a4100d62e1f3a6864f70e651b6b41517c662f496
markd
  Wed Dec 9 21:34:41 2020 -0800
improved doc on reserved files

diff --git src/jkOwnLib/genoFind.c src/jkOwnLib/genoFind.c
index d727250..56b50b3 100644
--- src/jkOwnLib/genoFind.c
+++ src/jkOwnLib/genoFind.c
@@ -114,34 +114,33 @@
     int stepSize;
     int tileSpaceSize;
     int tileMask;
     int sourceCount;
     bool isPep;
     bool allowOneMismatch;
     bool noSimpRepMask;
     int segSize;
     int totalSeqSize;
 
     off_t sourcesOff;     // offset of sequences sources
     off_t listSizesOff;   // offset of listSizes
     off_t listsOff;       // offset of lists or endLists
     off_t endListsOff;
 
-    // Reserved area. This is really padding, as all structures are accessed via
-    // offsets, so fields can be added without decreasing padding as long as the
-    // reserved is not consumed.
-    bits64 reserved[32];  // vesion 1.0: 32
+    // Reserved area. These are bytes of zero, so that need fields can be added
+    // that default to zero without needed check the version in code.
+    bits64 reserved[32];  // vesion 1.0: 32 words
 };
 
 static void genoFindInitHdr(struct genoFind *gf,
                             struct genoFindFileHdr *hdr)
 /* fill in the file header struct from in-memory struct */
 {
 zeroBytes(hdr, sizeof(struct genoFindFileHdr));
 hdr->maxPat = gf->maxPat;
 hdr->minMatch = gf->minMatch;
 hdr->maxGap = gf->maxGap;
 hdr->tileSize = gf->tileSize;
 hdr->stepSize = gf->stepSize;
 hdr->tileSpaceSize = gf->tileSpaceSize;
 hdr->tileMask = gf->tileMask;
 hdr->sourceCount = gf->sourceCount;
@@ -370,34 +369,33 @@
                                              stepSize, noSimpRepMask);
 return gfIdx;
 }
 
 struct genoFindIndexFileHdr
 /* header for genoFind section in file */
 {
     char magic[32];
     char version[32];
     bits32 indexAddressSize;  // 32 or 64 bit, compile time.
     boolean isTrans;
     // offsets to data, only one is filed in based on being translated or note
     off_t untransOff;
     off_t transOff[2][3];
 
-    // Reserved area. This is really padding, as all structures are accessed via
-    // offsets, so fields can be added without decreasing padding as long as the
-    // reserved is not consumed.
-    bits64 reserved[32];  // vesion 1.0: 32
+    // Reserved area. These are bytes of zero, so that need fields can be added
+    // that default to zero without needed check the version in code.
+    bits64 reserved[32];  // vesion 1.0: 32 words
 };
 
 static void genoFindIndexInitHeader(struct genoFindIndex *gfIdx,
                                     struct genoFindIndexFileHdr* hdr)
 /* fill in the file header struct from in-memory struct */
 {
 zeroBytes(hdr, sizeof(struct genoFindIndexFileHdr));
 safecpy(hdr->magic, sizeof(hdr->magic), indexFileMagic);
 safecpy(hdr->version, sizeof(hdr->version), indexFileVerison);
 hdr->indexAddressSize = 32;
 hdr->isTrans = gfIdx->isTrans;
 }
 
 static void genoFindIndexReadHeader(void* memMapped, struct genoFindIndexFileHdr* hdr,
                                     struct genoFindIndex* gfIdx)