From: Heng Li <lh3@me.com>
Date: Sun, 10 Jun 2012 22:45:38 +0000 (-0400)
Subject: added another radix_sort from gorset/radix
X-Git-Tag: spawn-final~46
X-Git-Url: http://www.kaiwu.me/postgresql/commit/static/gitweb.js?a=commitdiff_plain;h=0297736779d48aeab1e307755e5ed5b6f73e6bb4;p=klib.git

added another radix_sort from gorset/radix
---

diff --git a/test/ksort_test.cc b/test/ksort_test.cc
index 75420bd..8950d80 100644
--- a/test/ksort_test.cc
+++ b/test/ksort_test.cc
@@ -670,6 +670,45 @@ void rs_sort2(rstype_t *beg, rstype_t *end, int n_bits, int s)
 	}
 }
 */
+void radix_sort(unsigned *array, int offset, int end, int shift) {
+    int x, y, value, temp;
+    int last[256] = { 0 }, pointer[256];
+
+    for (x=offset; x<end; ++x) {
+        ++last[(array[x] >> shift) & 0xFF];
+    }
+
+    last[0] += offset;
+    pointer[0] = offset;
+    for (x=1; x<256; ++x) {
+        pointer[x] = last[x-1];
+        last[x] += last[x-1];
+    }
+
+    for (x=0; x<256; ++x) {
+        while (pointer[x] != last[x]) {
+            value = array[pointer[x]];
+            y = (value >> shift) & 0xFF;
+            while (x != y) {
+                temp = array[pointer[y]];
+                array[pointer[y]++] = value;
+                value = temp;
+                y = (value >> shift) & 0xFF;
+            }
+            array[pointer[x]++] = value;
+        }
+    }
+
+    if (shift > 0) {
+        shift -= 8;
+        for (x=0; x<256; ++x) {
+            temp = x > 0 ? pointer[x] - pointer[x-1] : pointer[0] - offset;
+            if (temp > 64) {
+                radix_sort(array, pointer[x] - temp, pointer[x], shift);
+            } else if (temp > 1) rs_insertsort(array + pointer[x] - temp, array + pointer[x]);
+        }
+    }
+}
 /*************************
  *** END OF RADIX SORT ***
  *************************/
@@ -785,6 +824,7 @@ int main(int argc, char *argv[])
 	for (i = 0; i < N; ++i) array[i] = (int)lrand48();
 	t1 = clock();
 	RadixSortInPlace_HybridUnsigned_Radix256((unsigned*)array, N);
+//	radix_sort((unsigned*)array, 0, N, 24);
 	t2 = clock();
 	fprintf(stderr, "vd's radix sort: %.3lf\n", (double)(t2-t1)/CLOCKS_PER_SEC);
 	for (i = 0; i < N-1; ++i) {
@@ -795,6 +835,7 @@ int main(int argc, char *argv[])
 	}
 	t1 = clock();
 	RadixSortInPlace_HybridUnsigned_Radix256((unsigned*)array, N);
+//	radix_sort((unsigned*)array, 0, N, 24);
 	t2 = clock();
 	fprintf(stderr, "vd's radix sort (sorted): %.3lf\n", (double)(t2-t1)/CLOCKS_PER_SEC);