Re: [PATCH 1/3] compat: add qsort_s()
Am 01.12.2016 um 17:26 schrieb René Scharfe:
Show 19 quoted lines
> The function qsort_s() was introduced with C11 Annex K; it provides the
> ability to pass a context pointer to the comparison function, supports
> the convention of using a NULL pointer for an empty array and performs a
> few safety checks.
>
> Add an implementation based on compat/qsort.c for platforms that lack a
> native standards-compliant qsort_s() (i.e. basically everyone). It
> doesn't perform the full range of possible checks: It uses size_t
> instead of rsize_t and doesn't check nmemb and size against RSIZE_MAX
> because we probably don't have the restricted size type defined. For
> the same reason it returns int instead of errno_t.
>
> Signed-off-by: Rene Scharfe <l.s.r@web.de>
> ---
> Makefile | 10 ++++++++
> compat/qsort_s.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> git-compat-util.h | 6 +++++
> 3 files changed, 85 insertions(+)
> create mode 100644 compat/qsort_s.c
And here's the diff for compat/qsort_s.c with copy detection (-C -C):
---
compat/{qsort.c => qsort_s.c} | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)diff --git a/compat/qsort.c b/compat/qsort_s.c
similarity index 62%
copy from compat/qsort.c
copy to compat/qsort_s.c
index 7d071afb7..52d1f0a73 100644
--- a/compat/qsort.c
+++ b/compat/qsort_s.c
@@ -3,11 +3,12 @@
/*
* 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 *),
- char *t)
+ int (*cmp)(const void *, const void *, void *),
+ char *t, void *ctx)
{
char *tmp;
char *b1, *b2;
@@ -21,13 +22,13 @@ static void msort_with_tmp(void *b, size_t n, size_t s,
b1 = b;
b2 = (char *)b + (n1 * s);
- msort_with_tmp(b1, n1, s, cmp, t);
- msort_with_tmp(b2, n2, s, cmp, t);
+ 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) <= 0) {
+ if (cmp(b1, b2, ctx) <= 0) {
memcpy(tmp, b1, s);
tmp += s;
b1 += s;
@@ -44,19 +45,25 @@ static void msort_with_tmp(void *b, size_t n, size_t s,
memcpy(b, t, (n - n2) * s);
}
-void git_qsort(void *b, size_t n, size_t s,
- int (*cmp)(const void *, const void *))
+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);
+ 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);
+ msort_with_tmp(b, n, s, cmp, tmp, ctx);
free(tmp);
}
+ return 0;
}
René Scharfe <l.s.r@web.de>