C++ StringPiece::size方法代码示例

std::string LogName::canonicalize(StringPiece input) {
  std::string cname;
  cname.reserve(input.size());

  // Ignore trailing category separator characters
  size_t end = input.size();
  while (end > 0 && isSeparator(input[end - 1])) {
    --end;
  }

  bool ignoreSeparator = true;
  for (size_t idx = 0; idx < end; ++idx) {
    if (isSeparator(input[idx])) {
      if (ignoreSeparator) {
        continue;
      }
      cname.push_back('.');
      ignoreSeparator = true;
    } else {
      cname.push_back(input[idx]);
      ignoreSeparator = false;
    }
  }
  return cname;
}

  void parseMessage(StringPiece msg, size_t* threadID, size_t* messageIndex) {
    // Validate and strip off the message prefix and suffix
    constexpr StringPiece prefix{"thread "};
    if (!msg.startsWith(prefix)) {
      throw std::runtime_error("bad message prefix");
    }
    msg.advance(prefix.size());
    if (!msg.endsWith(kMsgSuffix)) {
      throw std::runtime_error("bad message suffix");
    }
    msg.subtract(kMsgSuffix.size());

    // Parse then strip off the thread index
    auto threadIDEnd = msg.find(' ');
    if (threadIDEnd == StringPiece::npos) {
      throw std::runtime_error("no middle found");
    }
    *threadID = folly::to<size_t>(msg.subpiece(0, threadIDEnd));
    msg.advance(threadIDEnd);

    // Validate that the middle of the message is what we expect,
    // then strip it off
    constexpr StringPiece middle{" message "};
    if (!msg.startsWith(middle)) {
      throw std::runtime_error("bad message middle");
    }
    msg.advance(middle.size());

    // Parse the message index
    *messageIndex = folly::to<size_t>(msg);
  }

size_t qfind_first_byte_of_sse42(const StringPiece& haystack,
                                 const StringPiece& needles) {
  if (UNLIKELY(needles.empty() || haystack.empty())) {
    return StringPiece::npos;
  } else if (needles.size() <= 16) {
    // we can save some unnecessary load instructions by optimizing for
    // the common case of needles.size() <= 16
    return qfind_first_byte_of_needles16(haystack, needles);
  }

  if (haystack.size() < 16 &&
      PAGE_FOR(haystack.end() - 1) != PAGE_FOR(haystack.data() + 16)) {
    // We can't safely SSE-load haystack. Use a different approach.
    if (haystack.size() <= 2) {
      return qfind_first_of(haystack, needles, asciiCaseSensitive);
    }
    return qfind_first_byte_of_byteset(haystack, needles);
  }

  auto ret = scanHaystackBlock<false>(haystack, needles, 0);
  if (ret != StringPiece::npos) {
    return ret;
  }

  size_t i = nextAlignedIndex(haystack.data());
  for (; i < haystack.size(); i += 16) {
    auto ret = scanHaystackBlock<true>(haystack, needles, i);
    if (ret != StringPiece::npos) {
      return ret;
    }
  }

  return StringPiece::npos;
}

U_CAPI int32_t U_EXPORT2
unum_parseDecimal(const UNumberFormat*  fmt,
            const UChar*    text,
            int32_t         textLength,
            int32_t         *parsePos /* 0 = start */,
            char            *outBuf,
            int32_t         outBufLength,
            UErrorCode      *status)
{
    if (U_FAILURE(*status)) {
        return -1;
    }
    if ((outBuf == NULL && outBufLength != 0) || outBufLength < 0) {
        *status = U_ILLEGAL_ARGUMENT_ERROR;
        return -1;
    }
    Formattable res;
    parseRes(res, fmt, text, textLength, parsePos, status);
    StringPiece sp = res.getDecimalNumber(*status);
    if (U_FAILURE(*status)) {
       return -1;
    } else if (sp.size() > outBufLength) {
        *status = U_BUFFER_OVERFLOW_ERROR;
    } else if (sp.size() == outBufLength) {
        uprv_strncpy(outBuf, sp.data(), sp.size());
        *status = U_STRING_NOT_TERMINATED_WARNING;
    } else {
        U_ASSERT(outBufLength > 0);
        uprv_strcpy(outBuf, sp.data());
    }
    return sp.size();
}

bool LocalSequenceFileWriter::WriteRecord(const StringPiece& key, const StringPiece& value) {
    int record_size = key.size() + value.size();
    int key_len = key.size();
    int int_len = sizeof(int);
    int size = 2 * int_len + record_size;
    int used_bytes = 0;
    scoped_array<char> data(new char[size]);

    if (m_records_written_after_sync >= kSyncInterval) {
        size += int_len + SYNC_HASH_SIZE;
        data.reset(new char[size]);
        used_bytes += WriteSyncToBuf(data.get() + used_bytes);
        m_records_written_after_sync = 0;
    }

    // format:
    // record_size|key_len|key|value

    used_bytes += WriteInt(data.get() + used_bytes, record_size);
    used_bytes += WriteInt(data.get() + used_bytes, key_len);

    memcpy(data.get() + used_bytes, key.data(), key_len);
    used_bytes += key_len;
    memcpy(data.get() + used_bytes, value.data(), value.size());
    used_bytes += value.size();

    CHECK(used_bytes == size);

    if (!Write(data.get(), used_bytes)) {
        return false;
    }

    ++m_records_written_after_sync;
    return true;
}

void Item::resetKey(StringPiece k)
{
	assert(k.size() <= 250);
	keylen_ = k.size();
	receivedBytes_ = 0;
	append(k.data(), k.size());
	hash_ = boost::hash_range(k.begin(), k.end());
}

void ReplaceAll(std::string* s, const StringPiece& from, const StringPiece& to)
{
    size_t pos = 0;
    while ((pos = s->find(from.data(), pos, from.size())) != std::string::npos)
    {
        s->replace(pos, from.size(), to.data(), to.size());
        pos += to.size();
    }
}

// Updates contents so that any read accesses past the last byte will
// cause a SIGSEGV.  It accomplishes this by changing access to the page that
// begins immediately after the end of the contents (as allocators and mmap()
// all operate on page boundaries, this is a reasonable assumption).
// This function will also initialize buf, which caller must free().
void createProtectedBuf(StringPiece& contents, char** buf) {
  ASSERT_LE(contents.size(), kPageSize);
  const size_t kSuccess = 0;
  char* tmp;
  if (kSuccess != posix_memalign((void**)buf, kPageSize, 2 * kPageSize)) {
    ASSERT_FALSE(true);
  }
  mprotect(*buf + kPageSize, kPageSize, PROT_NONE);
  size_t newBegin = kPageSize - contents.size();
  memcpy(*buf + newBegin, contents.data(), contents.size());
  contents.reset(*buf + newBegin, contents.size());
}

bool IPAddressV6::validate(StringPiece ip) {
    if (ip.size() > 0 && ip.front() == '[' && ip.back() == ']') {
        ip = ip.subpiece(1, ip.size() - 2);
    }

    constexpr size_t kStrMaxLen = INET6_ADDRSTRLEN;
    std::array<char, kStrMaxLen + 1> ip_cstr;
    const size_t len = std::min(ip.size(), kStrMaxLen);
    std::memcpy(ip_cstr.data(), ip.data(), len);
    ip_cstr[len] = 0;
    struct in6_addr addr;
    return 1 == inet_pton(AF_INET6, ip_cstr.data(), &addr);
}

void FDSymbolizePrinter::doPrint(StringPiece sp) {
  if (buffer_) {
    if (sp.size() > buffer_->tailroom()) {
      flush();
      writeFull(fd_, sp.data(), sp.size());
    } else {
      memcpy(buffer_->writableTail(), sp.data(), sp.size());
      buffer_->append(sp.size());
    }
  } else {
    writeFull(fd_, sp.data(), sp.size());
  }
}

FFState* TargetBigramFeature::Evaluate(const Hypothesis& cur_hypo,
                                       const FFState* prev_state,
                                       ScoreComponentCollection* accumulator) const
{
  const TargetBigramState* tbState = dynamic_cast<const TargetBigramState*>(prev_state);
  assert(tbState);

  // current hypothesis target phrase
  const Phrase& targetPhrase = cur_hypo.GetCurrTargetPhrase();
  if (targetPhrase.GetSize() == 0) {
    return new TargetBigramState(*tbState);
  }

  // extract all bigrams w1 w2 from current hypothesis
  for (size_t i = 0; i < targetPhrase.GetSize(); ++i) {
    const Factor* f1 = NULL;
    if (i == 0) {
      f1 = tbState->GetWord().GetFactor(m_factorType);
    } else {
      f1 = targetPhrase.GetWord(i-1).GetFactor(m_factorType);
    }
    const Factor* f2 = targetPhrase.GetWord(i).GetFactor(m_factorType);
    const StringPiece w1 = f1->GetString();
    const StringPiece w2 = f2->GetString();

    // skip bigrams if they don't belong to a given restricted vocabulary
    if (m_vocab.size() &&
        (FindStringPiece(m_vocab, w1) == m_vocab.end() || FindStringPiece(m_vocab, w2) == m_vocab.end())) {
      continue;
    }

    string name(w1.data(), w1.size());
    name += ":";
    name.append(w2.data(), w2.size());
    accumulator->PlusEquals(this,name,1);
  }

  if (cur_hypo.GetWordsBitmap().IsComplete()) {
    const StringPiece w1 = targetPhrase.GetWord(targetPhrase.GetSize()-1).GetFactor(m_factorType)->GetString();
    const string& w2 = EOS_;
    if (m_vocab.empty() || (FindStringPiece(m_vocab, w1) != m_vocab.end())) {
      string name(w1.data(), w1.size());
      name += ":";
      name += w2;
      accumulator->PlusEquals(this,name,1);
    }
    return NULL;
  }
  return new TargetBigramState(targetPhrase.GetWord(targetPhrase.GetSize()-1));
}

int RML_RE::TryMatch(const StringPiece& text,
                 int startpos,
                 Anchor anchor,
                 int *vec,
                 int vecsize) const {
  pcre* re = (anchor == ANCHOR_BOTH) ? re_full_ : re_partial_;
  if (re == NULL) {
    //fprintf(stderr, "Matching against invalid re: %s\n", error_->c_str());
    return 0;
  }

  pcre_extra extra = { 0 };
  if (options_.match_limit() > 0) {
    extra.flags = PCRE_EXTRA_MATCH_LIMIT;
    extra.match_limit = options_.match_limit();
  }
  int rc = pcre_exec(re,              // The regular expression object
                     &extra,
                     text.data(),
                     text.size(),
                     startpos,
                     (anchor == UNANCHORED) ? 0 : PCRE_ANCHORED,
                     vec,
                     vecsize);

  // Handle errors
  if (rc == PCRE_ERROR_NOMATCH) {
    return 0;
  } else if (rc < 0) {
    //fprintf(stderr, "Unexpected return code: %d when matching '%s'\n",
    //        re, pattern_.c_str());
    return 0;
  } else if (rc == 0) {
    // pcre_exec() returns 0 as a special case when the number of
    // capturing subpatterns exceeds the size of the vector.
    // When this happens, there is a match and the output vector
    // is filled, but we miss out on the positions of the extra subpatterns.
    rc = vecsize / 2;
  }

  if ((anchor == ANCHOR_BOTH) && (re_full_ == re_partial_)) {
    // We need an extra check to make sure that the match extended
    // to the end of the input string
    assert(vec[0] == 0);                 // PCRE_ANCHORED forces starting match
    if (vec[1] != text.size()) return 0; // Did not get ending match
  }

  return rc;
}

size_t qfind_first_byte_of_memchr(const StringPiece& haystack,
                                  const StringPiece& needles) {
  size_t best = haystack.size();
  for (char needle: needles) {
    const void* ptr = memchr(haystack.data(), needle, best);
    if (ptr) {
      auto found = static_cast<const char*>(ptr) - haystack.data();
      best = std::min<size_t>(best, found);
    }
  }
  if (best == haystack.size()) {
    return StringPiece::npos;
  }
  return best;
}

bool Base64::WebSafeEncode(const StringPiece& input, std::string* output)
{
    std::string temp;
    temp.resize(modp_b64r_encode_len(input.size()));  // makes room for null byte

    // null terminates result since result is base64 text!
    int input_size = static_cast<int>(input.size());
    int output_size = modp_b64r_encode(&(temp[0]), input.data(), input_size);
    if (output_size < 0)
        return false;

    temp.resize(output_size);  // strips off null byte
    output->swap(temp);
    return true;
}

// Updates contents so that any read accesses past the last byte will
// cause a SIGSEGV.  It accomplishes this by changing access to the page that
// begins immediately after the end of the contents (as allocators and mmap()
// all operate on page boundaries, this is a reasonable assumption).
// This function will also initialize buf, which caller must free().
void createProtectedBuf(StringPiece& contents, char** buf) {
  ASSERT_LE(contents.size(), kPageSize);
  const size_t kSuccess = 0;
  char* pageAlignedBuf = (char*)aligned_malloc(2 * kPageSize, kPageSize);
  if (pageAlignedBuf == nullptr) {
    ASSERT_FALSE(true);
  }
  // Protect the page after the first full page-aligned region of the
  // malloc'ed buffer
  mprotect(pageAlignedBuf + kPageSize, kPageSize, PROT_NONE);
  size_t newBegin = kPageSize - contents.size();
  memcpy(pageAlignedBuf + newBegin, contents.data(), contents.size());
  contents.reset(pageAlignedBuf + newBegin, contents.size());
  *buf = pageAlignedBuf;
}