diff -r 000000000000 -r 7f656887cf89 libraries/clogger/inc/SensibleFormat.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libraries/clogger/inc/SensibleFormat.h Wed Jun 23 15:52:26 2010 +0100 @@ -0,0 +1,145 @@ +// SensibleFormat.h +// +// Copyright (c) 2006 - 2010 Accenture. All rights reserved. +// This component and the accompanying materials are made available +// under the terms of the "Eclipse Public License v1.0" +// which accompanies this distribution, and is available +// at the URL "http://www.eclipse.org/legal/epl-v10.html". +// +// Initial Contributors: +// Accenture - Initial contribution +// + +// The purpose of this file is to define a generic format command that works reasonably even when there's no heap free +// Because it uses a stack buffer in this case, it is very difficult to make this a generic function without macroing + +// Because I needed a 16-bit variant as well, and even templating would generate the same amount of code, I've done it +// as a #includable code snippet + +// Note: If you do define SF_WIDE, Collapse() will be called on the result of the format before being passed to SF_ACTION + +// If you want to pass in a VA_LIST, then #define SF_LIST aArgList +// If you want to pass in a bunch of arguments, #define SF_ARGLIST arg1,arg2,arg3 + +#if !defined(SF_FORMAT) || !defined(SF_BUF) || !defined(SF_ACTION) +#error "you must define all of SF_FORMAT, SF_BUF and SF_ACTION before including this file" +#endif + +#if !((defined(SF_LIST) && !defined(SF_ARGLIST)) || (!defined(SF_LIST) && defined(SF_ARGLIST))) +#error "you must define exactly one of SF_LIST and SF_ARGLIST before including this file" +#endif + +#ifndef COMMON_H +#error "you need to include common.h somewhere before including this file" +#endif + +#ifdef SF_WIDE +#define TOverflowX TOverflow16 +#define TBufX TBuf16<256> +#else +#define TOverflowX TOverflow8 +#define TBufX TBuf8<256> +#endif + +#ifdef SF_ARGLIST +#define SFAppend() AppendFormat(SF_FORMAT, &overflow, SF_ARGLIST) +#else +#define SFAppend() AppendFormatList(SF_FORMAT, SF_LIST, &overflow) +#endif + +// Think of this as Format(RBuf8& SF_BUF, FunctionPointer SF_ACTION, const TDesCX& SF_FORMAT, TBool SF_STACKONLY, VA_LIST SF_LIST) +// where SF_ACTION(SF_BUF) is called passing in the fully formatted string + { + const TInt minBufSize = Max(SF_BUF.MaxSize(), 512); + const TInt KMaxBufSize = 8192; + TInt err = KErrNone; + +#ifdef SF_STACKONLY + if (SF_STACKONLY) + { + err = KErrNoMemory; + } + else +#endif + { + if (SF_BUF.MaxSize() == 0) + { + err = SF_BUF.Create(256); + } + else + { + SF_BUF.Zero(); + } + } + + TOverflowX overflow; + if (err == KErrNone) + { + // Do clever things to try and ensure that the format string won't be truncated, while at the same time not allocating an insanely big buffer + for (TInt bufSize = minBufSize; bufSize <= KMaxBufSize; bufSize*=2) + { + #ifdef SF_WIDE + TPtr16 widePtr((TUint16*)SF_BUF.Ptr(), SF_BUF.MaxSize()/2); + widePtr.SFAppend(); + #else + SF_BUF.SFAppend(); + #endif + if (!overflow.iOverflow) + { + // Then the format went ok + #ifdef SF_WIDE + TPtr8 collapsed = widePtr.Collapse(); + SF_ACTION(collapsed); + #else + SF_ACTION(SF_BUF); + #endif + break; + } + else + { + // Overflowed + + if (bufSize == KMaxBufSize) + { + // We've grown up to our (self-imposed) max buf size, so just live with the truncation + #ifdef SF_WIDE + TPtr8 collapsed = widePtr.Collapse(); + SF_ACTION(collapsed); + #else + SF_ACTION(SF_BUF); + #endif + break; + } + + // Try and grow + SF_BUF.Close(); + err = SF_BUF.Create(bufSize*2); + if (err) break; + else continue; + } + } + } + if (err) + { + // Last resort, use 256 char buf on the stack + TBufX stackBuf; + stackBuf.SFAppend(); // Silently truncate if overflow happens now + #ifdef SF_WIDE + TPtr8 collapsed = stackBuf.Collapse(); + SF_ACTION(collapsed); + #else + SF_ACTION(stackBuf); + #endif + } + } + +#undef SF_WIDE +#undef SF_FORMAT +#undef SF_LIST +#undef SF_ARGLIST +#undef SF_BUF +#undef SF_ACTION +#undef TBufX +#undef TOverflowX +#undef SFAppend +#undef SF_STACKONLY