166 lines · cpp
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-exception6//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/ConvertUTF.h"15#include "llvm/Support/Debug.h"16#include "llvm/Support/Unicode.h"17#include "llvm/Support/raw_ostream.h"18#include <algorithm>19 20using namespace llvm;21 22/// UpdatePosition - Examine the given char sequence and figure out which23/// column we end up in after output, and how many line breaks are contained.24/// This assumes that the input string is well-formed UTF-8, and takes into25/// account Unicode characters which render as multiple columns wide.26void formatted_raw_ostream::UpdatePosition(const char *Ptr, size_t Size) {27 unsigned &Column = Position.first;28 unsigned &Line = Position.second;29 30 auto ProcessUTF8CodePoint = [&Line, &Column](StringRef CP) {31 int Width = sys::unicode::columnWidthUTF8(CP);32 if (Width != sys::unicode::ErrorNonPrintableCharacter)33 Column += Width;34 35 // The only special whitespace characters we care about are single-byte.36 if (CP.size() > 1)37 return;38 39 switch (CP[0]) {40 case '\n':41 Line += 1;42 [[fallthrough]];43 case '\r':44 Column = 0;45 break;46 case '\t':47 // Assumes tab stop = 8 characters.48 Column += (8 - (Column & 0x7)) & 0x7;49 break;50 }51 };52 53 // If we have a partial UTF-8 sequence from the previous buffer, check that54 // first.55 if (PartialUTF8Char.size()) {56 size_t BytesFromBuffer =57 getNumBytesForUTF8(PartialUTF8Char[0]) - PartialUTF8Char.size();58 if (Size < BytesFromBuffer) {59 // If we still don't have enough bytes for a complete code point, just60 // append what we have.61 PartialUTF8Char.append(StringRef(Ptr, Size));62 return;63 } else {64 // The first few bytes from the buffer will complete the code point.65 // Concatenate them and process their effect on the line and column66 // numbers.67 PartialUTF8Char.append(StringRef(Ptr, BytesFromBuffer));68 ProcessUTF8CodePoint(PartialUTF8Char);69 PartialUTF8Char.clear();70 Ptr += BytesFromBuffer;71 Size -= BytesFromBuffer;72 }73 }74 75 // Now scan the rest of the buffer.76 unsigned NumBytes;77 for (const char *End = Ptr + Size; Ptr < End; Ptr += NumBytes) {78 // Fast path for printable ASCII characters without special handling.79 if (*Ptr >= 0x20 && *Ptr <= 0x7e) {80 NumBytes = 1;81 ++Column;82 continue;83 }84 85 NumBytes = getNumBytesForUTF8(*Ptr);86 87 // The buffer might end part way through a UTF-8 code unit sequence for a88 // Unicode scalar value if it got flushed. If this happens, we can't know89 // the display width until we see the rest of the code point. Stash the90 // bytes we do have, so that we can reconstruct the whole code point later,91 // even if the buffer is being flushed.92 if ((unsigned)(End - Ptr) < NumBytes) {93 PartialUTF8Char = StringRef(Ptr, End - Ptr);94 return;95 }96 97 ProcessUTF8CodePoint(StringRef(Ptr, NumBytes));98 }99}100 101/// ComputePosition - Examine the current output and update line and column102/// counts.103void formatted_raw_ostream::ComputePosition(const char *Ptr, size_t Size) {104 if (DisableScan)105 return;106 107 // If our previous scan pointer is inside the buffer, assume we already108 // scanned those bytes. This depends on raw_ostream to not change our buffer109 // in unexpected ways.110 if (Ptr <= Scanned && Scanned <= Ptr + Size)111 // Scan all characters added since our last scan to determine the new112 // column.113 UpdatePosition(Scanned, Size - (Scanned - Ptr));114 else115 UpdatePosition(Ptr, Size);116 117 // Update the scanning pointer.118 Scanned = Ptr + Size;119}120 121/// PadToColumn - Align the output to some column number.122///123/// \param NewCol - The column to move to.124///125formatted_raw_ostream &formatted_raw_ostream::PadToColumn(unsigned NewCol) {126 // Figure out what's in the buffer and add it to the column count.127 ComputePosition(getBufferStart(), GetNumBytesInBuffer());128 129 // Output spaces until we reach the desired column.130 indent(std::max(int(NewCol - getColumn()), 1));131 return *this;132}133 134void formatted_raw_ostream::write_impl(const char *Ptr, size_t Size) {135 // Figure out what's in the buffer and add it to the column count.136 ComputePosition(Ptr, Size);137 138 // Write the data to the underlying stream (which is unbuffered, so139 // the data will be immediately written out).140 TheStream->write(Ptr, Size);141 142 // Reset the scanning pointer.143 Scanned = nullptr;144}145 146/// fouts() - This returns a reference to a formatted_raw_ostream for147/// standard output. Use it like: fouts() << "foo" << "bar";148formatted_raw_ostream &llvm::fouts() {149 static formatted_raw_ostream S(outs());150 return S;151}152 153/// ferrs() - This returns a reference to a formatted_raw_ostream for154/// standard error. Use it like: ferrs() << "foo" << "bar";155formatted_raw_ostream &llvm::ferrs() {156 static formatted_raw_ostream S(errs());157 return S;158}159 160/// fdbgs() - This returns a reference to a formatted_raw_ostream for161/// the debug stream. Use it like: fdbgs() << "foo" << "bar";162formatted_raw_ostream &llvm::fdbgs() {163 static formatted_raw_ostream S(dbgs());164 return S;165}166