text: // Copyright 2014 the V8 project 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 "src/ostreams.h"
  #include "src/objects.h"
  #include "src/objects/string.h"
  
  #if V8_OS_WIN
  #if _MSC_VER < 1900
  #define snprintf sprintf_s
  #endif
  #endif
  
  #if defined(ANDROID) && !defined(V8_ANDROID_LOG_STDOUT)
  #define LOG_TAG "v8"
  #include <android/log.h>  // NOLINT
  #endif
  
  namespace v8 {
  namespace internal {
  
  OFStreamBase::OFStreamBase(FILE* f) : f_(f) {}
  
  int OFStreamBase::sync() {
    std::fflush(f_);
    return 0;
  }
  
  
  OFStreamBase::int_type OFStreamBase::overflow(int_type c) {
    return (c != EOF) ? std::fputc(c, f_) : c;
  }
  
  
  std::streamsize OFStreamBase::xsputn(const char* s, std::streamsize n) {
    return static_cast<std::streamsize>(
        std::fwrite(s, 1, static_cast<size_t>(n), f_));
  }
  
  OFStream::OFStream(FILE* f) : std::ostream(nullptr), buf_(f) {
    DCHECK_NOT_NULL(f);
    rdbuf(&buf_);
  }
  
  #if defined(ANDROID) && !defined(V8_ANDROID_LOG_STDOUT)
  AndroidLogStream::~AndroidLogStream() {
    // If there is anything left in the line buffer, print it now, even though it
    // was not terminated by a newline.
    if (!line_buffer_.empty()) {
      __android_log_write(ANDROID_LOG_INFO, LOG_TAG, line_buffer_.c_str());
    }
  }
  
  std::streamsize AndroidLogStream::xsputn(const char* s, std::streamsize n) {
    const char* const e = s + n;
    while (s < e) {
      const char* newline = reinterpret_cast<const char*>(memchr(s, '\n', e - s));
      size_t line_chars = (newline ? newline : e) - s;
      line_buffer_.append(s, line_chars);
      // Without terminating newline, keep the characters in the buffer for the
      // next invocation.
      if (!newline) break;
      // Otherwise, write out the first line, then continue.
      __android_log_write(ANDROID_LOG_INFO, LOG_TAG, line_buffer_.c_str());
      line_buffer_.clear();
      s = newline + 1;
    }
    return n;
  }
  #endif
  
  namespace {
  
  // Locale-independent predicates.
  bool IsPrint(uint16_t c) { return 0x20 <= c && c <= 0x7E; }
  bool IsSpace(uint16_t c) { return (0x9 <= c && c <= 0xD) || c == 0x20; }
  bool IsOK(uint16_t c) { return (IsPrint(c) || IsSpace(c)) && c != '\\'; }
  
  
  std::ostream& PrintUC16(std::ostream& os, uint16_t c, bool (*pred)(uint16_t)) {
    char buf[10];
    const char* format = pred(c) ? "%c" : (c <= 0xFF) ? "\\x%02x" : "\\u%04x";
    snprintf(buf, sizeof(buf), format, c);
    return os << buf;
  }
  
  std::ostream& PrintUC16ForJSON(std::ostream& os, uint16_t c,
                                 bool (*pred)(uint16_t)) {
    // JSON does not allow \x99; must use \u0099.
    char buf[10];
    const char* format = pred(c) ? "%c" : "\\u%04x";
    snprintf(buf, sizeof(buf), format, c);
    return os << buf;
  }
  
  std::ostream& PrintUC32(std::ostream& os, int32_t c, bool (*pred)(uint16_t)) {
    if (c <= String::kMaxUtf16CodeUnit) {
      return PrintUC16(os, static_cast<uint16_t>(c), pred);
    }
    char buf[13];
    snprintf(buf, sizeof(buf), "\\u{%06x}", c);
    return os << buf;
  }
  
  }  // namespace
  
  
  std::ostream& operator<<(std::ostream& os, const AsReversiblyEscapedUC16& c) {
    return PrintUC16(os, c.value, IsOK);
  }
  
  
  std::ostream& operator<<(std::ostream& os, const AsEscapedUC16ForJSON& c) {
    if (c.value == '\n') return os << "\\n";
    if (c.value == '\r') return os << "\\r";
    if (c.value == '\t') return os << "\\t";
    if (c.value == '\"') return os << "\\\"";
    return PrintUC16ForJSON(os, c.value, IsOK);
  }
  
  
  std::ostream& operator<<(std::ostream& os, const AsUC16& c) {
    return PrintUC16(os, c.value, IsPrint);
  }
  
  
  std::ostream& operator<<(std::ostream& os, const AsUC32& c) {
    return PrintUC32(os, c.value, IsPrint);
  }
  
  std::ostream& operator<<(std::ostream& os, const AsHex& hex) {
    // Each byte uses up to two characters. Plus two characters for the prefix,
    // plus null terminator.
    DCHECK_GE(sizeof(hex.value) * 2, hex.min_width);
    static constexpr size_t kMaxHexLength = 3 + sizeof(hex.value) * 2;
    char buf[kMaxHexLength];
    snprintf(buf, kMaxHexLength, "%s%.*" PRIx64, hex.with_prefix ? "0x" : "",
             hex.min_width, hex.value);
    return os << buf;
  }
  
  std::ostream& operator<<(std::ostream& os, const AsHexBytes& hex) {
    uint8_t bytes = hex.min_bytes;
    while (bytes < sizeof(hex.value) && (hex.value >> (bytes * 8) != 0)) ++bytes;
    for (uint8_t b = 0; b < bytes; ++b) {
      if (b) os << " ";
      uint8_t printed_byte =
          hex.byte_order == AsHexBytes::kLittleEndian ? b : bytes - b - 1;
      os << AsHex((hex.value >> (8 * printed_byte)) & 0xFF, 2);
    }
    return os;
  }
  
  }  // namespace internal
  }  // namespace v8
  
  #undef snprintf
  #undef LOG_TAG
  