// - convert a single SI value into a string, e.g. to_string(12_m) #pragma once #include #include namespace SI { std::string format_of_to_string = "%.2Lf%s"; // <-- configurable (precision / whitespace) // internal function to join and convert both value and unit into a string. std::string _join(long double value, const std::string& unit) { char buf[256]; std::snprintf(buf, sizeof(buf), format_of_to_string.c_str(), value, unit.c_str()); return std::string(buf); } // convert the 7 SI base units: std::string to_string(length d) { if (d <= -1_Gpc || d >= 1_Gpc) return _join(d / 1_Gpc, "Gpc (gigaparsec)"); if (d <= -1_Mpc || d >= 1_Mpc) return _join(d / 1_Mpc, "Mpc (megaparsec)"); if (d <= -1_kpc || d >= 1_kpc) return _join(d / 1_kpc, "kpc (kiloparsec)"); if (d <= -1_pc || d >= 1_pc) return _join(d / 1_pc, "pc"); // parsec if (d <= -1_ly || d >= 1_ly) return _join(d / 1_ly, "ly"); // light-years if (d <= -1_au || d >= 1_au) return _join(d / 1_au, "au"); // astronomical unit if (d <= -1_km || d >= 1_km) return _join(d / 1_km, "km"); if (d <= -1_m || d >= 1_m || d == 0.0_m) return _join(d / 1_m, "m"); if (d <= -1_cm || d >= 1_cm) return _join(d / 1_cm, "cm"); if (d <= -1_mm || d >= 1_mm) return _join(d / 1_mm, "mm"); if (d <= -1_um || d >= 1_um) return _join(d / 1_um, "μm"); if (d <= -1_nm || d >= 1_nm) return _join(d / 1_nm, "nm"); return _join(d / 1_pm, "pm"); } std::string to_string(time t) { if (abs(t) > 365.25_days) return _join(t / 365.25_days, " years"); if (abs(t) > 10_days) return _join(t / 7_days, " weeks"); if (abs(t) > 2_day) return _join(t / 1_day, " days"); if (t <= -1_h || t >= 1_h) return _join(t / 1_h, "h"); if (t <= -1_min || t >= 1_min) return _join(t / 1_min, "min"); if (t <= -1_s || t >= 1_s || t == 0.0_s) return _join(t / 1_s, "s"); if (t <= -1_ms || t >= 1_ms) return _join(t / 1_ms, "ms"); if (t <= -1_us || t >= 1_us) return _join(t / 1_us, "μs"); if (t <= -1_ns || t >= 1_ns) return _join(t / 1_ns, "ns"); return _join(t / 1_ps, "ps"); } std::string to_string(mass m) { if (m <= -1_Gt || m >= 1_Gt) return _join(m / 1_Gt, "Gt"); if (m <= -1_Mt || m >= 1_Mt) return _join(m / 1_Mt, "Mt"); if (m <= -1_kt || m >= 1_kt) return _join(m / 1_kt, "kt"); if (m <= -1_t || m >= 1_t) return _join(m / 1_t, "t"); if (m <= -1_kg || m >= 1_kg || m == 0.0_kg) return _join(m / 1_kg, "kg"); if (m <= -1_g || m >= 1_g) return _join(m / 1_g, "g"); if (m <= -1_mg || m >= 1_mg) return _join(m / 1_mg, "mg"); if (m <= -1_ug || m >= 1_ug) return _join(m / 1_ug, "µg"); return _join(m / 1_ng, "ng"); } std::string to_string(temperature T) { if (T <= -1_GK || T >= 1_GK) return _join(T / 1_GK, "GK"); if (T <= -1_MK || T >= 1_MK) return _join(T / 1_MK, "MK"); if (T >= 250_K && T <= 470_K) // human temperature range return _join(celsius(T), "°C"); if (T <= -1_K || T >= 1_K || T == 0.0_K) return _join(T / 1_K, "K"); if (T <= -1_mK || T >= 1_mK) return _join(T / 1_mK, "mK"); if (T <= -1_uK || T >= 1_uK) return _join(T / 1_uK, "μK"); return _join(T / 1_nK, "nK"); } std::string to_string(electric_current I) { if (I <= -1_GA || I >= 1_GA) return _join(I / 1_GA, "GA"); if (I <= -1_MA || I >= 1_MA) return _join(I / 1_MA, "MA"); if (I <= -1_kA || I >= 1_kA) return _join(I / 1_kA, "kA"); if (I <= -1_A || I >= 1_A || I == 0.0_A) return _join(I / 1_A, "A"); if (I <= -1_mA || I >= 1_mA) return _join(I / 1_mA, "mA"); if (I <= -1_uA || I >= 1_uA) return _join(I / 1_uA, "μA"); if (I <= -1_nA || I >= 1_nA) return _join(I / 1_nA, "nA"); return _join(I / 1_pA, "pA"); } // Convert the 22 derived SI units: std::string to_string(area a) { if (a <= -1_km² || a >= 1_km²) return _join(a / 1_km², "km²"); if (a <= -1_hm² || a >= 1_hm²) return _join(a / 1_hm², "hm²"); if (a <= -1_m² || a >= 1_m² || a == 0.0_m²) return _join(a / 1_m², "m²"); if (a <= -1_cm² || a >= 1_cm²) return _join(a / 1_cm², "cm²"); if (a <= -1_mm² || a >= 1_mm²) return _join(a / 1_mm², "mm²"); return _join(a / 1_um², "μm²"); } std::string to_string(per_area a) { if (a <= -1_per_km² || a >= 1_per_km²) return _join(a / 1_per_km², "/km²"); if (a <= -1_per_hm² || a >= 1_per_hm²) return _join(a / 1_per_hm², "/hm²"); if (a <= -1_per_m² || a >= 1_per_m² || a == 0.0_per_m²) return _join(a / 1_per_m², "/m²"); if (a <= -1_per_cm² || a >= 1_per_cm²) return _join(a / 1_per_cm², "/cm²"); if (a <= -1_per_mm² || a >= 1_per_mm²) return _join(a / 1_per_mm², "/mm²"); return _join(a / 1_per_μm², "/μm²"); } std::string to_string(volume v) { if (v <= -1_km³ || v >= 1_km³) return _join(v / 1_km³, "km³"); if (v <= -1_m³ || v >= 1_m³) return _join(v / 1_m³, "m³"); if (v <= -1_l || v >= 1_l || v == 0.0_l) return _join(v / 1_l, "l"); if (v <= -1_ml || v >= 1_ml) return _join(v / 1_ml, "ml"); if (v <= -1_ul || v >= 1_ul) return _join(v / 1_ul, "μl"); if (v <= -1_nl || v >= 1_nl) return _join(v / 1_nl, "nl"); return _join(v / 1_pl, "pl"); } std::string to_string(velocity v) { if (v <= -1_km_per_h || v >= 1_km_per_h) return _join(v / 1_km_per_h, "km/h"); if (v <= -1_m_per_s || v >= 1_m_per_s || v == 0.0_m_per_s) return _join(v / 1_m_per_s, "m/s"); return _join(v / 1_mm_per_h, "mm/h"); } std::string to_string(acceleration a) { if (a <= -1_km_per_s² || a >= 1_km_per_s²) return _join(a / 1_km_per_s², "km/s"); return _join(a / 1_m_per_s², "m/s²"); } std::string to_string(frequency f) { if (f <= -1_THz || f >= 1_THz) return _join(f / 1_THz, "THz"); if (f <= -1_GHz || f >= 1_GHz) return _join(f / 1_GHz, "GHz"); if (f <= -1_MHz || f >= 1_MHz) return _join(f / 1_MHz, "MHz"); if (f <= -1_kHz || f >= 1_kHz) return _join(f / 1_kHz, "kHz"); if (f <= -1_Hz || f >= 1_Hz || f == 0.0_Hz) return _join(f / 1_Hz, "Hz"); return _join(f / 1_mHz, "mHz"); } std::string to_string(force F) { if (F <= -1_ZN || F >= 1_ZN) return _join(F / 1_ZN, "ZN"); if (F <= -1_EN || F >= 1_EN) return _join(F / 1_EN, "EN"); if (F <= -1_PN || F >= 1_PN) return _join(F / 1_PN, "PN"); if (F <= -1_TN || F >= 1_TN) return _join(F / 1_TN, "TN"); if (F <= -1_GN || F >= 1_GN) return _join(F / 1_GN, "GN"); if (F <= -1_MN || F >= 1_MN) return _join(F / 1_MN, "MN"); if (F <= -1_kN || F >= 1_kN) return _join(F / 1_kN, "kN"); if (F <= -1_N || F >= 1_N || F == 0.0_N) return _join(F / 1_N, "N"); if (F <= -1_mN || F >= 1_mN) return _join(F / 1_mN, "mN"); if (F <= -1_uN || F >= 1_uN) return _join(F / 1_uN, "µN"); return _join(F / 1_pN, "pN"); } std::string to_string(energy E) { if (E <= -1_PJ || E >= 1_PJ) return _join(E / 1_PJ, "PJ"); if (E <= -1_TJ || E >= 1_TJ) return _join(E / 1_TJ, "TJ"); if (E <= -1_GJ || E >= 1_GJ) return _join(E / 1_GJ, "GJ"); if (E <= -1_MJ || E >= 1_MJ) return _join(E / 1_MJ, "MJ"); if (E <= -1_kJ || E >= 1_kJ) return _join(E / 1_kJ, "kJ"); if (E <= -1_J || E >= 1_J || E == 0.0_J) return _join(E / 1_J, "J"); return _join(E / 1_mJ, "mJ"); } std::string to_string(power P) { if (P <= -1_TW || P >= 1_TW) return _join(P / 1_TW, "TW"); if (P <= -1_GW || P >= 1_GW) return _join(P / 1_GW, "GW"); if (P <= -1_MW || P >= 1_MW) return _join(P / 1_MW, "MW"); if (P <= -1_kW || P >= 1_kW) return _join(P / 1_kW, "kW"); return _join(P / 1_W, "W"); #if 0 if (P <= -1_TWh || P >= 1_TWh) return _join(P / 1_TWh, "TWh"); if (P <= -1_GWh || P >= 1_GWh) return _join(P / 1_GWh, "GWh"); if (P <= -1_MWh || P >= 1_MWh) return _join(P / 1_MWh, "MWh"); if (P <= -1_kWh || P >= 1_kWh) return _join(P / 1_kWh, "kWh"); return _join(P / 1_Wh, "Wh"); #endif } std::string to_string(power_intensity I) { if (I <= -1_MW_per_m² || I >= 1_MW_per_m²) return _join(I / 1_MW_per_m², "MW/m²"); if (I <= -1_kW_per_m² || I >= 1_kW_per_m²) return _join(I / 1_kW_per_m², "kW/m²"); if (I <= -1_W_per_m² || I >= 1_W_per_m²) return _join(I / 1_W_per_m², "W/m²"); return _join(I / 1_mW_per_m², "mW/m²"); } std::string to_string(pressure p) { if (p <= -1_MPa || p >= 1_MPa) return _join(p / 1_MPa, "MPa"); if (p <= -1_kPa || p >= 1_kPa) return _join(p / 1_kPa, "kPa"); if (p <= -1_hPa || p >= 1_hPa) return _join(p / 1_hPa, "hPa"); if (p <= -1_Pa || p >= 1_Pa || p == 0.0_Pa) return _join(p / 1_Pa, "Pa"); if (p <= -1_mPa || p >= 1_mPa) return _join(p / 1_mPa, "mPa"); return _join(p / 1_uPa, "µPa"); } std::string to_string(electric_potential U) { if (U <= -1_GV || U >= 1_GV) return _join(U / 1_GV, "GV"); if (U <= -1_MV || U >= 1_MV) return _join(U / 1_MV, "MV"); if (U <= -1_kV || U >= 1_kV) return _join(U / 1_kV, "kV"); if (U <= -1_V || U >= 1_V || U == 0.0_V) return _join(U / 1_V, "V"); if (U <= -1_mV || U >= 1_mV) return _join(U / 1_mV, "mV"); if (U <= -1_uV || U >= 1_uV) return _join(U / 1_uV, "μV"); if (U <= -1_nV || U >= 1_nV) return _join(U / 1_nV, "nV"); return _join(U / 1_pV, "pV"); } std::string to_string(electric_charge Q) { if (Q <= -1_GAh || Q >= 1_GAh) return _join(Q / 1_MAh, "MAh"); if (Q <= -1_MAh || Q >= 1_MAh) return _join(Q / 1_MAh, "MAh"); if (Q <= -1_kAh || Q >= 1_kAh) return _join(Q / 1_kAh, "kAh"); if (Q <= -1_Ah || Q >= 1_Ah || Q == 0.0_Ah) return _join(Q / 1_Ah, "Ah"); if (Q <= -1_mAh || Q >= 1_mAh) return _join(Q / 1_mAh, "mAh"); return _join(Q / 1_uAh, "µAh"); } std::string to_string(mass_per_area m) { if (m <= -1_t_per_m² || m >= 1_t_per_m²) return _join(m / 1_t_per_m², "t/m²"); return _join(m / 1_kg_per_m², "kg/m²"); } std::string to_string(mass_per_power m) { if (m <= -1_kg_per_kW || m >= 1_kg_per_kW) return _join(m / 1_kg_per_kW, "kg/kW"); return _join(m / 1_kg_per_W, "kg/W"); } std::string to_string(density d) { if (d <= -1_t_per_m³ || d >= 1_t_per_m³) return _join(d / 1_t_per_m³, "t/m³"); return _join(d / 1_kg_per_m³, "kg/m³"); } std::string to_string(angle a) { return _join(a / 1_deg, "°"); } std::string to_string(dimensionless value) { return _join(value, ""); } std::string to_string(unsigned char byte) { char buf[256]; std::snprintf(buf, sizeof(buf), "%u", byte); return std::string(buf); } std::string to_string(char glyph) { char buf[256]; std::snprintf(buf, sizeof(buf), "%c", glyph); return std::string(buf); } std::string to_string(const std::string& text) { return text; } } // namespace SI // References // ---------- // 1. https://en.wikipedia.org/wiki/International_System_of_Units