refactor: do some internal refactor.

source/util/src/tcompression.c

@@ -283,40 +283,39 @@ int32_t tsDecompressINTImp(const char *const input, const int32_t nelements, cha
       case TSDB_DATA_TYPE_BIGINT: {
         int64_t* p = (int64_t*) output;
 
-        if (selector == 0 || selector == 1) {
-          int32_t gRemainder = nelements - _pos;
-          int32_t num = gRemainder < elems? gRemainder:elems;
+        int32_t gRemainder = (nelements - _pos);
+        int32_t num = (gRemainder > elems)? elems:gRemainder;
 
         int32_t batch = num >> 2;
-          int32_t remainder = num & 0x03;
+        int32_t remain = num & 0x03;
+        if (selector == 0 || selector == 1) {
+          if (tsAVX2Enable && tsSIMDBuiltins) {
             for (int32_t i = 0; i < batch; ++i) {
-            p[_pos++] = prev_value;
-            p[_pos++] = prev_value;
-            p[_pos++] = prev_value;
-            p[_pos++] = prev_value;
+              __m256i prev = _mm256_set1_epi64x(prev_value);
+              _mm256_storeu_si256((__m256i *)&p[_pos], prev);
+              _pos += 4;
             }
 
-          for (int32_t i = 0; i < remainder; ++i) {
+            for (int32_t i = 0; i < remain; ++i) {
               p[_pos++] = prev_value;
             }
-
-          count += num;
           } else {
-          int32_t gRemainder = (nelements - _pos);
-          int32_t num = (gRemainder > elems)? elems:gRemainder;
-
-          int32_t batch = num >> 2;
-          int32_t remain = num & 0x03;
-#if 1
+            for (int32_t i = 0; i < elems && count < nelements; i++, count++) {
+              p[_pos++] = prev_value;
+              v += bit;
+            }
+          }
+        } else {
+          if (tsAVX2Enable && tsSIMDBuiltins) {
             __m256i base = _mm256_set1_epi64x(w);
             __m256i maskVal = _mm256_set1_epi64x(mask);
 
             __m256i shiftBits = _mm256_set_epi64x(bit * 3 + 4, bit * 2 + 4, bit + 4, 4);
             __m256i inc = _mm256_set1_epi64x(bit << 2);
 
-          for(int32_t i = 0; i < batch; ++i) {
+            for (int32_t i = 0; i < batch; ++i) {
               __m256i after = _mm256_srlv_epi64(base, shiftBits);
-            __m256i zigzagVal= _mm256_and_si256(after, maskVal);
+              __m256i zigzagVal = _mm256_and_si256(after, maskVal);
 
               // ZIGZAG_DECODE(T, v) (((v) >> 1) ^ -((T)((v)&1)))
               __m256i signmask = _mm256_and_si256(_mm256_set1_epi64x(1), zigzagVal);
@@ -364,7 +363,7 @@ int32_t tsDecompressINTImp(const char *const input, const int32_t nelements, cha
               p[_pos++] = prev_value;
               v += bit;
             }
-#else
+          } else {
             for (int32_t i = 0; i < elems && count < nelements; i++, count++) {
               zigzag_value = ((w >> v) & mask);
               prev_value += ZIGZAG_DECODE(int64_t, zigzag_value);
@@ -372,7 +371,7 @@ int32_t tsDecompressINTImp(const char *const input, const int32_t nelements, cha
               p[_pos++] = prev_value;
               v += bit;
             }
-#endif
+          }
         }
       } break;
       case TSDB_DATA_TYPE_INT: {