/*
 * Copyright (c) 2008-2015 Freescale Semiconductor, Inc.
 * Copyright 2016-2018 NXP
 * All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include "SRecordSourceFile.h"
#include "Logging.h"
#include "smart_ptr.h"
#include <assert.h>
#include <string.h>
enum
{
    //! Size in bytes of the buffer used to collect S-record data records
    //! before adding them to the executable image. Currently 64KB.
    COLLECTION_BUFFER_SIZE = 64 * 1024
};

using namespace elftosb;

SRecordSourceFile::SRecordSourceFile(const std::string &path)
    : SourceFile(path)
    , m_image(0)
    , m_hasEntryRecord(false)
{
}

bool SRecordSourceFile::isSRecordFile(std::istream &stream)
{
    StSRecordFile srec(stream);
    return srec.isSRecordFile();
}

void SRecordSourceFile::open()
{
    SourceFile::open();

    // create file parser and examine file
    m_file = new StSRecordFile(*m_stream);
    m_file->parse();

    // build an image of the file
    m_image = new StExecutableImage();
    buildMemoryImage();

    // dispose of file parser object
    delete m_file;
    m_file = 0;
}

void SRecordSourceFile::close()
{
    assert(m_image);

    SourceFile::close();

    // dispose of memory image
    delete m_image;
    m_image = 0;
}

//! \pre The file must be open before this method can be called.
//!
DataSource *SRecordSourceFile::createDataSource()
{
    assert(m_image);
    return new MemoryImageDataSource(m_image);
}

//! \retval true The file has an S7, S8, or S9 record.
//! \retval false No entry point is available.
bool SRecordSourceFile::hasEntryPoint()
{
    return m_hasEntryRecord;
}

//! If no entry point is available then 0 is returned instead. The method scans
//! the records in the file looking for S7, S8, or S9 records. Thus, 16-bit,
//! 24-bit, and 32-bit entry point records are supported.
//!
//! \return Entry point address.
//! \retval 0 No entry point is available.
uint32_t SRecordSourceFile::getEntryPointAddress()
{
    if (m_hasEntryRecord)
    {
        // the address in the record is the entry point
        Log::log(Logger::DEBUG2, "entry point address is 0x%08x\n", m_entryRecord.m_address);
        return m_entryRecord.m_address;
    }

    return 0;
}

//! Scans the S-records of the file looking for data records. These are S3, S2, or
//! S1 records. The contents of these records are added to an StExecutableImage
//! object, which coalesces the individual records into contiguous regions of
//! memory.
//!
//! Also looks for S7, S8, or S9 records that contain the entry point. The first
//! match of one of these records is saved off into the #m_entryRecord member.
//!
//! \pre The #m_file member must be valid.
//! \pre The #m_image member variable must have been instantiated.
void SRecordSourceFile::buildMemoryImage()
{
    assert(m_file);
    assert(m_image);

    // Clear the entry point related members.
    m_hasEntryRecord = false;
    memset(&m_entryRecord, 0, sizeof(m_entryRecord));

    // Allocate buffer to hold data before adding it to the executable image.
    // Contiguous records are added to this buffer. When overflowed or when a
    // non-contiguous record is encountered the buffer is added to the executable
    // image where it will be coalesced further. We don't add records individually
    // to the image because coalescing record by record is very slow.
    smart_array_ptr<uint8_t> buffer = new uint8_t[COLLECTION_BUFFER_SIZE];
    unsigned startAddress;
    unsigned nextAddress;
    unsigned dataLength = 0;

    // process SRecords
    StSRecordFile::const_iterator it = m_file->getBegin();
    for (; it != m_file->getEnd(); it++)
    {
        const StSRecordFile::SRecord &theRecord = *it;

        // only handle S3,2,1 records
        bool isDataRecord = theRecord.m_type == 3 || theRecord.m_type == 2 || theRecord.m_type == 1;
        bool hasData = theRecord.m_data && theRecord.m_dataCount;
        if (isDataRecord && hasData)
        {
            // If this record's data would overflow the collection buffer, or if the
            // record is not contiguous with the rest of the data in the collection
            // buffer, then flush the buffer to the executable image and restart.
            if (dataLength &&
                ((dataLength + theRecord.m_dataCount > COLLECTION_BUFFER_SIZE) || (theRecord.m_address != nextAddress)))
            {
                m_image->addTextRegion(startAddress, buffer, dataLength);

                dataLength = 0;
            }

            // Capture addresses when starting an empty buffer.
            if (dataLength == 0)
            {
                startAddress = theRecord.m_address;
                nextAddress = startAddress;
            }

            // Copy record data into place in the collection buffer and update
            // size and address.
            memcpy(&buffer[dataLength], theRecord.m_data, theRecord.m_dataCount);
            dataLength += theRecord.m_dataCount;
            nextAddress += theRecord.m_dataCount;
        }
        else if (!m_hasEntryRecord)
        {
            // look for S7,8,9 records
            bool isEntryPointRecord = theRecord.m_type == 7 || theRecord.m_type == 8 || theRecord.m_type == 9;
            if (isEntryPointRecord)
            {
                // save off the entry point record so we don't have to scan again
                memcpy(&m_entryRecord, &theRecord, sizeof(m_entryRecord));
                m_hasEntryRecord = true;
            }
        }
    }

    // Add any leftover data in the collection buffer to the executable image.
    if (dataLength)
    {
        m_image->addTextRegion(startAddress, buffer, dataLength);
    }
}
