new file mode 100644
--- /dev/null
+++ b/src/http/modules/ngx_http_gzip_filter_module.c
@@ -0,0 +1,1162 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_http.h>
+
+#include <zlib.h>
+
+
+typedef struct {
+    ngx_flag_t           enable;
+    ngx_flag_t           no_buffer;
+
+    ngx_array_t         *types;     /* array of ngx_http_gzip_type_t */
+
+    ngx_bufs_t           bufs;
+
+    ngx_uint_t           http_version;
+    ngx_uint_t           proxied;
+
+    int                  level;
+    size_t               wbits;
+    size_t               memlevel;
+    ssize_t              min_length;
+} ngx_http_gzip_conf_t;
+
+
+typedef struct {
+    ngx_str_t            name;
+    ngx_uint_t           enable;
+} ngx_http_gzip_type_t;
+
+
+#define NGX_HTTP_GZIP_PROXIED_OFF       0x0002
+#define NGX_HTTP_GZIP_PROXIED_EXPIRED   0x0004
+#define NGX_HTTP_GZIP_PROXIED_NO_CACHE  0x0008
+#define NGX_HTTP_GZIP_PROXIED_NO_STORE  0x0010
+#define NGX_HTTP_GZIP_PROXIED_PRIVATE   0x0020
+#define NGX_HTTP_GZIP_PROXIED_NO_LM     0x0040
+#define NGX_HTTP_GZIP_PROXIED_NO_ETAG   0x0080
+#define NGX_HTTP_GZIP_PROXIED_AUTH      0x0100
+#define NGX_HTTP_GZIP_PROXIED_ANY       0x0200
+
+
+typedef struct {
+    ngx_chain_t         *in;
+    ngx_chain_t         *free;
+    ngx_chain_t         *busy;
+    ngx_chain_t         *out;
+    ngx_chain_t        **last_out;
+    ngx_buf_t           *in_buf;
+    ngx_buf_t           *out_buf;
+    ngx_int_t            bufs;
+
+    off_t                length;
+
+    void                *preallocated;
+    char                *free_mem;
+    ngx_uint_t           allocated;
+
+    unsigned             flush:4;
+    unsigned             redo:1;
+    unsigned             done:1;
+
+    size_t               zin;
+    size_t               zout;
+
+    uint32_t             crc32;
+    z_stream             zstream;
+    ngx_http_request_t  *request;
+} ngx_http_gzip_ctx_t;
+
+
+static ngx_int_t ngx_http_gzip_proxied(ngx_http_request_t *r,
+    ngx_http_gzip_conf_t *conf);
+static void *ngx_http_gzip_filter_alloc(void *opaque, u_int items,
+    u_int size);
+static void ngx_http_gzip_filter_free(void *opaque, void *address);
+static void ngx_http_gzip_error(ngx_http_gzip_ctx_t *ctx);
+
+static u_char *ngx_http_gzip_log_ratio(ngx_http_request_t *r, u_char *buf,
+    ngx_http_log_op_t *op);
+
+static ngx_int_t ngx_http_gzip_add_log_formats(ngx_conf_t *cf);
+
+static ngx_int_t ngx_http_gzip_filter_init(ngx_cycle_t *cycle);
+static void *ngx_http_gzip_create_conf(ngx_conf_t *cf);
+static char *ngx_http_gzip_merge_conf(ngx_conf_t *cf,
+    void *parent, void *child);
+static char *ngx_http_gzip_set_types(ngx_conf_t *cf, ngx_command_t *cmd,
+    void *conf);
+static char *ngx_http_gzip_set_window(ngx_conf_t *cf, void *post, void *data);
+static char *ngx_http_gzip_set_hash(ngx_conf_t *cf, void *post, void *data);
+
+
+static ngx_conf_num_bounds_t  ngx_http_gzip_comp_level_bounds = {
+    ngx_conf_check_num_bounds, 1, 9
+};
+
+static ngx_conf_post_handler_pt  ngx_http_gzip_set_window_p =
+                                                      ngx_http_gzip_set_window;
+static ngx_conf_post_handler_pt  ngx_http_gzip_set_hash_p =
+                                                        ngx_http_gzip_set_hash;
+
+
+
+static ngx_conf_enum_t  ngx_http_gzip_http_version[] = {
+    { ngx_string("1.0"), NGX_HTTP_VERSION_10 },
+    { ngx_string("1.1"), NGX_HTTP_VERSION_11 },
+    { ngx_null_string, 0 }
+};
+
+
+static ngx_conf_bitmask_t  ngx_http_gzip_proxied_mask[] = {
+    { ngx_string("off"), NGX_HTTP_GZIP_PROXIED_OFF },
+    { ngx_string("expired"), NGX_HTTP_GZIP_PROXIED_EXPIRED },
+    { ngx_string("no-cache"), NGX_HTTP_GZIP_PROXIED_NO_CACHE },
+    { ngx_string("no-store"), NGX_HTTP_GZIP_PROXIED_NO_STORE },
+    { ngx_string("private"), NGX_HTTP_GZIP_PROXIED_PRIVATE },
+    { ngx_string("no_last_modified"), NGX_HTTP_GZIP_PROXIED_NO_LM },
+    { ngx_string("no_etag"), NGX_HTTP_GZIP_PROXIED_NO_ETAG },
+    { ngx_string("auth"), NGX_HTTP_GZIP_PROXIED_AUTH },
+    { ngx_string("any"), NGX_HTTP_GZIP_PROXIED_ANY },
+    { ngx_null_string, 0 }
+};
+
+
+static ngx_command_t  ngx_http_gzip_filter_commands[] = {
+
+    { ngx_string("gzip"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF
+                        |NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_gzip_conf_t, enable),
+      NULL },
+
+    { ngx_string("gzip_buffers"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
+      ngx_conf_set_bufs_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_gzip_conf_t, bufs),
+      NULL },
+
+    { ngx_string("gzip_types"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
+      ngx_http_gzip_set_types,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      0,
+      NULL },
+
+    { ngx_string("gzip_comp_level"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_gzip_conf_t, level),
+      &ngx_http_gzip_comp_level_bounds },
+
+    { ngx_string("gzip_window"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_size_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_gzip_conf_t, wbits),
+      &ngx_http_gzip_set_window_p },
+
+    { ngx_string("gzip_hash"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_size_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_gzip_conf_t, memlevel),
+      &ngx_http_gzip_set_hash_p },
+
+    { ngx_string("gzip_no_buffer"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_gzip_conf_t, no_buffer),
+      NULL },
+
+    { ngx_string("gzip_http_version"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_ANY,
+      ngx_conf_set_enum_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_gzip_conf_t, http_version),
+      &ngx_http_gzip_http_version },
+
+    { ngx_string("gzip_proxied"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_ANY,
+      ngx_conf_set_bitmask_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_gzip_conf_t, proxied),
+      &ngx_http_gzip_proxied_mask },
+
+    { ngx_string("gzip_min_length"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_size_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_gzip_conf_t, min_length),
+      NULL },
+
+      ngx_null_command
+};
+
+
+static ngx_http_module_t  ngx_http_gzip_filter_module_ctx = {
+    ngx_http_gzip_add_log_formats,         /* pre conf */
+
+    NULL,                                  /* create main configuration */
+    NULL,                                  /* init main configuration */
+
+    NULL,                                  /* create server configuration */
+    NULL,                                  /* merge server configuration */
+
+    ngx_http_gzip_create_conf,             /* create location configuration */
+    ngx_http_gzip_merge_conf               /* merge location configuration */
+};
+
+
+ngx_module_t  ngx_http_gzip_filter_module = {
+    NGX_MODULE,
+    &ngx_http_gzip_filter_module_ctx,      /* module context */
+    ngx_http_gzip_filter_commands,         /* module directives */
+    NGX_HTTP_MODULE,                       /* module type */
+    ngx_http_gzip_filter_init,             /* init module */
+    NULL                                   /* init process */
+};
+
+
+static ngx_http_log_op_name_t ngx_http_gzip_log_fmt_ops[] = {
+    { ngx_string("gzip_ratio"), NGX_INT32_LEN + 3,
+                                NULL, NULL, ngx_http_gzip_log_ratio },
+    { ngx_null_string, 0, NULL, NULL, NULL }
+};
+
+
+
+static u_char  gzheader[10] = { 0x1f, 0x8b, Z_DEFLATED, 0, 0, 0, 0, 0, 0, 3 };
+
+#if (NGX_HAVE_LITTLE_ENDIAN && NGX_HAVE_NONALIGNED)
+
+struct gztrailer {
+    uint32_t  crc32;
+    uint32_t  zlen;
+};
+
+#else /* NGX_HAVE_BIG_ENDIAN || !NGX_HAVE_NONALIGNED */
+
+struct gztrailer {
+    u_char  crc32[4];
+    u_char  zlen[4];
+};
+
+#endif
+
+
+static ngx_http_output_header_filter_pt  ngx_http_next_header_filter;
+static ngx_http_output_body_filter_pt    ngx_http_next_body_filter;
+
+
+static ngx_int_t
+ngx_http_gzip_header_filter(ngx_http_request_t *r)
+{
+    ngx_uint_t             i, found;
+    ngx_http_gzip_ctx_t   *ctx;
+    ngx_http_gzip_conf_t  *conf;
+    ngx_http_gzip_type_t  *type;
+
+    conf = ngx_http_get_module_loc_conf(r, ngx_http_gzip_filter_module);
+
+    if (!conf->enable
+        || (r->headers_out.status != NGX_HTTP_OK
+            && r->headers_out.status != NGX_HTTP_FORBIDDEN
+            && r->headers_out.status != NGX_HTTP_NOT_FOUND)
+        || r->header_only
+        || r->http_version < conf->http_version
+        || r->headers_out.content_type == NULL
+        || (r->headers_out.content_encoding
+            && r->headers_out.content_encoding->value.len)
+        || r->headers_in.accept_encoding == NULL
+        || (r->headers_out.content_length_n != -1
+            && r->headers_out.content_length_n < conf->min_length)
+        || ngx_strstr(r->headers_in.accept_encoding->value.data, "gzip") == NULL
+       )
+    {
+        return ngx_http_next_header_filter(r);
+    }
+
+
+    found = 0;
+    type = conf->types->elts;
+
+    for (i = 0; i < conf->types->nelts; i++) {
+        if (r->headers_out.content_type->value.len >= type[i].name.len
+            && ngx_strncasecmp(r->headers_out.content_type->value.data, 
+                               type[i].name.data, type[i].name.len) == 0)
+        {
+            found = 1;
+            break;
+        }
+    }
+
+    if (!found) {
+        return ngx_http_next_header_filter(r);
+    }
+
+
+    if (r->headers_in.via) {
+        if (conf->proxied & NGX_HTTP_GZIP_PROXIED_OFF) {
+            return ngx_http_next_header_filter(r);
+        }
+
+        if (!(conf->proxied & NGX_HTTP_GZIP_PROXIED_ANY)
+            && ngx_http_gzip_proxied(r, conf) == NGX_DECLINED)
+        {
+            return ngx_http_next_header_filter(r);
+        }
+    }
+
+
+    /*
+     * if the URL (without the "http://" prefix) is longer than 253 bytes
+     * then MSIE 4.x can not handle the compressed stream - it waits too long,
+     * hangs up or crashes
+     */
+
+    if (r->headers_in.msie4 && r->unparsed_uri.len > 200) {
+        return ngx_http_next_header_filter(r);
+    }
+
+    ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_gzip_ctx_t));
+    if (ctx == NULL) {
+        return NGX_ERROR;
+    }
+
+    ngx_http_set_ctx(r, ctx, ngx_http_gzip_filter_module);
+
+
+    ctx->request = r;
+
+    r->headers_out.content_encoding = ngx_list_push(&r->headers_out.headers);
+    if (r->headers_out.content_encoding == NULL) {
+        return NGX_ERROR;
+    }
+
+    r->headers_out.content_encoding->key.len = sizeof("Content-Encoding") - 1;
+    r->headers_out.content_encoding->key.data = (u_char *) "Content-Encoding";
+    r->headers_out.content_encoding->value.len = sizeof("gzip") - 1;
+    r->headers_out.content_encoding->value.data = (u_char *) "gzip";
+
+    ctx->length = r->headers_out.content_length_n;
+    r->headers_out.content_length_n = -1;
+    if (r->headers_out.content_length) {
+        r->headers_out.content_length->key.len = 0;
+        r->headers_out.content_length = NULL;
+    }
+    r->filter_need_in_memory = 1;
+
+    return ngx_http_next_header_filter(r);
+}
+
+
+static ngx_int_t
+ngx_http_gzip_proxied(ngx_http_request_t *r, ngx_http_gzip_conf_t *conf)
+{
+    time_t  date, expires;
+
+    if (r->headers_in.authorization
+        && (conf->proxied & NGX_HTTP_GZIP_PROXIED_AUTH))
+    {
+        return NGX_OK;
+    }
+
+    if (r->headers_out.expires) {
+
+        if (!(conf->proxied & NGX_HTTP_GZIP_PROXIED_EXPIRED)) {
+            return NGX_DECLINED;
+        }
+
+        expires = ngx_http_parse_time(r->headers_out.expires->value.data,
+                                      r->headers_out.expires->value.len);
+        if (expires == NGX_ERROR) {
+            return NGX_DECLINED;
+        }
+
+        if (r->headers_out.date) {
+            date = ngx_http_parse_time(r->headers_out.date->value.data,
+                                       r->headers_out.date->value.len);
+            if (date == NGX_ERROR) {
+                return NGX_DECLINED;
+            }
+
+        } else {
+            date = ngx_time();
+        }
+
+        if (expires < date) {
+            return NGX_OK;
+        }
+
+        return NGX_DECLINED;
+    }
+
+    if (r->headers_out.cache_control) {
+
+        if ((conf->proxied & NGX_HTTP_GZIP_PROXIED_NO_CACHE)
+            && ngx_strstr(r->headers_out.cache_control->value.data, "no-cache"))
+        {
+            return NGX_OK;
+        }
+
+        if ((conf->proxied & NGX_HTTP_GZIP_PROXIED_NO_STORE)
+            && ngx_strstr(r->headers_out.cache_control->value.data, "no-store"))
+        {
+            return NGX_OK;
+        }
+
+        if ((conf->proxied & NGX_HTTP_GZIP_PROXIED_PRIVATE)
+            && ngx_strstr(r->headers_out.cache_control->value.data, "private"))
+        {
+            return NGX_OK;
+        }
+
+        return NGX_DECLINED;
+    }
+
+    if ((conf->proxied & NGX_HTTP_GZIP_PROXIED_NO_LM)
+        && r->headers_out.last_modified)
+    {
+        return NGX_DECLINED;
+    }
+
+    if ((conf->proxied & NGX_HTTP_GZIP_PROXIED_NO_ETAG)
+        && r->headers_out.etag)
+    {
+        return NGX_DECLINED;
+    }
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_gzip_body_filter(ngx_http_request_t *r, ngx_chain_t *in)
+{
+    int                    rc, wbits, memlevel;
+    ngx_int_t              last;
+    struct gztrailer      *trailer;
+    ngx_buf_t             *b;
+    ngx_chain_t           *cl, out;
+    ngx_http_gzip_ctx_t   *ctx;
+    ngx_http_gzip_conf_t  *conf;
+
+    ctx = ngx_http_get_module_ctx(r, ngx_http_gzip_filter_module);
+
+    if (ctx == NULL || ctx->done) {
+        return ngx_http_next_body_filter(r, in);
+    }
+
+    conf = ngx_http_get_module_loc_conf(r, ngx_http_gzip_filter_module);
+
+    if (ctx->preallocated == NULL) {
+        wbits = conf->wbits;
+        memlevel = conf->memlevel;
+
+        if (ctx->length > 0) {
+
+            /* the actual zlib window size is smaller by 262 bytes */
+
+            while (ctx->length < ((1 << (wbits - 1)) - 262)) {
+                wbits--;
+                memlevel--;
+            }
+        }
+
+        /*
+         * We preallocate a memory for zlib in one buffer (200K-400K), this
+         * decreases a number of malloc() and free() calls and also probably
+         * decreases a number of syscalls (sbrk() and so on).
+         * Besides we free this memory as soon as the gzipping will complete
+         * and do not wait while a whole response will be sent to a client.
+         *
+         * 8K is for zlib deflate_state, it takes
+         *  * 5816 bytes on x86 and sparc64 (32-bit mode)
+         *  * 5920 bytes on amd64 and sparc64
+         */
+
+        ctx->allocated = 8192 + (1 << (wbits + 2)) + (1 << (memlevel + 9));
+
+        ctx->preallocated = ngx_palloc(r->pool, ctx->allocated);
+        if (ctx->preallocated == NULL) {
+            return NGX_ERROR;
+        }
+
+        ctx->free_mem = ctx->preallocated;
+
+        ctx->zstream.zalloc = ngx_http_gzip_filter_alloc;
+        ctx->zstream.zfree = ngx_http_gzip_filter_free;
+        ctx->zstream.opaque = ctx;
+
+        rc = deflateInit2(&ctx->zstream, conf->level, Z_DEFLATED,
+                          -wbits, memlevel, Z_DEFAULT_STRATEGY);
+
+        if (rc != Z_OK) {
+            ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                          "deflateInit2() failed: %d", rc);
+            ngx_http_gzip_error(ctx);
+            return NGX_ERROR;
+        }
+
+        b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));
+        if (b == NULL) {
+            ngx_http_gzip_error(ctx);
+            return NGX_ERROR;
+        }
+
+        b->memory = 1;
+        b->pos = gzheader;
+        b->last = b->pos + 10;
+
+        out.buf = b;
+        out.next = NULL;
+
+        /*
+         * We pass the gzheader to the next filter now to avoid its linking
+         * to the ctx->busy chain.  zlib does not usually output the compressed
+         * data in the initial iterations, so the gzheader that was linked
+         * to the ctx->busy chain would be flushed by ngx_http_write_filter().
+         */
+
+        if (ngx_http_next_body_filter(r, &out) == NGX_ERROR) {
+            ngx_http_gzip_error(ctx);
+            return NGX_ERROR;
+        }
+
+        ctx->last_out = &ctx->out;
+
+        ctx->crc32 = crc32(0L, Z_NULL, 0);
+        ctx->flush = Z_NO_FLUSH;
+    }
+
+    if (in) {
+        if (ngx_chain_add_copy(r->pool, &ctx->in, in) == NGX_ERROR) {
+            ngx_http_gzip_error(ctx);
+            return NGX_ERROR;
+        }
+    }
+
+    last = NGX_NONE;
+
+    for ( ;; ) {
+
+        for ( ;; ) {
+
+            /* does zlib need a new data ? */
+
+            if (ctx->zstream.avail_in == 0
+                && ctx->flush == Z_NO_FLUSH
+                && !ctx->redo)
+            {
+                ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                               "gzip in: %p", ctx->in);
+
+                if (ctx->in == NULL) {
+                    break;
+                }
+
+                ctx->in_buf = ctx->in->buf;
+                ctx->in = ctx->in->next;
+
+                ctx->zstream.next_in = ctx->in_buf->pos;
+                ctx->zstream.avail_in = ctx->in_buf->last - ctx->in_buf->pos;
+
+                ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                               "gzip in_buf:%p ni:%p ai:%ud",
+                               ctx->in_buf,
+                               ctx->zstream.next_in, ctx->zstream.avail_in);
+
+                /* STUB */
+                if (ctx->in_buf->last < ctx->in_buf->pos) {
+                    ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                                  "zstream.avail_in is huge");
+                    ctx->done = 1;
+                    return NGX_ERROR;
+                }
+                /**/
+
+                if (ctx->in_buf->last_buf) {
+                    ctx->flush = Z_FINISH;
+
+                } else if (ctx->in_buf->flush) {
+                    ctx->flush = Z_SYNC_FLUSH;
+                }
+
+                if (ctx->zstream.avail_in == 0) {
+                    if (ctx->flush == Z_NO_FLUSH) {
+                        continue;
+                    }
+
+                } else {
+                    ctx->crc32 = crc32(ctx->crc32, ctx->zstream.next_in,
+                                       ctx->zstream.avail_in);
+                }
+            }
+
+
+            /* is there a space for the gzipped data ? */
+
+            if (ctx->zstream.avail_out == 0) {
+
+                if (ctx->free) {
+                    ctx->out_buf = ctx->free->buf;
+                    ctx->free = ctx->free->next;
+
+                } else if (ctx->bufs < conf->bufs.num) {
+                    ctx->out_buf = ngx_create_temp_buf(r->pool,
+                                                       conf->bufs.size);
+                    if (ctx->out_buf == NULL) {
+                        ngx_http_gzip_error(ctx);
+                        return NGX_ERROR;
+                    }
+
+                    ctx->out_buf->tag = (ngx_buf_tag_t)
+                                                  &ngx_http_gzip_filter_module;
+                    ctx->out_buf->recycled = 1;
+                    ctx->bufs++;
+
+                } else {
+                    break;
+                }
+
+                ctx->zstream.next_out = ctx->out_buf->pos;
+                ctx->zstream.avail_out = conf->bufs.size;
+            }
+
+            ngx_log_debug6(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                         "deflate in: ni:%p no:%p ai:%ud ao:%ud fl:%d redo:%d",
+                         ctx->zstream.next_in, ctx->zstream.next_out,
+                         ctx->zstream.avail_in, ctx->zstream.avail_out,
+                         ctx->flush, ctx->redo);
+
+            rc = deflate(&ctx->zstream, ctx->flush);
+
+            if (rc != Z_OK && rc != Z_STREAM_END) {
+                ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                              "deflate() failed: %d, %d", ctx->flush, rc);
+                ngx_http_gzip_error(ctx);
+                return NGX_ERROR;
+            }
+
+            ngx_log_debug5(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "deflate out: ni:%p no:%p ai:%ud ao:%ud rc:%d",
+                           ctx->zstream.next_in, ctx->zstream.next_out,
+                           ctx->zstream.avail_in, ctx->zstream.avail_out,
+                           rc);
+
+            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "gzip in_buf:%p pos:%p",
+                           ctx->in_buf, ctx->in_buf->pos);
+
+
+            if (ctx->zstream.next_in) {
+                ctx->in_buf->pos = ctx->zstream.next_in;
+
+                if (ctx->zstream.avail_in == 0) {
+                    ctx->zstream.next_in = NULL;
+                }
+            }
+
+            ctx->out_buf->last = ctx->zstream.next_out;
+
+            if (ctx->zstream.avail_out == 0) {
+
+                /* zlib wants to output some more gzipped data */
+
+                cl = ngx_alloc_chain_link(r->pool);
+                if (cl == NULL) {
+                    ngx_http_gzip_error(ctx);
+                    return NGX_ERROR;
+                }
+
+                cl->buf = ctx->out_buf;
+                cl->next = NULL;
+                *ctx->last_out = cl;
+                ctx->last_out = &cl->next;
+
+                ctx->redo = 1;
+
+                continue;
+            }
+
+            ctx->redo = 0;
+
+            if (ctx->flush == Z_SYNC_FLUSH) {
+
+                ctx->out_buf->flush = 0;
+                ctx->flush = Z_NO_FLUSH;
+
+                cl = ngx_alloc_chain_link(r->pool);
+                if (cl == NULL) {
+                    ngx_http_gzip_error(ctx);
+                    return NGX_ERROR;
+                }
+
+                cl->buf = ctx->out_buf;
+                cl->next = NULL;
+                *ctx->last_out = cl;
+                ctx->last_out = &cl->next;
+
+                break;
+            }
+
+            if (rc == Z_STREAM_END) {
+
+                ctx->zin = ctx->zstream.total_in;
+                ctx->zout = 10 + ctx->zstream.total_out + 8;
+
+                rc = deflateEnd(&ctx->zstream);
+
+                if (rc != Z_OK) {
+                    ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                                  "deflateEnd() failed: %d", rc);
+                    ngx_http_gzip_error(ctx);
+                    return NGX_ERROR;
+                }
+
+                ngx_pfree(r->pool, ctx->preallocated);
+
+                cl = ngx_alloc_chain_link(r->pool);
+                if (cl == NULL) {
+                    ngx_http_gzip_error(ctx);
+                    return NGX_ERROR;
+                }
+
+                cl->buf = ctx->out_buf;
+                cl->next = NULL;
+                *ctx->last_out = cl;
+                ctx->last_out = &cl->next;
+
+                if (ctx->zstream.avail_out >= 8) {
+                    trailer = (struct gztrailer *) ctx->out_buf->last;
+                    ctx->out_buf->last += 8;
+                    ctx->out_buf->last_buf = 1;
+
+                } else {
+                    b = ngx_create_temp_buf(r->pool, 8);
+                    if (b == NULL) {
+                        ngx_http_gzip_error(ctx);
+                        return NGX_ERROR;
+                    }
+
+                    b->last_buf = 1;
+
+                    cl = ngx_alloc_chain_link(r->pool);
+                    if (cl == NULL) {
+                        ngx_http_gzip_error(ctx);
+                        return NGX_ERROR;
+                    }
+
+                    cl->buf = b;
+                    cl->next = NULL;
+                    *ctx->last_out = cl;
+                    ctx->last_out = &cl->next;
+                    trailer = (struct gztrailer *) b->pos;
+                    b->last += 8;
+                }
+
+#if (NGX_HAVE_LITTLE_ENDIAN && NGX_HAVE_NONALIGNED)
+
+                trailer->crc32 = ctx->crc32;
+                trailer->zlen = ctx->zin;
+
+#else
+                trailer->crc32[0] = (u_char) (ctx->crc32 & 0xff);
+                trailer->crc32[1] = (u_char) ((ctx->crc32 >> 8) & 0xff);
+                trailer->crc32[2] = (u_char) ((ctx->crc32 >> 16) & 0xff);
+                trailer->crc32[3] = (u_char) ((ctx->crc32 >> 24) & 0xff);
+
+                trailer->zlen[0] = (u_char) (ctx->zin & 0xff);
+                trailer->zlen[1] = (u_char) ((ctx->zin >> 8) & 0xff);
+                trailer->zlen[2] = (u_char) ((ctx->zin >> 16) & 0xff);
+                trailer->zlen[3] = (u_char) ((ctx->zin >> 24) & 0xff);
+#endif
+
+                ctx->zstream.avail_in = 0;
+                ctx->zstream.avail_out = 0;
+
+                ctx->done = 1;
+
+                break;
+            }
+
+            if (conf->no_buffer && ctx->in == NULL) {
+
+                cl = ngx_alloc_chain_link(r->pool);
+                if (cl == NULL) {
+                    ngx_http_gzip_error(ctx);
+                    return NGX_ERROR;
+                }
+
+                cl->buf = ctx->out_buf;
+                cl->next = NULL;
+                *ctx->last_out = cl;
+                ctx->last_out = &cl->next;
+
+                break;
+            }
+        }
+
+        if (last == NGX_AGAIN && !ctx->done) {
+            return NGX_AGAIN;
+        }
+
+        if (ctx->out == NULL && ctx->busy == NULL) {
+            return NGX_OK;
+        }
+
+        last = ngx_http_next_body_filter(r, ctx->out);
+
+        /*
+         * we do not check NGX_AGAIN here because the downstream filters
+         * may free some buffers and zlib may compress some data into them
+         */
+
+        if (last == NGX_ERROR) {
+            ngx_http_gzip_error(ctx);
+            return NGX_ERROR;
+        }
+
+        ngx_chain_update_chains(&ctx->free, &ctx->busy, &ctx->out,
+                                (ngx_buf_tag_t) &ngx_http_gzip_filter_module);
+        ctx->last_out = &ctx->out;
+
+        if (ctx->done) {
+            return last;
+        }
+    }
+}
+
+
+static void *
+ngx_http_gzip_filter_alloc(void *opaque, u_int items, u_int size)
+{
+    ngx_http_gzip_ctx_t *ctx = opaque;
+
+    void        *p;
+    ngx_uint_t   alloc;
+
+    alloc = items * size;
+
+    if (alloc % 512 != 0) {
+
+        /*
+         * The zlib deflate_state allocation, it takes about 6K,
+         * we allocate 8K.  Other allocations are divisible by 512.
+         */
+
+        alloc = (alloc + ngx_pagesize - 1) & ~(ngx_pagesize - 1);
+    }
+
+    if (alloc <= ctx->allocated) {
+        p = ctx->free_mem;
+        ctx->free_mem += alloc;
+        ctx->allocated -= alloc;
+
+        ngx_log_debug4(NGX_LOG_DEBUG_HTTP, ctx->request->connection->log, 0,
+                       "gzip alloc: n:%ud s:%ud a:%ud p:%p",
+                       items, size, alloc, p);
+
+        return p;
+    }
+
+    ngx_log_error(NGX_LOG_ALERT, ctx->request->connection->log, 0,
+                  "gzip filter failed to use preallocated memory: %ud of %ud",
+                  items * size, ctx->allocated);
+
+    p = ngx_palloc(ctx->request->pool, items * size);
+
+    return p;
+}
+
+
+static void
+ngx_http_gzip_filter_free(void *opaque, void *address)
+{
+#if 0
+    ngx_http_gzip_ctx_t *ctx = opaque;
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ctx->request->connection->log, 0,
+                   "gzip free: %p", address);
+#endif
+}
+
+
+static u_char *
+ngx_http_gzip_log_ratio(ngx_http_request_t *r, u_char *buf,
+    ngx_http_log_op_t *op)
+{
+    ngx_uint_t            zint, zfrac;
+    ngx_http_gzip_ctx_t  *ctx;
+
+    ctx = ngx_http_get_module_ctx(r, ngx_http_gzip_filter_module);
+
+    if (ctx == NULL || ctx->zout == 0) {
+        *buf = '-';
+        return buf + 1;
+    }
+
+    zint = (ngx_uint_t) (ctx->zin / ctx->zout);
+    zfrac = (ngx_uint_t) ((ctx->zin * 100 / ctx->zout) % 100);
+
+    if ((ctx->zin * 1000 / ctx->zout) % 10 > 4) {
+
+        /* the rounding, e.g., 2.125 to 2.13 */
+
+        zfrac++;
+
+        if (zfrac > 99) {
+            zint++;
+            zfrac = 0;
+        }
+    }
+
+    return ngx_sprintf(buf, "%ui.%02ui", zint, zfrac);
+}
+
+
+static void
+ngx_http_gzip_error(ngx_http_gzip_ctx_t *ctx)
+{
+    deflateEnd(&ctx->zstream);
+
+    if (ctx->preallocated) {
+        ngx_pfree(ctx->request->pool, ctx->preallocated);
+    }
+
+    ctx->zstream.avail_in = 0;
+    ctx->zstream.avail_out = 0;
+
+    ctx->done = 1;
+
+    return;
+}
+
+
+static ngx_int_t
+ngx_http_gzip_add_log_formats(ngx_conf_t *cf)
+{
+    ngx_http_log_op_name_t  *op;
+
+    for (op = ngx_http_gzip_log_fmt_ops; op->name.len; op++) { /* void */ }
+    op->run = NULL;
+
+    for (op = ngx_http_log_fmt_ops; op->run; op++) {
+        if (op->name.len == 0) {
+            op = (ngx_http_log_op_name_t *) op->run;
+        }
+    }
+
+    op->run = (ngx_http_log_op_run_pt) ngx_http_gzip_log_fmt_ops;
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_http_gzip_filter_init(ngx_cycle_t *cycle)
+{
+    ngx_http_next_header_filter = ngx_http_top_header_filter;
+    ngx_http_top_header_filter = ngx_http_gzip_header_filter;
+
+    ngx_http_next_body_filter = ngx_http_top_body_filter;
+    ngx_http_top_body_filter = ngx_http_gzip_body_filter;
+
+    return NGX_OK;
+}
+
+
+static void *
+ngx_http_gzip_create_conf(ngx_conf_t *cf)
+{
+    ngx_http_gzip_conf_t  *conf;
+
+    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_gzip_conf_t));
+    if (conf == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    /*
+     * set by ngx_pcalloc():
+     *
+     *     conf->bufs.num = 0;
+     *     conf->proxied = 0;
+     *     conf->types = NULL;
+     */
+
+    conf->enable = NGX_CONF_UNSET;
+    conf->no_buffer = NGX_CONF_UNSET;
+
+    conf->http_version = NGX_CONF_UNSET_UINT;
+
+    conf->level = NGX_CONF_UNSET;
+    conf->wbits = (size_t) NGX_CONF_UNSET;
+    conf->memlevel = (size_t) NGX_CONF_UNSET;
+    conf->min_length = NGX_CONF_UNSET;
+
+    return conf;
+}
+
+
+static char *
+ngx_http_gzip_merge_conf(ngx_conf_t *cf, void *parent, void *child)
+{
+    ngx_http_gzip_conf_t *prev = parent;
+    ngx_http_gzip_conf_t *conf = child;
+
+    ngx_http_gzip_type_t  *type;
+
+    ngx_conf_merge_value(conf->enable, prev->enable, 0);
+
+    ngx_conf_merge_bufs_value(conf->bufs, prev->bufs, 4, ngx_pagesize);
+
+    ngx_conf_merge_unsigned_value(conf->http_version, prev->http_version,
+                              NGX_HTTP_VERSION_11);
+    ngx_conf_merge_bitmask_value(conf->proxied, prev->proxied,
+                              (NGX_CONF_BITMASK_SET|NGX_HTTP_GZIP_PROXIED_OFF));
+
+    ngx_conf_merge_value(conf->level, prev->level, 1);
+    ngx_conf_merge_size_value(conf->wbits, prev->wbits, MAX_WBITS);
+    ngx_conf_merge_size_value(conf->memlevel, prev->memlevel,
+                              MAX_MEM_LEVEL - 1);
+    ngx_conf_merge_value(conf->min_length, prev->min_length, 0);
+    ngx_conf_merge_value(conf->no_buffer, prev->no_buffer, 0);
+
+    if (conf->types == NULL) {
+        if (prev->types == NULL) {
+            conf->types = ngx_array_create(cf->pool, 1,
+                                           sizeof(ngx_http_gzip_type_t));
+            if (conf->types == NULL) {
+                return NGX_CONF_ERROR;
+            }
+
+            type = ngx_array_push(conf->types);
+            if (type == NULL) {
+                return NGX_CONF_ERROR;
+            }
+
+            type->name.len = sizeof("text/html") - 1;
+            type->name.data = (u_char *) "text/html";
+            type->enable = 1;
+
+        } else {
+            conf->types = prev->types;
+        }
+    }
+
+    return NGX_CONF_OK;
+}
+
+
+static char *
+ngx_http_gzip_set_types(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+{
+    ngx_http_gzip_conf_t *gcf = conf;
+
+    ngx_str_t             *value;
+    ngx_uint_t             i;
+    ngx_http_gzip_type_t  *type;
+
+    if (gcf->types == NULL) {
+        gcf->types = ngx_array_create(cf->pool, 4,
+                                      sizeof(ngx_http_gzip_type_t));
+        if (gcf->types == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        type = ngx_array_push(gcf->types);
+        if (type == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        type->name.len = sizeof("text/html") - 1;
+        type->name.data = (u_char *) "text/html";
+        type->enable = 1;
+    }
+
+    value = cf->args->elts;
+
+    for (i = 1; i < cf->args->nelts; i++) {
+
+        if (ngx_strcmp(value[i].data, "text/html") == 0) {
+            continue;
+        }
+
+        type = ngx_array_push(gcf->types);
+        if (type == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        type->name.len = value[i].len;
+
+        type->name.data = ngx_palloc(cf->pool, type->name.len + 1);
+        if (type->name.data == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        ngx_cpystrn(type->name.data, value[i].data, type->name.len + 1);
+    }
+
+    return NGX_CONF_OK;
+}
+
+
+static char *
+ngx_http_gzip_set_window(ngx_conf_t *cf, void *post, void *data)
+{
+    int *np = data;
+
+    int  wbits, wsize;
+
+    wbits = 15;
+
+    for (wsize = 32 * 1024; wsize > 256; wsize >>= 1) {
+
+        if (wsize == *np) {
+            *np = wbits;
+
+            return NGX_CONF_OK;
+        }
+
+        wbits--;
+    }
+
+    return "must be 512, 1k, 2k, 4k, 8k, 16k, or 32k";
+}
+
+
+static char *
+ngx_http_gzip_set_hash(ngx_conf_t *cf, void *post, void *data)
+{
+    int *np = data;
+
+    int  memlevel, hsize;
+
+    memlevel = 9;
+
+    for (hsize = 128 * 1024; hsize > 256; hsize >>= 1) {
+
+        if (hsize == *np) {
+            *np = memlevel;
+
+            return NGX_CONF_OK;
+        }
+
+        memlevel--;
+    }
+
+    return "must be 512, 1k, 2k, 4k, 8k, 16k, 32k, 64k, or 128k";
+}