//////////////////////////////////////////////////////////////////////////////
//
//  inifile.cpp - Parser/Iterator for ini file generated by DistroBuilder
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  Note: The format is assumed to be:
//
//   #############################################
//   # Header comment
//   #############################################
//   Hash-MD5=XXX Size=XXX Path=XXX/YYY/ZZZ
//   Hash-MD5=XXX Size=XXX Path=XXX/YYY/ZZZ
//   ...
//   ############################################
//
#include "inifile.h"

#pragma warning(disable: 4505) // Compiler generated constructor unreferenced

// ----------------------------------------------------------------------------
// Utility routines

static bool IsWhitespace(UINT8 value)
{
    return (bool)(value == (UINT8)' ' || value == (UINT8)'\t');
}

static LPUINT8
SkipWhitespace(LPUINT8 pBuffer, LPUINT8 pBufferEnd)
{
    while (pBuffer != pBufferEnd && IsWhitespace(*pBuffer)) {
        pBuffer++;
    }
    return pBuffer;
}

static LPUINT8
SkipLine(LPUINT8 pBuffer, LPUINT8 pBufferEnd)
{
    // Skip ASCII text
    while (pBuffer != pBufferEnd && *pBuffer >= 32) {
        pBuffer++;
    }
    // Skip control characters
    while (pBuffer != pBufferEnd && *pBuffer < 32) {
        pBuffer++;
    }
    return pBuffer;
}

static LPUINT8
SkipComments(LPUINT8 pBuffer, UINT32 cbBuffer)
{
    LPUINT8 pBufferEnd = pBuffer + cbBuffer;

    while (pBuffer != pBufferEnd) {
        pBuffer = SkipWhitespace(pBuffer, pBufferEnd);
        if (*pBuffer != '#') {
            return pBuffer;
        }
        pBuffer = SkipLine(pBuffer, pBufferEnd);
    }
    return pBufferEnd;
}

static bool
ReverseMatch(LPUINT8 pBufferA, LPUINT8 pBufferB, INT8 nLength)
{
    while (--nLength >= 0) {
        if (*pBufferA-- != *pBufferB--) {
            return 0;
        }
    }
    return 1;
}

static LPUINT8
FindAndSkipString(LPCSTR pChars, INT8 nChars,
                  LPUINT8 pBuffer, LPUINT8 pBufferEnd)
{
    pBuffer += nChars - 1;

    if (pBuffer > pBufferEnd) {
        return pBufferEnd;
    }

    while (pBuffer < pBufferEnd) {
        if (*pBuffer == pChars[nChars - 1] &&
            ReverseMatch(pBuffer, (LPUINT8)(pChars + nChars - 1), nChars)) {
                return pBuffer + 1;
        }
        pBuffer++;
    }

    return pBufferEnd;
}

static UINT32
ParseFileSize(LPUINT8 pBuffer, LPUINT8 pBufferEnd)
{
    UINT32 nBytes = 0;
    pBuffer = FindAndSkipString("Size=", 5, pBuffer, pBufferEnd);
    while (pBuffer != pBufferEnd &&
           *pBuffer >= (UINT8)'0' && *pBuffer <= (UINT8)'9') {
        nBytes *= 10;
        nBytes += (UINT32)(*pBuffer - (UINT8)'0');
        pBuffer++;
    }
    return nBytes;
}

static LPUINT8
ParseFileName(LPUINT8 pBuffer, LPUINT8 pBufferEnd)
{
    pBuffer = FindAndSkipString("Path=", 5, pBuffer, pBufferEnd);
    // Force null termination
    for (LPUINT8 pTemp = pBuffer; pTemp != pBufferEnd; pTemp++) {
        if (*pTemp < 32) {
            *pTemp = 0;
            break;
        }
    }
    return pBuffer;
}

static LPUINT8 SkipToEndOfFile(LPUINT8 pBuffer, LPUINT8 pBufferEnd)
{
    // Last line of file is a comment.
    while (pBuffer != pBufferEnd && *pBuffer != '#') {
        pBuffer++;
    }
    return pBuffer;
}

// ----------------------------------------------------------------------------
// IniFile class

IniFile::IniFile(LPUINT8 pBuffer, UINT32 cbBuffer) __far
{
    this->_pBuffer    = SkipComments(pBuffer, cbBuffer);
    this->_pBufferEnd = SkipToEndOfFile(this->_pBuffer, pBuffer + cbBuffer);
    this->_pCurrent   = this->_pBuffer;
}

UINT16
IniFile::GetFileCount() __far
{
    LPUINT8 pBuffer = this->_pBuffer;
    UINT16 nFiles = 0;

    while (pBuffer != this->_pBufferEnd) {
        if (ParseFileSize(pBuffer, this->_pBufferEnd) == 0) {
            break;
        }
        pBuffer = SkipLine(pBuffer, this->_pBufferEnd);
        nFiles++;
    }
    return nFiles;
}

UINT32
IniFile::GetTotalBytes() __far
{
    LPUINT8 pBuffer = this->_pBuffer;
    UINT32 nTotalBytes = 0;
    while (pBuffer != this->_pBufferEnd) {
        nTotalBytes += ParseFileSize(pBuffer, this->_pBufferEnd);
        pBuffer = SkipLine(pBuffer, this->_pBufferEnd);
    }
    return nTotalBytes;
}

UINT32
IniFile::GetCurrentFileSize() __far
{
    return ParseFileSize(this->_pCurrent, this->_pBufferEnd);
}

LPUINT8
IniFile::GetCurrentFileName() __far
{
    LPUINT8 pFileName = ParseFileName(this->_pCurrent, this->_pBufferEnd);
    if (pFileName != this->_pBufferEnd) {
        return pFileName;
    }
    return NULL;
}

void
IniFile::Rewind() __far
{
    this->_pCurrent = this->_pBuffer;
}

bool
IniFile::MoveNext() __far
{
    this->_pCurrent = SkipLine(this->_pCurrent, this->_pBufferEnd);
    return (bool)(this->_pCurrent != this->_pBufferEnd);
}