vnc: add basic tight support

Add support for tight encoding [1]. This patch only add support
for "basic" tight compression without any filter.

[1] http://tigervnc.org/cgi-bin/rfbproto#tight-encoding.

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 295 insertions, 0 deletions

diff --git a/vnc-encoding-tight.c b/vnc-encoding-tight.c
new file mode 100644
index 0000000..ce9cc49
--- /dev/null
+++ b/vnc-encoding-tight.c
@@ -0,0 +1,295 @@
+/*
+ * QEMU VNC display driver: tight encoding
+ *
+ * From libvncserver/libvncserver/tight.c
+ * Copyright (C) 2000, 2001 Const Kaplinsky.  All Rights Reserved.
+ * Copyright (C) 1999 AT&T Laboratories Cambridge.  All Rights Reserved.
+ *
+ * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
+ *
+ * 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 <stdbool.h>
+
+#include "vnc.h"
+#include "vnc-encoding-tight.h"
+
+/* Compression level stuff. The following array contains various
+   encoder parameters for each of 10 compression levels (0..9).
+   Last three parameters correspond to JPEG quality levels (0..9). */
+
+static const struct {
+    int max_rect_size, max_rect_width;
+    int mono_min_rect_size, gradient_min_rect_size;
+    int idx_zlib_level, mono_zlib_level, raw_zlib_level, gradient_zlib_level;
+    int gradient_threshold, gradient_threshold24;
+    int idx_max_colors_divisor;
+    int jpeg_quality, jpeg_threshold, jpeg_threshold24;
+} tight_conf[] = {
+    {   512,   32,   6, 65536, 0, 0, 0, 0,   0,   0,   4,  5, 10000, 23000 },
+    {  2048,  128,   6, 65536, 1, 1, 1, 0,   0,   0,   8, 10,  8000, 18000 },
+    {  6144,  256,   8, 65536, 3, 3, 2, 0,   0,   0,  24, 15,  6500, 15000 },
+    { 10240, 1024,  12, 65536, 5, 5, 3, 0,   0,   0,  32, 25,  5000, 12000 },
+    { 16384, 2048,  12, 65536, 6, 6, 4, 0,   0,   0,  32, 37,  4000, 10000 },
+    { 32768, 2048,  12,  4096, 7, 7, 5, 4, 150, 380,  32, 50,  3000,  8000 },
+    { 65536, 2048,  16,  4096, 7, 7, 6, 4, 170, 420,  48, 60,  2000,  5000 },
+    { 65536, 2048,  16,  4096, 8, 8, 7, 5, 180, 450,  64, 70,  1000,  2500 },
+    { 65536, 2048,  32,  8192, 9, 9, 8, 6, 190, 475,  64, 75,   500,  1200 },
+    { 65536, 2048,  32,  8192, 9, 9, 9, 6, 200, 500,  96, 80,   200,   500 }
+};
+
+static int tight_init_stream(VncState *vs, int stream_id,
+                             int level, int strategy)
+{
+    z_streamp zstream = &vs->tight_stream[stream_id];
+
+    if (zstream->opaque == NULL) {
+        int err;
+
+        VNC_DEBUG("VNC: TIGHT: initializing zlib stream %d\n", stream_id);
+        VNC_DEBUG("VNC: TIGHT: opaque = %p | vs = %p\n", zstream->opaque, vs);
+        zstream->zalloc = vnc_zlib_zalloc;
+        zstream->zfree = vnc_zlib_zfree;
+
+        err = deflateInit2(zstream, level, Z_DEFLATED, MAX_WBITS,
+                           MAX_MEM_LEVEL, strategy);
+
+        if (err != Z_OK) {
+            fprintf(stderr, "VNC: error initializing zlib\n");
+            return -1;
+        }
+
+        vs->tight_levels[stream_id] = level;
+        zstream->opaque = vs;
+    }
+
+    if (vs->tight_levels[stream_id] != level) {
+        if (deflateParams(zstream, level, strategy) != Z_OK) {
+            return -1;
+        }
+        vs->tight_levels[stream_id] = level;
+    }
+    return 0;
+}
+
+static void tight_send_compact_size(VncState *vs, size_t len)
+{
+    int lpc = 0;
+    int bytes = 0;
+    char buf[3] = {0, 0, 0};
+
+    buf[bytes++] = len & 0x7F;
+    if (len > 0x7F) {
+        buf[bytes-1] |= 0x80;
+        buf[bytes++] = (len >> 7) & 0x7F;
+        if (len > 0x3FFF) {
+            buf[bytes-1] |= 0x80;
+            buf[bytes++] = (len >> 14) & 0xFF;
+        }
+    }
+    for(lpc = 0; lpc < bytes; lpc++) {
+        vnc_write_u8(vs, buf[lpc]);
+    }
+}
+
+static int tight_compress_data(VncState *vs, int stream_id, size_t bytes,
+                               int level, int strategy)
+{
+    z_streamp zstream = &vs->tight_stream[stream_id];
+    int previous_out;
+
+    if (bytes < VNC_TIGHT_MIN_TO_COMPRESS) {
+        vnc_write(vs, vs->tight.buffer, vs->tight.offset);
+        return bytes;
+    }
+
+    if (tight_init_stream(vs, stream_id, level, strategy)) {
+        return -1;
+    }
+
+    /* reserve memory in output buffer */
+    buffer_reserve(&vs->tight_zlib, bytes + 64);
+
+    /* set pointers */
+    zstream->next_in = vs->tight.buffer;
+    zstream->avail_in = vs->tight.offset;
+    zstream->next_out = vs->tight_zlib.buffer + vs->tight_zlib.offset;
+    zstream->avail_out = vs->tight_zlib.capacity - vs->tight_zlib.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 tight compression\n");
+        return -1;
+    }
+
+    vs->tight_zlib.offset = vs->tight_zlib.capacity - zstream->avail_out;
+    bytes = zstream->total_out - previous_out;
+
+    tight_send_compact_size(vs, bytes);
+    vnc_write(vs, vs->tight_zlib.buffer, bytes);
+
+    buffer_reset(&vs->tight_zlib);
+
+    return bytes;
+}
+
+/*
+ * Subencoding implementations.
+ */
+static void tight_pack24(VncState *vs, size_t count)
+{
+    unsigned char *buf;
+    uint32_t *buf32;
+    uint32_t pix;
+    int rshift, gshift, bshift;
+
+    buf = vs->tight.buffer;
+    buf32 = (uint32_t *)buf;
+
+    if ((vs->clientds.flags & QEMU_BIG_ENDIAN_FLAG) ==
+        (vs->ds->surface->flags & QEMU_BIG_ENDIAN_FLAG)) {
+        rshift = vs->clientds.pf.rshift;
+        gshift = vs->clientds.pf.gshift;
+        bshift = vs->clientds.pf.bshift;
+    } else {
+        rshift = 24 - vs->clientds.pf.rshift;
+        gshift = 24 - vs->clientds.pf.gshift;
+        bshift = 24 - vs->clientds.pf.bshift;
+    }
+
+    vs->tight.offset = count * 3;
+
+    while (count--) {
+        pix = *buf32++;
+        *buf++ = (char)(pix >> rshift);
+        *buf++ = (char)(pix >> gshift);
+        *buf++ = (char)(pix >> bshift);
+    }
+}
+
+static int send_full_color_rect(VncState *vs, int w, int h)
+{
+    int stream = 0;
+    size_t bytes;
+
+    vnc_write_u8(vs, stream << 4); /* no flushing, no filter */
+
+    if (vs->tight_pixel24) {
+        tight_pack24(vs, w * h);
+        bytes = 3;
+    } else {
+        bytes = vs->clientds.pf.bytes_per_pixel;
+    }
+
+    bytes = tight_compress_data(vs, stream, w * h * bytes,
+                                tight_conf[vs->tight_compression].raw_zlib_level,
+                                Z_DEFAULT_STRATEGY);
+
+    return (bytes >= 0);
+}
+
+static void vnc_tight_start(VncState *vs)
+{
+    buffer_reset(&vs->tight);
+
+    // make the output buffer be the zlib buffer, so we can compress it later
+    vs->tight_tmp = vs->output;
+    vs->output = vs->tight;
+}
+
+static void vnc_tight_stop(VncState *vs)
+{
+    // switch back to normal output/zlib buffers
+    vs->tight = vs->output;
+    vs->output = vs->tight_tmp;
+}
+
+static int send_sub_rect(VncState *vs, int x, int y, int w, int h)
+{
+    vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_TIGHT);
+
+    /*
+     * Convert pixels and store them in vs->tight
+     * We will probably rework that later, probably
+     * when adding other sub-encodings
+     */
+    vnc_tight_start(vs);
+    vnc_raw_send_framebuffer_update(vs, x, y, w, h);
+    vnc_tight_stop(vs);
+
+    return send_full_color_rect(vs, w, h);
+}
+
+static int send_rect_simple(VncState *vs, int x, int y, int w, int h)
+{
+    int max_size, max_width;
+    int max_sub_width, max_sub_height;
+    int dx, dy;
+    int rw, rh;
+    int n = 0;
+
+    max_size = tight_conf[vs->tight_compression].max_rect_size;
+    max_width = tight_conf[vs->tight_compression].max_rect_width;
+
+    if (w > max_width || w * h > max_size) {
+        max_sub_width = (w > max_width) ? max_width : w;
+        max_sub_height = max_size / max_sub_width;
+
+        for (dy = 0; dy < h; dy += max_sub_height) {
+            for (dx = 0; dx < w; dx += max_width) {
+                rw = MIN(max_sub_width, w - dx);
+                rh = MIN(max_sub_height, h - dy);
+                n += send_sub_rect(vs, x+dx, y+dy, rw, rh);
+            }
+        }
+    } else {
+        n += send_sub_rect(vs, x, y, w, h);
+    }
+
+    return n;
+}
+
+int vnc_tight_send_framebuffer_update(VncState *vs, int x, int y,
+                                      int w, int h)
+{
+    if (vs->clientds.pf.bytes_per_pixel == 4 && vs->clientds.pf.rmax == 0xFF &&
+        vs->clientds.pf.bmax == 0xFF && vs->clientds.pf.gmax == 0xFF) {
+        vs->tight_pixel24 = true;
+    } else {
+        vs->tight_pixel24 = false;
+    }
+
+    return send_rect_simple(vs, x, y, w, h);
+}
+
+void vnc_tight_clear(VncState *vs)
+{
+    int i;
+    for (i=0; i<ARRAY_SIZE(vs->tight_stream); i++) {
+        if (vs->tight_stream[i].opaque) {
+            deflateEnd(&vs->tight_stream[i]);
+        }
+    }
+
+    buffer_free(&vs->tight);
+    buffer_free(&vs->tight_zlib);
+}