Archipelago » qemu

/*

 * QEMU VNC display driver: zlib encoding

 *

 * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>

 * Copyright (C) 2006 Fabrice Bellard

 * Copyright (C) 2009 Red Hat, Inc

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "vnc.h"

#define ZALLOC_ALIGNMENT 16

static void *zalloc(void *x, unsigned items, unsigned size)

{

    void *p;

    size *= items;

    size = (size + ZALLOC_ALIGNMENT - 1) & ~(ZALLOC_ALIGNMENT - 1);

    p = qemu_mallocz(size);

    return (p);

}

static void zfree(void *x, void *addr)

{

    qemu_free(addr);

}

static void vnc_zlib_start(VncState *vs)

{

    buffer_reset(&vs->zlib);

    // make the output buffer be the zlib buffer, so we can compress it later

    vs->zlib_tmp = vs->output;

    vs->output = vs->zlib;

}

static int vnc_zlib_stop(VncState *vs, int stream_id)

{

    z_streamp zstream = &vs->zlib_stream[stream_id];

    int previous_out;

    // switch back to normal output/zlib buffers

    vs->zlib = vs->output;

    vs->output = vs->zlib_tmp;

    // compress the zlib buffer

    // initialize the stream

    // XXX need one stream per session

    if (zstream->opaque != vs) {

        int err;

        VNC_DEBUG("VNC: initializing zlib stream %d\n", stream_id);

        VNC_DEBUG("VNC: opaque = %p | vs = %p\n", zstream->opaque, vs);

        zstream->zalloc = zalloc;

        zstream->zfree = zfree;

        err = deflateInit2(zstream, vs->tight_compression, Z_DEFLATED, MAX_WBITS,

                           MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY);

        if (err != Z_OK) {

            fprintf(stderr, "VNC: error initializing zlib\n");

            return -1;

        }

        zstream->opaque = vs;

    }

    // XXX what to do if tight_compression changed in between?

    // reserve memory in output buffer

    buffer_reserve(&vs->output, vs->zlib.offset + 64);

    // set pointers

    zstream->next_in = vs->zlib.buffer;

    zstream->avail_in = vs->zlib.offset;

    zstream->next_out = vs->output.buffer + vs->output.offset;

    zstream->avail_out = vs->output.capacity - vs->output.offset;

    zstream->data_type = Z_BINARY;

    previous_out = zstream->total_out;

    // start encoding

    if (deflate(zstream, Z_SYNC_FLUSH) != Z_OK) {

        fprintf(stderr, "VNC: error during zlib compression\n");

        return -1;

    }

    vs->output.offset = vs->output.capacity - zstream->avail_out;

    return zstream->total_out - previous_out;

}

void vnc_zlib_send_framebuffer_update(VncState *vs, int x, int y, int w, int h)

{

    int old_offset, new_offset, bytes_written;

    vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_ZLIB);

    // remember where we put in the follow-up size

    old_offset = vs->output.offset;

    vnc_write_s32(vs, 0);

    // compress the stream

    vnc_zlib_start(vs);

    vnc_raw_send_framebuffer_update(vs, x, y, w, h);

    bytes_written = vnc_zlib_stop(vs, 0);

    if (bytes_written == -1)

        return;

    // hack in the size

    new_offset = vs->output.offset;

    vs->output.offset = old_offset;

    vnc_write_u32(vs, bytes_written);

    vs->output.offset = new_offset;

}

void vnc_zlib_init(VncState *vs)

{

    int i;

    for (i=0; i<(sizeof(vs->zlib_stream) / sizeof(z_stream)); i++)

        vs->zlib_stream[i].opaque = NULL;

}