實現qsort（和qsort差一個數量級啊，傷自尊了）

  1 #include <cstdio>
  2 #include <cstdint>
  3 #include <ctime>
  4 #include <cstring>
  5 #include <cstdlib>
  6 
  7 void GetPivot(uint8_t In_ui8A[], int64_t In_i64Begin, int64_t In_i64End)
  8 {
  9     uint8_t     ui8Tmp          = 0;
 10     uint64_t    ui64PivotIdx    = 0;
 11     if (In_ui8A == NULL || In_i64Begin >= In_i64End)
 12     {
 13         goto fun_ret;
 14     }
 15 
 16     ui64PivotIdx = (In_i64End - In_i64Begin + 1) / 2;
 17     ui8Tmp = In_ui8A[In_i64End];
 18     In_ui8A[In_i64End] = In_ui8A[ui64PivotIdx + In_i64Begin];
 19     In_ui8A[ui64PivotIdx + In_i64Begin] = ui8Tmp;
 20 fun_ret:
 21     return;
 22 }
 23 
 24 void QSort(uint8_t In_ui8A[], int64_t In_i64Begin, int64_t In_i64End)
 25 {
 26     int64_t i = 0, j = 0;
 27     uint8_t ui8Pivot = 0, ui8Tmp = 0;;
 28     if (In_ui8A == NULL || In_i64Begin >= In_i64End)
 29     {
 30         goto fun_ret;
 31     }
 32     GetPivot(In_ui8A, In_i64Begin, In_i64End);
 33 
 34     i = In_i64Begin - 1;
 35     j = In_i64Begin;
 36     ui8Pivot = In_ui8A[In_i64End];
 37 
 38     do 
 39     {
 40         if (In_ui8A[j] <= ui8Pivot)
 41         {
 42             ui8Tmp = In_ui8A[++ i];
 43             In_ui8A[i] = In_ui8A[j];
 44             In_ui8A[j] = ui8Tmp;
 45         }
 46         j ++;
 47     } while (j < In_i64End);
 48 
 49     ui8Tmp = In_ui8A[i + 1];
 50     In_ui8A[i + 1] = ui8Pivot;
 51     In_ui8A[In_i64End] = ui8Tmp;
 52 
 53     QSort(In_ui8A, In_i64Begin, i);
 54     QSort(In_ui8A, i + 2, In_i64End);
 55 
 56 fun_ret:
 57     return;
 58 }
 59 
 60 int compare (const void *p1, const void *p2)
 61 {
 62     if (*(uint8_t*)p1 < *(uint8_t*)p2) return -1;
 63     else if (*(uint8_t*)p1 == *(uint8_t*)p2) return 0;
 64     else return 1;
 65 }
 66 
 67 void main(int argc, char **argv)
 68 {
 69     uint8_t *pui8Buf1   = NULL, *pui8Buf2 = NULL;
 70     FILE    *pf         = NULL;
 71     long    lFileSize   = 0;
 72     clock_t ctBegin     = 0, ctQSortTime = 0, ctMyTime = 0;
 73 
 74     pf  = fopen(argv[1], "rb");
 75     fseek(pf, 0, SEEK_END);
 76     lFileSize = ftell(pf);
 77     fseek(pf, 0, SEEK_SET);
 78     pui8Buf1 = (uint8_t *)malloc(lFileSize);
 79     pui8Buf2 = (uint8_t *)malloc(lFileSize);
 80     memset(pui8Buf1, 0, lFileSize);
 81     memset(pui8Buf2, 0, lFileSize);
 82     fread(pui8Buf1, sizeof(pui8Buf1[0]), lFileSize, pf);
 83     memcpy(pui8Buf2, pui8Buf1, lFileSize);
 84     fclose(pf);
 85     pf  = NULL;
 86 
 87     ctBegin = clock();
 88     QSort(pui8Buf1, 0, lFileSize - 1);
 89     ctMyTime = clock() - ctBegin;
 90 
 91     ctBegin = clock();
 92     qsort((void *)pui8Buf2, lFileSize, sizeof(pui8Buf2[0]), compare);
 93     ctQSortTime = clock() - ctBegin;
 94 
 95     if (!memcmp((void *)pui8Buf1, (void *)pui8Buf2, lFileSize))
 96     {
 97         printf("MyQSort::%lu\nqsort::%lu\n", ctMyTime, ctQSortTime);
 98     }
 99     else
100     {
101         printf("FUCK!!!\n");
102     }
103 }

排序一個7,680字節的PE，本身實現的用了10+毫秒，qsort用了不到1毫秒，尼瑪傷自尊了。