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MB-10248 Add quicksort implementation

The re-entrant version of quicksort (qsort_r) has different function
prototype across different platforms. Also, qsort_r is not present
in glibc version < 2.8. Added a copy of widely used FreeBSD qsort
implementation from standard library. It will be used if platform
specific qsort_r method is not available.

Change-Id: I372974b6a0be3c36ed3dc94a754321d52c72f2ac
Reviewed-on: http://review.couchbase.org/33734
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>
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1 parent fc3edc7 commit 23b42d51b582f45c7185aa7caf5960dde639ad17 @t3rm1n4l t3rm1n4l committed with trondn Feb 19, 2014
Showing with 232 additions and 13 deletions.
  1. +2 −1 CMakeLists.txt
  2. +1 −0 config.cmake.h.in
  3. +5 −12 src/file_sorter.cc
  4. +210 −0 src/quicksort.c
  5. +14 −0 src/quicksort.h
View
@@ -18,6 +18,7 @@ CHECK_INCLUDE_FILES("netinet/in.h" HAVE_NETINET_IN_H)
CHECK_INCLUDE_FILES("inttypes.h" HAVE_INTTYPES_H)
CHECK_INCLUDE_FILES("unistd.h" HAVE_UNISTD_H)
CHECK_SYMBOL_EXISTS(fdatasync "unistd.h" HAVE_FDATASYNC)
+CHECK_SYMBOL_EXISTS(qsort_r "stdlib.h" HAVE_QSORT_R)
IF (WIN32)
SET(COUCHSTORE_FILE_OPS "src/os_win.c")
@@ -40,7 +41,7 @@ SET(COUCHSTORE_SOURCES src/arena.cc src/bitfield.c src/btree_modify.cc
src/views/reductions.c src/views/sorted_list.c
src/views/spatial.c src/views/util.c src/views/values.c
src/views/view_group.c src/views/purgers.c
- src/views/compaction.c ${COUCHSTORE_FILE_OPS})
+ src/views/compaction.c src/quicksort.c ${COUCHSTORE_FILE_OPS})
SET(COUCHSTORE_LIBRARIES ${V8_LIBRARIES} ${ICU_LIBRARIES} ${SNAPPY_LIBRARIES} platform)
ADD_LIBRARY(couchstore SHARED ${COUCHSTORE_SOURCES})
View
@@ -6,5 +6,6 @@
#cmakedefine HAVE_UNISTD_H ${HAVE_UNISTD_H}
#cmakedefine HAVE_FDATASYNC ${HAVE_FDATASYNC}
+#cmakedefine HAVE_QSORT_R ${HAVE_QSORT_R}
#include "config_static.h"
View
@@ -24,6 +24,7 @@
#include <string.h>
#include "file_sorter.h"
#include "file_name_utils.h"
+#include "quicksort.h"
#define NSORT_RECORDS_INIT 500000
#define NSORT_RECORD_INCR 100000
@@ -270,7 +271,8 @@ static file_sorter_error_t do_sort_file(file_sort_ctx_t *ctx)
failure:
if (records) {
- for (--i; i >= 0; --i) {
+ while (i) {
+ i--;
(*ctx->free_record)(records[i], ctx->user_ctx);
}
@@ -348,11 +350,8 @@ static tmp_file_t *create_tmp_file(file_sort_ctx_t *ctx)
return &ctx->tmp_files[i];
}
-#if(defined __APPLE__ || _WIN32)
-static int qsort_cmp(void *ctx, const void *a, const void *b)
-#elif (defined __linux__)
+
static int qsort_cmp(const void *a, const void *b, void *ctx)
-#endif
{
file_sort_ctx_t *sort_ctx = (file_sort_ctx_t *) ctx;
const void **k1 = (const void **) a, **k2 = (const void **) b;
@@ -363,13 +362,7 @@ static int qsort_cmp(const void *a, const void *b, void *ctx)
static void sort_records(void **records, size_t n,
file_sort_ctx_t *ctx)
{
-#if(defined __APPLE__)
- qsort_r(records, n, sizeof(void *), ctx, &qsort_cmp);
-#elif (defined __linux__)
- qsort_r(records, n, sizeof(void *), &qsort_cmp, ctx);
-#elif (defined _WIN32)
- qsort_s(records, n, sizeof(void *), &qsort_cmp, ctx);
-#endif
+ quicksort(records, n, sizeof(void *), &qsort_cmp, ctx);
}
View
@@ -0,0 +1,210 @@
+/* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+
+/*
+ * qsort taken from FreeBSD, slightly modified to match glibc's
+ * argument ordering
+ */
+
+/*-
+ * Copyright (c) 1992, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/* $FreeBSD: src/lib/libc/stdlib/qsort.c,v 1.13.2.1.8.1 2010/12/21 17:10:29 kensmith Exp $ */
+
+#include <stdlib.h>
+#include "quicksort.h"
+
+typedef struct {
+ sort_cmp_t *func;
+ void *ctx;
+} qsort_wrapper;
+
+#if(defined __APPLE__ || defined _WIN32)
+static int qsort_cmp_wrap(void *ctx, const void *a, const void *b)
+{
+ qsort_wrapper *wrap = (qsort_wrapper *) ctx;
+ return (*wrap->func)(a, b, wrap->ctx);
+}
+
+#elif(!defined HAVE_QSORT_R)
+
+static inline char *med3(char *, char *, char *, sort_cmp_t *, void *);
+static inline void swapfunc(char *, char *, int, int);
+
+#define min(a, b) (a) < (b) ? a : b
+
+/*
+ * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
+ */
+#define swapcode(TYPE, parmi, parmj, n) { \
+ long i = (n) / sizeof (TYPE); \
+ TYPE *pi = (TYPE *) (parmi); \
+ TYPE *pj = (TYPE *) (parmj); \
+ do { \
+ TYPE t = *pi; \
+ *pi++ = *pj; \
+ *pj++ = t; \
+ } while (--i > 0); \
+}
+
+#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
+ es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
+
+static inline void
+swapfunc(a, b, n, swaptype)
+ char *a, *b;
+ int n, swaptype;
+{
+ if(swaptype <= 1)
+ swapcode(long, a, b, n)
+ else
+ swapcode(char, a, b, n)
+}
+
+#define swap(a, b) \
+ if (swaptype == 0) { \
+ long t = *(long *)(a); \
+ *(long *)(a) = *(long *)(b); \
+ *(long *)(b) = t; \
+ } else \
+ swapfunc(a, b, es, swaptype)
+
+#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
+
+#define CMP(t, x, y) (cmp((x), (y), (t)))
+
+static inline char *med3(char *a, char *b, char *c, sort_cmp_t *cmp, void *thunk)
+{
+ return CMP(thunk, a, b) < 0 ?
+ (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
+ :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
+}
+
+static void qsort_fallback(void *a, size_t n, size_t es, sort_cmp_t *cmp, void *thunk)
+{
+ char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
+ size_t d, r;
+ int cmp_result;
+ int swaptype, swap_cnt;
+
+loop:
+ SWAPINIT(a, es);
+ swap_cnt = 0;
+ if (n < 7) {
+ for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
+ for (pl = pm;
+ pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
+ pl -= es)
+ swap(pl, pl - es);
+ return;
+ }
+ pm = (char *)a + (n / 2) * es;
+ if (n > 7) {
+ pl = a;
+ pn = (char *)a + (n - 1) * es;
+ if (n > 40) {
+ d = (n / 8) * es;
+ pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
+ pm = med3(pm - d, pm, pm + d, cmp, thunk);
+ pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
+ }
+ pm = med3(pl, pm, pn, cmp, thunk);
+ }
+ swap(a, pm);
+ pa = pb = (char *)a + es;
+
+ pc = pd = (char *)a + (n - 1) * es;
+ for (;;) {
+ while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
+ if (cmp_result == 0) {
+ swap_cnt = 1;
+ swap(pa, pb);
+ pa += es;
+ }
+ pb += es;
+ }
+ while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
+ if (cmp_result == 0) {
+ swap_cnt = 1;
+ swap(pc, pd);
+ pd -= es;
+ }
+ pc -= es;
+ }
+ if (pb > pc)
+ break;
+ swap(pb, pc);
+ swap_cnt = 1;
+ pb += es;
+ pc -= es;
+ }
+ if (swap_cnt == 0) { /* Switch to insertion sort */
+ for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
+ for (pl = pm;
+ pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
+ pl -= es)
+ swap(pl, pl - es);
+ return;
+ }
+
+ pn = (char *)a + n * es;
+ r = min(pa - (char *)a, pb - pa);
+ vecswap(a, pb - r, r);
+ r = min(pd - pc, pn - pd - es);
+ vecswap(pb, pn - r, r);
+ if ((r = pb - pa) > es)
+ qsort_fallback(a, r / es, es, cmp, thunk);
+ if ((r = pd - pc) > es) {
+ /* Iterate rather than recurse to save stack space */
+ a = pn - r;
+ n = r / es;
+ goto loop;
+ }
+/* qsort(pn - r, r / es, es, cmp);*/
+}
+
+#endif
+
+void quicksort(void *a, size_t n, size_t es, sort_cmp_t *cmp, void *ctx)
+{
+#if(defined __APPLE__ || _WIN32)
+ qsort_wrapper wrapper;
+ wrapper.func = cmp;
+ wrapper.ctx = ctx;
+#endif
+
+#if(defined __APPLE__)
+ qsort_r(a, n, es, &wrapper, qsort_cmp_wrap);
+#elif (defined _WIN32)
+ qsort_s(a, n, es, qsort_cmp_wrap, &wrapper);
+#elif (defined __linux__ && HAVE_QSORT_R)
+ qsort_r(a, n, es, cmp, ctx);
+#else
+ qsort_fallback(a, n, es, cmp, ctx);
+#endif
+}
View
@@ -0,0 +1,14 @@
+#ifndef QUICKSORT_H
+#define QUICKSORT_H
+
+typedef int sort_cmp_t(const void *, const void *, void *);
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+void quicksort(void *a, size_t n, size_t es, sort_cmp_t *cmp, void *thunk);
+#ifdef __cplusplus
+}
+#endif
+
+#endif

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