yaffs_qsort.c 4.5 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156
  1. /*
  2. * Copyright (c) 1992, 1993
  3. * The Regents of the University of California. All rights reserved.
  4. *
  5. * Redistribution and use in source and binary forms, with or without
  6. * modification, are permitted provided that the following conditions
  7. * are met:
  8. * 1. Redistributions of source code must retain the above copyright
  9. * notice, this list of conditions and the following disclaimer.
  10. * 2. Redistributions in binary form must reproduce the above copyright
  11. * notice, this list of conditions and the following disclaimer in the
  12. * documentation and/or other materials provided with the distribution.
  13. * 3. Neither the name of the University nor the names of its contributors
  14. * may be used to endorse or promote products derived from this software
  15. * without specific prior written permission.
  16. *
  17. * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20. * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27. * SUCH DAMAGE.
  28. */
  29. #include "yportenv.h"
  30. //#include <linux/string.h>
  31. /*
  32. * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
  33. */
  34. #define swapcode(TYPE, parmi, parmj, n) { \
  35. long i = (n) / sizeof (TYPE); \
  36. register TYPE *pi = (TYPE *) (parmi); \
  37. register TYPE *pj = (TYPE *) (parmj); \
  38. do { \
  39. register TYPE t = *pi; \
  40. *pi++ = *pj; \
  41. *pj++ = t; \
  42. } while (--i > 0); \
  43. }
  44. #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
  45. es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
  46. static __inline void
  47. swapfunc(char *a, char *b, int n, int swaptype)
  48. {
  49. if (swaptype <= 1)
  50. swapcode(long, a, b, n)
  51. else
  52. swapcode(char, a, b, n)
  53. }
  54. #define swap(a, b) \
  55. if (swaptype == 0) { \
  56. long t = *(long *)(a); \
  57. *(long *)(a) = *(long *)(b); \
  58. *(long *)(b) = t; \
  59. } else \
  60. swapfunc(a, b, es, swaptype)
  61. #define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
  62. static __inline char *
  63. med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
  64. {
  65. return cmp(a, b) < 0 ?
  66. (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
  67. :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
  68. }
  69. #define min(a,b) (((a) < (b)) ? (a) : (b))
  70. void
  71. qsort(void *aa, size_t n, size_t es, int (*cmp)(const void *, const void *))
  72. {
  73. char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
  74. int d, r, swaptype, swap_cnt;
  75. register char *a = aa;
  76. loop: SWAPINIT(a, es);
  77. swap_cnt = 0;
  78. if (n < 7) {
  79. for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
  80. for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
  81. pl -= es)
  82. swap(pl, pl - es);
  83. return;
  84. }
  85. pm = (char *)a + (n / 2) * es;
  86. if (n > 7) {
  87. pl = (char *)a;
  88. pn = (char *)a + (n - 1) * es;
  89. if (n > 40) {
  90. d = (n / 8) * es;
  91. pl = med3(pl, pl + d, pl + 2 * d, cmp);
  92. pm = med3(pm - d, pm, pm + d, cmp);
  93. pn = med3(pn - 2 * d, pn - d, pn, cmp);
  94. }
  95. pm = med3(pl, pm, pn, cmp);
  96. }
  97. swap(a, pm);
  98. pa = pb = (char *)a + es;
  99. pc = pd = (char *)a + (n - 1) * es;
  100. for (;;) {
  101. while (pb <= pc && (r = cmp(pb, a)) <= 0) {
  102. if (r == 0) {
  103. swap_cnt = 1;
  104. swap(pa, pb);
  105. pa += es;
  106. }
  107. pb += es;
  108. }
  109. while (pb <= pc && (r = cmp(pc, a)) >= 0) {
  110. if (r == 0) {
  111. swap_cnt = 1;
  112. swap(pc, pd);
  113. pd -= es;
  114. }
  115. pc -= es;
  116. }
  117. if (pb > pc)
  118. break;
  119. swap(pb, pc);
  120. swap_cnt = 1;
  121. pb += es;
  122. pc -= es;
  123. }
  124. if (swap_cnt == 0) { /* Switch to insertion sort */
  125. for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
  126. for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
  127. pl -= es)
  128. swap(pl, pl - es);
  129. return;
  130. }
  131. pn = (char *)a + n * es;
  132. r = min(pa - (char *)a, pb - pa);
  133. vecswap(a, pb - r, r);
  134. r = min((long)(pd - pc), (long)(pn - pd - es));
  135. vecswap(pb, pn - r, r);
  136. if ((r = pb - pa) > es)
  137. qsort(a, r / es, es, cmp);
  138. if ((r = pd - pc) > es) {
  139. /* Iterate rather than recurse to save stack space */
  140. a = pn - r;
  141. n = r / es;
  142. goto loop;
  143. }
  144. /* qsort(pn - r, r / es, es, cmp);*/
  145. }