--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/source/fitz/jmemcust.h	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,53 @@
+/* Copyright (C) 2001-2017 Artifex Software, Inc.
+ * All Rights Reserved.
+ *
+ * This software is provided AS-IS with no warranty, either express or
+ * implied.
+ *
+ * This software is distributed under license and may not be copied,
+ * modified or distributed except as expressly authorized under the terms
+ * of the license contained in the file LICENSE in this distribution.
+ *
+ * Refer to licensing information at http://www.artifex.com or contact
+ * Artifex Software, Inc., 7 Mt. Lassen Drive - Suite A-134, San Rafael,
+ * CA 94903, U.S.A., +1(415)492-9861, for further information.
+ */
+
+ #ifndef MUPDF_JMEMCUST_H
+ #define MUPDF_JMEMCUST_H
+
+typedef JMETHOD(long, j_custmem_init_ptr, (j_common_ptr cinfo));
+typedef JMETHOD(void, j_custmem_term_ptr, (j_common_ptr cinfo));
+typedef JMETHOD(long, j_custmem_avail_ptr, (j_common_ptr cinfo));
+typedef JMETHOD(void *, j_custmem_get_small_ptr, (j_common_ptr cinfo, size_t size));
+typedef JMETHOD(void, j_custmem_free_small_ptr, (j_common_ptr cinfo, void *object, size_t size));
+typedef JMETHOD(void *, j_cust_mem_get_large_ptr, (j_common_ptr cinfo, size_t size));
+typedef JMETHOD(void, j_custmem_free_large_ptr, (j_common_ptr cinfo, void *object, size_t size));
+typedef JMETHOD(void, j_custmem_open_backing_store_ptr, (j_common_ptr cinfo, backing_store_ptr info, long total_bytes_needed));
+
+typedef struct {
+	j_custmem_init_ptr j_mem_init;
+	j_custmem_term_ptr j_mem_term;
+	j_custmem_avail_ptr j_mem_avail;
+	j_custmem_get_small_ptr j_mem_get_small;
+	j_custmem_free_small_ptr j_mem_free_small;
+	j_cust_mem_get_large_ptr j_mem_get_large;
+	j_custmem_free_large_ptr j_mem_free_large;
+	j_custmem_open_backing_store_ptr j_mem_open_backing_store;
+	void *priv;
+} jpeg_cust_mem_data;
+
+#define GET_CUST_MEM_DATA(c) ((jpeg_cust_mem_data *)c->client_data)
+
+GLOBAL(jpeg_cust_mem_data *)
+	jpeg_cust_mem_init(jpeg_cust_mem_data *custm, void *priv,
+			j_custmem_init_ptr init,
+			j_custmem_term_ptr term,
+			j_custmem_avail_ptr avail,
+			j_custmem_get_small_ptr get_small,
+			j_custmem_free_small_ptr free_small,
+			j_cust_mem_get_large_ptr get_large,
+			j_custmem_free_large_ptr free_large,
+			j_custmem_open_backing_store_ptr open_backing_store);
+
+#endif