tag_processor_id3v2.cpp

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#include "foobar2000.h"

bool tag_processor_id3v2::g_get(service_ptr_t<tag_processor_id3v2> & p_out)
{
    return service_enum_t<tag_processor_id3v2>().first(p_out);
}

void tag_processor_id3v2::g_remove(const service_ptr_t<file> & p_file,t_uint64 & p_size_removed,abort_callback & p_abort) {
    tag_write_callback_dummy cb;
    g_remove_ex(cb,p_file,p_size_removed,p_abort);
}

void tag_processor_id3v2::g_remove_ex(tag_write_callback & p_callback,const service_ptr_t<file> & p_file,t_uint64 & p_size_removed,abort_callback & p_abort)
{
    p_file->ensure_seekable();

    t_filesize len;
    
    len = p_file->get_size(p_abort);

    if (len == filesize_invalid) throw exception_io_no_length();
    
    p_file->seek(0,p_abort);
    
    t_uint64 offset;
    g_multiskip(p_file,offset,p_abort);
    
    if (offset>0 && offset<len)
    {
        len-=offset;
        service_ptr_t<file> temp;
        if (p_callback.open_temp_file(temp,p_abort)) {
            file::g_transfer_object(p_file,temp,len,p_abort);
        } else {
            if (len > 16*1024*1024) filesystem::g_open_temp(temp,p_abort);
            else filesystem::g_open_tempmem(temp,p_abort);
            file::g_transfer_object(p_file,temp,len,p_abort);
            p_file->seek(0,p_abort);
            p_file->set_eof(p_abort);
            temp->seek(0,p_abort);
            file::g_transfer_object(temp,p_file,len,p_abort);
        }
    }
    p_size_removed = offset;
}

t_size tag_processor_id3v2::g_multiskip(const service_ptr_t<file> & p_file,t_filesize & p_size_skipped,abort_callback & p_abort) {
    t_filesize offset = 0;
    t_size count = 0;
    for(;;) {
        t_filesize delta;
        g_skip_at(p_file, offset, delta, p_abort);
        if (delta == 0) break;
        offset += delta;
        ++count;
    }
    p_size_skipped = offset;
    return count;
}
void tag_processor_id3v2::g_skip(const service_ptr_t<file> & p_file,t_uint64 & p_size_skipped,abort_callback & p_abort) {
    g_skip_at(p_file, 0, p_size_skipped, p_abort);
}

void tag_processor_id3v2::g_skip_at(const service_ptr_t<file> & p_file,t_filesize p_base, t_filesize & p_size_skipped,abort_callback & p_abort) {

    unsigned char  tmp[10];

    p_file->seek ( p_base, p_abort );

    if (p_file->read( tmp, sizeof(tmp),  p_abort) != sizeof(tmp))  {
        p_file->seek ( p_base, p_abort );
        p_size_skipped = 0;
        return;
    }

    if ( 
        0 != memcmp ( tmp, "ID3", 3) ||
        ( tmp[5] & 0x0F ) != 0 || 
        ((tmp[6] | tmp[7] | tmp[8] | tmp[9]) & 0x80) != 0 
        ) {
        p_file->seek ( p_base, p_abort );
        p_size_skipped = 0;
        return;
    }

    int FooterPresent     = tmp[5] & 0x10;

    t_uint32 ret;
    ret  = tmp[6] << 21;
    ret += tmp[7] << 14;
    ret += tmp[8] <<  7;
    ret += tmp[9]      ;
    ret += 10;
    if ( FooterPresent ) ret += 10;

    try {
        p_file->seek ( p_base + ret, p_abort );
    } catch(exception_io_seek_out_of_range) {
        p_file->seek( p_base, p_abort );
        p_size_skipped = 0;
        return;
    }

    p_size_skipped = ret;

}