pads_binary_utils.h

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright The KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 3
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/gpl-3.0.html
 * or you may search the http://www.gnu.org website for the version 3 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */
 
#ifndef PADS_BINARY_UTILS_H_
#define PADS_BINARY_UTILS_H_
 
#include <algorithm>
#include <cstdint>
#include <cstring>
#include <optional>
#include <fstream>
#include <string>
#include <vector>
 
#include <wx/string.h>
 
#include <ki_exception.h>
#include <string_utils.h>
 
namespace PADS_IO
{
 
// A live SDB record header carries the FE FF (little-endian 0xFFFE) sentinel.
constexpr uint16_t SDB_RECORD_SENTINEL = 0xFFFE;
 
// PADS BASIC coordinate units per mil (one BASIC unit is 1/38100 mil).
constexpr double SDB_BASIC_PER_MIL = 38100.0;

inline uint8_t getU8( const std::vector<uint8_t>& aData, size_t aOffset )
{
    return aData[aOffset];
}
 
 
inline uint16_t getU16LE( const std::vector<uint8_t>& aData, size_t aOffset )
{
    return static_cast<uint16_t>( aData[aOffset] )
           | ( static_cast<uint16_t>( aData[aOffset + 1] ) << 8 );
}
 
 
inline uint32_t getU32LE( const std::vector<uint8_t>& aData, size_t aOffset )
{
    return static_cast<uint32_t>( aData[aOffset] )
           | ( static_cast<uint32_t>( aData[aOffset + 1] ) << 8 )
           | ( static_cast<uint32_t>( aData[aOffset + 2] ) << 16 )
           | ( static_cast<uint32_t>( aData[aOffset + 3] ) << 24 );
}
 
 
inline double getF64LE( const std::vector<uint8_t>& aData, size_t aOffset )
{
    uint64_t bits = 0;
 
    for( int i = 0; i < 8; ++i )
        bits |= static_cast<uint64_t>( aData[aOffset + i] ) << ( 8 * i );
 
    double value = 0;
    std::memcpy( &value, &bits, sizeof( value ) );
 
    return value;
}
 
 
inline float getF32LE( const std::vector<uint8_t>& aData, size_t aOffset )
{
    uint32_t bits = getU32LE( aData, aOffset );
    float    value = 0;
    std::memcpy( &value, &bits, sizeof( value ) );
 
    return value;
}
 

inline bool ReadFileHeader( const wxString& aFileName, std::vector<uint8_t>& aOut, size_t aCount )
{
    std::ifstream file( aFileName.fn_str(), std::ios::binary );
 
    if( !file.is_open() )
        return false;
 
    aOut.resize( aCount );
    file.read( reinterpret_cast<char*>( aOut.data() ), static_cast<std::streamsize>( aCount ) );
    aOut.resize( static_cast<size_t>( file.gcount() ) );
 
    return true;
}
 

inline bool ReadFileToBuffer( const wxString& aFileName, std::vector<uint8_t>& aOut )
{
    std::ifstream file( aFileName.fn_str(), std::ios::binary | std::ios::ate );
 
    if( !file.is_open() )
        return false;
 
    std::streamoff len = file.tellg();
    file.seekg( 0, std::ios::beg );
 
    if( len <= 0 )
        return false;
 
    aOut.resize( static_cast<size_t>( len ) );
    file.read( reinterpret_cast<char*>( aOut.data() ), len );
 
    return file.gcount() == len;
}
 

inline std::string readFixedStringRaw( const std::vector<uint8_t>& aData, size_t aOffset,
                                       size_t aMaxLen )
{
    if( aOffset >= aData.size() )
        return {};
 
    size_t         available = std::min( aMaxLen, aData.size() - aOffset );
    const uint8_t* start = &aData[aOffset];
 
    const uint8_t* null_pos = std::find( start, start + available, 0 );
    size_t         len = static_cast<size_t>( null_pos - start );
 
    for( size_t i = 0; i < len; ++i )
    {
        if( start[i] < 0x20 || start[i] == 0x7F )
            return {};
    }
 
    return std::string( reinterpret_cast<const char*>( start ), len );
}
 

inline std::string readFixedString( const std::vector<uint8_t>& aData, size_t aOffset, size_t aMaxLen )
{
    std::string raw = readFixedStringRaw( aData, aOffset, aMaxLen );
 
    // Trimmed here rather than through StrPurge, which also strips leading whitespace and walks
    // one before the start on an empty string
    while( !raw.empty() && raw.back() == ' ' )
        raw.pop_back();
 
    return raw;
}
 

inline bool HasSdbMagic( const std::vector<uint8_t>& aData, uint8_t aMagic1 )
{
    return aData.size() >= 2 && aData[0] == 0x00 && aData[1] == aMagic1;
}
 

struct SDB_FOOTER_ERROR
{
    size_t      offset;
    const char* detail;
};
 

std::optional<SDB_FOOTER_ERROR> CheckSdbFooter( const std::vector<uint8_t>& aData, size_t aFooterStart,
                                                const char* aGuid, size_t aGuidLen );
 

void ValidateSdbFooter( const std::vector<uint8_t>& aData, size_t aFooterStart, const char* aGuid,
                        size_t aGuidLen );
 

class BINARY_CURSOR
{
public:
    explicit BINARY_CURSOR( const std::vector<uint8_t>& aData ) : m_data( aData ) {}
 
    size_t Size() const { return m_data.size(); }
 
    // Overflow-safe: a near-SIZE_MAX offset must not wrap aOffset + aCount into range.
    bool InBounds( size_t aOffset, size_t aCount ) const
    {
        return aOffset <= m_data.size() && aCount <= m_data.size() - aOffset;
    }
 
    uint8_t U8At( size_t aOffset ) const
    {
        check( aOffset, 1 );
        return getU8( m_data, aOffset );
    }
 
    uint16_t U16At( size_t aOffset ) const
    {
        check( aOffset, 2 );
        return getU16LE( m_data, aOffset );
    }
 
    uint32_t U32At( size_t aOffset ) const
    {
        check( aOffset, 4 );
        return getU32LE( m_data, aOffset );
    }
 
    int32_t I32At( size_t aOffset ) const { return static_cast<int32_t>( U32At( aOffset ) ); }
 
    double F64At( size_t aOffset ) const
    {
        check( aOffset, 8 );
        return getF64LE( m_data, aOffset );
    }
 
    float F32At( size_t aOffset ) const
    {
        check( aOffset, 4 );
        return getF32LE( m_data, aOffset );
    }
 
    // Unlike the numeric accessors this does not throw out of range; aMaxLen is
    // clamped to the available bytes and the read returns empty past EOF, so a
    // short field abutting a boundary still reads cleanly.
    std::string StringAt( size_t aOffset, size_t aMaxLen ) const
    {
        return readFixedString( m_data, aOffset, aMaxLen );
    }
 
private:
    void check( size_t aOffset, size_t aCount ) const
    {
        if( !InBounds( aOffset, aCount ) )
        {
            THROW_IO_ERROR( wxString::Format( "PADS binary read out of bounds at offset %zu (file size %zu)",
                                              aOffset, m_data.size() ) );
        }
    }
 
    const std::vector<uint8_t>& m_data;
};
 

class SDB_RECORD
{
public:
    SDB_RECORD( const BINARY_CURSOR& aCursor, size_t aBase ) : m_cursor( aCursor ), m_base( aBase )
    {
    }
 
    uint8_t     U8( size_t aOffset ) const { return m_cursor.U8At( m_base + aOffset ); }
    uint16_t    U16( size_t aOffset ) const { return m_cursor.U16At( m_base + aOffset ); }
    uint32_t    U32( size_t aOffset ) const { return m_cursor.U32At( m_base + aOffset ); }
    int32_t     I32( size_t aOffset ) const { return m_cursor.I32At( m_base + aOffset ); }
    double      F64( size_t aOffset ) const { return m_cursor.F64At( m_base + aOffset ); }
    std::string Str( size_t aOffset, size_t aMaxLen ) const
    {
        return m_cursor.StringAt( m_base + aOffset, aMaxLen );
    }
 
    size_t Base() const { return m_base; }
 
private:
    const BINARY_CURSOR& m_cursor;
    size_t               m_base;
};
 
} // namespace PADS_IO
 
#endif // PADS_BINARY_UTILS_H_