/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Cache routines
   Copyright (C) Matthew Chapman <matthewc.unsw.edu.au> 1999-2008
   Copyright (C) Jeroen Meijer <jeroen@oldambt7.com> 2005
   Copyright 2003-2011 Peter Astrand <astrand@cendio.se> for Cendio AB

   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "rdesktop.h"
#include <stdlib.h>
#include <string.h>
#include <stdint.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)

#define BUMP_COUNT 40

typedef struct bmpcache_entry {
    RD_HBITMAP bitmap;
    int16_t previous;
    int16_t next;
} bmpcache_entry_t;

static bmpcache_entry_t 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_t id, int16_t *idx, int count) {
    int n = count, c = 0;
    int16_t 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]) {
        logger(Core, Error,
               "cache_rebuild_bmpcache_linked_list(), %d in bitmap cache linked list, %d in ui cache...",
               c, g_bmpcache_count[id]);
        exit(EXIT_FAILURE);
    }
}

/* Move a bitmap to a new position in the linked list. */
void cache_bump_bitmap(uint8_t id, uint16_t idx, int bump) {
    int p_idx, n_idx, n;

    if (!IS_PERSISTENT(id))
        return;

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

    logger(Core, Debug, "cache_bump_bitmap(), id=%d, idx=%d, bump=%d", 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_t id) {
    uint16_t idx;
    int n_idx;

    if (!IS_PERSISTENT(id))
        return;

    idx = g_bmpcache_lru[id];
    n_idx = g_bmpcache[id][idx].next;

    logger(Core, Debug, "cache_evict_bitmap(), id=%d idx=%d n_idx=%d bmp=%p", 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_t id, uint16_t 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];
    }

    logger(Core, Debug, "cache_get_bitmap(), id=%d, idx=%d", id, idx);

    return NULL;
}

/* Store a bitmap in the cache */
void cache_put_bitmap(uint8_t id, uint16_t 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 {
        logger(Core, Error, "cache_put_bitmap(), failed, id=%d, idx=%d\n", id, idx);
    }
}

/* Updates the persistent bitmap cache MRU information on exit */
void cache_save_state(void) {
    uint32_t id = 0, t = 0;
    int idx;

    for (id = 0; id < NUM_ELEMENTS(g_bmpcache); id++)
        if (IS_PERSISTENT(id)) {
            logger(Core, Debug,
                   "cache_save_state(), saving cache state for bitmap cache %d", id);
            idx = g_bmpcache_lru[id];
            while (idx >= 0) {
                pstcache_touch_bitmap(id, idx, ++t);
                idx = g_bmpcache[id][idx].next;
            }
            logger(Core, Debug, "cache_save_state(), %d stamps written", t);
        }
}

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

/* Retrieve a glyph from the font cache */
FONTGLYPH *cache_get_font(uint8_t font, uint16_t character) {
    if ((font < NUM_ELEMENTS(g_fontcache)) && (character < NUM_ELEMENTS(g_fontcache[0]))) {
        FONTGLYPH *glyph = &g_fontcache[font][character];
        if (glyph->pixmap != NULL)
            return glyph;
    }

    logger(Core, Debug, "cache_get_font(), font=%d, char=%d", font, character);
    return NULL;
}

/* Store a glyph in the font cache */
void cache_put_font(uint8_t font, uint16_t character, uint16_t offset,
                    uint16_t baseline, uint16_t width, uint16_t height, RD_HGLYPH pixmap) {
    if ((font < NUM_ELEMENTS(g_fontcache)) && (character < NUM_ELEMENTS(g_fontcache[0]))) {
        FONTGLYPH *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 {
        logger(Core, Error, "cache_put_font(), failed, font=%d, char=%d", font, character);
    }
}

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

/* Retrieve a text item from the cache */
DATABLOB *cache_get_text(uint8_t cache_id) {
    return &g_textcache[cache_id];
}

/* Store a text item in the cache */
void cache_put_text(uint8_t cache_id, void *data, int length) {
    if (cache_id < NUM_ELEMENTS(g_textcache)) {
        DATABLOB *text = &g_textcache[cache_id];
        if (text->data != NULL)
            xfree(text->data);
        text->data = xmalloc(length);
        text->size = length;
        memcpy(text->data, data, length);
    } else {
        logger(Core, Error, "cache_put_text(), failed, cache_id=%d", cache_id);
    }
}

/* DESKTOP CACHE */
static uint8_t g_deskcache[0x38400 * 4];

/* Retrieve desktop data from the cache */
uint8_t *cache_get_desktop(uint32_t 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];
    }

    logger(Core, Debug, "cache_get_desktop(), offset=%d, length=%d", offset, length);
    return NULL;
}

/* Store desktop data in the cache */
void cache_put_desktop(uint32_t offset, int cx, int cy, int scanline, int bytes_per_pixel, uint8_t *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 {
        logger(Core, Error, "cache_put_desktop(), offset=%d, length=%d", offset, length);
    }
}

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

/* Retrieve cursor from cache */
RD_HCURSOR cache_get_cursor(uint16_t cache_idx) {
    if (cache_idx < NUM_ELEMENTS(g_cursorcache)) {
        RD_HCURSOR cursor = g_cursorcache[cache_idx];
        if (cursor != NULL)
            return cursor;
    }

    logger(Core, Debug, "cache_get_cursor(), idx=%d", cache_idx);
    return NULL;
}

/* Store cursor in cache */
void cache_put_cursor(uint16_t cache_idx, RD_HCURSOR cursor) {
    if (cache_idx < NUM_ELEMENTS(g_cursorcache)) {
        RD_HCURSOR old = g_cursorcache[cache_idx];
        if (old != NULL)
            ui_destroy_cursor(old);

        g_cursorcache[cache_idx] = cursor;
    } else {
        logger(Core, Error, "cache_put_cursor(), failed, idx=%d", cache_idx);
    }
}

/* BRUSH CACHE */
/* index 0 is 2 colour brush, index 1 is multi colour brush */
static BRUSHDATA g_brushcache[2][64];

/* Retrieve brush from cache */
BRUSHDATA *cache_get_brush_data(uint8_t colour_code, uint8_t idx) {
    colour_code = colour_code == 1 ? 0 : 1;
    if (idx < NUM_ELEMENTS(g_brushcache[0])) {
        return &g_brushcache[colour_code][idx];
    }
    logger(Core, Debug, "cache_get_brush_data(), colour=%d, idx=%d", colour_code, idx);
    return NULL;
}

/* Store brush in cache */
/* this function takes over the data pointer in struct, e.g. caller gives it up */
void cache_put_brush_data(uint8_t colour_code, uint8_t idx, BRUSHDATA *brush_data) {
    colour_code = colour_code == 1 ? 0 : 1;
    if (idx < NUM_ELEMENTS(g_brushcache[0])) {
        BRUSHDATA *bd = &g_brushcache[colour_code][idx];
        if (bd->data != 0) {
            xfree(bd->data);
        }
        memcpy(bd, brush_data, sizeof(BRUSHDATA));
    } else {
        logger(Core, Error, "cache_put_brush_data(), colour=%d, idx=%d", colour_code, idx);
    }
}