Add qsort - add support for sorting data arrays

Code adapted from uClibc-0.9.30.3 Signed-off-by: Wolfgang Denk <wd@denx.de>

Add qsort - add support for sorting data arrays
Code adapted from uClibc-0.9.30.3 Signed-off-by: Wolfgang Denk <wd@denx.de>
Wolfgang Denk
1 parent 65cd3fa81f
Showing 3 changed files with 74 additions and 0 deletions Side-by-side Diff
include/common.h
lib/Makefile
lib/qsort.c
@@ -631,6 +631,10 @@
 	return (string_to_ip(getenv(var)));
 }
  
+/* lib/qsort.c */
+void qsort(void *base, size_t nmemb, size_t size,
+	   int(*compar)(const void *, const void *));
+
 /* lib/time.c */
 void	udelay        (unsigned long);
  
@@ -43,6 +43,7 @@
 COBJS-y += ldiv.o
 COBJS-$(CONFIG_MD5) += md5.o
 COBJS-y += net_utils.o
+COBJS-y += qsort.o
 COBJS-$(CONFIG_SHA1) += sha1.o
 COBJS-$(CONFIG_SHA256) += sha256.o
 COBJS-y += string.o
+/*
+ * Code adapted from uClibc-0.9.30.3
+ *
+ * It is therefore covered by the GNU LESSER GENERAL PUBLIC LICENSE
+ * Version 2.1, February 1999
+ *
+ * Wolfgang Denk <wd@denx.de>
+ */
+
+/* This code is derived from a public domain shell sort routine by
+ * Ray Gardner and found in Bob Stout's snippets collection.  The
+ * original code is included below in an #if 0/#endif block.
+ *
+ * I modified it to avoid the possibility of overflow in the wgap
+ * calculation, as well as to reduce the generated code size with
+ * bcc and gcc. */
+
+#include <linux/types.h>
+#if 0
+#include <assert.h>
+#else
+#define assert(arg)
+#endif
+
+void qsort(void  *base,
+           size_t nel,
+           size_t width,
+           int (*comp)(const void *, const void *))
+{
+	size_t wgap, i, j, k;
+	char tmp;
+
+	if ((nel > 1) && (width > 0)) {
+		assert(nel <= ((size_t)(-1)) / width); /* check for overflow */
+		wgap = 0;
+		do {
+			wgap = 3 * wgap + 1;
+		} while (wgap < (nel-1)/3);
+		/* From the above, we know that either wgap == 1 < nel or */
+		/* ((wgap-1)/3 < (int) ((nel-1)/3) <= (nel-1)/3 ==> wgap <  nel. */
+		wgap *= width;			/* So this can not overflow if wnel doesn't. */
+		nel *= width;			/* Convert nel to 'wnel' */
+		do {
+			i = wgap;
+			do {
+				j = i;
+				do {
+					register char *a;
+					register char *b;
+
+					j -= wgap;
+					a = j + ((char *)base);
+					b = a + wgap;
+					if ((*comp)(a, b) <= 0) {
+						break;
+					}
+					k = width;
+					do {
+						tmp = *a;
+						*a++ = *b;
+						*b++ = tmp;
+					} while (--k);
+				} while (j >= wgap);
+				i += width;
+			} while (i < nel);
+			wgap = (wgap - width)/3;
+		} while (wgap);
+	}
+}
...	...	@@ -631,6 +631,10 @@
631	631	return (string_to_ip(getenv(var)));
632	632	}
633	633
	634	+/* lib/qsort.c */
	635	+void qsort(void *base, size_t nmemb, size_t size,
	636	+ int(compar)(const void , const void *));
	637	+
634	638	/* lib/time.c */
635	639	void udelay (unsigned long);
636	640
...	...	@@ -43,6 +43,7 @@
43	43	COBJS-y += ldiv.o
44	44	COBJS-$(CONFIG_MD5) += md5.o
45	45	COBJS-y += net_utils.o
	46	+COBJS-y += qsort.o
46	47	COBJS-$(CONFIG_SHA1) += sha1.o
47	48	COBJS-$(CONFIG_SHA256) += sha256.o
48	49	COBJS-y += string.o
	1	+/*
	2	+ * Code adapted from uClibc-0.9.30.3
	3	+ *
	4	+ * It is therefore covered by the GNU LESSER GENERAL PUBLIC LICENSE
	5	+ * Version 2.1, February 1999
	6	+ *
	7	+ * Wolfgang Denk <wd@denx.de>
	8	+ */
	9	+
	10	+/* This code is derived from a public domain shell sort routine by
	11	+ * Ray Gardner and found in Bob Stout's snippets collection. The
	12	+ * original code is included below in an #if 0/#endif block.
	13	+ *
	14	+ * I modified it to avoid the possibility of overflow in the wgap
	15	+ * calculation, as well as to reduce the generated code size with
	16	+ * bcc and gcc. */
	17	+
	18	+#include <linux/types.h>
	19	+#if 0
	20	+#include <assert.h>
	21	+#else
	22	+#define assert(arg)
	23	+#endif
	24	+
	25	+void qsort(void *base,
	26	+ size_t nel,
	27	+ size_t width,
	28	+ int (comp)(const void , const void *))
	29	+{
	30	+ size_t wgap, i, j, k;
	31	+ char tmp;
	32	+
	33	+ if ((nel > 1) && (width > 0)) {
	34	+ assert(nel <= ((size_t)(-1)) / width); /* check for overflow */
	35	+ wgap = 0;
	36	+ do {
	37	+ wgap = 3 * wgap + 1;
	38	+ } while (wgap < (nel-1)/3);
	39	+ /* From the above, we know that either wgap == 1 < nel or */
	40	+ /* ((wgap-1)/3 < (int) ((nel-1)/3) <= (nel-1)/3 ==> wgap < nel. */
	41	+ wgap = width; / So this can not overflow if wnel doesn't. */
	42	+ nel = width; / Convert nel to 'wnel' */
	43	+ do {
	44	+ i = wgap;
	45	+ do {
	46	+ j = i;
	47	+ do {
	48	+ register char *a;
	49	+ register char *b;
	50	+
	51	+ j -= wgap;
	52	+ a = j + ((char *)base);
	53	+ b = a + wgap;
	54	+ if ((*comp)(a, b) <= 0) {
	55	+ break;
	56	+ }
	57	+ k = width;
	58	+ do {
	59	+ tmp = *a;
	60	+ a++ = b;
	61	+ *b++ = tmp;
	62	+ } while (--k);
	63	+ } while (j >= wgap);
	64	+ i += width;
	65	+ } while (i < nel);
	66	+ wgap = (wgap - width)/3;
	67	+ } while (wgap);
	68	+ }
	69	+}