update fst core struct

source/libs/index/inc/index_fst.h

@@ -230,10 +230,12 @@ typedef struct FstMeta {
 } FstMeta;
 
 typedef struct Fst {
-  FstMeta meta; 
+  FstMeta *meta; 
   void    *data;  //  
 } Fst;
 
+Fst* fstCreate(FstSlice *data);
+void fstDestroy(Fst *fst);
 // ops  
 
 typedef struct FstIndexedValue {

source/libs/index/inc/index_fst_util.h

@@ -32,9 +32,9 @@ extern const CompiledAddr EMPTY_ADDRESS;
 extern const CompiledAddr NONE_ADDRESS;
 
 // This version number is written to every finite state transducer created by
-// this crate. When a finite state transducer is read, its version number is
+// this version When a finite state transducer is read, its version number is
 // checked against this value.
-extern const uint64_t    version;
+extern const uint64_t    VERSION;
 // The threshold (in number of transitions) at which an index is created for                                   
 // a node's transitions. This speeds up lookup time at the expense of FST size 
 

source/libs/index/src/index_fst.c

@@ -919,4 +919,61 @@ void fstBuilderNodeUnfinishedAddOutputPrefix(FstBuilderNodeUnfinished *unNode, O
   return;
 }
 
+Fst* fstCreate(FstSlice *slice) {
+  
+  char *buf = slice->data;
+  uint64_t skip = 0;  
+  uint64_t len = slice->dLen;
+  if (len < 36) { 
+    return NULL; 
+  }
+
+  uint64_t version; 
+  taosDecodeFixedU64(buf, &version); 
+  skip += sizeof(version); 
+  if (version == 0 || version > VERSION) {
+    return NULL; 
+  }  
+
+  uint64_t type;
+  taosDecodeFixedU64(buf + skip, &type);
+  skip += sizeof(type); 
+
+  uint32_t checkSum = 0;
+  len -= sizeof(checkSum);
+  taosDecodeFixedU32(buf + len, &checkSum); 
+
+  CompiledAddr rootAddr;
+  len -= sizeof(rootAddr); 
+  taosDecodeFixedU64(buf + len, &rootAddr); 
+
+  uint64_t fstLen; 
+  len -= sizeof(fstLen); 
+  taosDecodeFixedU64(buf + len, &fstLen);
+  //TODO(validat root addr)
+  // 
+  Fst *fst= (Fst *)calloc(1, sizeof(Fst)); 
+  if (fst == NULL) { return NULL; }  
+  
+  fst->meta = (FstMeta *)malloc(sizeof(FstMeta));
+  if (NULL == fst->meta) { 
+    goto FST_CREAT_FAILED; 
+  }
+
+  fst->meta->version   = version;  
+  fst->meta->rootAddr = rootAddr; 
+  fst->meta->ty       = type;
+  fst->meta->len      = fstLen;
+  fst->meta->checkSum = checkSum;
+  return fst;
+
+FST_CREAT_FAILED: 
+  free(fst->meta); 
+  free(fst);
+
+}
+void fstDestroy(Fst *fst) {
+
+}
+
 

source/libs/index/src/index_fst_util.c

@@ -25,7 +25,7 @@ const CompiledAddr NONE_ADDRESS   = 1;
 // This version number is written to every finite state transducer created by
 // this crate. When a finite state transducer is read, its version number is
 // checked against this value.
-const uint64_t    version        = 3;
+const uint64_t    VERSION        = 3;
 // The threshold (in number of transitions) at which an index is created for                                   
 // a node's transitions. This speeds up lookup time at the expense of FST size