The header will have 12 elements unconditionally (i.e. metalayers wil…

…l always be there)
Blosc · Aug 30, 2019 · 9755813 · 9755813
1 parent a62b5ba
commit 9755813
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Showing 3 changed files with 5 additions and 19 deletions.
diff --git a/README_FRAME_FORMAT.rst b/README_FRAME_FORMAT.rst
@@ -26,7 +26,7 @@ The header of a frame is encoded via  `msgpack <https://msgpack.org>`_ and it fo
       |   |       |                           +--[msgpack] int32
       |   |       +---magic number, currently "b2frame"
       |   +------[msgpack] str with 8 elements
-      +---[msgpack] fixarray with X=0xB (11, no metalayers) or X=0xC (12) elements
+      +---[msgpack] fixarray with X=0xC (12) elements
 
     |-18|-19|-1A|-1B|-1C|-1D|-1E|-1F|-20|-21|-22|-23|-24|-25|-26|-27|-28|-29|-2A|-2B|-2C|-2D|-2E|
     | a4|_f0|_f1|_f2|_f3| d3| uncompressed_size             | d3| compressed_size               |
@@ -52,7 +52,7 @@ The header of a frame is encoded via  `msgpack <https://msgpack.org>`_ and it fo
       |                   +------[msgpack] int32
       +---[msgpack] int32
 
-The it follows the info about the filter pipeline.  There is place for a pipeline that is 8 slots deep, and there is a reserved byte per every filter code and a possible associated meta-info::
+Then it follows the info about the filter pipeline.  There is place for a pipeline that is 8 slots deep, and there is a reserved byte per every filter code and another byte for a possible associated meta-info::
 
     |-40|-41|-42|-43|-44|-45|-46|-47|-48|-49|-4A|-4B|-4C|-4D|-4E|-4F|-50|-51|
     | d2| X | filter_codes                  | filter_meta                   |

diff --git a/blosc/frame.c b/blosc/frame.c
@@ -114,7 +114,9 @@ void *new_header_frame(blosc2_schunk *schunk, blosc2_frame *frame) {
   uint8_t* h2 = calloc(FRAME_HEADER_MINLEN, 1);
   uint8_t* h2p = h2;
 
-  // Make space for the first array
+  // The msgpack header starts here
+  *h2p = 0x90;  // fixarray...
+  *h2p += 12;   // ...with 12 elements
   h2p += 1;
 
   // Magic number
@@ -240,13 +242,6 @@ void *new_header_frame(blosc2_schunk *schunk, blosc2_frame *frame) {
 
   // Now, deal with metalayers
   int16_t nmetalayers = schunk->nmetalayers;
-  // The msgpack header will start as a fix array of 11 or 12 elements (if it has metalayers)
-  *h2 = 0x90;
-  *h2 += (nmetalayers > 0) ? FRAME_HEADER_NFIELDS_METALAYER : FRAME_HEADER_NFIELDS_NOMETALAYER;
-
-  if (nmetalayers == 0) {
-    goto out;
-  }
 
   // Make space for the header of metalayers (array marker, size, map of offsets)
   h2 = realloc(h2, (size_t)hsize + 1 + 1 + 2 + 1 + 2);
@@ -325,7 +320,6 @@ void *new_header_frame(blosc2_schunk *schunk, blosc2_frame *frame) {
   hsize = (int32_t)(h2p - h2);
   assert(hsize == current_header_len);  // sanity check
 
-  out:
   // Set the length of the whole header now that we know it
   swap_store(h2 + FRAME_HEADER_LEN, &hsize, sizeof(hsize));
 
@@ -864,11 +858,6 @@ int frame_get_metalayers(blosc2_frame* frame, blosc2_schunk* schunk) {
     fclose(fp);
   }
 
-  bool has_metalayers = ((header[0] & 0xFu) == FRAME_HEADER_NFIELDS_METALAYER) ? true : false;
-  if (!has_metalayers) {
-    goto out;
-  }
-
   // Get the size for the index of metalayers
   uint16_t idx_size;
   swap_store(&idx_size, header + FRAME_IDX_SIZE, sizeof(idx_size));
@@ -920,7 +909,6 @@ int frame_get_metalayers(blosc2_frame* frame, blosc2_schunk* schunk) {
     metalayer->content = (uint8_t*)content;
   }
 
-  out:
   if (frame->sdata == NULL) {
     free(header);
   }

diff --git a/blosc/frame.h b/blosc/frame.h
@@ -32,8 +32,6 @@
 
 // Other constants
 #define FRAME_FILTER_PIPELINE_MAX (8)  // the maximum number of filters that can be stored in header
-#define FRAME_HEADER_NFIELDS_NOMETALAYER (11)
-#define FRAME_HEADER_NFIELDS_METALAYER (12)
 #define FRAME_TRAILER_VERSION (0U)  // can be up to 127
 #define FRAME_TRAILER_USERMETA_LEN_OFFSET (3)  // offset to usermeta length
 #define FRAME_TRAILER_USERMETA_OFFSET (7)  // offset to usermeta chunk