StreamHelper.h

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//===-- StreamHelper.h ------------------------------------------*- C++ -*-===//
//
// Part of the LLZK Project, under the Apache License v2.0.
// See LICENSE.txt for license information.
// Copyright 2025 Veridise Inc.
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//
 
#pragma once
 
#include <llvm/Support/raw_ostream.h>
 
namespace llzk {

class filtered_raw_ostream : public llvm::raw_ostream {
  llvm::raw_ostream &underlyingStream;
  std::function<bool(char)> filterFunc;
 
  void write_impl(const char *ptr, size_t size) override {
    for (size_t i = 0; i < size; ++i) {
      if (!filterFunc(ptr[i])) {
        underlyingStream << ptr[i];
      }
    }
  }
 
  uint64_t current_pos() const override { return underlyingStream.tell(); }
 
public:
  filtered_raw_ostream(llvm::raw_ostream &os, std::function<bool(char)> filter)
      : underlyingStream(os), filterFunc(std::move(filter)) {}
 
  ~filtered_raw_ostream() override { flush(); }
};

template <typename Func, typename... Args>
inline std::string buildStringViaCallback(Func &&appendFn, Args &&...args) {
  std::string output;
  llvm::raw_string_ostream oss(output);
  std::invoke(std::forward<Func>(appendFn), oss, std::forward<Args>(args)...);
  return output;
}

template <typename T> inline std::string buildStringViaPrint(const T &base) {
  return buildStringViaCallback([](llvm::raw_ostream &ss, const T &b) { b.print(ss); }, base);
}

template <typename... Args> inline std::string buildStringViaInsertionOp(Args &&...args) {
  std::string output;
  llvm::raw_string_ostream oss(output);
  (oss << ... << std::forward<Args>(args));
  return output;
}
 
} // namespace llzk