# is a simplified version of the merge sort used in glibc. This is
# recommended if Git triggers O(n^2) behavior in your platform's qsort().
#
+# Define HAVE_ISO_QSORT_S if your platform provides a qsort_s() that's
+# compatible with the one described in C11 Annex K.
+#
# Define UNRELIABLE_FSTAT if your system's fstat does not return the same
# information on a not yet closed file that lstat would return for the same
# file after it was closed.
COMPAT_CFLAGS += -DINTERNAL_QSORT
COMPAT_OBJS += compat/qsort.o
endif
+ifdef HAVE_ISO_QSORT_S
+ COMPAT_CFLAGS += -DHAVE_ISO_QSORT_S
+else
+ COMPAT_OBJS += compat/qsort_s.o
+endif
ifdef RUNTIME_PREFIX
COMPAT_CFLAGS += -DRUNTIME_PREFIX
endif
--- /dev/null
+#include "../git-compat-util.h"
+
+/*
+ * A merge sort implementation, simplified from the qsort implementation
+ * by Mike Haertel, which is a part of the GNU C Library.
+ * Added context pointer, safety checks and return value.
+ */
+
+static void msort_with_tmp(void *b, size_t n, size_t s,
+ int (*cmp)(const void *, const void *, void *),
+ char *t, void *ctx)
+{
+ char *tmp;
+ char *b1, *b2;
+ size_t n1, n2;
+
+ if (n <= 1)
+ return;
+
+ n1 = n / 2;
+ n2 = n - n1;
+ b1 = b;
+ b2 = (char *)b + (n1 * s);
+
+ msort_with_tmp(b1, n1, s, cmp, t, ctx);
+ msort_with_tmp(b2, n2, s, cmp, t, ctx);
+
+ tmp = t;
+
+ while (n1 > 0 && n2 > 0) {
+ if (cmp(b1, b2, ctx) <= 0) {
+ memcpy(tmp, b1, s);
+ tmp += s;
+ b1 += s;
+ --n1;
+ } else {
+ memcpy(tmp, b2, s);
+ tmp += s;
+ b2 += s;
+ --n2;
+ }
+ }
+ if (n1 > 0)
+ memcpy(tmp, b1, n1 * s);
+ memcpy(b, t, (n - n2) * s);
+}
+
+int git_qsort_s(void *b, size_t n, size_t s,
+ int (*cmp)(const void *, const void *, void *), void *ctx)
+{
+ const size_t size = st_mult(n, s);
+ char buf[1024];
+
+ if (!n)
+ return 0;
+ if (!b || !cmp)
+ return -1;
+
+ if (size < sizeof(buf)) {
+ /* The temporary array fits on the small on-stack buffer. */
+ msort_with_tmp(b, n, s, cmp, buf, ctx);
+ } else {
+ /* It's somewhat large, so malloc it. */
+ char *tmp = xmalloc(size);
+ msort_with_tmp(b, n, s, cmp, tmp, ctx);
+ free(tmp);
+ }
+ return 0;
+}
qsort(base, nmemb, size, compar);
}
+#ifndef HAVE_ISO_QSORT_S
+int git_qsort_s(void *base, size_t nmemb, size_t size,
+ int (*compar)(const void *, const void *, void *), void *ctx);
+#define qsort_s git_qsort_s
+#endif
+
+#define QSORT_S(base, n, compar, ctx) do { \
+ if (qsort_s((base), (n), sizeof(*(base)), compar, ctx)) \
+ die("BUG: qsort_s() failed"); \
+} while (0)
+
#ifndef REG_STARTEND
#error "Git requires REG_STARTEND support. Compile with NO_REGEX=NeedsStartEnd"
#endif
return (s->reverse) ? -cmp : cmp;
}
-static struct ref_sorting *ref_sorting;
-static int compare_refs(const void *a_, const void *b_)
+static int compare_refs(const void *a_, const void *b_, void *ref_sorting)
{
struct ref_array_item *a = *((struct ref_array_item **)a_);
struct ref_array_item *b = *((struct ref_array_item **)b_);
void ref_array_sort(struct ref_sorting *sorting, struct ref_array *array)
{
- ref_sorting = sorting;
- QSORT(array->items, array->nr, compare_refs);
+ QSORT_S(array->items, array->nr, compare_refs, sorting);
}
static void append_literal(const char *cp, const char *ep, struct ref_formatting_state *state)
list->strdup_strings ? xstrdup(string) : (char *)string);
}
-/* Yuck */
-static compare_strings_fn compare_for_qsort;
-
-/* Only call this from inside string_list_sort! */
-static int cmp_items(const void *a, const void *b)
+static int cmp_items(const void *a, const void *b, void *ctx)
{
+ compare_strings_fn cmp = ctx;
const struct string_list_item *one = a;
const struct string_list_item *two = b;
- return compare_for_qsort(one->string, two->string);
+ return cmp(one->string, two->string);
}
void string_list_sort(struct string_list *list)
{
- compare_for_qsort = list->cmp ? list->cmp : strcmp;
- QSORT(list->items, list->nr, cmp_items);
+ QSORT_S(list->items, list->nr, cmp_items,
+ list->cmp ? list->cmp : strcmp);
}
struct string_list_item *unsorted_string_list_lookup(struct string_list *list,
return 0;
}
+ if (argc == 2 && !strcmp(argv[1], "sort")) {
+ struct string_list list = STRING_LIST_INIT_NODUP;
+ struct strbuf sb = STRBUF_INIT;
+ struct string_list_item *item;
+
+ strbuf_read(&sb, 0, 0);
+
+ /*
+ * Split by newline, but don't create a string_list item
+ * for the empty string after the last separator.
+ */
+ if (sb.buf[sb.len - 1] == '\n')
+ strbuf_setlen(&sb, sb.len - 1);
+ string_list_split_in_place(&list, sb.buf, '\n', -1);
+
+ string_list_sort(&list);
+
+ for_each_string_list_item(item, &list)
+ puts(item->string);
+
+ string_list_clear(&list, 0);
+ strbuf_release(&sb);
+ return 0;
+ }
+
fprintf(stderr, "%s: unknown function name: %s\n", argv[0],
argv[1] ? argv[1] : "(there was none)");
return 1;
--- /dev/null
+#!/bin/sh
+
+test_description='Basic sort performance tests'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+test_expect_success 'setup' '
+ git ls-files --stage "*.[ch]" "*.sh" |
+ cut -f2 -d" " |
+ git cat-file --batch >unsorted
+'
+
+test_perf 'sort(1)' '
+ sort <unsorted >expect
+'
+
+test_perf 'string_list_sort()' '
+ test-string-list sort <unsorted >actual
+'
+
+test_expect_success 'string_list_sort() sorts like sort(1)' '
+ test_cmp_bin expect actual
+'
+
+test_done