--- a/src/http/modules/ngx_http_charset_filter_module.c
+++ b/src/http/modules/ngx_http_charset_filter_module.c
@@ -9,56 +9,94 @@
 #include <ngx_http.h>
 
 
-#define NGX_HTTP_NO_CHARSET  -2
+#define NGX_HTTP_NO_CHARSET    -2
+
+/* 1 byte length and up to 3 bytes for the UTF-8 encoding of the UCS-2 */
+#define NGX_UTF_LEN             4
+
+#define NGX_HTML_ENTITY_LEN     (sizeof("&#1114111;") - 1)
 
 
 typedef struct {
-    u_char     **tables;
-    ngx_str_t     name;
+    u_char                    **tables;
+    ngx_str_t                   name;
 
-    ngx_uint_t    utf8;   /* unsigned     utf8:1; */
+    unsigned                    length:16;
+    unsigned                    utf8:1;
 } ngx_http_charset_t;
 
 
 typedef struct {
-    ngx_int_t     src;
-    ngx_int_t     dst;
+    ngx_int_t                   src;
+    ngx_int_t                   dst;
 } ngx_http_charset_recode_t;
 
 
 typedef struct {
-    ngx_int_t     src;
-    ngx_int_t     dst;
-    u_char       *src2dst;
-    u_char       *dst2src;
+    ngx_int_t                   src;
+    ngx_int_t                   dst;
+    u_char                     *src2dst;
+    u_char                     *dst2src;
 } ngx_http_charset_tables_t;
 
 
 typedef struct {
-    ngx_array_t   charsets;               /* ngx_http_charset_t */
-    ngx_array_t   tables;                 /* ngx_http_charset_tables_t */
-    ngx_array_t   recodes;                /* ngx_http_charset_recode_t */
+    ngx_array_t                 charsets;       /* ngx_http_charset_t */
+    ngx_array_t                 tables;         /* ngx_http_charset_tables_t */
+    ngx_array_t                 recodes;        /* ngx_http_charset_recode_t */
 } ngx_http_charset_main_conf_t;
 
 
 typedef struct {
-    ngx_int_t     charset;
-    ngx_int_t     source_charset;
-    ngx_flag_t    override_charset;
+    ngx_int_t                   charset;
+    ngx_int_t                   source_charset;
+    ngx_flag_t                  override_charset;
 } ngx_http_charset_loc_conf_t;
 
 
 typedef struct {
-    u_char       *table;
-    ngx_int_t     charset;
+    u_char                     *table;
+    ngx_int_t                   charset;
+
+    ngx_chain_t                *busy;
+    ngx_chain_t                *free_bufs;
+    ngx_chain_t                *free_buffers;
+
+    size_t                      saved_len;
+    u_char                      saved[NGX_UTF_LEN];
+
+    unsigned                    length:16;
+    unsigned                    from_utf8:1;
+    unsigned                    to_utf8:1;
 } ngx_http_charset_ctx_t;
 
 
-static ngx_uint_t ngx_http_charset_recode(ngx_buf_t *b, u_char *table);
+typedef struct {
+    ngx_http_charset_tables_t  *table;
+    ngx_http_charset_t         *charset;
+    ngx_uint_t                  characters;
+} ngx_http_charset_conf_ctx_t;
+
 
-static char *ngx_charset_map_block(ngx_conf_t *cf, ngx_command_t *cmd,
+static ngx_int_t ngx_http_charset_get_charset(ngx_http_charset_t *charsets,
+    ngx_uint_t n, u_char *charset);
+static ngx_int_t ngx_http_charset_set_charset(ngx_http_request_t *r,
+    ngx_http_charset_t *charsets, ngx_int_t charset, ngx_int_t source_charset);
+static ngx_uint_t ngx_http_charset_recode(ngx_buf_t *b, u_char *table);
+static ngx_chain_t *ngx_http_charset_recode_from_utf8(ngx_pool_t *pool,
+    ngx_buf_t *buf, ngx_http_charset_ctx_t *ctx);
+static ngx_chain_t *ngx_http_charset_recode_to_utf8(ngx_pool_t *pool,
+    ngx_buf_t *buf, ngx_http_charset_ctx_t *ctx);
+
+static ngx_chain_t *ngx_http_charset_get_buf(ngx_pool_t *pool,
+    ngx_http_charset_ctx_t *ctx);
+static ngx_chain_t *ngx_http_charset_get_buffer(ngx_pool_t *pool,
+    ngx_http_charset_ctx_t *ctx, size_t size);
+
+static char *ngx_http_charset_map_block(ngx_conf_t *cf, ngx_command_t *cmd,
     void *conf);
-static char *ngx_charset_map(ngx_conf_t *cf, ngx_command_t *dummy, void *conf);
+static char *ngx_http_charset_map(ngx_conf_t *cf, ngx_command_t *dummy,
+    void *conf);
 
 static char *ngx_http_set_charset_slot(ngx_conf_t *cf, ngx_command_t *cmd,
     void *conf);
@@ -101,7 +139,7 @@ static ngx_command_t  ngx_http_charset_f
 
     { ngx_string("charset_map"),
       NGX_HTTP_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_TAKE2,
-      ngx_charset_map_block,
+      ngx_http_charset_map_block,
       NGX_HTTP_MAIN_CONF_OFFSET,
       0,
       NULL },
@@ -148,10 +186,10 @@ static ngx_http_output_body_filter_pt   
 static ngx_int_t
 ngx_http_charset_header_filter(ngx_http_request_t *r)
 {
-    size_t                         len;
-    u_char                        *p;
+    u_char                        *ct;
     ngx_int_t                      charset, source_charset;
-    ngx_uint_t                     i;
+    ngx_str_t                     *mc;
+    ngx_uint_t                     n;
     ngx_http_charset_t            *charsets;
     ngx_http_charset_ctx_t        *ctx;
     ngx_http_charset_loc_conf_t   *lcf, *mlcf;
@@ -159,112 +197,153 @@ ngx_http_charset_header_filter(ngx_http_
 
     mcf = ngx_http_get_module_main_conf(r, ngx_http_charset_filter_module);
 
-    ctx = ngx_http_get_module_ctx(r->main, ngx_http_charset_filter_module);
-
-    if (ctx == NULL) {
-        mlcf = ngx_http_get_module_loc_conf(r->main,
-                                            ngx_http_charset_filter_module);
-        charset = mlcf->charset;
+    charsets = mcf->charsets.elts;
+    n = mcf->charsets.nelts;
 
-        if (charset == NGX_HTTP_NO_CHARSET) {
-            return ngx_http_next_header_filter(r);
-        }
-
-    } else {
-        charset = ctx->charset;
-    }
-
-    charsets = mcf->charsets.elts;
+    /* destination charset */
 
     if (r == r->main) {
+
         if (r->headers_out.content_type.len == 0) {
             return ngx_http_next_header_filter(r);
         }
 
-        if (ngx_strncasecmp(r->headers_out.content_type.data, "text/", 5) != 0
-            && ngx_strncasecmp(r->headers_out.content_type.data,
-                               "application/x-javascript", 24) != 0)
+        if (r->headers_out.override_charset
+            && r->headers_out.override_charset->len)
         {
-            return ngx_http_next_header_filter(r);
+            charset = ngx_http_charset_get_charset(charsets, n,
+                                        r->headers_out.override_charset->data);
+
+            if (charset == NGX_HTTP_NO_CHARSET) {
+                ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                              "unknown charset \"%V\" to override",
+                              &r->headers_out.override_charset);
+
+                return ngx_http_next_header_filter(r);
+            }
+
+        } else {
+            mlcf = ngx_http_get_module_loc_conf(r,
+                                                ngx_http_charset_filter_module);
+            charset = mlcf->charset;
+
+            if (charset == NGX_HTTP_NO_CHARSET) {
+                return ngx_http_next_header_filter(r);
+            }
+
+            if (r->headers_out.charset.len) {
+                if (mlcf->override_charset == 0) {
+                    return ngx_http_next_header_filter(r);
+                }
+
+            } else {
+                ct = r->headers_out.content_type.data;
+
+                if (ngx_strncasecmp(ct, "text/", 5) != 0
+                    && ngx_strncasecmp(ct, "application/x-javascript", 24) != 0)
+                {
+                    return ngx_http_next_header_filter(r);
+                }
+            }
         }
 
     } else {
-        if (r->headers_out.content_type.len == 0) {
-            mlcf = ngx_http_get_module_loc_conf(r->main,
-                                                ngx_http_charset_filter_module);
-            source_charset = mlcf->source_charset;
+        ctx = ngx_http_get_module_ctx(r->main, ngx_http_charset_filter_module);
+
+        if (ctx == NULL) {
+
+            mc = &r->main->headers_out.charset;
+
+            if (mc->len == 0) {
+                return ngx_http_next_header_filter(r);
+            }
+
+            ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_charset_ctx_t));
+            if (ctx == NULL) {
+                return NGX_ERROR;
+            }
+
+            ngx_http_set_ctx(r->main, ctx, ngx_http_charset_filter_module);
 
-            goto found;
+            charset = ngx_http_charset_get_charset(charsets, n, mc->data);
+
+            ctx->charset = charset;
+
+            if (charset == NGX_HTTP_NO_CHARSET) {
+                ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                              "unknown charset \"%V\" of main request", mc);
+
+                return ngx_http_next_header_filter(r);
+            }
+        }
+
+        charset = ctx->charset;
+
+        if (charset == NGX_HTTP_NO_CHARSET) {
+            return ngx_http_next_header_filter(r);
         }
     }
 
-    lcf = ngx_http_get_module_loc_conf(r, ngx_http_charset_filter_module);
-
-    len = 0;
+    /* source charset */
 
-    for (p = r->headers_out.content_type.data; *p; p++) {
-        if (*p == ';') {
-            len = p - r->headers_out.content_type.data;
-        }
-
-        if (ngx_strncasecmp(p, "charset=", 8) != 0) {
-            continue;
-        }
-
-        p += 8;
+    if (r->headers_out.charset.len == 0) {
+        lcf = ngx_http_get_module_loc_conf(r, ngx_http_charset_filter_module);
 
-        for (i = 0; i < mcf->charsets.nelts; i++) {
-
-            if (ngx_strcasecmp(p, charsets[i].name.data) == 0) {
+        return ngx_http_charset_set_charset(r, mcf->charsets.elts, charset,
+                                            lcf->source_charset);
+    }
 
-                if (r == r->main && lcf->override_charset == 0) {
-                    ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_charset_ctx_t));
-                    if (ctx == NULL) {
-                        return NGX_ERROR;
-                    }
-
-                    ngx_http_set_ctx(r, ctx, ngx_http_charset_filter_module);
-
-                    ctx->charset = i;
-
-                    return ngx_http_next_header_filter(r);
-                }
+    source_charset = ngx_http_charset_get_charset(charsets, n,
+                                                  r->headers_out.charset.data);
 
-                if (i != (ngx_uint_t) charset
-                    && (charsets[i].tables == NULL
-                        || charsets[i].tables[charset] == NULL))
-                {
-                    ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
-                                  "no \"charset_map\" between the charsets "
-                                  "\"%V\" and \"%V\"",
-                                  &charsets[i].name, &charsets[charset].name);
+    if (source_charset == NGX_HTTP_NO_CHARSET) {
+        ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                      "unknown source charset \"%V\"", &r->headers_out.charset);
 
-                    return ngx_http_next_header_filter(r);
-                }
-
-                r->headers_out.content_type.len = len;
+        return ngx_http_next_header_filter(r);
+    }
 
-                if (r->headers_out.status == NGX_HTTP_MOVED_PERMANENTLY
-                    || r->headers_out.status == NGX_HTTP_MOVED_TEMPORARILY)
-                {
-                    /*
-                     * do not set charset for the redirect because NN 4.x
-                     * uses this charset instead of the next page charset
-                     */
-
-                    r->headers_out.charset.len = 0;
-                    return ngx_http_next_header_filter(r);
-                }
-
-                source_charset = i;
-
-                goto found;
-            }
-        }
+    if (source_charset != charset
+        && (charsets[source_charset].tables == NULL
+            || charsets[source_charset].tables[charset] == NULL))
+    {
+        ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                      "no \"charset_map\" between the charsets "
+                      "\"%V\" and \"%V\"",
+                      &charsets[source_charset].name, &charsets[charset].name);
 
         return ngx_http_next_header_filter(r);
     }
 
+    r->headers_out.content_type.len = r->headers_out.content_type_len;
+
+    return ngx_http_charset_set_charset(r, mcf->charsets.elts, charset,
+                                        source_charset);
+}
+
+
+static ngx_int_t
+ngx_http_charset_get_charset(ngx_http_charset_t *charsets, ngx_uint_t n,
+    u_char *charset)
+{
+    ngx_uint_t  i;
+
+    for (i = 0; i < n; i++) {
+        if (ngx_strcasecmp(charsets[i].name.data, charset) == 0) {
+            return i;
+        }
+    }
+
+    return NGX_HTTP_NO_CHARSET;
+}
+
+
+static ngx_int_t
+ngx_http_charset_set_charset(ngx_http_request_t *r,
+    ngx_http_charset_t *charsets, ngx_int_t charset, ngx_int_t source_charset)
+{
+    ngx_http_charset_ctx_t  *ctx;
+
     if (r->headers_out.status == NGX_HTTP_MOVED_PERMANENTLY
         || r->headers_out.status == NGX_HTTP_MOVED_TEMPORARILY)
     {
@@ -274,17 +353,10 @@ ngx_http_charset_header_filter(ngx_http_
          */
 
         r->headers_out.charset.len = 0;
+
         return ngx_http_next_header_filter(r);
     }
 
-    if (r->headers_out.charset.len) {
-        return ngx_http_next_header_filter(r);
-    }
-
-    source_charset = lcf->source_charset;
-
-found:
-
     r->headers_out.charset = charsets[charset].name;
     r->utf8 = charsets[charset].utf8;
 
@@ -301,6 +373,13 @@ found:
 
     ctx->table = charsets[source_charset].tables[charset];
     ctx->charset = charset;
+    ctx->length = charsets[charset].length;
+    ctx->from_utf8 = charsets[source_charset].utf8;
+    ctx->to_utf8 = charsets[charset].utf8;
+
+    if ((ctx->to_utf8 || ctx->from_utf8) && r == r->main) {
+        ngx_http_clear_content_length(r);
+    }
 
     r->filter_need_in_memory = 1;
 
@@ -311,7 +390,9 @@ found:
 static ngx_int_t
 ngx_http_charset_body_filter(ngx_http_request_t *r, ngx_chain_t *in)
 {
-    ngx_chain_t             *cl;
+    ngx_int_t                rc;
+    ngx_buf_t               *b;
+    ngx_chain_t             *cl, *out, **ll;
     ngx_http_charset_ctx_t  *ctx;
 
     ctx = ngx_http_get_module_ctx(r, ngx_http_charset_filter_module);
@@ -320,6 +401,84 @@ ngx_http_charset_body_filter(ngx_http_re
         return ngx_http_next_body_filter(r, in);
     }
 
+    if ((ctx->to_utf8 || ctx->from_utf8) || ctx->busy) {
+
+        out = NULL;
+        ll = &out;
+
+        for (cl = in; cl; cl = cl->next) {
+            b = cl->buf;
+
+            if (ngx_buf_size(b) == 0) {
+                continue;
+            }
+
+            if (ctx->to_utf8) {
+                *ll = ngx_http_charset_recode_to_utf8(r->pool, b, ctx);
+
+            } else {
+                *ll = ngx_http_charset_recode_from_utf8(r->pool, b, ctx);
+            }
+
+            if (*ll == NULL) {
+                return NGX_ERROR;
+            }
+
+            while (*ll) {
+                ll = &(*ll)->next;
+            }
+        }
+
+        rc = ngx_http_next_body_filter(r, out);
+
+        if (out) {
+            if (ctx->busy == NULL) {
+                ctx->busy = out;
+
+            } else {
+                for (cl = ctx->busy; cl->next; cl = cl->next) { /* void */ }
+                cl->next = out;
+            }
+        }
+
+        while (ctx->busy) {
+
+            cl = ctx->busy;
+            b = cl->buf;
+
+            if (ngx_buf_size(b) != 0) {
+                break;
+            }
+
+#if (NGX_HAVE_WRITE_ZEROCOPY)
+            if (b->zerocopy_busy) {
+                break;
+            }
+#endif
+
+            ctx->busy = cl->next;
+
+            if (b->tag != (ngx_buf_tag_t) &ngx_http_charset_filter_module) {
+                continue;
+            }
+
+            if (b->shadow) {
+                b->shadow->pos = b->shadow->last;
+            }
+
+            if (b->pos) {
+                cl->next = ctx->free_buffers;
+                ctx->free_buffers = cl;
+                continue;
+            }
+
+            cl->next = ctx->free_bufs;
+            ctx->free_bufs = cl;
+        }
+
+        return rc;
+    }
+
     for (cl = in; cl; cl = cl->next) {
         (void) ngx_http_charset_recode(cl->buf, ctx->table);
     }
@@ -353,17 +512,506 @@ ngx_http_charset_recode(ngx_buf_t *b, u_
 }
 
 
+static ngx_chain_t *
+ngx_http_charset_recode_from_utf8(ngx_pool_t *pool, ngx_buf_t *buf,
+    ngx_http_charset_ctx_t *ctx)
+{
+    size_t        len, size;
+    u_char        c, *p, *src, *dst, *saved, **table;
+    uint32_t      n;
+    ngx_buf_t    *b;
+    ngx_uint_t    i;
+    ngx_chain_t  *out, *cl, **ll;
+
+    src = buf->pos;
+
+    if (ctx->saved_len == 0) {
+
+        for ( /* void */ ; src < buf->last; src++) {
+
+            if (*src < 0x80) {
+                continue;
+            }
+
+            len = src - buf->pos;
+
+            if (len > 512) {
+                out = ngx_http_charset_get_buf(pool, ctx);
+                if (out == NULL) {
+                    return NULL;
+                }
+
+                b = out->buf;
+
+                b->temporary = buf->temporary;
+                b->memory = buf->memory;
+                b->mmap = buf->mmap;
+                b->flush = buf->flush;
+
+                b->pos = buf->pos;
+                b->last = src;
+
+                out->buf = b;
+                out->next = NULL;
+
+                size = buf->last - src;
+
+                saved = src;
+                n = ngx_utf_decode(&saved, size);
+
+                if (n == 0xfffffffe) {
+                    /* incomplete UTF-8 symbol */
+
+                    ngx_memcpy(ctx->saved, src, size);
+                    ctx->saved_len = size;
+
+                    b->shadow = buf;
+
+                    return out;
+                }
+
+            } else {
+                out = NULL;
+                size = len + buf->last - src;
+                src = buf->pos;
+            }
+
+            if (size < NGX_HTML_ENTITY_LEN) {
+                size += NGX_HTML_ENTITY_LEN;
+            }
+
+            cl = ngx_http_charset_get_buffer(pool, ctx, size);
+            if (cl == NULL) {
+                return NULL;
+            }
+
+            if (out) {
+                out->next = cl;
+
+            } else {
+                out = cl;
+            }
+
+            b = cl->buf;
+            dst = b->pos;
+
+            goto recode;
+        }
+
+        out = ngx_alloc_chain_link(pool);
+        if (out == NULL) {
+            return NULL;
+        }
+
+        out->buf = buf;
+        out->next = NULL;
+
+        return out;
+    }
+
+    /* process incomplete UTF sequence from previous buffer */
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pool->log, 0,
+                   "http charset utf saved: %z", ctx->saved_len);
+
+    p = src;
+
+    for (i = ctx->saved_len; i < NGX_UTF_LEN; i++) {
+        ctx->saved[i] = *p++;
+
+        if (p == buf->last) {
+            break;
+        }
+    }
+
+    saved = ctx->saved;
+    n = ngx_utf_decode(&saved, i);
+
+    c = '\0';
+
+    if (n < 0x10000) {
+        table = (u_char **) ctx->table;
+        p = table[n >> 8];
+
+        if (p) {
+            c = p[n & 0xff];
+        }
+
+    } else if (n == 0xfffffffe) {
+
+        /* incomplete UTF-8 symbol */
+
+        if (i < NGX_UTF_LEN) {
+            out = ngx_http_charset_get_buf(pool, ctx);
+            if (out == NULL) {
+                return NULL;
+            }
+
+            b = out->buf;
+
+            b->pos = buf->pos;
+            b->last = buf->last;
+            b->sync = 1;
+            b->shadow = buf;
+
+            ngx_memcpy(&ctx->saved[ctx->saved_len], src, i);
+            ctx->saved_len += i;
+
+            return out;
+        }
+    }
+
+    size = buf->last - buf->pos;
+
+    if (size < NGX_HTML_ENTITY_LEN) {
+        size += NGX_HTML_ENTITY_LEN;
+    }
+
+    cl = ngx_http_charset_get_buffer(pool, ctx, size);
+    if (cl == NULL) {
+        return NULL;
+    }
+
+    out = cl;
+
+    b = cl->buf;
+    dst = b->pos;
+
+    if (c) {
+        *dst++ = c;
+
+    } else if (n == 0xfffffffe) {
+        *dst++ = '?';
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pool->log, 0,
+                       "http charset invalid utf 0");
+
+        saved = &ctx->saved[NGX_UTF_LEN];
+
+    } else if (n > 0x10ffff) {
+        *dst++ = '?';
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pool->log, 0,
+                       "http charset invalid utf 1");
+
+    } else {
+        dst = ngx_sprintf(dst, "&#%uD;", n);
+    }
+
+    src += (saved - ctx->saved) - ctx->saved_len;
+    ctx->saved_len = 0;
+
+recode:
+
+    ll = &cl->next;
+
+    table = (u_char **) ctx->table;
+
+    while (src < buf->last) {
+
+        if ((size_t) (b->end - dst) < NGX_HTML_ENTITY_LEN) {
+            b->last = dst;
+
+            size = buf->last - src + NGX_HTML_ENTITY_LEN;
+
+            cl = ngx_http_charset_get_buffer(pool, ctx, size);
+            if (cl == NULL) {
+                return NULL;
+            }
+
+            *ll = cl;
+            ll = &cl->next;
+
+            b = cl->buf;
+            dst = b->pos;
+        }
+
+        if (*src < 0x80) {
+            *dst++ = *src++;
+            continue;
+        }
+
+        len = buf->last - src;
+
+        n = ngx_utf_decode(&src, len);
+
+        if (n < 0x10000) {
+
+            p = table[n >> 8];
+
+            if (p) {
+                c = p[n & 0xff];
+
+                if (c) {
+                    *dst++ = c;
+                    continue;
+                }
+            }
+
+            dst = ngx_sprintf(dst, "&#%uD;", n);
+
+            continue;
+        }
+
+        if (n == 0xfffffffe) {
+            /* incomplete UTF-8 symbol */
+
+            ngx_memcpy(ctx->saved, src, len);
+            ctx->saved_len = len;
+
+            if (b->pos == dst) {
+                b->sync = 1;
+                b->temporary = 0;
+            }
+
+            break;
+        }
+
+        if (n > 0x10ffff) {
+            *dst++ = '?';
+
+            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pool->log, 0,
+                           "http charset invalid utf 2");
+
+            continue;
+        }
+
+        /* n > 0xffff */
+
+        dst = ngx_sprintf(dst, "&#%uD;", n);
+    }
+
+    b->last = dst;
+
+    b->last_buf = buf->last_buf;
+    b->last_in_chain = buf->last_in_chain;
+    b->flush = buf->flush;
+
+    b->shadow = buf;
+
+    return out;
+}
+
+
+static ngx_chain_t *
+ngx_http_charset_recode_to_utf8(ngx_pool_t *pool, ngx_buf_t *buf,
+    ngx_http_charset_ctx_t *ctx)
+{
+    size_t        len, size;
+    u_char       *p, *src, *dst, *table;
+    ngx_buf_t    *b;
+    ngx_chain_t  *out, *cl, **ll;
+
+    table = ctx->table;
+
+    for (src = buf->pos; src < buf->last; src++) {
+        if (table[*src * NGX_UTF_LEN] == '\1') {
+            continue;
+        }
+
+        goto recode;
+    }
+
+    out = ngx_alloc_chain_link(pool);
+    if (out == NULL) {
+        return NULL;
+    }
+
+    out->buf = buf;
+    out->next = NULL;
+
+    return out;
+
+recode:
+
+    /*
+     * we assume that there are about half of characters to be recoded,
+     * so we preallocate "size / 2 + size / 2 * ctx->length"
+     */
+
+    len = src - buf->pos;
+
+    if (len > 512) {
+        out = ngx_http_charset_get_buf(pool, ctx);
+        if (out == NULL) {
+            return NULL;
+        }
+
+        b = out->buf;
+
+        b->temporary = buf->temporary;
+        b->memory = buf->memory;
+        b->mmap = buf->mmap;
+        b->flush = buf->flush;
+
+        b->pos = buf->pos;
+        b->last = src;
+
+        out->buf = b;
+        out->next = NULL;
+
+        size = buf->last - src;
+        size = size / 2 + size / 2 * ctx->length;
+
+    } else {
+        out = NULL;
+
+        size = buf->last - src;
+        size = len + size / 2 + size / 2 * ctx->length;
+
+        src = buf->pos;
+    }
+
+    cl = ngx_http_charset_get_buffer(pool, ctx, size);
+    if (cl == NULL) {
+        return NULL;
+    }
+
+    if (out) {
+        out->next = cl;
+
+    } else {
+        out = cl;
+    }
+
+    ll = &cl->next;
+
+    b = cl->buf;
+    dst = b->pos;
+
+    while (src < buf->last) {
+
+        p = &table[*src++ * NGX_UTF_LEN];
+        len = *p++;
+
+        if ((size_t) (b->end - dst) < len) {
+            b->last = dst;
+
+            size = buf->last - src;
+            size = len + size / 2 + size / 2 * ctx->length;
+
+            cl = ngx_http_charset_get_buffer(pool, ctx, size);
+            if (cl == NULL) {
+                return NULL;
+            }
+
+            *ll = cl;
+            ll = &cl->next;
+
+            b = cl->buf;
+            dst = b->pos;
+        }
+
+        while (len) {
+            *dst++ = *p++;
+            len--;
+        }
+    }
+
+    b->last = dst;
+
+    b->last_buf = buf->last_buf;
+    b->last_in_chain = buf->last_in_chain;
+    b->flush = buf->flush;
+
+    b->shadow = buf;
+
+    return out;
+}
+
+
+static ngx_chain_t *
+ngx_http_charset_get_buf(ngx_pool_t *pool, ngx_http_charset_ctx_t *ctx)
+{
+    ngx_chain_t  *cl;
+
+    cl = ctx->free_bufs;
+
+    if (cl) {
+        ctx->free_bufs = cl->next;
+
+        cl->buf->shadow = NULL;
+        cl->next = NULL;
+
+        return cl;
+    }
+
+    cl = ngx_alloc_chain_link(pool);
+    if (cl == NULL) {
+        return NULL;
+    }
+
+    cl->buf = ngx_calloc_buf(pool);
+    if (cl->buf == NULL) {
+        return NULL;
+    }
+
+    cl->next = NULL;
+
+    cl->buf->tag = (ngx_buf_tag_t) &ngx_http_charset_filter_module;
+
+    return cl;
+}
+
+
+static ngx_chain_t *
+ngx_http_charset_get_buffer(ngx_pool_t *pool, ngx_http_charset_ctx_t *ctx,
+    size_t size)
+{
+    ngx_buf_t    *b;
+    ngx_chain_t  *cl, **ll;
+
+    for (ll = &ctx->free_buffers, cl = ctx->free_buffers;
+         cl;
+         ll = &cl->next, cl = cl->next)
+    {
+        b = cl->buf;
+
+        if ((size_t) (b->end - b->start) >= size) {
+            *ll = cl->next;
+            cl->next = NULL;
+
+            b->pos = b->start;
+            b->temporary = 1;
+            b->shadow = NULL;
+
+            return cl;
+        }
+    }
+
+    cl = ngx_alloc_chain_link(pool);
+    if (cl == NULL) {
+        return NULL;
+    }
+
+    cl->buf = ngx_create_temp_buf(pool, size);
+    if (cl->buf == NULL) {
+        return NULL;
+    }
+
+    cl->next = NULL;
+
+    cl->buf->temporary = 1;
+    cl->buf->tag = (ngx_buf_tag_t) &ngx_http_charset_filter_module;
+
+    return cl;
+}
+
+
 static char *
-ngx_charset_map_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+ngx_http_charset_map_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 {
     ngx_http_charset_main_conf_t  *mcf = conf;
 
-    char                       *rv;
-    ngx_int_t                   src, dst;
-    ngx_uint_t                  i;
-    ngx_str_t                  *value;
-    ngx_conf_t                  pvcf;
-    ngx_http_charset_tables_t  *table;
+    char                         *rv;
+    u_char                       *p, *dst2src, **pp;
+    ngx_int_t                     src, dst;
+    ngx_uint_t                    i, n;
+    ngx_str_t                    *value;
+    ngx_conf_t                    pvcf;
+    ngx_http_charset_t           *charset;
+    ngx_http_charset_tables_t    *table;
+    ngx_http_charset_conf_ctx_t   ctx;
 
     value = cf->args->elts;
 
@@ -404,45 +1052,98 @@ ngx_charset_map_block(ngx_conf_t *cf, ng
     table->src = src;
     table->dst = dst;
 
-    table->src2dst = ngx_palloc(cf->pool, 256);
-    if (table->src2dst == NULL) {
-        return NGX_CONF_ERROR;
-    }
+    if (ngx_strcasecmp(value[2].data, "utf-8") == 0) {
+        table->src2dst = ngx_pcalloc(cf->pool, 256 * NGX_UTF_LEN);
+        if (table->src2dst == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        table->dst2src = ngx_pcalloc(cf->pool, 256 * sizeof(void *));
+        if (table->dst2src == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        dst2src = ngx_pcalloc(cf->pool, 256);
+        if (dst2src == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        pp = (u_char **) &table->dst2src[0];
+        pp[0] = dst2src;
+
+        for (i = 0; i < 128; i++) {
+            p = &table->src2dst[i * NGX_UTF_LEN];
+            p[0] = '\1';
+            p[1] = (u_char) i;
+            dst2src[i] = (u_char) i;
+        }
 
-    table->dst2src = ngx_palloc(cf->pool, 256);
-    if (table->dst2src == NULL) {
-        return NGX_CONF_ERROR;
+        for (/* void */; i < 256; i++) {
+            p = &table->src2dst[i * NGX_UTF_LEN];
+            p[0] = '\1';
+            p[1] = '?';
+        }
+
+    } else {
+        table->src2dst = ngx_palloc(cf->pool, 256);
+        if (table->src2dst == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        table->dst2src = ngx_palloc(cf->pool, 256);
+        if (table->dst2src == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        for (i = 0; i < 128; i++) {
+            table->src2dst[i] = (u_char) i;
+            table->dst2src[i] = (u_char) i;
+        }
+
+        for (/* void */; i < 256; i++) {
+            table->src2dst[i] = '?';
+            table->dst2src[i] = '?';
+        }
     }
 
-    for (i = 0; i < 128; i++) {
-        table->src2dst[i] = (u_char) i;
-        table->dst2src[i] = (u_char) i;
-    }
+    charset = mcf->charsets.elts;
 
-    for (/* void */; i < 256; i++) {
-        table->src2dst[i] = '?';
-        table->dst2src[i] = '?';
-    }
+    ctx.table = table;
+    ctx.charset = &charset[dst];
+    ctx.characters = 0;
 
     pvcf = *cf;
-    cf->ctx = table;
-    cf->handler = ngx_charset_map;
+    cf->ctx = &ctx;
+    cf->handler = ngx_http_charset_map;
     cf->handler_conf = conf;
 
     rv = ngx_conf_parse(cf, NULL);
 
     *cf = pvcf;
 
+    if (ctx.characters) {
+        n = ctx.charset->length;
+        ctx.charset->length /= ctx.characters;
+
+        if (((n * 10) / ctx.characters) % 10 > 4) {
+            ctx.charset->length++;
+        }
+    }
+
     return rv;
 }
 
 
 static char *
-ngx_charset_map(ngx_conf_t *cf, ngx_command_t *dummy, void *conf)
+ngx_http_charset_map(ngx_conf_t *cf, ngx_command_t *dummy, void *conf)
 {
-    ngx_int_t                   src, dst;
-    ngx_str_t                  *value;
-    ngx_http_charset_tables_t  *table;
+    u_char                       *p, *dst2src, **pp;
+    uint32_t                      n;
+    ngx_int_t                     src, dst;
+    ngx_str_t                    *value;
+    ngx_uint_t                    i;
+    ngx_http_charset_tables_t    *table;
+    ngx_http_charset_conf_ctx_t  *ctx;
 
     if (cf->args->nelts != 2) {
         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid parameters number");
@@ -458,18 +1159,67 @@ ngx_charset_map(ngx_conf_t *cf, ngx_comm
         return NGX_CONF_ERROR;
     }
 
-    dst = ngx_hextoi(value[1].data, value[1].len);
-    if (dst == NGX_ERROR || dst > 255) {
-        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
-                           "invalid value \"%V\"", &value[1]);
-        return NGX_CONF_ERROR;
+    ctx = cf->ctx;
+    table = ctx->table;
+
+    if (ctx->charset->utf8) {
+        p = &table->src2dst[src * NGX_UTF_LEN];
+
+        *p++ = (u_char) (value[1].len / 2);
+
+        for (i = 0; i < value[1].len; i += 2) {
+            dst = ngx_hextoi(&value[1].data[i], 2);
+            if (dst == NGX_ERROR || dst > 255) {
+                ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                                   "invalid value \"%V\"", &value[1]);
+                return NGX_CONF_ERROR;
+            }
+
+            *p++ = (u_char) dst;
+        }
+
+        i /= 2;
+
+        ctx->charset->length += i;
+        ctx->characters++;
+
+        p = &table->src2dst[src * NGX_UTF_LEN] + 1;
+
+        n = ngx_utf_decode(&p, i);
+
+        if (n > 0xffff) {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "invalid value \"%V\"", &value[1]);
+            return NGX_CONF_ERROR;
+        }
+
+        pp = (u_char **) &table->dst2src[0];
+
+        dst2src = pp[n >> 8];
+
+        if (dst2src == NULL) {
+            dst2src = ngx_pcalloc(cf->pool, 256);
+            if (dst2src == NULL) {
+                return NGX_CONF_ERROR;
+            }
+
+            pp[n >> 8] = dst2src;
+        }
+
+        dst2src[n & 0xff] = (u_char) src;
+
+    } else {
+        dst = ngx_hextoi(value[1].data, value[1].len);
+        if (dst == NGX_ERROR || dst > 255) {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "invalid value \"%V\"", &value[1]);
+            return NGX_CONF_ERROR;
+        }
+
+        table->src2dst[src] = (u_char) dst;
+        table->dst2src[dst] = (u_char) src;
     }
 
-    table = cf->ctx;
-
-    table->src2dst[src] = (u_char) dst;
-    table->dst2src[dst] = (u_char) src;
-
     return NGX_CONF_OK;
 }
 
@@ -538,6 +1288,7 @@ ngx_http_add_charset(ngx_array_t *charse
 
     c->tables = NULL;
     c->name = *name;
+    c->length = 0;
 
     if (ngx_strcasecmp(name->data, "utf-8") == 0) {
         c->utf8 = 1;