fixed issue #4786 , revert compact BigDecimal optimize

dbsync/src/main/java/com/taobao/tddl/dbsync/binlog/LogBuffer.java

@@ -1306,15 +1306,6 @@ public class LogBuffer {
             throw new IllegalArgumentException("limit excceed: " + (position + binSize - origin));
         }
 
-        if (precision <= 20 && intg <= 18 && frac <= 9) {
-            // use compact BigDecimal
-            BigDecimal compactDecimal = getBigDecimalCompact(precision, scale, intg, frac, intg0x);
-            if (compactDecimal != null) {
-                position += binSize;
-                return compactDecimal;
-            }
-        }
-
         BigDecimal decimal = getDecimal0(position, intg, frac, // NL
             intg0,
             frac0,
@@ -1324,162 +1315,6 @@ public class LogBuffer {
         return decimal;
     }
 
-    /**
-     * use compact BigDecimal
-     */
-    private BigDecimal getBigDecimalCompact(int precision, int scale, int intg, int frac, int intg0x) {
-        if (precision > 20 || intg > 18 && frac > 9) {
-            return null;
-        }
-
-        BigDecimal compactDecimal = null;
-        long longValue = 0;
-        int small = 0;
-        int pos = position;
-        byte b0 = buffer[position];
-        final int mask = ((b0 & 0x80) == 0x80) ? 0 : -1;
-        b0 ^= 0x80;
-
-        switch (intg0x) {
-            case 0:
-                if (intg == 0) {
-                    longValue = 0;
-                } else {
-                    longValue = (b0 << 24)
-                                | ((0xff & buffer[pos + 1]) << 16)
-                                | ((0xff & buffer[pos + 2]) << 8)
-                                | (0xff & buffer[pos + 3]);
-                    longValue ^= mask;
-                    pos += 4;
-                }
-                break;
-            case 1:
-            case 2:
-                longValue = b0;
-                longValue ^= mask;
-                pos += 1;
-                break;
-            case 3:
-            case 4:
-                longValue = (b0 << 8) | (0xff & buffer[pos + 1]);
-                longValue ^= mask;
-                pos += 2;
-                break;
-            case 5:
-            case 6:
-                longValue = (b0 << 16) | ((0xff & buffer[pos + 1]) << 8) | (0xff & buffer[pos + 2]);
-                longValue ^= mask;
-                pos += 3;
-                break;
-            case 7:
-            case 8:
-                longValue = (b0 << 24)
-                            | ((0xff & buffer[pos + 1]) << 16)
-                            | ((0xff & buffer[pos + 2]) << 8)
-                            | (0xff & buffer[pos + 3]);
-                longValue ^= mask;
-                pos += 4;
-                break;
-            default:
-                break;
-        }
-
-        if (intg > 9) {
-            int value = getInt32BE(buffer, pos);
-            value ^= mask;
-            longValue *= 1_000_000_000;
-            longValue += value;
-            pos += 4;
-        }
-
-        int power = 1;
-        if (pos != position) {
-            b0 = buffer[pos];
-        }
-        switch (frac) {
-            case 0:
-                small = 0;
-                break;
-            case 1:
-            case 2:
-                power = frac == 1 ? 10 : 100;
-                small = b0;
-                small ^= mask;
-                break;
-            case 3:
-            case 4:
-                power = frac == 3 ? 1_000 : 10_000;
-                small = (b0 << 8) | (0xff & buffer[pos + 1]);
-                small ^= mask;
-                break;
-            case 5:
-            case 6:
-                power = frac == 5 ? 100_000 : 1_000_000;
-                small = (b0 << 16) | ((0xff & buffer[pos + 1]) << 8) | (0xff & buffer[pos + 2]);
-                small ^= mask;
-                break;
-            case 7:
-            case 8:
-            case 9:
-                power = frac == 7 ? 10_000_000 : frac == 8 ? 100_000_000 : 1_000_000_000;
-                small = (b0 << 24)
-                        | ((0xff & buffer[pos + 1]) << 16)
-                        | ((0xff & buffer[pos + 2]) << 8)
-                        | (0xff & buffer[pos + 3]);
-                small ^= mask;
-                break;
-            default:
-                break;
-        }
-
-        if (small == 0) {
-            if (frac == 0) {
-                if (mask != 0) {
-                    longValue = -longValue;
-                }
-                compactDecimal = BigDecimal.valueOf(longValue, 0);
-            } else if (longValue == 0) {
-                if (scale < 9) {
-                    compactDecimal = DECIMAL_ZERO_1_SCALE;
-                } else {
-                    compactDecimal = BigDecimal.valueOf(longValue, scale);
-                }
-            } else {
-                if (scale < 9) {
-                    long unscaleValue = longValue * 10;
-                    if (unscaleValue >= longValue) {
-                        if (mask != 0) {
-                            unscaleValue = -unscaleValue;
-                        }
-                        if (unscaleValue == 10) {
-                            compactDecimal = DECIMAL_ONE_1_SCALE;
-                        } else {
-                            compactDecimal = BigDecimal.valueOf(unscaleValue, 1);
-                        }
-                    }
-                } else {
-                    long unscaleValue = longValue * power;
-                    if (unscaleValue >= longValue) {
-                        if (mask != 0) {
-                            unscaleValue = -unscaleValue;
-                        }
-                        compactDecimal = BigDecimal.valueOf(unscaleValue, scale);
-                    }
-                }
-            }
-        } else {
-            long unscaleValue = longValue * power + small;
-            if (unscaleValue >= longValue) {
-                if (mask != 0) {
-                    unscaleValue = -unscaleValue;
-                }
-                compactDecimal = BigDecimal.valueOf(unscaleValue, scale);
-            }
-        }
-
-        return compactDecimal;
-    }
-
     /**
      * Return big decimal from buffer.
      *