From ab810275448c34c072c47be1f16ae1d679bfd20c Mon Sep 17 00:00:00 2001 From: Daniel Dunbar Date: Tue, 18 Aug 2009 23:36:04 +0000 Subject: [PATCH] raw_ostream: Reduce FormattedStream's reliance on raw_ostream's implementation. - Kill off begin(), end(), and iterator. It isn't clear what these mean. Instead provide getBufferStart(), which can be used with GetNumBytesInBuffer to the same effect. - Update ComputeColumn to take arguments for the buffer to scan, this simplifies the implementation of write_impl substantially. - This should also fix possible problems with the scanning pointer pointing outside of the current raw_ostream buffer. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79379 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Support/FormattedStream.h | 12 ++++---- include/llvm/Support/raw_ostream.h | 6 ++-- lib/Support/FormattedStream.cpp | 39 ++++++++++++-------------- 3 files changed, 27 insertions(+), 30 deletions(-) diff --git a/include/llvm/Support/FormattedStream.h b/include/llvm/Support/FormattedStream.h index 6157c40de68..3a872058c9d 100644 --- a/include/llvm/Support/FormattedStream.h +++ b/include/llvm/Support/FormattedStream.h @@ -58,7 +58,7 @@ namespace llvm /// Scanned - This points to one past the last character in the /// buffer we've scanned. /// - iterator Scanned; + const char *Scanned; virtual void write_impl(const char *Ptr, size_t Size); @@ -70,10 +70,10 @@ namespace llvm return TheStream->tell() - TheStream->GetNumBytesInBuffer(); } - /// ComputeColumn - Examine the current output and figure out - /// which column we end up in after output. + /// ComputeColumn - Examine the given output buffer and figure out which + /// column we end up in after output. /// - void ComputeColumn(); + void ComputeColumn(const char *Ptr, size_t size); public: /// formatted_raw_ostream - Open the specified file for @@ -92,7 +92,7 @@ namespace llvm } explicit formatted_raw_ostream() : raw_ostream(), TheStream(0), DeleteStream(false), ColumnScanned(0) { - Scanned = begin(); + Scanned = 0; } ~formatted_raw_ostream() { @@ -116,7 +116,7 @@ namespace llvm SetUnbuffered(); TheStream->SetUnbuffered(); - Scanned = begin(); + Scanned = 0; } /// PadToColumn - Align the output to some column number. If the current diff --git a/include/llvm/Support/raw_ostream.h b/include/llvm/Support/raw_ostream.h index b1b96f23169..5e20deb1664 100644 --- a/include/llvm/Support/raw_ostream.h +++ b/include/llvm/Support/raw_ostream.h @@ -251,9 +251,9 @@ protected: /// been encountered. void error_detected() { Error = true; } - typedef char * iterator; - iterator begin() { return OutBufStart; } - iterator end() { return OutBufCur; } + /// getBufferStart - Return the beginning of the current stream buffer, or 0 + /// if the stream is unbuffered. + const char *getBufferStart() const { return OutBufStart; } //===--------------------------------------------------------------------===// // Private Interface diff --git a/lib/Support/FormattedStream.cpp b/lib/Support/FormattedStream.cpp index 0c787f8c4f9..4e624275300 100644 --- a/lib/Support/FormattedStream.cpp +++ b/lib/Support/FormattedStream.cpp @@ -36,13 +36,20 @@ static unsigned CountColumns(unsigned Column, const char *Ptr, size_t Size) { /// ComputeColumn - Examine the current output and figure out which /// column we end up in after output. -void formatted_raw_ostream::ComputeColumn() { - // The buffer may have been allocated underneath us. - if (Scanned == 0) Scanned = begin(); - // Scan all characters added since our last scan to determine the new column. - ColumnScanned = CountColumns(ColumnScanned, Scanned, end() - Scanned); - // We're now current with everything in the buffer. - Scanned = end(); +void formatted_raw_ostream::ComputeColumn(const char *Ptr, size_t Size) { + // If our previous scan pointer is inside the buffer, assume we already + // scanned those bytes. This depends on raw_ostream to not change our buffer + // in unexpected ways. + if (Ptr <= Scanned && Scanned <= Ptr + Size) { + // Scan all characters added since our last scan to determine the new + // column. + ColumnScanned = CountColumns(ColumnScanned, Scanned, + Size - (Scanned - Ptr)); + } else + ColumnScanned = CountColumns(ColumnScanned, Ptr, Size); + + // Update the scanning pointer. + Scanned = Ptr + Size; } /// PadToColumn - Align the output to some column number. @@ -53,7 +60,7 @@ void formatted_raw_ostream::ComputeColumn() { /// void formatted_raw_ostream::PadToColumn(unsigned NewCol) { // Figure out what's in the buffer and add it to the column count. - ComputeColumn(); + ComputeColumn(getBufferStart(), GetNumBytesInBuffer()); // Output spaces until we reach the desired column. unsigned num = NewCol - ColumnScanned; @@ -70,24 +77,14 @@ void formatted_raw_ostream::PadToColumn(unsigned NewCol) { void formatted_raw_ostream::write_impl(const char *Ptr, size_t Size) { // Figure out what's in the buffer and add it to the column count. - ComputeColumn(); + ComputeColumn(Ptr, Size); // Write the data to the underlying stream (which is unbuffered, so // the data will be immediately written out). TheStream->write(Ptr, Size); - // If this FormattedStream is unbuffered, scan the string that - // was just written to determine the new column. - if (Ptr == begin()) { - // Buffered mode. The buffer is being flushed; reset the scanning - // position to the beginning of the buffer. - assert(Ptr + Size == end() && "Buffer is not being fully flushed!"); - Scanned = begin(); - } else { - // Unbuffered mode. Immediately scan the string that was just - // written to determine the new column. - ColumnScanned = CountColumns(ColumnScanned, Ptr, Size); - } + // Reset the scanning pointer. + Scanned = 0; } /// fouts() - This returns a reference to a formatted_raw_ostream for