--- a/contrib/s390/dfltcc.c

+++ b/contrib/s390/dfltcc.c

@@ -539,10 +539,6 @@ int ZLIB_INTERNAL dfltcc_can_inflate(strm)

     struct inflate_state FAR *state = (struct inflate_state FAR *)strm->state;

     struct dfltcc_state FAR *dfltcc_state = GET_DFLTCC_STATE(state);

-    /* Unsupported compression settings */

-    if (state->wbits != HB_BITS)

-        return 0;

-

     /* Unsupported hardware */

     return is_bit_set(dfltcc_state->af.fns, DFLTCC_XPND) &&

                is_bit_set(dfltcc_state->af.fmts, DFLTCC_FMT0);

@@ -606,8 +602,6 @@ dfltcc_inflate_action ZLIB_INTERNAL dfltcc_inflate(strm, flush, ret)

     /* Translate stream to parameter block */

     param->cvt = state->flags ? CVT_CRC32 : CVT_ADLER32;

     param->sbb = state->bits;

-    param->hl = state->whave; /* Software and hardware history formats match */

-    param->ho = (state->wnext - state->whave) & ((1 << HB_BITS) - 1);

     if (param->hl)

         param->nt = 0; /* Honor history for the first block */

     param->cv = state->flags ? ZSWAP32(state->check) : state->check;

@@ -621,8 +615,6 @@ dfltcc_inflate_action ZLIB_INTERNAL dfltcc_inflate(strm, flush, ret)

     strm->msg = oesc_msg(dfltcc_state->msg, param->oesc);

     state->last = cc == DFLTCC_CC_OK;

     state->bits = param->sbb;

-    state->whave = param->hl;

-    state->wnext = (param->ho + param->hl) & ((1 << HB_BITS) - 1);

     strm->adler = state->check = state->flags ? ZSWAP32(param->cv) : param->cv;

     if (cc == DFLTCC_CC_OP2_CORRUPT && param->oesc != 0) {

         /* Report an error if stream is corrupted */

@@ -644,11 +636,52 @@ int ZLIB_INTERNAL dfltcc_was_inflate_used(strm)

     return !param->nt;

 }

+/*

+   Rotates a circular buffer.

+   The implementation is based on https://cplusplus.com/reference/algorithm/rotate/

+ */

+local void rotate OF((Bytef *start, Bytef *pivot, Bytef *end));

+local void rotate(start, pivot, end)

+    Bytef *start;

+    Bytef *pivot;

+    Bytef *end;

+{

+    Bytef *p = pivot;

+    Bytef tmp;

+

+    while (p != start) {

+        tmp = *start;

+        *start = *p;

+        *p = tmp;

+

+        start++;

+        p++;

+

+        if (p == end)

+            p = pivot;

+        else if (start == pivot)

+            pivot = p;

+    }

+}

+

+#define MIN(x, y) ({    \

+    typeof(x) _x = (x); \

+    typeof(y) _y = (y); \

+    _x < _y ? _x : _y;  \

+})

+

+#define MAX(x, y) ({    \

+    typeof(x) _x = (x); \

+    typeof(y) _y = (y); \

+    _x > _y ? _x : _y;  \

+})

+

 int ZLIB_INTERNAL dfltcc_inflate_disable(strm)

     z_streamp strm;

 {

     struct inflate_state FAR *state = (struct inflate_state FAR *)strm->state;

     struct dfltcc_state FAR *dfltcc_state = GET_DFLTCC_STATE(state);

+    struct dfltcc_param_v0 *param = &dfltcc_state->param;

     if (!dfltcc_can_inflate(strm))

         return 0;

@@ -660,6 +693,9 @@ int ZLIB_INTERNAL dfltcc_inflate_disable(strm)

         return 1;

     /* DFLTCC was not used yet - decompress in software */

     memset(&dfltcc_state->af, 0, sizeof(dfltcc_state->af));

+    /* Convert the window from the hardware to the software format */

+    rotate(state->window, state->window + param->ho, state->window + HB_SIZE);

+    state->whave = state->wnext = MIN(param->hl, state->wsize);

     return 0;

 }

@@ -830,9 +866,9 @@ voidpf ZLIB_INTERNAL dfltcc_alloc_window(strm, items, size)

     voidpf p, w;

     /* To simplify freeing, we store the pointer to the allocated buffer right

-     * before the window.

+     * before the window. Note that DFLTCC always uses HB_SIZE bytes.

      */

-    p = ZALLOC(strm, sizeof(voidpf) + items * size + PAGE_ALIGN,

+    p = ZALLOC(strm, sizeof(voidpf) + MAX(items * size, HB_SIZE) + PAGE_ALIGN,

                sizeof(unsigned char));

     if (p == NULL)

         return NULL;

@@ -841,6 +877,14 @@ voidpf ZLIB_INTERNAL dfltcc_alloc_window(strm, items, size)

     return w;

 }

+void ZLIB_INTERNAL dfltcc_copy_window(dest, src, n)

+    void *dest;

+    const void *src;

+    size_t n;

+{

+    memcpy(dest, src, MAX(n, HB_SIZE));

+}

+

 void ZLIB_INTERNAL dfltcc_free_window(strm, w)

     z_streamp strm;

     voidpf w;

@@ -951,6 +995,24 @@ local void append_history(param, history, buf, count)

     }

 }

+local void get_history OF((struct dfltcc_param_v0 FAR *param,

+                           const Bytef *history,

+                           Bytef *buf));

+local void get_history(param, history, buf)

+    struct dfltcc_param_v0 FAR *param;

+    const Bytef *history;

+    Bytef *buf;

+{

+    if (param->ho + param->hl <= HB_SIZE)

+        /* Circular history buffer does not wrap - copy one chunk */

+        memcpy(buf, history + param->ho, param->hl);

+    else {

+        /* Circular history buffer wraps - copy two chunks */

+        memcpy(buf, history + param->ho, HB_SIZE - param->ho);

+        memcpy(buf + HB_SIZE - param->ho, history, param->ho + param->hl - HB_SIZE);

+    }

+}

+

 int ZLIB_INTERNAL dfltcc_deflate_set_dictionary(strm, dictionary, dict_length)

     z_streamp strm;

     const Bytef *dictionary;

@@ -975,20 +1037,43 @@ int ZLIB_INTERNAL dfltcc_deflate_get_dictionary(strm, dictionary, dict_length)

     struct dfltcc_state FAR *dfltcc_state = GET_DFLTCC_STATE(state);

     struct dfltcc_param_v0 FAR *param = &dfltcc_state->param;

-    if (dictionary) {

-        if (param->ho + param->hl <= HB_SIZE)

-            /* Circular history buffer does not wrap - copy one chunk */

-            zmemcpy(dictionary, state->window + param->ho, param->hl);

-        else {

-            /* Circular history buffer wraps - copy two chunks */

-            zmemcpy(dictionary,

-                    state->window + param->ho,

-                    HB_SIZE - param->ho);

-            zmemcpy(dictionary + HB_SIZE - param->ho,

-                    state->window,

-                    param->ho + param->hl - HB_SIZE);

-        }

+    if (dictionary)

+        get_history(param, state->window, dictionary);

+    if (dict_length)

+        *dict_length = param->hl;

+    return Z_OK;

+}

+

+int ZLIB_INTERNAL dfltcc_inflate_set_dictionary(strm, dictionary, dict_length)

+    z_streamp strm;

+    const Bytef *dictionary;

+    uInt dict_length;

+{

+    struct inflate_state *state = (struct inflate_state *)strm->state;

+    struct dfltcc_state *dfltcc_state = GET_DFLTCC_STATE(state);

+    struct dfltcc_param_v0 *param = &dfltcc_state->param;

+

+    if (inflate_ensure_window(state)) {

+        state->mode = MEM;

+        return Z_MEM_ERROR;

     }

+

+    append_history(param, state->window, dictionary, dict_length);

+    state->havedict = 1;

+    return Z_OK;

+}

+

+int ZLIB_INTERNAL dfltcc_inflate_get_dictionary(strm, dictionary, dict_length)

+    z_streamp strm;

+    Bytef *dictionary;

+    uInt *dict_length;

+{

+    struct inflate_state *state = (struct inflate_state *)strm->state;

+    struct dfltcc_state *dfltcc_state = GET_DFLTCC_STATE(state);

+    struct dfltcc_param_v0 *param = &dfltcc_state->param;

+

+    if (dictionary && state->window)

+        get_history(param, state->window, dictionary);

     if (dict_length)

         *dict_length = param->hl;

     return Z_OK;

--- a/contrib/s390/dfltcc.h

+++ b/contrib/s390/dfltcc.h

@@ -11,6 +11,8 @@ void ZLIB_INTERNAL dfltcc_copy_state OF((voidpf dst, const voidpf src,

 void ZLIB_INTERNAL dfltcc_reset OF((z_streamp strm, uInt size));

 voidpf ZLIB_INTERNAL dfltcc_alloc_window OF((z_streamp strm, uInt items,

                                              uInt size));

+void ZLIB_INTERNAL dfltcc_copy_window OF((void *dest, const void *src,

+                                          size_t n));

 void ZLIB_INTERNAL dfltcc_free_window OF((z_streamp strm, voidpf w));

 #define DFLTCC_BLOCK_HEADER_BITS 3

 #define DFLTCC_HLITS_COUNT_BITS 5

@@ -44,11 +46,18 @@ dfltcc_inflate_action ZLIB_INTERNAL dfltcc_inflate OF((z_streamp strm,

                                                        int flush, int *ret));

 int ZLIB_INTERNAL dfltcc_was_inflate_used OF((z_streamp strm));

 int ZLIB_INTERNAL dfltcc_inflate_disable OF((z_streamp strm));

+int ZLIB_INTERNAL dfltcc_inflate_set_dictionary OF((z_streamp strm,

+                                                    const Bytef *dictionary,

+                                                    uInt dict_length));

+int ZLIB_INTERNAL dfltcc_inflate_get_dictionary OF((z_streamp strm,

+                                                    Bytef *dictionary,

+                                                    uInt* dict_length));

 #define ZALLOC_STATE dfltcc_alloc_state

 #define ZFREE_STATE ZFREE

 #define ZCOPY_STATE dfltcc_copy_state

 #define ZALLOC_WINDOW dfltcc_alloc_window

+#define ZCOPY_WINDOW dfltcc_copy_window

 #define ZFREE_WINDOW dfltcc_free_window

 #define TRY_FREE_WINDOW dfltcc_free_window

 #define INFLATE_RESET_KEEP_HOOK(strm) \

@@ -77,5 +86,15 @@ int ZLIB_INTERNAL dfltcc_inflate_disable OF((z_streamp strm));

     do { \

         if (dfltcc_was_inflate_used((strm))) return Z_STREAM_ERROR; \

     } while (0)

+#define INFLATE_SET_DICTIONARY_HOOK(strm, dict, dict_len) \

+    do { \

+        if (dfltcc_can_inflate(strm)) \

+            return dfltcc_inflate_set_dictionary(strm, dict, dict_len); \

+    } while (0)

+#define INFLATE_GET_DICTIONARY_HOOK(strm, dict, dict_len) \

+    do { \

+        if (dfltcc_can_inflate(strm)) \

+            return dfltcc_inflate_get_dictionary(strm, dict, dict_len); \

+    } while (0)

 #endif

\ No newline at end of file

diff --git a/inflate.c b/inflate.c

index 3750152..a0e2169 100644

--- a/inflate.c

+++ b/inflate.c

@@ -93,6 +93,7 @@

 #define ZFREE_STATE ZFREE

 #define ZCOPY_STATE zmemcpy

 #define ZALLOC_WINDOW ZALLOC

+#define ZCOPY_WINDOW zmemcpy

 #define ZFREE_WINDOW ZFREE

 #define INFLATE_RESET_KEEP_HOOK(strm) do {} while (0)

 #define INFLATE_PRIME_HOOK(strm, bits, value) do {} while (0)

@@ -101,6 +102,8 @@

 #define INFLATE_NEED_UPDATEWINDOW(strm) 1

 #define INFLATE_MARK_HOOK(strm) do {} while (0)

 #define INFLATE_SYNC_POINT_HOOK(strm) do {} while (0)

+#define INFLATE_SET_DICTIONARY_HOOK(strm, dict, dict_len) do {} while (0)

+#define INFLATE_GET_DICTIONARY_HOOK(strm, dict, dict_len) do {} while (0)

 #endif

 #ifdef MAKEFIXED

@@ -1330,6 +1333,8 @@ uInt *dictLength;

     if (inflateStateCheck(strm)) return Z_STREAM_ERROR;

     state = (struct inflate_state FAR *)strm->state;

+    INFLATE_GET_DICTIONARY_HOOK(strm, dictionary, dictLength);

+

     /* copy dictionary */

     if (state->whave && dictionary != Z_NULL) {

         zmemcpy(dictionary, state->window + state->wnext,

@@ -1365,6 +1370,8 @@ uInt dictLength;

             return Z_DATA_ERROR;

     }

+    INFLATE_SET_DICTIONARY_HOOK(strm, dictionary, dictLength);

+

     /* copy dictionary to window using updatewindow(), which will amend the

        existing dictionary if appropriate */

     ret = updatewindow(strm, dictionary + dictLength, dictLength);

@@ -1529,8 +1536,7 @@ z_streamp source;

     }

     copy->next = copy->codes + (state->next - state->codes);

     if (window != Z_NULL) {

-        wsize = 1U << state->wbits;

-        zmemcpy(window, state->window, wsize);

+        ZCOPY_WINDOW(window, state->window, 1U << state->wbits);

     }

     copy->window = window;

     dest->state = (struct internal_state FAR *)copy;