1 //===-- llvm/Support/FormattedStream.cpp - Formatted streams ----*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains the implementation of formatted_raw_ostream. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/Support/FormattedStream.h" 14 #include "llvm/Support/Debug.h" 15 #include "llvm/Support/raw_ostream.h" 16 #include <algorithm> 17 18 using namespace llvm; 19 20 /// UpdatePosition - Examine the given char sequence and figure out which 21 /// column we end up in after output, and how many line breaks are contained. 22 /// 23 static void UpdatePosition(std::pair<unsigned, unsigned> &Position, const char *Ptr, size_t Size) { 24 unsigned &Column = Position.first; 25 unsigned &Line = Position.second; 26 27 // Keep track of the current column and line by scanning the string for 28 // special characters 29 for (const char *End = Ptr + Size; Ptr != End; ++Ptr) { 30 ++Column; 31 switch (*Ptr) { 32 case '\n': 33 Line += 1; 34 LLVM_FALLTHROUGH; 35 case '\r': 36 Column = 0; 37 break; 38 case '\t': 39 // Assumes tab stop = 8 characters. 40 Column += (8 - (Column & 0x7)) & 0x7; 41 break; 42 } 43 } 44 } 45 46 /// ComputePosition - Examine the current output and update line and column 47 /// counts. 48 void formatted_raw_ostream::ComputePosition(const char *Ptr, size_t Size) { 49 // If our previous scan pointer is inside the buffer, assume we already 50 // scanned those bytes. This depends on raw_ostream to not change our buffer 51 // in unexpected ways. 52 if (Ptr <= Scanned && Scanned <= Ptr + Size) 53 // Scan all characters added since our last scan to determine the new 54 // column. 55 UpdatePosition(Position, Scanned, Size - (Scanned - Ptr)); 56 else 57 UpdatePosition(Position, Ptr, Size); 58 59 // Update the scanning pointer. 60 Scanned = Ptr + Size; 61 } 62 63 /// PadToColumn - Align the output to some column number. 64 /// 65 /// \param NewCol - The column to move to. 66 /// 67 formatted_raw_ostream &formatted_raw_ostream::PadToColumn(unsigned NewCol) { 68 // Figure out what's in the buffer and add it to the column count. 69 ComputePosition(getBufferStart(), GetNumBytesInBuffer()); 70 71 // Output spaces until we reach the desired column. 72 indent(std::max(int(NewCol - getColumn()), 1)); 73 return *this; 74 } 75 76 void formatted_raw_ostream::write_impl(const char *Ptr, size_t Size) { 77 // Figure out what's in the buffer and add it to the column count. 78 ComputePosition(Ptr, Size); 79 80 // Write the data to the underlying stream (which is unbuffered, so 81 // the data will be immediately written out). 82 TheStream->write(Ptr, Size); 83 84 // Reset the scanning pointer. 85 Scanned = nullptr; 86 } 87 88 /// fouts() - This returns a reference to a formatted_raw_ostream for 89 /// standard output. Use it like: fouts() << "foo" << "bar"; 90 formatted_raw_ostream &llvm::fouts() { 91 static formatted_raw_ostream S(outs()); 92 return S; 93 } 94 95 /// ferrs() - This returns a reference to a formatted_raw_ostream for 96 /// standard error. Use it like: ferrs() << "foo" << "bar"; 97 formatted_raw_ostream &llvm::ferrs() { 98 static formatted_raw_ostream S(errs()); 99 return S; 100 } 101 102 /// fdbgs() - This returns a reference to a formatted_raw_ostream for 103 /// the debug stream. Use it like: fdbgs() << "foo" << "bar"; 104 formatted_raw_ostream &llvm::fdbgs() { 105 static formatted_raw_ostream S(dbgs()); 106 return S; 107 } 108