diff --git a/lib/zip_replace_data.c b/lib/zip_replace_data.c
new file mode 100644
index 0000000..994e4cc
--- /dev/null
+++ b/lib/zip_replace_data.c
@@ -0,0 +1,75 @@
+#include <stdlib.h>
+
+#include "zip.h"
+#include "zipint.h"
+
+struct read_data {
+    char *buf, *data;
+    int size;
+    int freep;
+};
+
+static zip_read_func read_data;
+
+
+
+int
+zip_replace_data(struct zf *zf, int idx, char *name, struct zip_meta *meta,
+		 char *data, int len, int freep)
+{
+    struct read_data *f;
+    
+    if (srcidx < -1 || srcidx >= srczf->nentry) {
+	zip_err = ZERR_NOENT;
+	return -1;
+    }
+
+    if ((f=(struct read_data *)malloc(sizeof(struct read_data))) == NULL) {
+	zip_err = ZERR_MEMORY;
+	return -1;
+    }
+
+    f->data = data;
+    f->len = len;
+    f->freep = freep;
+    
+    return zip_replace(zf, idx, name, meta, read_data, f, 0);
+}
+
+
+
+static int
+read_data(void *state, void *data, int len, enum zip_cmd cmd)
+{
+    struct read_data *z;
+    char *buf;
+    int n;
+
+    z = (struct read_file *)state;
+    buf = (char *)data;
+
+    switch (cmd) {
+    case ZIP_CMD_INIT:
+	z->buf = z->data;
+	return 0;
+	
+    case ZIP_CMD_READ:
+	n = len > z->len ? z->len : len;
+
+	memcpy(buf, z->buf, n);
+	z->buf += n;
+	z->len -= n;
+
+	return n;
+	
+    case ZIP_CMD_META:
+	return 0;
+
+    case ZIP_CMD_CLOSE:
+	if (z->freep) {
+	    free(z->data);
+	    z->data = NULL;
+	}
+	return 0;
+    }
+}