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)

3 files changed, 187 insertions, 37 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;
diff --git a/test/liberasurecode_test.c b/test/liberasurecode_test.c
index 6291be5..c9d67af 100644
--- a/test/liberasurecode_test.c
+++ b/test/liberasurecode_test.c
@@ -57,6 +57,8 @@ struct ec_args null_args = {
     .ct = CHKSUM_NONE,
 };
 
+struct ec_args *null_test_args[] = { &null_args, NULL };
+
 struct ec_args flat_xor_hd_args = {
     .k = 3,
     .m = 3,
@@ -64,6 +66,8 @@ struct ec_args flat_xor_hd_args = {
     .ct = CHKSUM_NONE,
 };
 
+struct ec_args *flat_xor_test_args[] = { &flat_xor_hd_args, NULL };
+
 struct ec_args jerasure_rs_vand_args = {
     .k = 10,
     .m = 4,
@@ -72,6 +76,35 @@ struct ec_args jerasure_rs_vand_args = {
     .ct = CHKSUM_NONE,
 };
 
+struct ec_args jerasure_rs_vand_44_args = {
+    .k = 4,
+    .m = 4,
+    .w = 16,
+    .hd = 5,
+    .ct = CHKSUM_NONE,
+};
+
+struct ec_args jerasure_rs_vand_48_args = {
+    .k = 4,
+    .m = 8,
+    .w = 16,
+    .hd = 9,
+    .ct = CHKSUM_NONE,
+};
+
+struct ec_args jerasure_rs_vand_1010_args = {
+    .k = 10,
+    .m = 10,
+    .w = 16,
+    .hd = 11,
+    .ct = CHKSUM_NONE,
+};
+
+struct ec_args *jerasure_rs_vand_test_args[] = { &jerasure_rs_vand_args, 
+                                                 &jerasure_rs_vand_44_args, 
+                                                 &jerasure_rs_vand_1010_args, 
+                                                 &jerasure_rs_vand_48_args, 
+                                                 NULL };
 struct ec_args jerasure_rs_cauchy_args = {
     .k = 10,
     .m = 4,
@@ -80,6 +113,37 @@ struct ec_args jerasure_rs_cauchy_args = {
     .ct = CHKSUM_NONE,
 };
 
+struct ec_args jerasure_rs_cauchy_44_args = {
+    .k = 4,
+    .m = 4,
+    .w = 4,
+    .hd = 5,
+    .ct = CHKSUM_NONE,
+};
+
+struct ec_args jerasure_rs_cauchy_48_args = {
+    .k = 4,
+    .m = 8,
+    .w = 8,
+    .hd = 9,
+    .ct = CHKSUM_NONE,
+};
+
+
+struct ec_args jerasure_rs_cauchy_1010_args = {
+    .k = 10,
+    .m = 10,
+    .w = 8,
+    .hd = 11,
+    .ct = CHKSUM_NONE,
+};
+
+struct ec_args *jerasure_rs_cauchy_test_args[] = { &jerasure_rs_cauchy_args, 
+                                                   &jerasure_rs_cauchy_44_args, 
+                                                   &jerasure_rs_cauchy_48_args, 
+                                                   &jerasure_rs_cauchy_1010_args, 
+                                                   NULL };
+
 struct ec_args isa_l_args = {
     .k = 10,
     .m = 4,
@@ -87,6 +151,25 @@ struct ec_args isa_l_args = {
     .hd = 5,
 };
 
+struct ec_args isa_l_44_args = {
+    .k = 4,
+    .m = 4,
+    .w = 8,
+    .hd = 5,
+};
+
+struct ec_args isa_l_1010_args = {
+    .k = 10,
+    .m = 10,
+    .w = 8,
+    .hd = 11,
+};
+
+struct ec_args *isa_l_test_args[] = { &isa_l_args, 
+                                      &isa_l_44_args,
+                                      &isa_l_1010_args,
+                                      NULL };
+
 int priv = 128;
 struct ec_args shss_args = {
     .k = 6,
@@ -95,6 +178,43 @@ struct ec_args shss_args = {
     .priv_args2 = &priv,
 };
 
+struct ec_args *shss_test_args[] = { &shss_args, NULL };
+
+struct ec_args **all_backend_tests[] = {  null_test_args, 
+                                          flat_xor_test_args, 
+                                          jerasure_rs_vand_test_args, 
+                                          jerasure_rs_cauchy_test_args, 
+                                          isa_l_test_args, 
+                                          shss_test_args , NULL};
+
+int num_backends()
+{
+  int i = 0;
+
+  while (NULL != all_backend_tests[i]) {
+    i++;
+  }
+
+  return i;
+}
+
+int max_tests_for_backends()
+{
+  int n_backends = num_backends();
+  int i = 0;
+  int max = 0;
+
+  for (i = 0; i < n_backends; i++) {
+    int j = 0;
+    while (NULL != all_backend_tests[i][j]) {
+      j++;
+    }
+    if (j > max) {
+      max = j;
+    }
+  }
+  return max;
+}
 
 typedef enum {
     LIBEC_VERSION_MISMATCH,
@@ -122,32 +242,48 @@ char * get_name_from_backend_id(ec_backend_id_t be) {
     }
 }
 
-struct ec_args *create_ec_args(ec_backend_id_t be, ec_checksum_type_t ct)
+struct ec_args *create_ec_args(ec_backend_id_t be, ec_checksum_type_t ct, int backend_test_idx)
 {
     size_t ec_args_size = sizeof(struct ec_args);
     struct ec_args *template = NULL;
+    struct ec_args** backend_args_array = NULL;
+    int i = 0;
+
     switch(be) {
         case EC_BACKEND_NULL:
-            template = &null_args;
+            backend_args_array = null_test_args;
             break;
         case EC_BACKEND_JERASURE_RS_VAND:
-            template = &jerasure_rs_vand_args;
+            backend_args_array = jerasure_rs_vand_test_args;
             break;
         case EC_BACKEND_JERASURE_RS_CAUCHY:
-            template = &jerasure_rs_cauchy_args;
+            backend_args_array = jerasure_rs_cauchy_test_args;
             break;
         case EC_BACKEND_FLAT_XOR_HD:
-            template = &flat_xor_hd_args;
+            backend_args_array = flat_xor_test_args;
             break;
         case EC_BACKEND_ISA_L_RS_VAND:
-            template = &isa_l_args;
+            backend_args_array = isa_l_test_args;
             break;
         case EC_BACKEND_SHSS:
-            template = &shss_args;
+            backend_args_array = shss_test_args;
             break;
         default:
             return NULL;
     }
+
+    while (NULL != backend_args_array && NULL != backend_args_array[i]) {
+        if (i == backend_test_idx) {
+            template = backend_args_array[i];
+            break;
+        }
+        i++;
+    }
+
+    if (NULL == template) {
+      return NULL;
+    }
+
     struct ec_args *args = malloc(ec_args_size);
     assert(args);
     memcpy(args, template, ec_args_size);
@@ -1077,13 +1213,13 @@ static void test_decode_with_missing_parity(const ec_backend_id_t be_id,
 static void test_decode_with_missing_multi_data(const ec_backend_id_t be_id,
                                                 struct ec_args *args)
 {
-    int max_num_missing = args->hd - 1;
+    int max_num_missing = args->k <= (args->hd - 1) ? args->k : args->hd - 1;
     int i,j;
     for (i = 0; i < args->k - max_num_missing + 1; i++) {
         int *skip = create_skips_array(args,-1);
         assert(skip != NULL);
         for (j = i; j < i + max_num_missing; j++) {
-            skip[j]=1;
+            skip[j % args->k]=1;
         }
         encode_decode_test_impl(be_id, args, skip);
         free(skip);
@@ -1111,8 +1247,8 @@ static void test_decode_with_missing_multi_data_parity(
 {
     int i,j;
     int max_num_missing = args->hd - 1;
-    int start = args->k - max_num_missing + 1;
-    for (i = start; i < start + max_num_missing -1; i++) {
+    int end = (args->k + args->m) - max_num_missing + 1;
+    for (i = 0; i < end; i++) {
         int *skip = create_skips_array(args,-1);
         assert(skip != NULL);
         for (j = i; j < i + max_num_missing; j++) {
@@ -1651,30 +1787,30 @@ struct testcase testcases[] = {
 
 int main(int argc, char **argv)
 {
-    int ii = 0, num_cases = 0;
-
-    for (num_cases = 0; testcases[num_cases].description; num_cases++) {
-        /* Just counting */
-    }
-
-    printf("1..%d\n", num_cases);
-
-    for (ii = 0; testcases[ii].description != NULL; ++ii) {
-        const char *testname = get_name_from_backend_id(testcases[ii].be_id);
-        fflush(stdout);
-        if (testcases[ii].skip) {
-            fprintf(stdout, "ok # SKIP %d - %s: %s\n", ii + 1,
-                    testcases[ii].description,
-                    (testname) ? testname : "");
-            continue;
+    int ii = 0, num_cases = 0, i = 0;
+    int max_backend_tests = max_tests_for_backends();
+
+    for (i = 0; i < max_backend_tests; i++) {
+		    for (ii = 0; testcases[ii].description != NULL; ++ii) {
+		        const char *testname = get_name_from_backend_id(testcases[ii].be_id);
+		        fflush(stdout);
+		        if (testcases[ii].skip) {
+		            fprintf(stdout, "ok # SKIP %d - %s: %s (idx=%d)\n", num_cases,
+		                    testcases[ii].description,
+		                    (testname) ? testname : "", i);
+		            continue;
+		        }
+		        struct ec_args *args = create_ec_args(testcases[ii].be_id, testcases[ii].ct, i);
+            if (NULL != args) {
+		            testcases[ii].function(testcases[ii].be_id, args);
+		            fprintf(stdout, "ok %d - %s: %s (idx=%d)\n", num_cases,
+		                    testcases[ii].description,
+		                    (testname) ? testname : "", i);
+		            fflush(stdout);
+		            free(args);
+		            num_cases++;
+            } 
         }
-        struct ec_args *args = create_ec_args(testcases[ii].be_id, testcases[ii].ct);
-        testcases[ii].function(testcases[ii].be_id, args);
-        fprintf(stdout, "ok %d - %s: %s\n", ii + 1,
-                testcases[ii].description,
-                (testname) ? testname : "");
-        fflush(stdout);
-        free(args);
     }
     return 0;
 }