Use liberasurecode_get_fragment_size

Currently both liberasurecode and PyECLib have fragment size
calculation by dividing alignment data length. However it might cause
size mismatch because of backend specific metadata added to each
fragment. To prevent such a mismatch, we should use
liberasurecode_get_fragment_size which allows to retrieve fragment_size
from liberasurecode directly instead of calculation itself.

1 files changed, 6 insertions, 17 deletions

diff --git a/src/c/pyeclib_c/pyeclib_c.c b/src/c/pyeclib_c/pyeclib_c.c
index 1830932..f46235d 100644
--- a/src/c/pyeclib_c/pyeclib_c.c
+++ b/src/c/pyeclib_c/pyeclib_c.c
@@ -215,8 +215,6 @@ pyeclib_c_get_segment_info(PyObject *self, PyObject *args)
   int num_segments;                        /* total number of segments */
   int fragment_size, last_fragment_size;   /* fragment sizes in bytes */
   int min_segment_size;                    /* EC algorithm's min. size (B) */
-  int aligned_segment_size;                /* size (B) adjusted for addr alignment */
-  int aligned_data_len;                    /* size (B) adjusted for addr alignment */
   
   /* Obtain and validate the method parameters */
   if (!PyArg_ParseTuple(args, "Oii", &pyeclib_obj_handle, &data_len, &segment_size)) {
@@ -251,13 +249,10 @@ pyeclib_c_get_segment_info(PyObject *self, PyObject *args)
      */
 
     /*
-     * This will copmpute a size algined to the number of data
-     * and the underlying wordsize of the EC algorithm.
+     * This will retrieve fragment_size calculated by liberasurecode with
+     * specified backend.
      */
-    aligned_data_len = liberasurecode_get_aligned_data_size(pyeclib_handle->ec_desc, data_len);
-
-    /* aligned_data_len is guaranteed to be divisible by k */
-    fragment_size = aligned_data_len / pyeclib_handle->ec_args.k;
+    fragment_size = liberasurecode_get_fragment_size(pyeclib_handle->ec_desc, data_len);
 
     /* Segment size is the user-provided segment size */
     segment_size = data_len;
@@ -269,10 +264,7 @@ pyeclib_c_get_segment_info(PyObject *self, PyObject *args)
      * the minimum segment size.
      */
 
-    aligned_segment_size = liberasurecode_get_aligned_data_size(pyeclib_handle->ec_desc, segment_size);
-
-    /* aligned_data_len is guaranteed to be divisible by k */
-    fragment_size = aligned_segment_size / pyeclib_handle->ec_args.k;
+    fragment_size = liberasurecode_get_fragment_size(pyeclib_handle->ec_desc, segment_size);
 
     last_segment_size = data_len - (segment_size * (num_segments - 1)); 
 
@@ -288,12 +280,9 @@ pyeclib_c_get_segment_info(PyObject *self, PyObject *args)
       last_segment_size = last_segment_size + segment_size;
     } 
     
-    aligned_segment_size = liberasurecode_get_aligned_data_size(pyeclib_handle->ec_desc, last_segment_size);
-     
-    /* Compute the last fragment size from the last segment size */
-    last_fragment_size = aligned_segment_size / pyeclib_handle->ec_args.k;
+    last_fragment_size = liberasurecode_get_fragment_size(pyeclib_handle->ec_desc, last_segment_size);
   }
-  
+
   /* Add header to fragment sizes */
   last_fragment_size += sizeof(fragment_header_t);
   fragment_size += sizeof(fragment_header_t);