INTERNAL: Refactor the memcached_io_read function

libmemcached/io.cc

@@ -539,7 +539,8 @@ memcached_return_t memcached_io_read(memcached_server_write_instance_st ptr,
   }
 
   char *buffer_ptr= static_cast<char *>(buffer);
-  while (length)
+  size_t remain= length;
+  while (remain)
   {
     if (ptr->read_buffer_length == 0)
     {
@@ -551,27 +552,31 @@ memcached_return_t memcached_io_read(memcached_server_write_instance_st ptr,
         return io_fill_ret;
       }
     }
-    if (length > 1)
+    if (remain > 1)
     {
-      size_t difference= (length > ptr->read_buffer_length) ? ptr->read_buffer_length : length;
-      memcpy(buffer_ptr, ptr->read_ptr, difference);
+      size_t difference= (remain > ptr->read_buffer_length) ? ptr->read_buffer_length : remain;
+      if (buffer_ptr) {
+        memcpy(buffer_ptr, ptr->read_ptr, difference);
+        buffer_ptr+= difference;
+      }
 
-      length-= difference;
       ptr->read_ptr+= difference;
       ptr->read_buffer_length-= difference;
-      buffer_ptr+= difference;
+      remain-= difference;
     }
     else
     {
-      *buffer_ptr= *ptr->read_ptr;
+      if (buffer_ptr) {
+        *buffer_ptr= *ptr->read_ptr;
+        buffer_ptr++;
+      }
       ptr->read_ptr++;
       ptr->read_buffer_length--;
-      buffer_ptr++;
       break;
     }
   }
 
-  *nread = (ssize_t)(buffer_ptr - (char*)buffer);
+  *nread = (ssize_t)(length - remain);
 
   return MEMCACHED_SUCCESS;
 }
@@ -847,22 +852,14 @@ memcached_return_t memcached_safe_read(memcached_server_write_instance_st ptr,
                                        void *dta,
                                        size_t size)
 {
-  size_t offset= 0;
   char *data= static_cast<char *>(dta);
+  ssize_t nread;
+  memcached_return_t rc;
 
-  while (offset < size)
-  {
-    ssize_t nread;
-    memcached_return_t rc;
-
-    while (memcached_continue(rc= memcached_io_read(ptr, data + offset, size - offset, &nread))) { };
-
-    if (memcached_failed(rc))
-    {
-      return rc;
-    }
+  while (memcached_continue(rc= memcached_io_read(ptr, data, size, &nread))) {}
 
-    offset+= (size_t) nread;
+  if (memcached_failed(rc)) {
+    return rc;
   }
 
   return MEMCACHED_SUCCESS;