppabyData, GIntBig nVal)
{
    WriteVarUInt(ppabyData, EncodeSInt(nVal));
}

/************************************************************************/
/*                           WriteFloat32()                             */
/************************************************************************/

inline void WriteFloat32(GByte **ppabyData, float fVal)
{
    CPL_LSBPTR32(&fVal);
    memcpy(*ppabyData, &fVal, sizeof(float));
    *ppabyData += sizeof(float);
}

/************************************************************************/
/*                           WriteFloat64()                             */
/************************************************************************/

inline void WriteFloat64(GByte **ppabyData, double dfVal)
{
    CPL_LSBPTR64(&dfVal);
    memcpy(*ppabyData, &dfVal, sizeof(double));
    *ppabyData += sizeof(double);
}

/************************************************************************/
/*                           GetTextSize()                              */
/************************************************************************/

inline int GetTextSize(const char *pszText)
{
    size_t nTextSize = strlen(pszText);
    return GetVarUIntSize(nTextSize) + static_cast<int>(nTextSize);
}

inline int GetTextSize(const std::string &osText)
{
    size_t nTextSize = osText.size();
    return GetVarUIntSize(nTextSize) + static_cast<int>(nTextSize);
}

/************************************************************************/
/*                            WriteText()                               */
/************************************************************************/

inline void WriteText(GByte **ppabyData, const char *pszText)
{
    size_t nTextSize = strlen(pszText);
    WriteVarUInt(ppabyData, nTextSize);
    memcpy(*ppabyData, pszText, nTextSize);
    *ppabyData += nTextSize;
}

inline void WriteText(GByte **ppabyData, const std::string &osText)
{
    size_t nTextSize = osText.size();
    WriteVarUInt(ppabyData, nTextSize);
    memcpy(*ppabyData, osText.c_str(), nTextSize);
    *ppabyData += nTextSize;
}

#endif /* GPB_H_INCLUDED */
