Windows2000/private/windbg64/langapi/shared/buffer_t.h

#ifndef __BUFFER_INCLUDED__
#define __BUFFER_INCLUDED__

#ifndef _VC_VER_INC
#include "..\include\vcver.h"
#endif

// implementation of class Buffer
#include <stdlib.h>
#include "vcbudefs.h"

class Buffer {
public:
    Buffer(void (*pfn)(void*, void*, void*) = 0, void* pfnArg = 0)
        : cb(0), pbStart(0), pbEnd(0), pfnMove(pfn), pfnMoveArg(pfnArg) {}
    ~Buffer();
    BOOL Alloc(CB cbIn);
    BOOL Append(PB pbIn, CB cbIn, OUT PB* ppbOut = 0);
    BOOL AppendNoCheck(BYTE b);
    BOOL AppendNoCheck(short s);
    BOOL AppendNoCheck(long l);
    BOOL AppendNoCheck(float& f);
    BOOL AppendNoCheck(double& d);
    BOOL AppendNoCheck(PB pbIn, CB cbIn);
    BOOL CDECL AppendFmt(SZ szFmt, ...);
    BOOL Reserve(CB cbIn, OUT PB* ppbOut = 0);
    BOOL Ensure(CB cbIn, PB* ppbOut);
    BOOL Ensure(CB cbIn);
    PB Start() const { return pbStart; }
    PB End() const { return pbEnd; }
    CB Size() const { return pbEnd - pbStart; }
    void Free();
    void Reset()
    {
        pbEnd = pbStart;
    }

    void Clear()
    {
        if (pbStart)
        {
            memset(pbStart, 0, pbEnd - pbStart);
            Reset();
        }
    }
private:
    enum { cbPage = 4096 };
    CB   cbRoundUp(CB cb, CB cbMult) { return (cb + cbMult-1) & ~(cbMult-1); }
    inline BOOL grow(CB dcbGrow);
    BOOL setPbExtent(PB pbStartNew, PB pbEndNew) {
        if (!pbStartNew)
            return FALSE;
        PB pbStartOld = pbStart;
        pbStart = pbStartNew;
        pbEnd = pbEndNew;
        if (pbStartOld != pbStartNew && pfnMove)
            (*pfnMove)(pfnMoveArg, pbStartOld, pbStartNew);
        return TRUE;
    }

    PB    pbStart;
    PB    pbEnd;
    CB    cb;
    void (*pfnMove)(void* pArg, void* pOld, void* pNew);
    void* pfnMoveArg;
};

inline Buffer::~Buffer()
{
    if (pbStart) {
        Free();
    }
}


inline BOOL Buffer::Alloc(CB cbNew)
{
    dassert(cbNew > 0);

    if (pbStart)
        return FALSE;

    PB pbNew = new (zeroed) BYTE[cbNew];

    if (setPbExtent(pbNew, pbNew)) {
        cb = cbNew;
        return TRUE;
    }

    return FALSE;
}

inline void Buffer::Free()
{
    delete [] pbStart;
    setPbExtent(0, 0);
    cb = 0;
}

inline BOOL Buffer::Ensure(CB cbIn)
{
    if (cbIn < 0)
        return FALSE;

    if (pbEnd + cbIn > pbStart + cb) {
#pragma inline_depth(0)
        if (!grow(cbIn)) {
#pragma inline_depth()
            return FALSE;
        }
    }
    return TRUE;
}

inline BOOL Buffer::Ensure(CB cbIn, PB* ppbOut)
{
    if (!Ensure(cbIn))
        return FALSE;

    if (ppbOut)
        *ppbOut = pbEnd;

    return TRUE;

}

inline BOOL Buffer::Reserve(CB cbIn, OUT PB* ppbOut)
{
    if (!Ensure(cbIn, ppbOut))
        return FALSE;

    setPbExtent(pbStart, pbEnd + cbIn);
    return TRUE;
}

inline BOOL Buffer::Append(PB pbIn, CB cbIn, OUT PB* ppbOut)
{
    if (!pbIn)
        return FALSE;

    PB pb;
    if (!Reserve(cbIn, &pb))
        return FALSE;

     if (ppbOut)
        *ppbOut = pb;

    memcpy(pb, pbIn, cbIn);
    return TRUE;
}

inline BOOL CDECL Buffer::AppendFmt(SZ szFmt, ...)
{
    va_list args;
    va_start(args, szFmt);

    for (;;) {
        switch (*szFmt++) {
        case 0:
            va_end(args);
            return TRUE;
        case 'b': {
            BYTE b = va_arg(args, BYTE);
            if (!Append(&b, sizeof b, 0))
                goto fail;
            break;
        }
        case 's': {
            USHORT us = va_arg(args, USHORT);
            if (!Append((PB)&us, sizeof us, 0))
                goto fail;
            break;
        }
        case 'l': {
            ULONG ul = va_arg(args, ULONG);
            if (!Append((PB)&ul, sizeof ul, 0))
                goto fail;
            break;
        }
        case 'f': {
            static BYTE zeroes[3] = { 0, 0, 0 };
            int cb = va_arg(args, int);
            dassert(cb <= sizeof(zeroes));
            if (cb != 0 && !Append(zeroes, cb, 0))
                goto fail;
            break;
        }
        case 'z': {
            SZ sz = va_arg(args, SZ);
            int cb = strlen(sz);
            if (!Append((PB)sz, cb, 0))
                goto fail;
            break;
        }
        default:
            dassert(0);
            break;
        }
    }

fail:
    va_end(args);
    return FALSE;
}

inline BOOL Buffer::AppendNoCheck(BYTE b)
{
    *pbEnd++ = b;
    return TRUE;

}

inline BOOL Buffer::AppendNoCheck(short s)
{
    *(UNALIGNED short *)pbEnd = s;
    pbEnd += sizeof(short);
    return TRUE;

}

inline BOOL Buffer::AppendNoCheck(long l)
{
    *(UNALIGNED long *)pbEnd = l;
    pbEnd += sizeof(long);
    return TRUE;

}

inline BOOL Buffer::AppendNoCheck(float& f)
{
    *(UNALIGNED float *)pbEnd = f;
    pbEnd += sizeof(float);
    return TRUE;

}

inline BOOL Buffer::AppendNoCheck(double& d)
{
    *(UNALIGNED double *)pbEnd = d;
    pbEnd += sizeof(double);
    return TRUE;

}

inline BOOL Buffer::AppendNoCheck(PB pbIn, CB cbIn)
{
    memcpy(pbEnd, pbIn, cbIn);
    pbEnd += cbIn;
    return TRUE;
}

inline BOOL Buffer::grow(CB dcbGrow)
{
    CB cbNew = cbRoundUp(cb + __max(cbPage + dcbGrow, cb/2), cbPage);
    PB pbNew = new BYTE[cbNew];

    if (pbNew) {
        cb = cbNew;
        CB cbUsed = pbEnd - pbStart;
        memcpy(pbNew, pbStart, cbUsed);
        memset(pbNew + cbUsed, 0, cb - cbUsed);

        delete [] pbStart;
        setPbExtent(pbNew, pbNew + cbUsed);
        return TRUE;
    }

    return FALSE;
}

#endif // !__BUFFER_INCLUDED__