* fcl-db/dbase: cosmetic: more file structure annotations, clarify comments

git-svn-id: trunk@24150 -

packages/fcl-db/src/dbase/dbf_dbffile.pas

@@ -646,7 +646,7 @@ begin
       // init field ptr
       lFieldDescPtr := @lFieldDescIII;
     end;
-    // begin writing fields
+    // begin writing field definitions
     FFieldDefs.Clear;
     // deleted mark 1 byte
     lFieldOffset := 1;
@@ -1083,7 +1083,7 @@ begin
         PChar(pNormal)^ := '*';
         WriteRecord(iNormal, pNormal);
       end else begin
-        // Cannot found a record after iDel so iDel must be deleted
+        // Cannot find a record after iDel so iDel must be deleted
         dec(iDel);
         break;
       end;
@@ -1286,7 +1286,7 @@ begin
   else
     GetMem(pDestBuff, DestDbfFile.RecordSize);
 
-  // let the games begin!
+  // Go through record data:
   try
 {$ifdef USE_CACHE}
     BufferAhead := true;
@@ -1297,7 +1297,7 @@ begin
     begin
       // read record from original dbf
       ReadRecord(lRecNo, pBuff);
-      // copy record?
+      // copy record unless (deleted or user wants packing)
       if (ansichar(pBuff^) <> '*') or not Pack then
       begin
         // if restructure, initialize dest

packages/fcl-db/src/dbase/dbf_struct.inc

@@ -19,20 +19,20 @@ type
   PDbfHdr = ^rDbfHdr;
   rDbfHdr = packed record
     VerDBF      : Byte;     // 0
-    Year        : Byte;     // 1
-    Month       : Byte;     // 2
-    Day         : Byte;     // 3
-    RecordCount : Integer;  // 4-7
+    Year        : Byte;     // 1 year last updated
+    Month       : Byte;     // 2 month last updated
+    Day         : Byte;     // 3 day last updated
+    RecordCount : Integer;  // 4-7 number of records in file
     FullHdrSize : Word;     // 8-9
-    RecordSize  : Word;     // 10-11
+    RecordSize  : Word;     // 10-11 sum of all field sizes, including delete flag
     Dummy1      : Word;     // 12-13
     IncTrans    : Byte;     // 14
-    Encrypt     : Byte;     // 15
+    Encrypt     : Byte;     // 15 DBase encryption flag
     MultiUse    : Integer;  // 16-19
     LastUserID  : Integer;  // 20-23
     Dummy2      : array[24..27] of Byte;
     MDXFlag     : Byte;     // 28
-    Language    : Byte;     // 29
+    Language    : Byte;     // 29 code page mark
     Dummy3      : Word;     // 30-31
   end;
 //====================================================================
@@ -61,7 +61,7 @@ type
     WorkAreaID      : Byte;    // 20
     // WorkAreaID only for DBase III, is always $01
     Reserved2       : array[21..30] of Byte;
-    MDXIndexField   : Byte; //31
+    MDXIndexField   : Byte;    //31
     // DBase IV:
     // $00: no key for this field;
     // $01: key exists for this field in MDX index file