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libvips/libsrc/iofuncs/window.c

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/* Manage sets of mmap buffers on an image.
*
* 30/10/06
* - from region.c
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
/*
#define DEBUG_TOTAL
#define DEBUG_ENVIRONMENT
#define DEBUG
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /*HAVE_UNISTD_H*/
#include <errno.h>
#include <string.h>
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#include <assert.h>
#include <vips/vips.h>
#include <vips/internal.h>
#include <vips/thread.h>
#ifdef OS_WIN32
#include <windows.h>
#endif /*OS_WIN32*/
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
/* Sanity checking ... write to this during read tests to make sure we don't
* get optimised out.
*/
int im__read_test;
/* Add this many lines above and below the mmap() window.
*/
int im__window_margin = IM__WINDOW_MARGIN;
/* Track global mmap usage.
*/
#ifdef DEBUG_TOTAL
static int total_mmap_usage = 0;
static int max_mmap_usage = 0;
#endif /*DEBUG_TOTAL*/
static int
im_window_unmap( im_window_t *window )
{
/* unmap the old window
*/
if( window->baseaddr ) {
if( im__munmap( window->baseaddr, window->length ) )
return( -1 );
#ifdef DEBUG_TOTAL
g_mutex_lock( im__global_lock );
total_mmap_usage -= window->length;
assert( total_mmap_usage >= 0 );
g_mutex_unlock( im__global_lock );
#endif /*DEBUG_TOTAL*/
window->data = NULL;
window->baseaddr = NULL;
window->length = 0;
}
return( 0 );
}
static int
im_window_free( im_window_t *window )
{
assert( window->ref_count == 0 );
#ifdef DEBUG
printf( "** im_window_free: window top = %d, height = %d (%p)\n",
window->top, window->height, window );
#endif /*DEBUG*/
if( im_window_unmap( window ) )
return( -1 );
window->im = NULL;
im_free( window );
return( 0 );
}
int
im_window_unref( im_window_t *window )
{
IMAGE *im = window->im;
g_mutex_lock( im->sslock );
#ifdef DEBUG
printf( "im_window_unref: window top = %d, height = %d, count = %d\n",
window->top, window->height, window->ref_count );
#endif /*DEBUG*/
assert( window->ref_count > 0 );
window->ref_count -= 1;
if( window->ref_count == 0 ) {
assert( g_slist_find( im->windows, window ) );
im->windows = g_slist_remove( im->windows, window );
#ifdef DEBUG
printf( "im_window_unref: %d windows left\n",
g_slist_length( im->windows ) );
#endif /*DEBUG*/
if( im_window_free( window ) ) {
g_mutex_unlock( im->sslock );
return( -1 );
}
}
g_mutex_unlock( im->sslock );
return( 0 );
}
#ifdef DEBUG_TOTAL
static void
trace_mmap_usage( void )
{
g_mutex_lock( im__global_lock );
{
static int last_total = 0;
int total = total_mmap_usage / (1024 * 1024);
int max = max_mmap_usage / (1024 * 1024);
if( total != last_total ) {
printf( "im_window_set: current mmap "
"usage of ~%dMB (high water mark %dMB)\n",
total, max );
last_total = total;
}
}
g_mutex_unlock( im__global_lock );
}
#endif /*DEBUG_TOTAL*/
static int
im_getpagesize()
{
static int pagesize = 0;
if( !pagesize ) {
#ifdef OS_WIN32
SYSTEM_INFO si;
GetSystemInfo( &si );
pagesize = si.dwAllocationGranularity;
#else /*OS_WIN32*/
pagesize = getpagesize();
#endif /*OS_WIN32*/
#ifdef DEBUG_TOTAL
printf( "im_getpagesize: 0x%x\n", pagesize );
#endif /*DEBUG_TOTAL*/
}
return( pagesize );
}
/* Map a window into a file.
*/
static int
im_window_set( im_window_t *window, int top, int height )
{
int pagesize = im_getpagesize();
void *baseaddr;
gint64 start, end, pagestart;
size_t length, pagelength;
/* Calculate start and length for our window.
*/
start = window->im->sizeof_header +
(gint64) IM_IMAGE_SIZEOF_LINE( window->im ) * top;
length = (size_t) IM_IMAGE_SIZEOF_LINE( window->im ) * height;
pagestart = start - start % pagesize;
end = start + length;
pagelength = end - pagestart;
if( !(baseaddr = im__mmap( window->im->fd, 0, pagelength, pagestart )) )
return( -1 );
window->baseaddr = baseaddr;
window->length = pagelength;
window->data = (char *) baseaddr + (start - pagestart);
window->top = top;
window->height = height;
/* Sanity check ... make sure the data pointer is readable.
*/
im__read_test &= window->data[0];
#ifdef DEBUG_TOTAL
g_mutex_lock( im__global_lock );
total_mmap_usage += window->length;
if( total_mmap_usage > max_mmap_usage )
max_mmap_usage = total_mmap_usage;
g_mutex_unlock( im__global_lock );
trace_mmap_usage();
#endif /*DEBUG_TOTAL*/
return( 0 );
}
/* Make a new window.
*/
static im_window_t *
im_window_new( IMAGE *im, int top, int height )
{
im_window_t *window;
if( !(window = IM_NEW( NULL, im_window_t )) )
return( NULL );
window->ref_count = 0;
window->im = im;
window->top = 0;
window->height = 0;
window->data = NULL;
window->baseaddr = NULL;
window->length = 0;
if( im_window_set( window, top, height ) ) {
im_window_free( window );
return( NULL );
}
im->windows = g_slist_prepend( im->windows, window );
window->ref_count += 1;
#ifdef DEBUG
printf( "** im_window_new: window top = %d, height = %d (%p)\n",
window->top, window->height, window );
#endif /*DEBUG*/
return( window );
}
/* A request for an area of pixels.
*/
typedef struct {
int top;
int height;
} request_t;
static void *
im_window_fits( im_window_t *window, request_t *req )
{
if( window->top <= req->top &&
window->top + window->height >= req->top + req->height )
return( window );
return( NULL );
}
/* Find an existing window that fits within top/height and return a ref.
*/
static im_window_t *
im_window_find( IMAGE *im, int top, int height )
{
request_t req;
im_window_t *window;
req.top = top;
req.height = height;
window = im_slist_map2( im->windows,
(VSListMap2Fn) im_window_fits, &req, NULL );
if( window ) {
window->ref_count += 1;
#ifdef DEBUG
printf( "im_window_find: ref window top = %d, height = %d, "
"count = %d\n",
top, height, window->ref_count );
#endif /*DEBUG*/
}
return( window );
}
/* Return a ref to a window that encloses top/height.
*/
im_window_t *
im_window_ref( IMAGE *im, int top, int height )
{
im_window_t *window;
#ifdef DEBUG_ENVIRONMENT
static const char *str = NULL;
#endif /*DEBUG_ENVIRONMENT*/
#ifdef DEBUG_ENVIRONMENT
if( !str ) {
if( (str = g_getenv( "IM_WINDOW_MARGIN" )) ) {
printf( "iofuncs/region.c: "
"compiled with DEBUG_ENVIRONMENT enabled\n" );
im__window_margin = atoi( str );
printf( "im_region_create: setting window margin to %d "
"from environment\n", im__window_margin );
}
else
str = "done";
}
#endif /*DEBUG_ENVIRONMENT*/
g_mutex_lock( im->sslock );
if( !(window = im_window_find( im, top, height )) ) {
/* No existing window ... make a new one.
*/
top -= im__window_margin;
height += im__window_margin * 2;
top = IM_CLIP( 0, top, im->Ysize - 1 );
height = IM_CLIP( 0, height, im->Ysize - top );
if( !(window = im_window_new( im, top, height )) ) {
g_mutex_unlock( im->sslock );
return( NULL );
}
}
g_mutex_unlock( im->sslock );
return( window );
}
void
im_window_print( im_window_t *window )
{
printf( "im_window_t: %p ref_count = %d, ", window, window->ref_count );
printf( "im = %p, ", window->im );
printf( "top = %d, ", window->top );
printf( "height = %d, ", window->height );
printf( "data = %p, ", window->data );
printf( "baseaddr = %p, ", window->baseaddr );
printf( "length = %zd\n", window->length );
}
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