add buffer_init_allocbuf, buffer_init_read, buffer_init_write, buffer_init_read_allocbuf, buffer_init_write_allocbuf

buffer/buffer_init_allocbuf.c

@@ -0,0 +1,13 @@
+#include <stdlib.h>
+#include <unistd.h>
+#include "buffer.h"
+
+int buffer_init_allocbuf(buffer* b, ssize_t (*op)(), int fd, size_t ylen) {
+  if (fd==-1) return -1;
+  char* thebuffer;
+  if (!(thebuffer=malloc(ylen)))
+    return -1;
+  buffer_init_free(b, op, fd, thebuffer, ylen);
+  return 0;
+}
+