计算机字节可读取封装

小鱼儿 2022-11-28 15:10 81阅读 0赞

import java.math.BigDecimal;
    import java.math.RoundingMode;
    import java.text.DecimalFormat;
    
    
    public enum ByteUnitFormat {
        B(Unit.B) {
            @Override
            long toB(long value, Rate rate) {
                return value;
            }
        },
        K(Unit.K) {
            @Override
            long toB(long value, Rate rate) {
                return value * rate.rate;
            }
        },
        M(Unit.M) {
            @Override
            long toB(long value, Rate rate) {
                return value * rate.rate * rate.rate;
            }
        },
        G(Unit.G) {
            @Override
            long toB(long value, Rate rate) {
                return value * rate.rate * rate.rate * rate.rate;
            }
        },
        T(Unit.T) {
            @Override
            long toB(long value, Rate rate) {
                return value * rate.rate * rate.rate * rate.rate * rate.rate;
            }
        },
        P(Unit.P) {
            @Override
            long toB(long value, Rate rate) {
                return value * rate.rate * rate.rate * rate.rate * rate.rate * rate.rate;
            }
        },
        E(Unit.E) {
            @Override
            long toB(long value, Rate rate) {
                return value * rate.rate * rate.rate * rate.rate * rate.rate * rate.rate * rate.rate;
            }
        };
    
        private Unit unit;
    
        ByteUnitFormat(Unit unit) {
            this.unit = unit;
        }
    
        /**
         * Formatting byte size to human readable format
         * @param value original value
         * @param rate advance rate
         * @param scale scale of value to be returned
         * @param roundingMode roundingMode for value to be returned
         * @param displayUnitName return a value end with unit name if true
         * @return human readable byte value as String
         */
        public final String humanReadable(long value, Rate rate, int scale, RoundingMode roundingMode, boolean displayUnitName) {
            long b = toB(value, rate);
            String suffix = displayUnitName ? B.unit.name : "";
            if (b < rate.rate) {
                return b + suffix;
            }
            int level = (int) (Math.log(b) / Math.log(rate.rate));
    
            return ByteUnitFormat.B.to(ByteUnitFormat.values()[level], b, rate, scale, roundingMode, displayUnitName);
        }
    
        public final String humanReadable(long value, Rate rate, boolean displayUnitName) {
            return humanReadable(value, rate, 1, RoundingMode.HALF_UP, displayUnitName);
        }
    
        public final String humanReadable(long value, boolean displayUnitName) {
            return humanReadable(value, Rate.IEC, displayUnitName);
        }
    
        public final String humanReadable(long value) {
            return humanReadable(value, Rate.IEC, true);
        }
    
        public final String to(ByteUnitFormat targetFormat, long value, Rate rate) {
            return to(targetFormat, value, rate, 2, RoundingMode.HALF_UP, true);
        }
        public final String to(ByteUnitFormat targetFormat, long value) {
            return to(targetFormat, value, Rate.IEC, 2, RoundingMode.HALF_UP, true);
        }
    
        /**
         * Converts the specified {@code long value} from this format to the specified {@code targetFormat}.
         * @param targetFormat target unit format
         * @param value specified value
         * @param rate advance rate
         * @param scale scale of value to be returned
         * @param roundingMode roundingMode for value to be returned
         * @param displayUnitName return a value end with unit name if true
         * @return return value with {@code targetFormat} as String
         */
        public final String to(ByteUnitFormat targetFormat, long value, Rate rate, int scale, RoundingMode roundingMode, boolean displayUnitName) {
            int level = targetFormat.unit.ordinal() - unit.ordinal();
            DecimalFormat df = new DecimalFormat("#" + (scale > 0 ? ("#." + repeat("#", scale)) : ""));
            String suffix = displayUnitName ? targetFormat.unit.name : "";
    
            if (level == 0) {//同级
                return value + suffix;
            } else if (level > 0) {//升级
                BigDecimal result = new BigDecimal(value);
                for (int i = 0; i < level; i++) {
                    result = result.divide(new BigDecimal(rate.rate), 8, roundingMode);
                }
                return df.format(result.setScale(scale, roundingMode).doubleValue()) + suffix;
            } else {//降级
                level = Math.abs(level);
                BigDecimal result = new BigDecimal(value);
                for (int i = 0; i < level; i++) {
                    result = result.multiply(new BigDecimal(rate.rate));
                }
                return df.format(result.setScale(scale, roundingMode).doubleValue()) + suffix;
            }
        }
    
        public static String repeat(String seq, int n) {
            StringBuilder s = new StringBuilder();
            for (int i = 0; i < n; i++) {
                s.append(seq);
            }
            return s.toString();
        }
    
        abstract long toB(long value, Rate rate);
    
        public enum Unit {
            B("B"), K("K"), M("M"), G("G"), T("T"), P("P"), E("E");
    
            private String name;
    
            Unit(String name) {
                this.name = name;
            }
        }
    
        public enum Rate {
            SI(1000), IEC(1024);
    
            private int rate;
    
            Rate(int rate) {
                this.rate = rate;
            }
        }
    
        public static void main(String[] args) {
            System.out.println(ByteUnitFormat.B.to(ByteUnitFormat.K, 1024L, Rate.SI));
            System.out.println(ByteUnitFormat.B.to(ByteUnitFormat.K, 1024L, Rate.IEC));
            System.out.println(ByteUnitFormat.M.to(ByteUnitFormat.G, 4096L, Rate.IEC));
            System.out.println(ByteUnitFormat.M.to(ByteUnitFormat.G, 4096L));
            System.out.println(ByteUnitFormat.B.humanReadable(174541987L));
            System.out.println(M.humanReadable(1024L));
            System.out.println(M.humanReadable(1024L, false));
        }
    
    }