zircon/system/ulib/trace-test-utils/squelch.cc

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "trace-test-utils/squelch.h"

#include <fbl/string_buffer.h>

namespace trace_testing {

std::unique_ptr<Squelcher> Squelcher::Create(const char* regex_str) {
  // We don't make any assumptions about the copyability of |regex_t|.
  // Therefore we construct it in place.
  auto squelcher = new Squelcher;
  if (regcomp(&squelcher->regex_, regex_str, REG_EXTENDED | REG_NEWLINE) != 0) {
    return nullptr;
  }
  return std::unique_ptr<Squelcher>(squelcher);
}

Squelcher::~Squelcher() { regfree(&regex_); }

fbl::String Squelcher::Squelch(const char* str) {
  fbl::StringBuffer<1024u> buf;
  const char* cur = str;
  const char* end = str + strlen(str);

  while (*cur) {
    // size must be 1 + number of parenthesized subexpressions
    size_t match_count = regex_.re_nsub + 1;
    regmatch_t match[match_count];
    if (regexec(&regex_, cur, match_count, match, 0) != 0) {
      buf.Append(cur, end - cur);
      break;
    }
    size_t offset = 0u;
    for (size_t i = 1; i < match_count; i++) {
      if (match[i].rm_so == -1)
        continue;
      buf.Append(cur, match[i].rm_so - offset);
      buf.Append("<>");
      cur += match[i].rm_eo - offset;
      offset = match[i].rm_eo;
    }
  }

  return buf;
}

}  // namespace trace_testing