new file mode 100644
--- /dev/null
+++ b/src/http/v3/ngx_http_v3.c
@@ -0,0 +1,176 @@
+
+/*
+ * Copyright (C) Roman Arutyunyan
+ * Copyright (C) Nginx, Inc.
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_http.h>
+
+
+uintptr_t
+ngx_http_v3_encode_varlen_int(u_char *p, uint64_t value)
+{
+    if (value <= 63) {
+        if (p == NULL) {
+            return 1;
+        }
+
+        *p++ = value;
+        return (uintptr_t) p;
+    }
+
+    if (value <= 16383) {
+        if (p == NULL) {
+            return 2;
+        }
+
+        *p++ = 0x40 | (value >> 8);
+        *p++ = value;
+        return (uintptr_t) p;
+    }
+
+    if (value <= 1073741823) {
+        if (p == NULL) {
+            return 3;
+        }
+
+        *p++ = 0x80 | (value >> 16);
+        *p++ = (value >> 8);
+        *p++ = value;
+        return (uintptr_t) p;
+
+    }
+
+    if (p == NULL) {
+        return 4;
+    }
+
+    *p++ = 0xc0 | (value >> 24);
+    *p++ = (value >> 16);
+    *p++ = (value >> 8);
+    *p++ = value;
+    return (uintptr_t) p;
+}
+
+
+uintptr_t
+ngx_http_v3_encode_prefix_int(u_char *p, uint64_t value, ngx_uint_t prefix)
+{
+    ngx_uint_t  thresh, n;
+
+    thresh = (1 << prefix) - 1;
+
+    if (value < thresh) {
+        if (p == NULL) {
+            return 1;
+        }
+
+        *p++ |= value;
+        return (uintptr_t) p;
+    }
+
+    value -= thresh;
+
+    for (n = 10; n > 1; n--) {
+        if (value >> (7 * (n - 1))) {
+            break;
+        }
+    }
+
+    if (p == NULL) {
+        return n + 1;
+    }
+
+    *p++ |= thresh;
+
+    for ( /* void */ ; n > 1; n--) {
+        *p++ = 0x80 | (value >> 7 * (n - 1));
+    }
+
+    *p++ = value & 0x7f;
+
+    return (uintptr_t) p;
+}
+
+
+uint64_t
+ngx_http_v3_decode_varlen_int(u_char *p)
+{
+    uint64_t    value;
+    ngx_uint_t  len;
+
+    len = *p >> 6;
+    value = *p & 0x3f;
+
+    while (len--) {
+        value = (value << 8) + *p++;
+    }
+
+    return value;
+}
+
+
+int64_t
+ngx_http_v3_decode_prefix_int(u_char **src, size_t len, ngx_uint_t prefix)
+{
+    u_char   *p;
+    int64_t   value, thresh;
+
+    if (len == 0) {
+        return NGX_ERROR;
+    }
+
+    p = *src;
+
+    thresh = (1 << prefix) - 1;
+    value = *p++ & thresh;
+
+    if (value != thresh) {
+        *src = p;
+        return value;
+    }
+
+    value = 0;
+
+    /* XXX handle overflows */
+
+    while (--len) {
+        value = (value << 7) + (*p & 0x7f);
+        if ((*p++ & 0x80) == 0) {
+            *src = p;
+            return value + thresh;
+        }
+    }
+
+    return NGX_ERROR;
+}
+
+
+ngx_int_t
+ngx_http_v3_decode_huffman(ngx_connection_t *c, ngx_str_t *s)
+{
+    u_char  state, *p, *data;
+
+    state = 0;
+
+    p = ngx_pnalloc(c->pool, s->len * 8 / 5);
+    if (p == NULL) {
+        return NGX_ERROR;
+    }
+
+    data = p;
+
+    if (ngx_http_v2_huff_decode(&state, s->data, s->len, &p, 1, c->log)
+        != NGX_OK)
+    {
+        return NGX_ERROR;
+    }
+
+    s->len = p - data;
+    s->data = data;
+
+    return NGX_OK;
+}