block.cpp

これは C++ で書かれたレコードのロックおよびロック解除の例です。

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <stdint.h>
 
#include "btrieveCpp.h"
 
static char *btrieveFileName = (char *)"squaresAndSquareRoots.btr";
 
#define MIN_X 0
#define MAX_X 255
 
#pragma pack(1)
typedef struct {
        uint8_t x;
        uint16_t xSquared;
        double xSquareRoot;
} record_t;
#pragma pack()
 
static Btrieve::StatusCode
createFile(BtrieveClient *btrieveClient)
{
   Btrieve::StatusCode status;
   BtrieveFileAttributes btrieveFileAttributes;
 
   // If SetFixedRecordLength() fails.
   if ((status = btrieveFileAttributes.SetFixedRecordLength(sizeof(record_t))) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      printf("Error: BtrieveFileAttributes::SetFixedRecordLength():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
   // If FileCreate() fails.
   if ((status = btrieveClient->FileCreate(&btrieveFileAttributes, btrieveFileName, Btrieve::CREATE_MODE_OVERWRITE)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      printf("Error: BtrieveClient::FileCreate():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
leave:
   return status;
}
 
static Btrieve::StatusCode
openFile(BtrieveClient *btrieveClient, BtrieveFile *btrieveFile)
{
   Btrieve::StatusCode status;
 
   // If FileOpen() fails.
   if ((status = btrieveClient->FileOpen(btrieveFile, btrieveFileName, NULL, Btrieve::OPEN_MODE_NORMAL)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      printf("Error: BtrieveClient::FileOpen():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
leave:
   return status;
}
 
static Btrieve::StatusCode
loadFile(BtrieveFile *btrieveFile)
{
   Btrieve::StatusCode status = Btrieve::STATUS_CODE_NO_ERROR;
   int i;
   record_t record;
 
   for (i = MIN_X; i <= MAX_X; i++)
   {
      record.x = (uint8_t)i;
      record.xSquared = (uint16_t)(i * i);
      record.xSquareRoot = sqrt((double)i);
 
      // If RecordCreate() fails.
      if ((status = btrieveFile->RecordCreate((char *)&record, sizeof(record))) != Btrieve::STATUS_CODE_NO_ERROR)
      {
         printf("Error: BtrieveFile::RecordCreate():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
         goto leave;
      }
   }
 
leave:
   return status;
}
 
static Btrieve::StatusCode
closeFile(BtrieveClient *btrieveClient, BtrieveFile *btrieveFile)
{
   Btrieve::StatusCode status;
 
   // If FileClose() fails.
   if ((status = btrieveClient->FileClose(btrieveFile)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      printf("Error: BtrieveClient::FileClose():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
leave:
   return status;
}
 
static Btrieve::StatusCode
deleteFile(BtrieveClient *btrieveClient)
{
   Btrieve::StatusCode status;
 
   // If FileDelete() fails.
   if ((status = btrieveClient->FileDelete(btrieveFileName)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      printf("Error: BtrieveClient::FileDelete():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
leave:
   return status;
}
 
static Btrieve::StatusCode
createIndex(BtrieveFile *btrieveFile)
{
   Btrieve::StatusCode status;
   BtrieveIndexAttributes btrieveIndexAttributes;
   BtrieveKeySegment btrieveKeySegment;
 
   // If SetField() fails.
   if ((status = btrieveKeySegment.SetField(0, 1, Btrieve::DATA_TYPE_UNSIGNED_BINARY)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      printf("Error: BtrieveKeySegment::SetField():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
   // If AddKeySegment() fails.
   if ((status = btrieveIndexAttributes.AddKeySegment(&btrieveKeySegment)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      printf("Error: BtrieveIndexAttributes::AddKeySegment():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
   // If IndexCreate() fails.
   if ((status = btrieveFile->IndexCreate(&btrieveIndexAttributes)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      printf("Error: BtrieveFile::IndexCreate():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
leave:
   return status;
}
 
static Btrieve::StatusCode
updateRecord(bool expectRecordInUse)
{
   BtrieveClient btrieveClient(0x4233, 0);
   Btrieve::StatusCode status = Btrieve::STATUS_CODE_UNKNOWN;
   BtrieveFile btrieveFile;
   record_t record;
 
   // If openFile() fails.
   if ((status = openFile(&btrieveClient, &btrieveFile)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      goto leave;
   }
 
   // If RecordRetrieveFirst() fails.
   if (btrieveFile.RecordRetrieveFirst(Btrieve::INDEX_1, (char *)&record, sizeof(record)) != sizeof(record))
   {
      status = btrieveFile.GetLastStatusCode();
      printf("Error: Client2: BtrieveFile::RecordRetrieveFirst():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
        record.xSquared++;
        record.xSquareRoot++;
 
   status = btrieveFile.RecordUpdate((char *)&record, sizeof(record));
 
        if ((expectRecordInUse == true) && (status != Btrieve::STATUS_CODE_RECORD_INUSE))
   {
      printf("Error: Client2: BtrieveFile::RecordUpdate():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
        else
        if ((expectRecordInUse == false) && (status != Btrieve::STATUS_CODE_NO_ERROR))
   {
      printf("Error: Client2: BtrieveFile::RecordUpdate():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
   // If closeFile() fails.
   if ((status = closeFile(&btrieveClient, &btrieveFile)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      goto leave;
   }
 
leave:
   return status;
}
 
static Btrieve::StatusCode
retrieveRecord(BtrieveFile *btrieveFile)
{
   Btrieve::StatusCode status = Btrieve::STATUS_CODE_NO_ERROR;
   record_t record;
 
   // If RecordRetrieveFirst() fails.
   if (btrieveFile->RecordRetrieveFirst(Btrieve::INDEX_1, (char *)&record, sizeof(record), Btrieve::LOCK_MODE_SINGLE_WAIT) != sizeof(record))
   {
      status = btrieveFile->GetLastStatusCode();
      printf("Error: BtrieveFile::RecordRetrieveFirst():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
        printf("record before update: (%u, %u, %f)\n", record.x, record.xSquared, record.xSquareRoot);
 
   // If updateRecord() fails.
   if ((status = updateRecord(true)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      goto leave;
   }
 
   // If RecordUnlock() fails.
   if ((status = btrieveFile->RecordUnlock(Btrieve::UNLOCK_MODE_SINGLE)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      printf("Error: BtrieveFile::RecordUnlock():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
   // If RecordRetrieveFirst() fails.
   if (btrieveFile->RecordRetrieveFirst(Btrieve::INDEX_1, (char *)&record, sizeof(record)) != sizeof(record))
   {
      status = btrieveFile->GetLastStatusCode();
      printf("Error: BtrieveFile::RecordRetrieveFirst():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
        printf("record after update while locked: (%u, %u, %f)\n", record.x, record.xSquared, record.xSquareRoot);
 
   // If updateRecord() fails.
   if ((status = updateRecord(false)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      goto leave;
   }
 
   // If RecordRetrieveFirst() fails.
   if (btrieveFile->RecordRetrieveFirst(Btrieve::INDEX_1, (char *)&record, sizeof(record), Btrieve::LOCK_MODE_SINGLE_WAIT) != sizeof(record))
   {
      status = btrieveFile->GetLastStatusCode();
      printf("Error: BtrieveFile::RecordRetrieveFirst():%d:%s.\n", status, Btrieve::StatusCodeToString(status));
      goto leave;
   }
 
        printf("record after update while unlocked: (%u, %u, %f)\n", record.x, record.xSquared, record.xSquareRoot);
 
leave:
   return status;
}
 
int
main(int argc, char *argv[])
{
   static const char *usage = "Usage: %s\n";
 
   BtrieveClient btrieveClient;
   Btrieve::StatusCode status = Btrieve::STATUS_CODE_UNKNOWN;
   BtrieveFile btrieveFile;
 
   // If the incorrect number of arguments were given.
   if (argc != 1)
   {
      printf(usage, argv[0]);
      goto leave;
   }
 
   // If createFile() fails.
   if ((status = createFile(&btrieveClient)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      goto leave;
   }
 
   // If openFile() fails.
   if ((status = openFile(&btrieveClient, &btrieveFile)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      goto leave;
   }
 
   // If loadFile() fails.
   if ((status = loadFile(&btrieveFile)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      goto leave;
   }
 
   // If createIndex() fails.
   if ((status = createIndex(&btrieveFile)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      goto leave;
   }
 
   // If retrieveRecord() fails.
   if ((status = retrieveRecord(&btrieveFile)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      goto leave;
   }
 
   // If closeFile() fails.
   if ((status = closeFile(&btrieveClient, &btrieveFile)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      goto leave;
   }
 
   // If deleteFile() fails.
   if ((status = deleteFile(&btrieveClient)) != Btrieve::STATUS_CODE_NO_ERROR)
   {
      goto leave;
   }
 
leave:
   // If there wasn't a failure.
   if (status == Btrieve::STATUS_CODE_NO_ERROR)
      return 0;
 
   return 1;
}