more TDB

source/libs/tdb/src/db/btree.c

@@ -27,13 +27,19 @@ typedef struct {
 } SBtIdx;
 
 // Btree page header definition
-typedef struct {
+typedef struct __attribute__((__packed__)) {
   uint8_t  flags;
   uint16_t ncells;
   pgsz_t   pldOffset;  // payload offset
   /* TODO */
 } SBtPgHdr;
 
+typedef int (*BtreeCmprFn)(const void *, const void *);
+
+#define BTREE_PAGE_HDR(pPage) NULL             /* TODO */
+#define BTREE_PAGE_PAYLOAD_AT(pPage, idx) NULL /*TODO*/
+#define BTREE_PAGE_IS_LEAF(pPage) 0            /* TODO */
+
 static int btreeCreate(SBTree **pBt);
 static int btreeDestroy(SBTree *pBt);
 static int btreeCursorMoveToChild(SBtCursor *pBtCur, pgno_t pgno);
@@ -78,23 +84,63 @@ int btreeCursorClose(SBtCursor *pBtCur) {
 
 int btreeCursorMoveTo(SBtCursor *pBtCur, int kLen, const void *pKey) {
   SPage *     pPage;
-  SBtPgHdr *pBtPgHdr;
+  SBtPgHdr *  pBtPgHdr;
+  SPgFile *   pPgFile;
   pgno_t      childPgno;
-  int       idx;
+  pgno_t      rootPgno;
+  int         nPayload;
+  void *      pPayload;
+  BtreeCmprFn cmpFn;
 
   // 1. Move the cursor to the root page
+  if (rootPgno == TDB_IVLD_PGNO) {
+    // No any data in this btree, just return not found (TODO)
+    return 0;
+  } else {
+    // Load the page from the file by the SPgFile handle
+    pPage = pgFileFetch(pPgFile, rootPgno);
+
+    pBtCur->pPage = pPage;
+  }
 
   // 2. Loop to search over the whole tree
   for (;;) {
+    int lidx, ridx, midx, cret;
+
     pPage = pBtCur->pPage;
+    pBtPgHdr = BTREE_PAGE_HDR(pPage);
+    nPayload = pBtPgHdr->ncells;
 
-    // Loop to search in current page
+    // Binary search the page
+    lidx = 0;
+    ridx = nPayload - 1;
+    midx = (lidx + ridx) >> 1;
     for (;;) {
-      /* code */
+      // get the payload ptr at midx
+      pPayload = BTREE_PAGE_PAYLOAD_AT(pPage, midx);
+
+      // the payload and the key
+      cret = cmpFn(pKey, pPayload);
+
+      if (cret < 0) {
+        /* TODO */
+      } else if (cret > 0) {
+        /* TODO */
+      } else {
+        /* TODO */
       }
 
+      if (lidx > ridx) break;
+      midx = (lidx + ridx) >> 1;
+    }
+    if (BTREE_PAGE_IS_LEAF(pPage)) {
+      /* TODO */
+      break;
+    } else {
+      /* TODO */
       btreeCursorMoveToChild(pBtCur, childPgno);
     }
+  }
 
   return 0;
 }

source/libs/tdb/src/inc/pgfile.h

@@ -30,7 +30,7 @@ typedef struct __attribute__((__packed__)) {
 
 #define TDB_PG_FILE_HDR_SIZE 128
 
-TD_STATIC_ASSERT(sizeof(SPgFileHdr) == TDB_PG_FILE_HDR_SIZE, "Page file header size if not 128");
+TDB_STATIC_ASSERT(sizeof(SPgFileHdr) == TDB_PG_FILE_HDR_SIZE, "Page file header size if not 128");
 
 struct SPgFile {
   char *    fname;                    // backend file name

source/libs/tdb/src/inc/tdbInt.h

@@ -29,7 +29,7 @@ typedef struct SPgFile SPgFile;
 
 // pgno_t
 typedef int32_t pgno_t;
-#define TDB_IVLD_PGNO ((pgno_t)-1)
+#define TDB_IVLD_PGNO ((pgno_t)0)
 
 // fileid
 #define TDB_FILE_ID_LEN 24

source/libs/tdb/src/inc/tdbUtil.h

@@ -21,9 +21,9 @@ extern "C" {
 #endif
 
 #if __STDC_VERSION__ >= 201112L
-#define TD_STATIC_ASSERT(op, info) static_assert(op, info)
+#define TDB_STATIC_ASSERT(op, info) static_assert(op, info)
 #else
-#define TD_STATIC_ASSERT(op, info)
+#define TDB_STATIC_ASSERT(op, info)
 #endif
 
 #define TDB_ROUND8(x) (((x) + 7) & ~7)