Method DetermineMode

tools/io.cpp:187–246

Determine how to read the hex stream based on the first token.

  // Determine how to read the hex stream based on the first token.
  void DetermineMode() {
    SkipSpace();

    // Read 11 bytes, that is the size of the biggest token (10) + one more.
    char first_token[11];
    for (uint32_t i = 0; i < 11; ++i) {
      first_token[i] = Next();
    }

    // Table of how to match the first token with a mode.
    struct {
      const char* expect;
      bool must_have_delimiter;
      HexMode mode;
    } parse_info[] = {
        {"0x07230203", true, HexMode::Words},
        {"0x7230203", true, HexMode::Words},
        {"x07230203", true, HexMode::Words},
        {"x7230203", true, HexMode::Words},

        {"0x07", true, HexMode::BytesBigEndian},
        {"0x7", true, HexMode::BytesBigEndian},
        {"x07", true, HexMode::BytesBigEndian},
        {"x7", true, HexMode::BytesBigEndian},

        {"0x03", true, HexMode::BytesLittleEndian},
        {"0x3", true, HexMode::BytesLittleEndian},
        {"x03", true, HexMode::BytesLittleEndian},
        {"x3", true, HexMode::BytesLittleEndian},

        {"07", false, HexMode::StreamBigEndian},
        {"03", false, HexMode::StreamLittleEndian},
    };

    // Check to see if any of the possible first tokens are matched.  If not,
    // this is not a recognized hex stream.
    encountered_error_ = true;
    for (const auto& info : parse_info) {
      const size_t expect_len = strlen(info.expect);
      const bool matches_expect =
          MatchIgnoreCase(first_token, info.expect, expect_len);
      const bool satisfies_delimeter =
          !info.must_have_delimiter || IsSpace(first_token[expect_len]);
      if (matches_expect && satisfies_delimeter) {
        mode_ = info.mode;
        encountered_error_ = false;
        break;
      }
    }

    if (encountered_error_) {
      fprintf(stderr,
              "error: hex format detected, but pattern '%.11s' is not "
              "recognized '%s'\n",
              first_token, filename_);
    }

    // Reset the position to restart parsing with the determined mode.