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root / ui / vnc-enc-zlib.c @ d6e58090

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/*
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 * QEMU VNC display driver: zlib encoding
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 *
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 * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
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 * Copyright (C) 2006 Fabrice Bellard
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 * Copyright (C) 2009 Red Hat, Inc
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 *
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 * Permission is hereby granted, free of charge, to any person obtaining a copy
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 * of this software and associated documentation files (the "Software"), to deal
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 * in the Software without restriction, including without limitation the rights
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 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * copies of the Software, and to permit persons to whom the Software is
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 * furnished to do so, subject to the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be included in
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 * all copies or substantial portions of the Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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 * THE SOFTWARE.
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 */
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#include "vnc.h"
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#define ZALLOC_ALIGNMENT 16
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void *vnc_zlib_zalloc(void *x, unsigned items, unsigned size)
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{
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    void *p;
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    size *= items;
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    size = (size + ZALLOC_ALIGNMENT - 1) & ~(ZALLOC_ALIGNMENT - 1);
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    p = qemu_mallocz(size);
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    return (p);
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}
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void vnc_zlib_zfree(void *x, void *addr)
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{
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    qemu_free(addr);
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}
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static void vnc_zlib_start(VncState *vs)
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{
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    buffer_reset(&vs->zlib.zlib);
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    // make the output buffer be the zlib buffer, so we can compress it later
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    vs->zlib.tmp = vs->output;
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    vs->output = vs->zlib.zlib;
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}
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static int vnc_zlib_stop(VncState *vs)
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{
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    z_streamp zstream = &vs->zlib.stream;
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    int previous_out;
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    // switch back to normal output/zlib buffers
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    vs->zlib.zlib = vs->output;
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    vs->output = vs->zlib.tmp;
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    // compress the zlib buffer
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    // initialize the stream
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    // XXX need one stream per session
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    if (zstream->opaque != vs) {
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        int err;
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        VNC_DEBUG("VNC: initializing zlib stream\n");
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        VNC_DEBUG("VNC: opaque = %p | vs = %p\n", zstream->opaque, vs);
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        zstream->zalloc = vnc_zlib_zalloc;
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        zstream->zfree = vnc_zlib_zfree;
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        err = deflateInit2(zstream, vs->tight.compression, Z_DEFLATED, MAX_WBITS,
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                           MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY);
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        if (err != Z_OK) {
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            fprintf(stderr, "VNC: error initializing zlib\n");
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            return -1;
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        }
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        vs->zlib.level = vs->tight.compression;
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        zstream->opaque = vs;
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    }
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    if (vs->tight.compression != vs->zlib.level) {
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        if (deflateParams(zstream, vs->tight.compression,
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                          Z_DEFAULT_STRATEGY) != Z_OK) {
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            return -1;
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        }
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        vs->zlib.level = vs->tight.compression;
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    }
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    // reserve memory in output buffer
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    buffer_reserve(&vs->output, vs->zlib.zlib.offset + 64);
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    // set pointers
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    zstream->next_in = vs->zlib.zlib.buffer;
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    zstream->avail_in = vs->zlib.zlib.offset;
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    zstream->next_out = vs->output.buffer + vs->output.offset;
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    zstream->avail_out = vs->output.capacity - vs->output.offset;
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    zstream->data_type = Z_BINARY;
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    previous_out = zstream->total_out;
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    // start encoding
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    if (deflate(zstream, Z_SYNC_FLUSH) != Z_OK) {
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        fprintf(stderr, "VNC: error during zlib compression\n");
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        return -1;
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    }
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    vs->output.offset = vs->output.capacity - zstream->avail_out;
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    return zstream->total_out - previous_out;
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}
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int vnc_zlib_send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
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{
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    int old_offset, new_offset, bytes_written;
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    vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_ZLIB);
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    // remember where we put in the follow-up size
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    old_offset = vs->output.offset;
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    vnc_write_s32(vs, 0);
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    // compress the stream
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    vnc_zlib_start(vs);
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    vnc_raw_send_framebuffer_update(vs, x, y, w, h);
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    bytes_written = vnc_zlib_stop(vs);
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    if (bytes_written == -1)
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        return 0;
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    // hack in the size
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    new_offset = vs->output.offset;
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    vs->output.offset = old_offset;
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    vnc_write_u32(vs, bytes_written);
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    vs->output.offset = new_offset;
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    return 1;
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}
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void vnc_zlib_clear(VncState *vs)
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{
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    if (vs->zlib.stream.opaque) {
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        deflateEnd(&vs->zlib.stream);
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    }
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    buffer_free(&vs->zlib.zlib);
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}