applying zlib compression over glz on WAN connection

1 files changed, 104 insertions, 0 deletions

diff --git a/server/zlib_encoder.c b/server/zlib_encoder.c
new file mode 100644
index 00000000..e0d8d830
--- /dev/null
+++ b/server/zlib_encoder.c
@@ -0,0 +1,104 @@
+#include "red_common.h"
+#include "zlib_encoder.h"
+#include <zlib.h>
+
+struct ZlibEncoder {
+    ZlibEncoderUsrContext *usr;
+
+    z_stream strm;
+    int last_level;
+};
+
+ZlibEncoder* zlib_encoder_create(ZlibEncoderUsrContext *usr, int level)
+{
+    ZlibEncoder *enc;
+    int z_ret;
+
+    if (!usr->more_space || !usr->more_input) {
+        return NULL;
+    }
+
+    enc = spice_new0(ZlibEncoder, 1);
+
+    enc->usr = usr;
+
+    enc->strm.zalloc = Z_NULL;
+    enc->strm.zfree = Z_NULL;
+    enc->strm.opaque = Z_NULL;
+
+    z_ret = deflateInit(&enc->strm, level);
+    enc->last_level = level;
+    if (z_ret != Z_OK) {
+        red_printf("zlib error");
+        free(enc);
+        return NULL;
+    }
+
+    return enc;
+}
+
+void zlib_encoder_destroy(ZlibEncoder *encoder)
+{
+    deflateEnd(&encoder->strm);
+    free(encoder);
+}
+
+/* returns the total size of the encoded data */
+int zlib_encode(ZlibEncoder *zlib, int level, int input_size,
+                uint8_t *io_ptr, unsigned int num_io_bytes)
+{
+    int flush;
+    int enc_size = 0;
+    int out_size = 0;
+    int z_ret;
+
+    z_ret = deflateReset(&zlib->strm);
+
+    if (z_ret != Z_OK) {
+        red_error("deflateReset failed");
+    }
+
+    zlib->strm.next_out = io_ptr;
+    zlib->strm.avail_out = num_io_bytes;
+
+    if (level != zlib->last_level) {
+        if (zlib->strm.avail_out == 0) {
+            zlib->strm.avail_out = zlib->usr->more_space(zlib->usr, &zlib->strm.next_out);
+            if (zlib->strm.avail_out == 0) {
+                red_error("not enough space");
+            }
+        }
+        z_ret = deflateParams(&zlib->strm, level, Z_DEFAULT_STRATEGY);
+        if (z_ret != Z_OK) {
+            red_error("deflateParams failed");
+        }
+        zlib->last_level = level;
+    }
+
+
+    do {
+        zlib->strm.avail_in = zlib->usr->more_input(zlib->usr, &zlib->strm.next_in);
+        if (zlib->strm.avail_in <= 0) {
+            red_error("more input failed\n");
+        }
+        enc_size += zlib->strm.avail_in;
+        flush = (enc_size == input_size) ?  Z_FINISH : Z_NO_FLUSH;
+        while (1) {
+            int deflate_size = zlib->strm.avail_out;
+            z_ret = deflate(&zlib->strm, flush);
+            ASSERT(z_ret != Z_STREAM_ERROR);
+            out_size += deflate_size - zlib->strm.avail_out;
+            if (zlib->strm.avail_out) {
+                break;
+            }
+
+            zlib->strm.avail_out = zlib->usr->more_space(zlib->usr, &zlib->strm.next_out);
+            if (zlib->strm.avail_out == 0) {
+                red_error("not enough space");
+            }
+        }
+    } while (flush != Z_FINISH);
+
+    ASSERT(z_ret == Z_STREAM_END);
+    return out_size;
+}