CppSQLite3.cpp

#include "CppSQLite3.h"
#include <cstdlib>
#include <utility>


// Named constant for passing to CppSQLite3Exception when passing it a string
// that cannot be deleted.
static const bool DONT_DELETE_MSG=false;

// Error message used when throwing CppSQLite3Exception when allocations fail.
static const char* const ALLOCATION_ERROR_MESSAGE = "Cannot allocate memory";

////////////////////////////////////////////////////////////////////////////////
// Prototypes for SQLite functions not included in SQLite DLL, but copied below
// from SQLite encode.c
////////////////////////////////////////////////////////////////////////////////
int sqlite3_encode_binary(const unsigned char *in, int n, unsigned char *out);
int sqlite3_decode_binary(const unsigned char *in, unsigned char *out);

////////////////////////////////////////////////////////////////////////////////

namespace detail
{

SQLite3Memory::SQLite3Memory() :
    mnBufferLen(0),
    mpBuf(nullptr)
{
}

SQLite3Memory::SQLite3Memory(int nBufferLen) :
    mnBufferLen(nBufferLen),
    mpBuf(sqlite3_malloc(nBufferLen))
{
    if (!mpBuf && mnBufferLen>0)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                ALLOCATION_ERROR_MESSAGE,
                                DONT_DELETE_MSG);
    }
}

SQLite3Memory::SQLite3Memory(const char* szFormat, va_list list) :
    mnBufferLen(0),
    mpBuf(sqlite3_vmprintf(szFormat, list))
{
    if (!mpBuf)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                ALLOCATION_ERROR_MESSAGE,
                                DONT_DELETE_MSG);
    }
    mnBufferLen = std::strlen(static_cast<char const*>(mpBuf))+1;
}

SQLite3Memory::~SQLite3Memory()
{
    clear();
}

SQLite3Memory::SQLite3Memory(SQLite3Memory const& other) :
    mnBufferLen(other.mnBufferLen),
    mpBuf(sqlite3_malloc(other.mnBufferLen))
{
    if (!mpBuf && mnBufferLen>0)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                ALLOCATION_ERROR_MESSAGE,
                                DONT_DELETE_MSG);
    }
    std::memcpy(mpBuf, other.mpBuf, mnBufferLen);
}

SQLite3Memory& SQLite3Memory::operator=(SQLite3Memory const& lhs)
{
    SQLite3Memory tmp(lhs);
    swap(tmp);
    return *this;
}

SQLite3Memory::SQLite3Memory(SQLite3Memory&& other) :
    mnBufferLen(other.mnBufferLen),
    mpBuf(other.mpBuf)
{
    other.mnBufferLen = 0;
    other.mpBuf = nullptr;
}

SQLite3Memory& SQLite3Memory::operator=(SQLite3Memory&& lhs)
{
    swap(lhs);
    return *this;
}

void SQLite3Memory::swap(SQLite3Memory& other)
{
    std::swap(mnBufferLen, other.mnBufferLen);
    std::swap(mpBuf, other.mpBuf);
}

void SQLite3Memory::clear()
{
    sqlite3_free(mpBuf);
    mpBuf = nullptr;
    mnBufferLen = 0;
}

}

////////////////////////////////////////////////////////////////////////////////

CppSQLite3Exception::CppSQLite3Exception(const int nErrCode,
                                    const char* szErrMess,
                                    bool bDeleteMsg/*=true*/) :
                                    mnErrCode(nErrCode)
{
    mpszErrMess = sqlite3_mprintf("%s[%d]: %s",
                                errorCodeAsString(nErrCode),
                                nErrCode,
                                szErrMess ? szErrMess : "");

    if (bDeleteMsg && szErrMess)
    {
        sqlite3_free((void*)szErrMess);
    }
}


CppSQLite3Exception::CppSQLite3Exception(const CppSQLite3Exception&  e) :
                                    mnErrCode(e.mnErrCode)
{
    mpszErrMess = 0;
    if (e.mpszErrMess)
    {
        mpszErrMess = sqlite3_mprintf("%s", e.mpszErrMess);
    }
}


const char* CppSQLite3Exception::errorCodeAsString(int nErrCode)
{
    switch (nErrCode)
    {
        case SQLITE_OK          : return "SQLITE_OK";
        case SQLITE_ERROR       : return "SQLITE_ERROR";
        case SQLITE_INTERNAL    : return "SQLITE_INTERNAL";
        case SQLITE_PERM        : return "SQLITE_PERM";
        case SQLITE_ABORT       : return "SQLITE_ABORT";
        case SQLITE_BUSY        : return "SQLITE_BUSY";
        case SQLITE_LOCKED      : return "SQLITE_LOCKED";
        case SQLITE_NOMEM       : return "SQLITE_NOMEM";
        case SQLITE_READONLY    : return "SQLITE_READONLY";
        case SQLITE_INTERRUPT   : return "SQLITE_INTERRUPT";
        case SQLITE_IOERR       : return "SQLITE_IOERR";
        case SQLITE_CORRUPT     : return "SQLITE_CORRUPT";
        case SQLITE_NOTFOUND    : return "SQLITE_NOTFOUND";
        case SQLITE_FULL        : return "SQLITE_FULL";
        case SQLITE_CANTOPEN    : return "SQLITE_CANTOPEN";
        case SQLITE_PROTOCOL    : return "SQLITE_PROTOCOL";
        case SQLITE_EMPTY       : return "SQLITE_EMPTY";
        case SQLITE_SCHEMA      : return "SQLITE_SCHEMA";
        case SQLITE_TOOBIG      : return "SQLITE_TOOBIG";
        case SQLITE_CONSTRAINT  : return "SQLITE_CONSTRAINT";
        case SQLITE_MISMATCH    : return "SQLITE_MISMATCH";
        case SQLITE_MISUSE      : return "SQLITE_MISUSE";
        case SQLITE_NOLFS       : return "SQLITE_NOLFS";
        case SQLITE_AUTH        : return "SQLITE_AUTH";
        case SQLITE_FORMAT      : return "SQLITE_FORMAT";
        case SQLITE_RANGE       : return "SQLITE_RANGE";
        case SQLITE_ROW         : return "SQLITE_ROW";
        case SQLITE_DONE        : return "SQLITE_DONE";
        case CPPSQLITE_ERROR    : return "CPPSQLITE_ERROR";
        default: return "UNKNOWN_ERROR";
    }
}


CppSQLite3Exception::~CppSQLite3Exception()
{
    if (mpszErrMess)
    {
        sqlite3_free(mpszErrMess);
        mpszErrMess = 0;
    }
}


////////////////////////////////////////////////////////////////////////////////

void CppSQLite3Buffer::clear()
{
    mBuf.clear();
}


const char* CppSQLite3Buffer::format(const char* szFormat, ...)
{
    clear();
    va_list va;
    try
    {
        va_start(va, szFormat);
        mBuf = detail::SQLite3Memory(szFormat, va);
        va_end(va);
        return static_cast<const char*>(mBuf.getBuffer());
    }
    catch(CppSQLite3Exception&)
    {
        va_end(va);
        throw;
    }
}


////////////////////////////////////////////////////////////////////////////////

CppSQLite3Binary::CppSQLite3Binary() :
                        mpBuf(0),
                        mnBinaryLen(0),
                        mnBufferLen(0),
                        mnEncodedLen(0),
                        mbEncoded(false)
{
}


CppSQLite3Binary::~CppSQLite3Binary()
{
    clear();
}


void CppSQLite3Binary::setBinary(const unsigned char* pBuf, int nLen)
{
    mpBuf = allocBuffer(nLen);
    memcpy(mpBuf, pBuf, nLen);
}


void CppSQLite3Binary::setEncoded(const unsigned char* pBuf)
{
    clear();

    mnEncodedLen = strlen((const char*)pBuf);
    mnBufferLen = mnEncodedLen + 1; // Allow for NULL terminator

    mpBuf = (unsigned char*)malloc(mnBufferLen);

    if (!mpBuf)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                ALLOCATION_ERROR_MESSAGE,
                                DONT_DELETE_MSG);
    }

    memcpy(mpBuf, pBuf, mnBufferLen);
    mbEncoded = true;
}


const unsigned char* CppSQLite3Binary::getEncoded()
{
    if (!mbEncoded)
    {
        unsigned char* ptmp = (unsigned char*)malloc(mnBinaryLen);
        memcpy(ptmp, mpBuf, mnBinaryLen);
        mnEncodedLen = sqlite3_encode_binary(ptmp, mnBinaryLen, mpBuf);
        free(ptmp);
        mbEncoded = true;
    }

    return mpBuf;
}


const unsigned char* CppSQLite3Binary::getBinary()
{
    if (mbEncoded)
    {
        // in/out buffers can be the same
        mnBinaryLen = sqlite3_decode_binary(mpBuf, mpBuf);

        if (mnBinaryLen == -1)
        {
            throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                    "Cannot decode binary",
                                    DONT_DELETE_MSG);
        }

        mbEncoded = false;
    }

    return mpBuf;
}


int CppSQLite3Binary::getBinaryLength()
{
    getBinary();
    return mnBinaryLen;
}


unsigned char* CppSQLite3Binary::allocBuffer(int nLen)
{
    clear();

    // Allow extra space for encoded binary as per comments in
    // SQLite encode.c See bottom of this file for implementation
    // of SQLite functions use 3 instead of 2 just to be sure ;-)
    mnBinaryLen = nLen;
    mnBufferLen = 3 + (257*nLen)/254;

    mpBuf = (unsigned char*)malloc(mnBufferLen);

    if (!mpBuf)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                ALLOCATION_ERROR_MESSAGE,
                                DONT_DELETE_MSG);
    }

    mbEncoded = false;

    return mpBuf;
}


void CppSQLite3Binary::clear()
{
    if (mpBuf)
    {
        mnBinaryLen = 0;
        mnBufferLen = 0;
        free(mpBuf);
        mpBuf = 0;
    }
}


////////////////////////////////////////////////////////////////////////////////

CppSQLite3Query::CppSQLite3Query()
{
    mpVM = 0;
    mbEof = true;
    mnCols = 0;
    mbOwnVM = false;
}


CppSQLite3Query::CppSQLite3Query(const CppSQLite3Query& rQuery)
{
    mpVM = rQuery.mpVM;
    // Only one object can own the VM
    const_cast<CppSQLite3Query&>(rQuery).mpVM = 0;
    mbEof = rQuery.mbEof;
    mnCols = rQuery.mnCols;
    mbOwnVM = rQuery.mbOwnVM;
}


CppSQLite3Query::CppSQLite3Query(sqlite3* pDB,
                            sqlite3_stmt* pVM,
                            bool bEof,
                            bool bOwnVM/*=true*/)
{
    mpDB = pDB;
    mpVM = pVM;
    mbEof = bEof;
    mnCols = sqlite3_column_count(mpVM);
    mbOwnVM = bOwnVM;
}


CppSQLite3Query::~CppSQLite3Query()
{
    try
    {
        finalize();
    }
    catch (...)
    {
    }
}


CppSQLite3Query& CppSQLite3Query::operator=(const CppSQLite3Query& rQuery)
{
    try
    {
        finalize();
    }
    catch (...)
    {
    }
    mpVM = rQuery.mpVM;
    // Only one object can own the VM
    const_cast<CppSQLite3Query&>(rQuery).mpVM = 0;
    mbEof = rQuery.mbEof;
    mnCols = rQuery.mnCols;
    mbOwnVM = rQuery.mbOwnVM;
    return *this;
}


int CppSQLite3Query::numFields() const
{
    checkVM();
    return mnCols;
}


const char* CppSQLite3Query::fieldValue(int nField) const
{
    checkVM();

    if (nField < 0 || nField > mnCols-1)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Invalid field index requested",
                                DONT_DELETE_MSG);
    }

    return (const char*)sqlite3_column_text(mpVM, nField);
}


const char* CppSQLite3Query::fieldValue(const char* szField) const
{
    int nField = fieldIndex(szField);
    return (const char*)sqlite3_column_text(mpVM, nField);
}


int CppSQLite3Query::getIntField(int nField, int nNullValue/*=0*/) const
{
    if (fieldDataType(nField) == SQLITE_NULL)
    {
        return nNullValue;
    }
    else
    {
        return sqlite3_column_int(mpVM, nField);
    }
}


int CppSQLite3Query::getIntField(const char* szField, int nNullValue/*=0*/) const
{
    int nField = fieldIndex(szField);
    return getIntField(nField, nNullValue);
}


long long CppSQLite3Query::getInt64Field(int nField, long long nNullValue/*=0*/) const
{
    if (fieldDataType(nField) == SQLITE_NULL)
    {
        return nNullValue;
    }
    else
    {
        return sqlite3_column_int64(mpVM, nField);
    }
}


long long CppSQLite3Query::getInt64Field(const char* szField, long long nNullValue/*=0*/) const
{
    int nField = fieldIndex(szField);
    return getInt64Field(nField, nNullValue);
}


double CppSQLite3Query::getFloatField(int nField, double fNullValue/*=0.0*/) const
{
    if (fieldDataType(nField) == SQLITE_NULL)
    {
        return fNullValue;
    }
    else
    {
        return sqlite3_column_double(mpVM, nField);
    }
}


double CppSQLite3Query::getFloatField(const char* szField, double fNullValue/*=0.0*/) const
{
    int nField = fieldIndex(szField);
    return getFloatField(nField, fNullValue);
}


const char* CppSQLite3Query::getStringField(int nField, const char* szNullValue/*=""*/) const
{
    if (fieldDataType(nField) == SQLITE_NULL)
    {
        return szNullValue;
    }
    else
    {
        return (const char*)sqlite3_column_text(mpVM, nField);
    }
}


const char* CppSQLite3Query::getStringField(const char* szField, const char* szNullValue/*=""*/) const
{
    int nField = fieldIndex(szField);
    return getStringField(nField, szNullValue);
}


const unsigned char* CppSQLite3Query::getBlobField(int nField, int& nLen) const
{
    checkVM();

    if (nField < 0 || nField > mnCols-1)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Invalid field index requested",
                                DONT_DELETE_MSG);
    }

    nLen = sqlite3_column_bytes(mpVM, nField);
    return (const unsigned char*)sqlite3_column_blob(mpVM, nField);
}


const unsigned char* CppSQLite3Query::getBlobField(const char* szField, int& nLen) const
{
    int nField = fieldIndex(szField);
    return getBlobField(nField, nLen);
}


bool CppSQLite3Query::fieldIsNull(int nField) const
{
    return (fieldDataType(nField) == SQLITE_NULL);
}


bool CppSQLite3Query::fieldIsNull(const char* szField) const
{
    int nField = fieldIndex(szField);
    return (fieldDataType(nField) == SQLITE_NULL);
}


int CppSQLite3Query::fieldIndex(const char* szField) const
{
    checkVM();

    if (szField)
    {
        for (int nField = 0; nField < mnCols; nField++)
        {
            const char* szTemp = sqlite3_column_name(mpVM, nField);

            if (strcmp(szField, szTemp) == 0)
            {
                return nField;
            }
        }
    }

    throw CppSQLite3Exception(CPPSQLITE_ERROR,
                            "Invalid field name requested",
                            DONT_DELETE_MSG);
}


const char* CppSQLite3Query::fieldName(int nCol) const
{
    checkVM();

    if (nCol < 0 || nCol > mnCols-1)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Invalid field index requested",
                                DONT_DELETE_MSG);
    }

    return sqlite3_column_name(mpVM, nCol);
}


const char* CppSQLite3Query::fieldDeclType(int nCol) const
{
    checkVM();

    if (nCol < 0 || nCol > mnCols-1)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Invalid field index requested",
                                DONT_DELETE_MSG);
    }

    return sqlite3_column_decltype(mpVM, nCol);
}


int CppSQLite3Query::fieldDataType(int nCol) const
{
    checkVM();

    if (nCol < 0 || nCol > mnCols-1)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Invalid field index requested",
                                DONT_DELETE_MSG);
    }

    return sqlite3_column_type(mpVM, nCol);
}


bool CppSQLite3Query::eof() const
{
    checkVM();
    return mbEof;
}


void CppSQLite3Query::nextRow()
{
    checkVM();

    int nRet = sqlite3_step(mpVM);

    if (nRet == SQLITE_DONE)
    {
        // no rows
        mbEof = true;
    }
    else if (nRet == SQLITE_ROW)
    {
        // more rows, nothing to do
    }
    else
    {
        nRet = sqlite3_finalize(mpVM);
        mpVM = 0;
        const char* szError = sqlite3_errmsg(mpDB);
        throw CppSQLite3Exception(nRet,
                                (char*)szError,
                                DONT_DELETE_MSG);
    }
}


void CppSQLite3Query::finalize()
{
    if (mpVM && mbOwnVM)
    {
        int nRet = sqlite3_finalize(mpVM);
        mpVM = 0;
        if (nRet != SQLITE_OK)
        {
            const char* szError = sqlite3_errmsg(mpDB);
            throw CppSQLite3Exception(nRet, (char*)szError, DONT_DELETE_MSG);
        }
    }
}


void CppSQLite3Query::checkVM() const
{
    if (mpVM == 0)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Null Virtual Machine pointer",
                                DONT_DELETE_MSG);
    }
}


////////////////////////////////////////////////////////////////////////////////

CppSQLite3Table::CppSQLite3Table()
{
    mpaszResults = 0;
    mnRows = 0;
    mnCols = 0;
    mnCurrentRow = 0;
}


CppSQLite3Table::CppSQLite3Table(const CppSQLite3Table& rTable)
{
    mpaszResults = rTable.mpaszResults;
    // Only one object can own the results
    const_cast<CppSQLite3Table&>(rTable).mpaszResults = 0;
    mnRows = rTable.mnRows;
    mnCols = rTable.mnCols;
    mnCurrentRow = rTable.mnCurrentRow;
}


CppSQLite3Table::CppSQLite3Table(char** paszResults, int nRows, int nCols)
{
    mpaszResults = paszResults;
    mnRows = nRows;
    mnCols = nCols;
    mnCurrentRow = 0;
}


CppSQLite3Table::~CppSQLite3Table()
{
    try
    {
        finalize();
    }
    catch (...)
    {
    }
}


CppSQLite3Table& CppSQLite3Table::operator=(const CppSQLite3Table& rTable)
{
    try
    {
        finalize();
    }
    catch (...)
    {
    }
    mpaszResults = rTable.mpaszResults;
    // Only one object can own the results
    const_cast<CppSQLite3Table&>(rTable).mpaszResults = 0;
    mnRows = rTable.mnRows;
    mnCols = rTable.mnCols;
    mnCurrentRow = rTable.mnCurrentRow;
    return *this;
}


void CppSQLite3Table::finalize()
{
    if (mpaszResults)
    {
        sqlite3_free_table(mpaszResults);
        mpaszResults = 0;
    }
}


int CppSQLite3Table::numFields() const
{
    checkResults();
    return mnCols;
}


int CppSQLite3Table::numRows() const
{
    checkResults();
    return mnRows;
}


const char* CppSQLite3Table::fieldValue(int nField) const
{
    checkResults();

    if (nField < 0 || nField > mnCols-1)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Invalid field index requested",
                                DONT_DELETE_MSG);
    }

    int nIndex = (mnCurrentRow*mnCols) + mnCols + nField;
    return mpaszResults[nIndex];
}


const char* CppSQLite3Table::fieldValue(const char* szField) const
{
    checkResults();

    if (szField)
    {
        for (int nField = 0; nField < mnCols; nField++)
        {
            if (strcmp(szField, mpaszResults[nField]) == 0)
            {
                int nIndex = (mnCurrentRow*mnCols) + mnCols + nField;
                return mpaszResults[nIndex];
            }
        }
    }

    throw CppSQLite3Exception(CPPSQLITE_ERROR,
                            "Invalid field name requested",
                            DONT_DELETE_MSG);
}


int CppSQLite3Table::getIntField(int nField, int nNullValue/*=0*/) const
{
    if (fieldIsNull(nField))
    {
        return nNullValue;
    }
    else
    {
        return atoi(fieldValue(nField));
    }
}


int CppSQLite3Table::getIntField(const char* szField, int nNullValue/*=0*/) const
{
    if (fieldIsNull(szField))
    {
        return nNullValue;
    }
    else
    {
        return atoi(fieldValue(szField));
    }
}


double CppSQLite3Table::getFloatField(int nField, double fNullValue/*=0.0*/) const
{
    if (fieldIsNull(nField))
    {
        return fNullValue;
    }
    else
    {
        return atof(fieldValue(nField));
    }
}


double CppSQLite3Table::getFloatField(const char* szField, double fNullValue/*=0.0*/) const
{
    if (fieldIsNull(szField))
    {
        return fNullValue;
    }
    else
    {
        return atof(fieldValue(szField));
    }
}


const char* CppSQLite3Table::getStringField(int nField, const char* szNullValue/*=""*/) const
{
    if (fieldIsNull(nField))
    {
        return szNullValue;
    }
    else
    {
        return fieldValue(nField);
    }
}


const char* CppSQLite3Table::getStringField(const char* szField, const char* szNullValue/*=""*/) const
{
    if (fieldIsNull(szField))
    {
        return szNullValue;
    }
    else
    {
        return fieldValue(szField);
    }
}


bool CppSQLite3Table::fieldIsNull(int nField) const
{
    checkResults();
    return (fieldValue(nField) == 0);
}


bool CppSQLite3Table::fieldIsNull(const char* szField) const
{
    checkResults();
    return (fieldValue(szField) == 0);
}


const char* CppSQLite3Table::fieldName(int nCol) const
{
    checkResults();

    if (nCol < 0 || nCol > mnCols-1)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Invalid field index requested",
                                DONT_DELETE_MSG);
    }

    return mpaszResults[nCol];
}


void CppSQLite3Table::setRow(int nRow)
{
    checkResults();

    if (nRow < 0 || nRow > mnRows-1)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Invalid row index requested",
                                DONT_DELETE_MSG);
    }

    mnCurrentRow = nRow;
}


void CppSQLite3Table::checkResults() const
{
    if (mpaszResults == 0)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Null Results pointer",
                                DONT_DELETE_MSG);
    }
}


////////////////////////////////////////////////////////////////////////////////

CppSQLite3Statement::CppSQLite3Statement()
{
    mpDB = 0;
    mpVM = 0;
}


CppSQLite3Statement::CppSQLite3Statement(const CppSQLite3Statement& rStatement)
{
    mpDB = rStatement.mpDB;
    mpVM = rStatement.mpVM;
    // Only one object can own VM
    const_cast<CppSQLite3Statement&>(rStatement).mpVM = 0;
}


CppSQLite3Statement::CppSQLite3Statement(sqlite3* pDB, sqlite3_stmt* pVM)
{
    mpDB = pDB;
    mpVM = pVM;
}


CppSQLite3Statement::~CppSQLite3Statement()
{
    try
    {
        finalize();
    }
    catch (...)
    {
    }
}


CppSQLite3Statement& CppSQLite3Statement::operator=(const CppSQLite3Statement& rStatement)
{
    mpDB = rStatement.mpDB;
    mpVM = rStatement.mpVM;
    // Only one object can own VM
    const_cast<CppSQLite3Statement&>(rStatement).mpVM = 0;
    return *this;
}


int CppSQLite3Statement::execDML()
{
    checkDB();
    checkVM();

    const char* szError=0;

    int nRet = sqlite3_step(mpVM);

    if (nRet == SQLITE_DONE)
    {
        int nRowsChanged = sqlite3_changes(mpDB);

        nRet = sqlite3_reset(mpVM);

        if (nRet != SQLITE_OK)
        {
            szError = sqlite3_errmsg(mpDB);
            throw CppSQLite3Exception(nRet, (char*)szError, DONT_DELETE_MSG);
        }

        return nRowsChanged;
    }
    else
    {
        nRet = sqlite3_reset(mpVM);
        szError = sqlite3_errmsg(mpDB);
        throw CppSQLite3Exception(nRet, (char*)szError, DONT_DELETE_MSG);
    }
}


CppSQLite3Query CppSQLite3Statement::execQuery()
{
    checkDB();
    checkVM();

    int nRet = sqlite3_step(mpVM);

    if (nRet == SQLITE_DONE)
    {
        // no rows
        return CppSQLite3Query(mpDB, mpVM, true/*eof*/, false);
    }
    else if (nRet == SQLITE_ROW)
    {
        // at least 1 row
        return CppSQLite3Query(mpDB, mpVM, false/*eof*/, false);
    }
    else
    {
        nRet = sqlite3_reset(mpVM);
        const char* szError = sqlite3_errmsg(mpDB);
        throw CppSQLite3Exception(nRet, (char*)szError, DONT_DELETE_MSG);
    }
}


void CppSQLite3Statement::bind(int nParam, const char* szValue)
{
    checkVM();
    int nRes = sqlite3_bind_text(mpVM, nParam, szValue, -1, SQLITE_TRANSIENT);

    if (nRes != SQLITE_OK)
    {
        throw CppSQLite3Exception(nRes,
                                "Error binding string param",
                                DONT_DELETE_MSG);
    }
}


void CppSQLite3Statement::bind(int nParam, const int nValue)
{
    checkVM();
    int nRes = sqlite3_bind_int(mpVM, nParam, nValue);

    if (nRes != SQLITE_OK)
    {
        throw CppSQLite3Exception(nRes,
                                "Error binding int param",
                                DONT_DELETE_MSG);
    }
}


void CppSQLite3Statement::bind(int nParam, const long long nValue)
{
    checkVM();
    int nRes = sqlite3_bind_int64(mpVM, nParam, nValue);

    if (nRes != SQLITE_OK)
    {
        throw CppSQLite3Exception(nRes,
                                  "Error binding int64 param",
                                  DONT_DELETE_MSG);
    }
}


void CppSQLite3Statement::bind(int nParam, const double dValue)
{
    checkVM();
    int nRes = sqlite3_bind_double(mpVM, nParam, dValue);

    if (nRes != SQLITE_OK)
    {
        throw CppSQLite3Exception(nRes,
                                "Error binding double param",
                                DONT_DELETE_MSG);
    }
}


void CppSQLite3Statement::bind(int nParam, const unsigned char* blobValue, int nLen)
{
    checkVM();
    int nRes = sqlite3_bind_blob(mpVM, nParam,
                                (const void*)blobValue, nLen, SQLITE_TRANSIENT);

    if (nRes != SQLITE_OK)
    {
        throw CppSQLite3Exception(nRes,
                                "Error binding blob param",
                                DONT_DELETE_MSG);
    }
}


void CppSQLite3Statement::bindNull(int nParam)
{
    checkVM();
    int nRes = sqlite3_bind_null(mpVM, nParam);

    if (nRes != SQLITE_OK)
    {
        throw CppSQLite3Exception(nRes,
                                "Error binding NULL param",
                                DONT_DELETE_MSG);
    }
}


void CppSQLite3Statement::reset()
{
    if (mpVM)
    {
        int nRet = sqlite3_reset(mpVM);

        if (nRet != SQLITE_OK)
        {
            const char* szError = sqlite3_errmsg(mpDB);
            throw CppSQLite3Exception(nRet, (char*)szError, DONT_DELETE_MSG);
        }
    }
}


void CppSQLite3Statement::finalize()
{
    if (mpVM)
    {
        int nRet = sqlite3_finalize(mpVM);
        mpVM = 0;

        if (nRet != SQLITE_OK)
        {
            const char* szError = sqlite3_errmsg(mpDB);
            throw CppSQLite3Exception(nRet, (char*)szError, DONT_DELETE_MSG);
        }
    }
}


void CppSQLite3Statement::checkDB() const
{
    if (mpDB == 0)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Database not open",
                                DONT_DELETE_MSG);
    }
}


void CppSQLite3Statement::checkVM() const
{
    if (mpVM == 0)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Null Virtual Machine pointer",
                                DONT_DELETE_MSG);
    }
}


////////////////////////////////////////////////////////////////////////////////

CppSQLite3DB::CppSQLite3DB()
{
    mpDB = 0;
    mnBusyTimeoutMs = 60000; // 60 seconds
}


CppSQLite3DB::CppSQLite3DB(const CppSQLite3DB& db)
{
    mpDB = db.mpDB;
    mnBusyTimeoutMs = 60000; // 60 seconds
}


CppSQLite3DB::~CppSQLite3DB()
{
    close();
}


CppSQLite3DB& CppSQLite3DB::operator=(const CppSQLite3DB& db)
{
    mpDB = db.mpDB;
    mnBusyTimeoutMs = 60000; // 60 seconds
    return *this;
}


void CppSQLite3DB::open(const char* szFile)
{
    int nRet = sqlite3_open(szFile, &mpDB);

    if (nRet != SQLITE_OK)
    {
        const char* szError = sqlite3_errmsg(mpDB);
        throw CppSQLite3Exception(nRet, (char*)szError, DONT_DELETE_MSG);
    }

    setBusyTimeout(mnBusyTimeoutMs);
}


void CppSQLite3DB::close()
{
    if (mpDB)
    {
        sqlite3_close(mpDB);
        mpDB = 0;
    }
}


CppSQLite3Statement CppSQLite3DB::compileStatement(const char* szSQL)
{
    checkDB();

    sqlite3_stmt* pVM = compile(szSQL);
    return CppSQLite3Statement(mpDB, pVM);
}


bool CppSQLite3DB::tableExists(const char* szTable)
{
    CppSQLite3Buffer sql;
    sql.format( "select count(*) from sqlite_master where type='table' and name=%Q",
                szTable );
    int nRet = execScalar(sql);
    return (nRet > 0);
}


int CppSQLite3DB::execDML(const char* szSQL)
{
    checkDB();

    char* szError=0;

    int nRet = sqlite3_exec(mpDB, szSQL, 0, 0, &szError);

    if (nRet == SQLITE_OK)
    {
        return sqlite3_changes(mpDB);
    }
    else
    {
        throw CppSQLite3Exception(nRet, szError);
    }
}


CppSQLite3Query CppSQLite3DB::execQuery(const char* szSQL)
{
    checkDB();

    sqlite3_stmt* pVM = compile(szSQL);

    int nRet = sqlite3_step(pVM);

    if (nRet == SQLITE_DONE)
    {
        // no rows
        return CppSQLite3Query(mpDB, pVM, true/*eof*/);
    }
    else if (nRet == SQLITE_ROW)
    {
        // at least 1 row
        return CppSQLite3Query(mpDB, pVM, false/*eof*/);
    }
    else
    {
        nRet = sqlite3_finalize(pVM);
        const char* szError= sqlite3_errmsg(mpDB);
        throw CppSQLite3Exception(nRet, (char*)szError, DONT_DELETE_MSG);
    }
}


int CppSQLite3DB::execScalar(const char* szSQL)
{
    CppSQLite3Query q = execQuery(szSQL);

    if (q.eof() || q.numFields() < 1)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Invalid scalar query",
                                DONT_DELETE_MSG);
    }

    return atoi(q.fieldValue(0));
}


CppSQLite3Table CppSQLite3DB::getTable(const char* szSQL)
{
    checkDB();

    char* szError=0;
    char** paszResults=0;
    int nRet;
    int nRows(0);
    int nCols(0);

    nRet = sqlite3_get_table(mpDB, szSQL, &paszResults, &nRows, &nCols, &szError);

    if (nRet == SQLITE_OK)
    {
        return CppSQLite3Table(paszResults, nRows, nCols);
    }
    else
    {
        throw CppSQLite3Exception(nRet, szError);
    }
}


sqlite_int64 CppSQLite3DB::lastRowId() const
{
    return sqlite3_last_insert_rowid(mpDB);
}


void CppSQLite3DB::setBusyTimeout(int nMillisecs)
{
    mnBusyTimeoutMs = nMillisecs;
    sqlite3_busy_timeout(mpDB, mnBusyTimeoutMs);
}


void CppSQLite3DB::checkDB() const
{
    if (!mpDB)
    {
        throw CppSQLite3Exception(CPPSQLITE_ERROR,
                                "Database not open",
                                DONT_DELETE_MSG);
    }
}


sqlite3_stmt* CppSQLite3DB::compile(const char* szSQL)
{
    checkDB();

    char* szError=0;
    const char* szTail=0;
    sqlite3_stmt* pVM;

    int nRet = sqlite3_prepare(mpDB, szSQL, -1, &pVM, &szTail);

    if (nRet != SQLITE_OK)
    {
        throw CppSQLite3Exception(nRet, szError);
    }

    return pVM;
}


////////////////////////////////////////////////////////////////////////////////
// SQLite encode.c reproduced here, containing implementation notes and source
// for sqlite3_encode_binary() and sqlite3_decode_binary()
////////////////////////////////////////////////////////////////////////////////

/*
** 2002 April 25
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains helper routines used to translate binary data into
** a null-terminated string (suitable for use in SQLite) and back again.
** These are convenience routines for use by people who want to store binary
** data in an SQLite database.  The code in this file is not used by any other
** part of the SQLite library.
**
** $Id: encode.c,v 1.10 2004/01/14 21:59:23 drh Exp $
*/

/*
** How This Encoder Works
**
** The output is allowed to contain any character except 0x27 (') and
** 0x00.  This is accomplished by using an escape character to encode
** 0x27 and 0x00 as a two-byte sequence.  The escape character is always
** 0x01.  An 0x00 is encoded as the two byte sequence 0x01 0x01.  The
** 0x27 character is encoded as the two byte sequence 0x01 0x03.  Finally,
** the escape character itself is encoded as the two-character sequence
** 0x01 0x02.
**
** To summarize, the encoder works by using an escape sequences as follows:
**
**       0x00  ->  0x01 0x01
**       0x01  ->  0x01 0x02
**       0x27  ->  0x01 0x03
**
** If that were all the encoder did, it would work, but in certain cases
** it could double the size of the encoded string.  For example, to
** encode a string of 100 0x27 characters would require 100 instances of
** the 0x01 0x03 escape sequence resulting in a 200-character output.
** We would prefer to keep the size of the encoded string smaller than
** this.
**
** To minimize the encoding size, we first add a fixed offset value to each
** byte in the sequence.  The addition is modulo 256.  (That is to say, if
** the sum of the original character value and the offset exceeds 256, then
** the higher order bits are truncated.)  The offset is chosen to minimize
** the number of characters in the string that need to be escaped.  For
** example, in the case above where the string was composed of 100 0x27
** characters, the offset might be 0x01.  Each of the 0x27 characters would
** then be converted into an 0x28 character which would not need to be
** escaped at all and so the 100 character input string would be converted
** into just 100 characters of output.  Actually 101 characters of output -
** we have to record the offset used as the first byte in the sequence so
** that the string can be decoded.  Since the offset value is stored as
** part of the output string and the output string is not allowed to contain
** characters 0x00 or 0x27, the offset cannot be 0x00 or 0x27.
**
** Here, then, are the encoding steps:
**
**     (1)   Choose an offset value and make it the first character of
**           output.
**
**     (2)   Copy each input character into the output buffer, one by
**           one, adding the offset value as you copy.
**
**     (3)   If the value of an input character plus offset is 0x00, replace
**           that one character by the two-character sequence 0x01 0x01.
**           If the sum is 0x01, replace it with 0x01 0x02.  If the sum
**           is 0x27, replace it with 0x01 0x03.
**
**     (4)   Put a 0x00 terminator at the end of the output.
**
** Decoding is obvious:
**
**     (5)   Copy encoded characters except the first into the decode
**           buffer.  Set the first encoded character aside for use as
**           the offset in step 7 below.
**
**     (6)   Convert each 0x01 0x01 sequence into a single character 0x00.
**           Convert 0x01 0x02 into 0x01.  Convert 0x01 0x03 into 0x27.
**
**     (7)   Subtract the offset value that was the first character of
**           the encoded buffer from all characters in the output buffer.
**
** The only tricky part is step (1) - how to compute an offset value to
** minimize the size of the output buffer.  This is accomplished by testing
** all offset values and picking the one that results in the fewest number
** of escapes.  To do that, we first scan the entire input and count the
** number of occurances of each character value in the input.  Suppose
** the number of 0x00 characters is N(0), the number of occurances of 0x01
** is N(1), and so forth up to the number of occurances of 0xff is N(255).
** An offset of 0 is not allowed so we don't have to test it.  The number
** of escapes required for an offset of 1 is N(1)+N(2)+N(40).  The number
** of escapes required for an offset of 2 is N(2)+N(3)+N(41).  And so forth.
** In this way we find the offset that gives the minimum number of escapes,
** and thus minimizes the length of the output string.
*/

/*
** Encode a binary buffer "in" of size n bytes so that it contains
** no instances of characters '\'' or '\000'.  The output is
** null-terminated and can be used as a string value in an INSERT
** or UPDATE statement.  Use sqlite3_decode_binary() to convert the
** string back into its original binary.
**
** The result is written into a preallocated output buffer "out".
** "out" must be able to hold at least 2 +(257*n)/254 bytes.
** In other words, the output will be expanded by as much as 3
** bytes for every 254 bytes of input plus 2 bytes of fixed overhead.
** (This is approximately 2 + 1.0118*n or about a 1.2% size increase.)
**
** The return value is the number of characters in the encoded
** string, excluding the "\000" terminator.
*/
int sqlite3_encode_binary(const unsigned char *in, int n, unsigned char *out){
  int i, j, e, m;
  int cnt[256];
  if( n<=0 ){
    out[0] = 'x';
    out[1] = 0;
    return 1;
  }
  memset(cnt, 0, sizeof(cnt));
  for(i=n-1; i>=0; i--){ cnt[in[i]]++; }
  m = n;
  for(i=1; i<256; i++){
    int sum;
    if( i=='\'' ) continue;
    sum = cnt[i] + cnt[(i+1)&0xff] + cnt[(i+'\'')&0xff];
    if( sum<m ){
      m = sum;
      e = i;
      if( m==0 ) break;
    }
  }
  out[0] = e;
  j = 1;
  for(i=0; i<n; i++){
    int c = (in[i] - e)&0xff;
    if( c==0 ){
      out[j++] = 1;
      out[j++] = 1;
    }else if( c==1 ){
      out[j++] = 1;
      out[j++] = 2;
    }else if( c=='\'' ){
      out[j++] = 1;
      out[j++] = 3;
    }else{
      out[j++] = c;
    }
  }
  out[j] = 0;
  return j;
}

/*
** Decode the string "in" into binary data and write it into "out".
** This routine reverses the encoding created by sqlite3_encode_binary().
** The output will always be a few bytes less than the input.  The number
** of bytes of output is returned.  If the input is not a well-formed
** encoding, -1 is returned.
**
** The "in" and "out" parameters may point to the same buffer in order
** to decode a string in place.
*/
int sqlite3_decode_binary(const unsigned char *in, unsigned char *out){
  int i, c, e;
  e = *(in++);
  i = 0;
  while( (c = *(in++))!=0 ){
    if( c==1 ){
      c = *(in++);
      if( c==1 ){
        c = 0;
      }else if( c==2 ){
        c = 1;
      }else if( c==3 ){
        c = '\'';
      }else{
        return -1;
      }
    }
    out[i++] = (c + e)&0xff;
  }
  return i;
}