This is the fix for Issue #13:

https://bitbucket.org/tsg-/liberasurecode/issue/13/decode-fails-for-many-cases-when-m-k

This fix includes:

1.) Proper buffer allocation for the 'missing_idxs' structure, which was not allocating enough
    space when k > m.
2.) Checks to use header fields of parity fragments during decode when *no* data fragments
    are available.
3.) Fixed the unit tests to properly handle the case where k <= m.
4.) Extended the unit test framework to support multiple tests per backend
5.) Added tests for all RS implementations: (4,8), (4,4), (10,10)

2 files changed, 17 insertions, 3 deletions

diff --git a/src/erasurecode.c b/src/erasurecode.c
index 2c6a30b..d9a868c 100644
--- a/src/erasurecode.c
+++ b/src/erasurecode.c
@@ -587,7 +587,7 @@ int liberasurecode_decode(int desc,
         goto out;
     }
 
-    missing_idxs = alloc_and_set_buffer(sizeof(char*) * k, -1);
+    missing_idxs = alloc_and_set_buffer(sizeof(char*) * (k + m), -1);
     if (NULL == missing_idxs) {
         log_error("Could not allocate missing_idxs buffer!");
         goto out;
@@ -771,7 +771,7 @@ int liberasurecode_reconstruct_fragment(int desc,
         goto out;
     }
 
-    missing_idxs = alloc_and_set_buffer(sizeof(int*) * k, -1);
+    missing_idxs = alloc_and_set_buffer(sizeof(int*) * (k + m), -1);
     if (NULL == missing_idxs) {
         log_error("Could not allocate missing_idxs buffer!");
         goto out;
diff --git a/src/erasurecode_preprocessing.c b/src/erasurecode_preprocessing.c
index d8da1f6..e23b028 100644
--- a/src/erasurecode_preprocessing.c
+++ b/src/erasurecode_preprocessing.c
@@ -119,7 +119,7 @@ int prepare_fragments_for_decode(
     unsigned long long missing_bm;  /* bitmap form of missing indexes list */
     int orig_data_size = -1;
     int payload_size = -1;
- 
+
     missing_bm = convert_list_to_bitmap(missing_idxs);
 
     /*
@@ -192,6 +192,20 @@ int prepare_fragments_for_decode(
             *realloc_bm = *realloc_bm | (1 << (k + i));
         }
 
+       /* Need to determine the size of the original data */
+       if (((missing_bm & (1 << (k + i))) == 0) && orig_data_size < 0) {
+            orig_data_size = get_orig_data_size(parity[i]);
+            if (orig_data_size < 0) {
+                log_error("Invalid orig_data_size in fragment header!");
+                return -EBADHEADER;
+            }
+            payload_size = get_fragment_payload_size(parity[i]);
+            if (orig_data_size < 0) {
+                log_error("Invalid fragment_size in fragment header!");
+                return -EBADHEADER;
+            }
+       }
+
     }
 
     *orig_size = orig_data_size;