io_utils.cpp

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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 2
* 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, see <https://www.gnu.org/licenses/>.
*/
 
#include "io_utils.h"
 
#include <wx/wfstream.h>
#include <wx/txtstrm.h>
 
#include <mmh3_hash.h>
 
namespace IO_UTILS
{
    const std::vector<uint8_t> COMPOUND_FILE_HEADER = { 0xD0, 0xCF, 0x11, 0xE0,
                                                        0xA1, 0xB1, 0x1A, 0xE1 };
 
bool fileStartsWithPrefix( const wxString& aFilePath, const wxString& aPrefix,
                           bool aIgnoreWhitespace )
{
    wxFFileInputStream input( aFilePath );
 
    if( input.IsOk() && !input.Eof() )
    {
        // Find first non-empty line
        wxTextInputStream text( input );
        wxString          line = text.ReadLine();
 
        if( aIgnoreWhitespace )
        {
            while( !input.Eof() && line.IsEmpty() )
                line = text.ReadLine().Trim( false /*trim from left*/ );
        }
 
        if( line.StartsWith( aPrefix ) )
            return true;
    }
 
    return false;
}
 
 
bool fileHasBinaryHeader( const wxString& aFilePath, const std::vector<uint8_t>& aHeader,
    size_t aOffset )
{
    wxFFileInputStream input( aFilePath );
 
    if( input.IsOk() && !input.Eof() )
    {
        if( static_cast<size_t>( input.GetLength() ) < aOffset + aHeader.size() )
            return false;
 
        // Move the stream to the offset
        if( aOffset )
        {
            if( !input.SeekI( aOffset, wxFromStart ) )
                return false;
        }
 
        std::vector<uint8_t> parsedHeader( aHeader.size() );
 
        if( !input.ReadAll( parsedHeader.data(), parsedHeader.size() ) )
            return false;
 
        return parsedHeader == aHeader;
    }
 
    return false;
}
 
 
std::optional<wxString> fileHashMMH3( const wxString& aFilePath )
{
    constexpr size_t c_BufSize = 1024;
    wxFFileInputStream input( aFilePath );
    MMH3_HASH hash( 0x68AF835D ); // Arbitrary seed
 
    if( input.IsOk() )
    {
        uint8_t buf[ c_BufSize ];
        while ( !input.Eof() )
        {
            input.Read( buf, c_BufSize);
            size_t byteCount = input.LastRead();
            if( byteCount > 0 )
            {
                hash.addData( buf, byteCount );
            }
            else
            {
                break;
            }
        }
 
        return hash.digest().ToString();
    }
 
    return std::optional<wxString>();
}
 
 
}