seekabilizer

#include <seekabilizer.h>

Inheritance diagram for seekabilizer:

Public Member Functions
bool	can_seek ()
bool	get_content_type (pfc::string_base &p_out)
t_filesize	get_position (abort_callback &p_abort)
t_filesize	get_size (abort_callback &p_abort)
t_filetimestamp	get_timestamp (abort_callback &p_abort)
void	initialize (service_ptr_t< file > p_base, t_size p_buffer_size, abort_callback &p_abort)
bool	is_in_memory ()
bool	is_remote ()
void	on_idle (abort_callback &p_abort)
t_size	read (void *p_buffer, t_size p_bytes, abort_callback &p_abort)
void	reopen (abort_callback &p_abort)
void	seek (t_filesize p_position, abort_callback &p_abort)

Static Public Member Functions
static void	g_seekabilize (service_ptr_t< file > &p_reader, t_size p_buffer_size, abort_callback &p_abort)

Private Attributes
seekabilizer_backbuffer	m_buffer
service_ptr_t< file >	m_file
t_filesize	m_position
t_filesize	m_position_base
t_filesize	m_size

Detailed Description

Definition at line 15 of file seekabilizer.h.

Member Function Documentation

bool seekabilizer::can_seek

(

)

Definition at line 190 of file seekabilizer.cpp.

{
    return true;
}

void seekabilizer::g_seekabilize ( service_ptr_t< file > &  p_reader, t_size  p_buffer_size, abort_callback &  p_abort  )

static

Definition at line 87 of file seekabilizer.cpp.

                                                                                                             {
    if (p_reader.is_valid() && p_reader->is_remote() && p_buffer_size > 0) {
        service_ptr_t<seekabilizer> instance = new service_impl_t<seekabilizer>();
        instance->initialize(p_reader,p_buffer_size,p_abort);
        p_reader = instance.get_ptr();
    }
}

bool seekabilizer::get_content_type

(

pfc::string_base &

p_out

)

Definition at line 195 of file seekabilizer.cpp.

{return m_file->get_content_type(p_out);}

t_filesize seekabilizer::get_position

(

abort_callback &

p_abort

)

Definition at line 156 of file seekabilizer.cpp.

                                                              {
    p_abort.check_e();
    return m_position;
}

t_filesize seekabilizer::get_size

(

abort_callback &

p_abort

)

Definition at line 151 of file seekabilizer.cpp.

                                                          {
    p_abort.check_e();
    return m_size;
}

t_filetimestamp seekabilizer::get_timestamp

(

abort_callback &

p_abort

)

Definition at line 201 of file seekabilizer.cpp.

                                                                    {
    p_abort.check_e();
    return m_file->get_timestamp(p_abort);
}

void seekabilizer::initialize	(	service_ptr_t< file >	p_base,
		t_size	p_buffer_size,
		abort_callback &	p_abort
	)

Definition at line 80 of file seekabilizer.cpp.

                                                                                                      {
    m_buffer.initialize(p_buffer_size);
    m_file = p_base;
    m_position = m_position_base = 0;
    m_size = m_file->get_size(p_abort);
}

bool seekabilizer::is_in_memory

(

)

Definition at line 197 of file seekabilizer.cpp.

{return false;}

bool seekabilizer::is_remote

(

)

Definition at line 216 of file seekabilizer.cpp.

{
    return m_file->is_remote();
}

void seekabilizer::on_idle

(

abort_callback &

p_abort

)

Definition at line 199 of file seekabilizer.cpp.

{return m_file->on_idle(p_abort);}

t_size seekabilizer::read	(	void *	p_buffer,
		t_size	p_bytes,
		abort_callback &	p_abort
	)

Definition at line 95 of file seekabilizer.cpp.

                                                                                 {
    p_abort.check_e();

    if (m_position > m_position_base + pfc::max_t<t_size>(m_buffer.get_max_depth(),backread_on_seek) && m_file->can_seek()) {
        m_buffer.reset();
        t_filesize target = m_position;
        if (target < backread_on_seek) target = 0;
        else target -= backread_on_seek;
        m_file->seek(target,p_abort);
        m_position_base = target;
    }

    //seek ahead
    while(m_position > m_position_base) {
        enum {tempsize = 1024};
        t_uint8 temp[tempsize];
        t_size delta = (t_size) pfc::min_t<t_filesize>(tempsize,m_position - m_position_base);
        t_size bytes_read = 0;
        bytes_read = m_file->read(temp,delta,p_abort);
        m_buffer.write(temp,bytes_read);
        m_position_base += bytes_read;

        if (bytes_read < delta) {
            return 0;
        }
    }

    t_size done = 0;
    t_uint8 * targetptr = (t_uint8*) p_buffer;

    //try to read backbuffer
    if (m_position < m_position_base) {
        if (m_position_base - m_position > (t_filesize)m_buffer.get_depth()) throw exception_io_seek_out_of_range();
        t_size backread_depth = (t_size) (m_position_base - m_position);
        t_size delta = pfc::min_t<t_size>(backread_depth,p_bytes-done);
        m_buffer.read(backread_depth,targetptr,delta);
        done += delta;
        m_position += delta;
    }

    //regular read
    if (done < p_bytes)
    {
        t_size bytes_read;
        bytes_read = m_file->read(targetptr+done,p_bytes-done,p_abort);

        m_buffer.write(targetptr+done,bytes_read);

        done += bytes_read;
        m_position += bytes_read;
        m_position_base += bytes_read;
    }

    return done;
}

void seekabilizer::reopen

(

abort_callback &

p_abort

)

Definition at line 206 of file seekabilizer.cpp.

                                                  {
    if (m_position_base - m_buffer.get_depth() == 0) {
        seek(0,p_abort);
    } else {
        m_position = m_position_base = 0;
        m_buffer.reset();
        m_file->reopen(p_abort);
    }
}

void seekabilizer::seek	(	t_filesize	p_position,
		abort_callback &	p_abort
	)

Definition at line 161 of file seekabilizer.cpp.

                                                                      {
    assert(m_position_base >= m_buffer.get_depth());
    p_abort.check_e();

    if (m_size != filesize_invalid && p_position > m_size) throw exception_io_seek_out_of_range();

    t_filesize lowest = m_position_base - m_buffer.get_depth();

    if (p_position < lowest) {
        if (m_file->can_seek()) {
            m_buffer.reset();
            t_filesize target = p_position;
            t_size delta = m_buffer.get_max_depth();
            if (delta > backread_on_seek) delta = backread_on_seek;
            if (target > delta) target -= delta;
            else target = 0;
            m_file->seek(target,p_abort);
            m_position_base = target;
        }
        else {
            m_buffer.reset();
            m_file->reopen(p_abort);
            m_position_base = 0;
        }
    }

    m_position = p_position;
}

Field Documentation

seekabilizer_backbuffer seekabilizer::m_buffer

private

Definition at line 34 of file seekabilizer.h.

service_ptr_t<file> seekabilizer::m_file

private

Definition at line 33 of file seekabilizer.h.

t_filesize seekabilizer::m_position

private

Definition at line 35 of file seekabilizer.h.

t_filesize seekabilizer::m_position_base

private

Definition at line 35 of file seekabilizer.h.

t_filesize seekabilizer::m_size

private

Definition at line 35 of file seekabilizer.h.

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The documentation for this class was generated from the following files:

• foobar2000/helpers/seekabilizer.h
• foobar2000/helpers/seekabilizer.cpp