cache.c

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/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Cache routines
   Copyright (C) Matthew Chapman 1999-2005
   Copyright (C) Jeroen Meijer 2005

   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, write to the Free Software Foundation, Inc.,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include <precomp.h>

/* BITMAP CACHE */
extern int g_pstcache_fd[];

#define NUM_ELEMENTS(array) (sizeof(array) / sizeof(array[0]))
//#define IS_PERSISTENT(id) (g_pstcache_fd[id] > 0)
#define TO_TOP -1
#define NOT_SET -1
#define IS_SET(idx) (idx >= 0)

/*
 * TODO: Test for optimal value of BUMP_COUNT. TO_TOP gives lowest cpu utilisation but using
 * a positive value will hopefully result in less frequently used bitmaps having a greater chance
 * of being evicted from the cache, and therby reducing the need to load bitmaps from disk.
 * (Jeroen)
 */
#define BUMP_COUNT 40

struct bmpcache_entry
{
    RD_HBITMAP bitmap;
    sint16 previous;
    sint16 next;
};

static struct bmpcache_entry g_bmpcache[3][0xa00];
static RD_HBITMAP g_volatile_bc[3];

static int g_bmpcache_lru[3] = { NOT_SET, NOT_SET, NOT_SET };
static int g_bmpcache_mru[3] = { NOT_SET, NOT_SET, NOT_SET };
static int g_bmpcache_count[3];

/* Setup the bitmap cache lru/mru linked list */
void
cache_rebuild_bmpcache_linked_list(uint8 id, sint16 * idx, int count)
{
    int n = count, c = 0;
    sint16 n_idx;

    /* find top, skip evicted bitmaps */
    while (--n >= 0 && g_bmpcache[id][idx[n]].bitmap == NULL);
    if (n < 0)
    {
        g_bmpcache_mru[id] = g_bmpcache_lru[id] = NOT_SET;
        return;
    }

    g_bmpcache_mru[id] = idx[n];
    g_bmpcache[id][idx[n]].next = NOT_SET;
    n_idx = idx[n];
    c++;

    /* link list */
    while (n >= 0)
    {
        /* skip evicted bitmaps */
        while (--n >= 0 && g_bmpcache[id][idx[n]].bitmap == NULL);

        if (n < 0)
            break;

        g_bmpcache[id][n_idx].previous = idx[n];
        g_bmpcache[id][idx[n]].next = n_idx;
        n_idx = idx[n];
        c++;
    }

    g_bmpcache[id][n_idx].previous = NOT_SET;
    g_bmpcache_lru[id] = n_idx;

    if (c != g_bmpcache_count[id])
    {
        error("Oops. %d in bitmap cache linked list, %d in ui cache...\n", c,
              g_bmpcache_count[id]);
        exit(1);
    }
}

/* Move a bitmap to a new position in the linked list. */
void
cache_bump_bitmap(uint8 id, uint16 idx, int bump)
{
    int p_idx, n_idx, n;

    if (!IS_PERSISTENT(id))
        return;

    if (g_bmpcache_mru[id] == idx)
        return;

    DEBUG_RDP5(("bump bitmap: id=%d, idx=%d, bump=%d\n", id, idx, bump));

    n_idx = g_bmpcache[id][idx].next;
    p_idx = g_bmpcache[id][idx].previous;

    if (IS_SET(n_idx))
    {
        /* remove */
        --g_bmpcache_count[id];
        if (IS_SET(p_idx))
            g_bmpcache[id][p_idx].next = n_idx;
        else
            g_bmpcache_lru[id] = n_idx;
        if (IS_SET(n_idx))
            g_bmpcache[id][n_idx].previous = p_idx;
        else
            g_bmpcache_mru[id] = p_idx;
    }
    else
    {
        p_idx = NOT_SET;
        n_idx = g_bmpcache_lru[id];
    }

    if (bump >= 0)
    {
        for (n = 0; n < bump && IS_SET(n_idx); n++)
        {
            p_idx = n_idx;
            n_idx = g_bmpcache[id][p_idx].next;
        }
    }
    else
    {
        p_idx = g_bmpcache_mru[id];
        n_idx = NOT_SET;
    }

    /* insert */
    ++g_bmpcache_count[id];
    g_bmpcache[id][idx].previous = p_idx;
    g_bmpcache[id][idx].next = n_idx;

    if (p_idx >= 0)
        g_bmpcache[id][p_idx].next = idx;
    else
        g_bmpcache_lru[id] = idx;

    if (n_idx >= 0)
        g_bmpcache[id][n_idx].previous = idx;
    else
        g_bmpcache_mru[id] = idx;
}

/* Evict the least-recently used bitmap from the cache */
void
cache_evict_bitmap(uint8 id)
{
    uint16 idx;
    int n_idx;

    if (!IS_PERSISTENT(id))
        return;

    idx = g_bmpcache_lru[id];
    n_idx = g_bmpcache[id][idx].next;
    DEBUG_RDP5(("evict bitmap: id=%d idx=%d n_idx=%d bmp=0x%x\n", id, idx, n_idx,
            g_bmpcache[id][idx].bitmap));

    ui_destroy_bitmap(g_bmpcache[id][idx].bitmap);
    --g_bmpcache_count[id];
    g_bmpcache[id][idx].bitmap = 0;

    g_bmpcache_lru[id] = n_idx;
    g_bmpcache[id][n_idx].previous = NOT_SET;

    pstcache_touch_bitmap(id, idx, 0);
}

/* Retrieve a bitmap from the cache */
RD_HBITMAP
cache_get_bitmap(uint8 id, uint16 idx)
{
    if ((id < NUM_ELEMENTS(g_bmpcache)) && (idx < NUM_ELEMENTS(g_bmpcache[0])))
    {
        if (g_bmpcache[id][idx].bitmap || pstcache_load_bitmap(id, idx))
        {
            if (IS_PERSISTENT(id))
                cache_bump_bitmap(id, idx, BUMP_COUNT);

            return g_bmpcache[id][idx].bitmap;
        }
    }
    else if ((id < NUM_ELEMENTS(g_volatile_bc)) && (idx == 0x7fff))
    {
        return g_volatile_bc[id];
    }

    error("get bitmap %d:%d\n", id, idx);
    return NULL;
}

/* Store a bitmap in the cache */
void
cache_put_bitmap(uint8 id, uint16 idx, RD_HBITMAP bitmap)
{
    RD_HBITMAP old;

    if ((id < NUM_ELEMENTS(g_bmpcache)) && (idx < NUM_ELEMENTS(g_bmpcache[0])))
    {
        old = g_bmpcache[id][idx].bitmap;
        if (old != NULL)
            ui_destroy_bitmap(old);
        g_bmpcache[id][idx].bitmap = bitmap;

        if (IS_PERSISTENT(id))
        {
            if (old == NULL)
                g_bmpcache[id][idx].previous = g_bmpcache[id][idx].next = NOT_SET;

            cache_bump_bitmap(id, idx, TO_TOP);
            if (g_bmpcache_count[id] > BMPCACHE2_C2_CELLS)
                cache_evict_bitmap(id);
        }
    }
    else if ((id < NUM_ELEMENTS(g_volatile_bc)) && (idx == 0x7fff))
    {
        old = g_volatile_bc[id];
        if (old != NULL)
            ui_destroy_bitmap(old);
        g_volatile_bc[id] = bitmap;
    }
    else
    {
        error("put bitmap %d:%d\n", id, idx);
    }
}

/* Updates the persistent bitmap cache MRU information on exit */
void
cache_save_state(void)
{
    uint32 id = 0, t = 0;
    int idx;

    for (id = 0; id < NUM_ELEMENTS(g_bmpcache); id++)
        if (IS_PERSISTENT(id))
        {
            DEBUG_RDP5(("Saving cache state for bitmap cache %d...", id));
            idx = g_bmpcache_lru[id];
            while (idx >= 0)
            {
                pstcache_touch_bitmap((uint8) id, (uint16) idx, ++t);
                idx = g_bmpcache[id][idx].next;
            }
            DEBUG_RDP5((" %d stamps written.\n", t));
        }
}


/* FONT CACHE */
static FONTGLYPH g_fontcache[12][256];

/* Retrieve a glyph from the font cache */
FONTGLYPH *
cache_get_font(uint8 font, uint16 character)
{
    FONTGLYPH *glyph;

    if ((font < NUM_ELEMENTS(g_fontcache)) && (character < NUM_ELEMENTS(g_fontcache[0])))
    {
        glyph = &g_fontcache[font][character];
        if (glyph->pixmap != NULL)
            return glyph;
    }

    error("get font %d:%d\n", font, character);
    return NULL;
}

/* Store a glyph in the font cache */
void
cache_put_font(uint8 font, uint16 character, uint16 offset,
           uint16 baseline, uint16 width, uint16 height, RD_HGLYPH pixmap)
{
    FONTGLYPH *glyph;

    if ((font < NUM_ELEMENTS(g_fontcache)) && (character < NUM_ELEMENTS(g_fontcache[0])))
    {
        glyph = &g_fontcache[font][character];
        if (glyph->pixmap != NULL)
            ui_destroy_glyph(glyph->pixmap);

        glyph->offset = offset;
        glyph->baseline = baseline;
        glyph->width = width;
        glyph->height = height;
        glyph->pixmap = pixmap;
    }
    else
    {
        error("put font %d:%d\n", font, character);
    }
}


/* TEXT CACHE */
static DATABLOB g_textcache[256];

/* Retrieve a text item from the cache */
DATABLOB *
cache_get_text(uint8 cache_id)
{
    DATABLOB *text;

    text = &g_textcache[cache_id];
    return text;
}

/* Store a text item in the cache */
void
cache_put_text(uint8 cache_id, void *data, int length)
{
    DATABLOB *text;

    text = &g_textcache[cache_id];
    if (text->data != NULL)
        xfree(text->data);
    text->data = xmalloc(length);
    text->size = length;
    memcpy(text->data, data, length);
}


/* DESKTOP CACHE */
static uint8 g_deskcache[0x38400 * 4];

/* Retrieve desktop data from the cache */
uint8 *
cache_get_desktop(uint32 offset, int cx, int cy, int bytes_per_pixel)
{
    int length = cx * cy * bytes_per_pixel;

    if (offset > sizeof(g_deskcache))
        offset = 0;

    if ((offset + length) <= sizeof(g_deskcache))
    {
        return &g_deskcache[offset];
    }

    error("get desktop %d:%d\n", offset, length);
    return NULL;
}

/* Store desktop data in the cache */
void
cache_put_desktop(uint32 offset, int cx, int cy, int scanline, int bytes_per_pixel, uint8 * data)
{
    int length = cx * cy * bytes_per_pixel;

    if (offset > sizeof(g_deskcache))
        offset = 0;

    if ((offset + length) <= sizeof(g_deskcache))
    {
        cx *= bytes_per_pixel;
        while (cy--)
        {
            memcpy(&g_deskcache[offset], data, cx);
            data += scanline;
            offset += cx;
        }
    }
    else
    {
        error("put desktop %d:%d\n", offset, length);
    }
}


/* CURSOR CACHE */
static RD_HCURSOR g_cursorcache[0x20];

/* Retrieve cursor from cache */
RD_HCURSOR
cache_get_cursor(uint16 cache_idx)
{
    RD_HCURSOR cursor;

    if (cache_idx < NUM_ELEMENTS(g_cursorcache))
    {
        cursor = g_cursorcache[cache_idx];
        if (cursor != NULL)
            return cursor;
    }

    error("get cursor %d\n", cache_idx);
    return NULL;
}

/* Store cursor in cache */
void
cache_put_cursor(uint16 cache_idx, RD_HCURSOR cursor)
{
    RD_HCURSOR old;

    if (cache_idx < NUM_ELEMENTS(g_cursorcache))
    {
        old = g_cursorcache[cache_idx];
        if (old != NULL)
            ui_destroy_cursor(old);

        g_cursorcache[cache_idx] = cursor;
    }
    else
    {
        error("put cursor %d\n", cache_idx);
    }
}