Update documentation about metadata_adder

2 files changed, 15 insertions, 2 deletions

diff --git a/README.md b/README.md
index a04f3b3..0ced36d 100644
--- a/README.md
+++ b/README.md
@@ -277,7 +277,8 @@ struct
 fragment_metadata

 {

     uint32_t    idx;                /* 4 */

-    uint32_t    size;               /* 4 */

+    uint32_t    size;               /* 4 (raw data bytes size of each fragment used for encode/fragment_to_string) */

+    uint32_t    frag_adder_size;    /* 4 (extra metadata_adder bytes size of backend specification) */
     uint64_t    orig_data_size;     /* 8 */

     uint8_t     chksum_type;        /* 1 */

     uint32_t    chksum[LIBERASURECODE_MAX_CHECKSUM_LEN]; /* 16 */

@@ -339,6 +340,18 @@ int liberasurecode_get_aligned_data_size(int desc, uint64_t data_len);
  * @return minimum data length length, or -error code on error

  */

 int liberasurecode_get_minimum_encode_size(int desc);

+
+/**
+ * This will return the fragment size, which is each fragment data
+ * length the backend will allocate when encoding.
+ *
+ * @param desc - liberasurecode descriptor/handle
+ *        from liberasurecode_instance_create()
+ * @param data_len - original data length in bytes
+ *
+ * @return fragment size - sizeof(fragment_header) + size + frag_adder_size
+ */
+int liberasurecode_get_fragment_size(int desc, int data_len);
 

 ```

 ----

diff --git a/include/erasurecode/erasurecode.h b/include/erasurecode/erasurecode.h
index 7dc7ba7..7f78b55 100644
--- a/include/erasurecode/erasurecode.h
+++ b/include/erasurecode/erasurecode.h
@@ -336,7 +336,7 @@ int liberasurecode_get_minimum_encode_size(int desc);
  *        from liberasurecode_instance_create()
  * @param data_len - original data length in bytes
  *
- * @return fragment size
+ * @return fragment size - sizeof(fragment_header) + size + frag_adder_size
  */
 int liberasurecode_get_fragment_size(int desc, int data_len);