diff -r 809581724cc7 -r 0358f1d9c506 ucx/utils.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ucx/utils.c	Mon May 22 16:17:26 2023 +0200
@@ -0,0 +1,94 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "cx/utils.h"
+
+#define CX_STREAM_BCOPY_BUF_SIZE 8192
+#define CX_STREAM_COPY_BUF_SIZE 1024
+
+size_t cx_stream_bncopy(
+        void *src,
+        void *dest,
+        cx_read_func rfnc,
+        cx_write_func wfnc,
+        char *buf,
+        size_t bufsize,
+        size_t n
+) {
+    if (n == 0) {
+        return 0;
+    }
+
+    char *lbuf;
+    size_t ncp = 0;
+
+    if (buf) {
+        if (bufsize == 0) return 0;
+        lbuf = buf;
+    } else {
+        if (bufsize == 0) bufsize = CX_STREAM_BCOPY_BUF_SIZE;
+        lbuf = malloc(bufsize);
+        if (lbuf == NULL) {
+            return 0;
+        }
+    }
+
+    size_t r;
+    size_t rn = bufsize > n ? n : bufsize;
+    while ((r = rfnc(lbuf, 1, rn, src)) != 0) {
+        r = wfnc(lbuf, 1, r, dest);
+        ncp += r;
+        n -= r;
+        rn = bufsize > n ? n : bufsize;
+        if (r == 0 || n == 0) {
+            break;
+        }
+    }
+
+    if (lbuf != buf) {
+        free(lbuf);
+    }
+
+    return ncp;
+}
+
+size_t cx_stream_ncopy(
+        void *src,
+        void *dest,
+        cx_read_func rfnc,
+        cx_write_func wfnc,
+        size_t n
+) {
+    char buf[CX_STREAM_COPY_BUF_SIZE];
+    return cx_stream_bncopy(src, dest, rfnc, wfnc,
+                            buf, CX_STREAM_COPY_BUF_SIZE, n);
+}
+
+#ifndef CX_SZMUL_BUILTIN
+#include "szmul.c"
+#endif