pdf::PagesCache Class Reference

#include <pdf_pages_cache.h>

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Public Member Functions
	PagesCache (void)
	~PagesCache (void)
bool	reset (const unsigned int size)
	Reset the size of pages cache.
unsigned int	size ()
	Get the size of pages cache.
void	clear ()
	Clear the pages cache.
void	add_page (PagePtr p)
	Add a new page.
bool	make_enough_memory (const int page_num, const int length)
void	clear_cached_bitmaps ()
	Clear the cached bitmaps but locked page.
PagePtr	get_page (const size_t idx)
	Get a page.
void	update_mem_usage (const int length)
	Increase total length by adding the page length.
Mutex &	get_mutex ()
	Get the mutex, for externally locking the cache.

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Detailed Description

Definition at line 41 of file pdf_pages_cache.h.

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Constructor & Destructor Documentation

pdf::PagesCache::PagesCache

(

void

)

Definition at line 33 of file pdf_pages_cache.cpp.

: size_limit(0)
, total_length(0)
, pages()
, cache_mutex()
{
}

pdf::PagesCache::~PagesCache

(

void

)

Definition at line 41 of file pdf_pages_cache.cpp.

References clear().

{
    clear();
}

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Member Function Documentation

void pdf::PagesCache::add_page

(

PagePtr

p

)

Add a new page.

Definition at line 91 of file pdf_pages_cache.cpp.

Referenced by pdf::PDFRenderer::gen_page().

{
    ScopeMutex m(&cache_mutex);
    // insert the new page into cache
    pages[(*p)()] = p;
}

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void pdf::PagesCache::clear

(

void

)

Clear the pages cache.

Definition at line 75 of file pdf_pages_cache.cpp.

Referenced by ~PagesCache().

{
    ScopeMutex m(&cache_mutex);

    PagesIter begin = pages.begin();
    PagesIter end = pages.end();
    PagesIter iter = begin;
    for(; iter != end; ++iter)
    {
        delete iter->second;
    }
    pages.clear();
    total_length = 0;
}

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void pdf::PagesCache::clear_cached_bitmaps

(

)

Clear the cached bitmaps but locked page.

Definition at line 136 of file pdf_pages_cache.cpp.

References pdf::PDFPage::destroy(), pdf::PDFPage::get_bitmap(), pdf::PDFPage::locked(), and LOGPRINTF.

{
    ScopeMutex m(&cache_mutex);
    // clear all cached bitmaps
    LOGPRINTF("Clear cached bitmaps due to out of memory\n\n");
    PagePtr page = 0;
    PagesIter iter = pages.begin();
    for (; iter != pages.end(); ++iter)
    {
        page = iter->second;
        if (page->get_bitmap() && !page->locked())
        {
            int delta = static_cast<int>(page->destroy());

            // update the total length
            total_length -= delta;
        }
    }
}

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Mutex& pdf::PagesCache::get_mutex

(

)

[inline]

Get the mutex, for externally locking the cache.

Definition at line 73 of file pdf_pages_cache.h.

Referenced by pdf::PDFRenderer::post_render_task().

{ return cache_mutex; }

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PagePtr pdf::PagesCache::get_page

(

const size_t

idx

)

Get a page.

Definition at line 156 of file pdf_pages_cache.cpp.

Referenced by pdf::PDFController::get_page().

{
    ScopeMutex m(&cache_mutex);

    PagePtr page = 0;
    PagesIter iter = pages.find(idx);
    if (iter != pages.end())
    {
        page = iter->second;
    }
    return page;
}

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bool pdf::PagesCache::make_enough_memory	(	const int	page_num,
		const int	length
	)

Remove the old pages to make sure the memory is enough NOTE: length might be less than 0

Definition at line 100 of file pdf_pages_cache.cpp.

References LOGPRINTF, and size().

{
    ScopeMutex m(&cache_mutex);

    int sum = total_length + length;
    if (sum <= static_cast<int>(size_limit))
    {
        return true;
    }

    // remove the most useless pages until the sum is less than
    // a quarter of the size limitation
    unsigned int size = (size_limit >> 1);
    while (sum > static_cast<int>(size))
    {
        if (!remove_page(page_num))
        {
            // remove fails, because:
            // 1. there is no any cached images any more
            // 2. the image is locked
            if ((total_length + length) <= static_cast<int>(size_limit))
            {
                // if the total length plus with the length is less
                // than the size limitation, it means there is enough
                // space left, otherwise return false.
                return true;
            }
            LOGPRINTF("Skip Page:%d", page_num);
            return false;
        }
        sum = total_length + length;
    }

    return true;
}

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bool pdf::PagesCache::reset

(

const unsigned int

size

)

Reset the size of pages cache.

Definition at line 46 of file pdf_pages_cache.cpp.

Referenced by pdf::PDFController::set_memory_limit().

{
    ScopeMutex m(&cache_mutex);

    int real_size = static_cast<int>(size);

    if (size_limit > static_cast<unsigned int>(real_size))
    {
        //remove the redundant pages
        while (total_length > real_size)
        {
            if (!remove_page())
            {
                // cannot remove the needed page
                return false;
            }
        }
    }

    size_limit = static_cast<unsigned int>(real_size);
    return true;
}

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unsigned int pdf::PagesCache::size

(

)

Get the size of pages cache.

Definition at line 69 of file pdf_pages_cache.cpp.

Referenced by pdf::PDFController::get_memory_limit(), and make_enough_memory().

{
    ScopeMutex m(&cache_mutex);
    return size_limit;
}

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void pdf::PagesCache::update_mem_usage

(

const int

length

)

Increase total length by adding the page length.

Definition at line 169 of file pdf_pages_cache.cpp.

{
    ScopeMutex m(&cache_mutex);
    total_length += length;
    /*LOGPRINTF("Add memory usage:%d, total length:%d\n"
            , length
            , total_length);*/
}

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

• pdf_pages_cache.h
• pdf_pages_cache.cpp