SQLite

          aFrameCksum[0] = pWal->hdr.aFrameCksum[0];
          aFrameCksum[1] = pWal->hdr.aFrameCksum[1];
        }
      }
      pWal->apWiData[iPg] = aShare;
      nHdr = (iPg==0 ? WALINDEX_HDR_SIZE : 0);
      nHdr32 = nHdr / sizeof(u32);
#ifndef SQLITE_SAFER_WALINDEX_RECOVERY
      /* Memcpy() should work fine here, on all reasonable implementations.
      ** Technically, memcpy() might change the destination to some
      ** intermediate value before setting to the final value, and that might
      ** cause a concurrent reader to malfunction.  Memcpy() is allowed to
      ** do that, according to the spec, but no memcpy() implementation that
      ** we know of actually does that, which is why we say that memcpy()
      ** is safe for this.  Memcpy() is certainly a lot faster.
      */
      memcpy(&aShare[nHdr32], &aPrivate[nHdr32], WALINDEX_PGSZ-nHdr);
#else
      /* In the event that some platform is found for which memcpy()
      ** changes the destination to some intermediate value before
      ** setting the final value, this alternative copy routine is
      ** provided.
      */
      {
        int i;
        for(i=nHdr32; i<WALINDEX_PGSZ/sizeof(u32); i++){
          if( aShare[i]!=aPrivate[i] ){
            /* Atomic memory operations are not required here because if
            ** the value needs to be changed, that means it is not being
            ** accessed concurrently. */
            aShare[i] = aPrivate[i];
          }
        }
      }
#endif
      if( iFrame<=iLast ) break;
    }

    sqlite3_free(aFrame);
  }

finished: