Merge pull request #690 from sanpeqf/feat-knuth

Feat knuth

Author: sanpeqf

examples/CMakeLists.txt

@@ -28,6 +28,7 @@ add_subdirectory(hashtbl)
 add_subdirectory(heap)
 add_subdirectory(hlist)
 add_subdirectory(ilist)
+add_subdirectory(knuth)
 add_subdirectory(levenshtein)
 add_subdirectory(list)
 add_subdirectory(log)

examples/knuth/.gitignore

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+/knuth-simple

examples/knuth/CMakeLists.txt

@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright(c) 2023 ffashion <[email protected]>
+#
+
+add_executable(knuth-simple simple.c)
+target_link_libraries(knuth-simple bfdev)
+add_test(knuth-simple knuth-simple)
+
+if(${CMAKE_PROJECT_NAME} STREQUAL "bfdev")
+    install(FILES
+        simple.c
+        DESTINATION
+        ${CMAKE_INSTALL_DOCDIR}/examples/knuth
+    )
+
+    install(TARGETS
+        knuth-simple
+        DESTINATION
+        ${CMAKE_INSTALL_DOCDIR}/bin
+    )
+endif()

examples/knuth/simple.c

@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright(c) 2025 John Sanpe <[email protected]>
+ */
+
+#define MODULE_NAME "knuth-simple"
+#define bfdev_log_fmt(fmt) MODULE_NAME ": " fmt
+
+#include <stdlib.h>
+#include <time.h>
+#include <bfdev/macro.h>
+#include <bfdev/log.h>
+#include <bfdev/knuth.h>
+
+static const char *
+cards[12] = {
+    "Ace", "2", "3", "4", "5", "6", "7",
+    "8", "9", "Jack", "Queen", "King"
+};
+
+int
+main(int argc, const char *argv[])
+{
+    unsigned int index;
+
+    srand(time(NULL));
+    bfdev_knuth(cards, BFDEV_ARRAY_SIZE(cards), sizeof(*cards));
+    for (index = 0; index < BFDEV_ARRAY_SIZE(cards); ++index)
+        bfdev_log_info("card%u: %s\n", index, cards[index]);
+
+    return 0;
+}

include/bfdev/knuth.h

@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * Copyright(c) 2025 John Sanpe <[email protected]>
+ */
+
+#ifndef _BFDEV_KNUTH_H_
+#define _BFDEV_KNUTH_H_
+
+#include <bfdev/config.h>
+#include <bfdev/types.h>
+
+BFDEV_BEGIN_DECLS
+
+/**
+ * bfdev_knuth() - Knuth-Shuffle algorithm.
+ * @base: pointer to data to sort.
+ * @num: number of elements.
+ * @cells: size of each element.
+ *
+ * The algorithm takes a list of all the elements of the sequence, and
+ * continually determines the next element in the shuffled sequence
+ * by randomly drawing an element from the list until no elements remain.
+ * The algorithm produces an unbiased permutation, every permutation
+ * is equally likely.
+ *
+ * Return 0 on success or a negative error code on failure.
+ */
+extern int
+bfdev_knuth(void *base, bfdev_size_t num, bfdev_size_t cells);
+
+BFDEV_END_DECLS
+
+#endif /* _BFDEV_KNUTH_H_ */

include/bfdev/port/stdlib.h

@@ -10,6 +10,9 @@
 
 BFDEV_BEGIN_DECLS
 
+extern int
+bfdev_rand(void);
+
 extern __bfdev_noreturn void
 bfdev_abort(void);
 

src/build.cmake

@@ -26,6 +26,7 @@ set(BFDEV_SOURCE
     ${CMAKE_CURRENT_LIST_DIR}/heap.c
     ${CMAKE_CURRENT_LIST_DIR}/ilist.c
     ${CMAKE_CURRENT_LIST_DIR}/jhash.c
+    ${CMAKE_CURRENT_LIST_DIR}/knuth.c
     ${CMAKE_CURRENT_LIST_DIR}/levenshtein.c
     ${CMAKE_CURRENT_LIST_DIR}/list-sort.c
     ${CMAKE_CURRENT_LIST_DIR}/llist.c

src/knuth.c

@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * Copyright(c) 2023 John Sanpe <[email protected]>
+ */
+
+#include <base.h>
+#include <bfdev/knuth.h>
+#include <bfdev/stdlib.h>
+#include <export.h>
+
+static __bfdev_noinline void
+knuth_swap(bfdev_size_t cells, void *cel1, void *cel2)
+{
+    void *buff;
+
+    /* alloca hates inline */
+    buff = bfdev_alloca(cells);
+
+    bfdev_memcpy(buff, cel1, cells);
+    bfdev_memcpy(cel1, cel2, cells);
+    bfdev_memcpy(cel2, buff, cells);
+}
+
+export int
+bfdev_knuth(void *base, bfdev_size_t num, bfdev_size_t cells)
+{
+    bfdev_size_t idx1, idx2;
+
+    if (bfdev_unlikely(!base || !num || !cells))
+        return -BFDEV_EINVAL;
+
+    for (idx1 = num - 1; idx1; --idx1) {
+        idx2 = bfdev_rand() % (idx1 + 1);
+        if (bfdev_unlikely(idx1 == idx2))
+            continue;
+        knuth_swap(cells, base + idx1 * cells, base + idx2 * cells);
+    }
+
+    return -BFDEV_ENOERR;
+}

src/port/stdlib.c

@@ -7,6 +7,12 @@
 #include <port/stdlib.h>
 #include <export.h>
 
+export int
+bfdev_rand(void)
+{
+    return bfport_rand();
+}
+
 export __bfdev_noreturn void
 bfdev_abort(void)
 {

src/skiplist.c

@@ -4,8 +4,8 @@
  */
 
 #include <base.h>
+#include <bfdev/stdlib.h>
 #include <bfdev/skiplist.h>
-#include <port/stdlib.h>
 #include <export.h>
 
 static unsigned int
@@ -15,7 +15,7 @@ random_level(bfdev_skip_head_t *head)
 
     level = 1;
     while (level < head->levels) {
-        if ((bfport_rand() & 0xffff) > 0xffff >> 2)
+        if ((bfdev_rand() & 0xffff) > 0xffff >> 2)
             break;
         level++;
     }

testsuite/memalloc/fuzzy.c

@@ -13,9 +13,9 @@
 #include <bfdev/log.h>
 #include <bfdev/errno.h>
 #include <bfdev/memalloc.h>
+#include <bfdev/knuth.h>
 #include <bfdev/size.h>
 #include <testsuite.h>
-#include <randpool.h>
 
 #define POOL_SIZE BFDEV_SZ_32MiB
 #define TEST_SIZE BFDEV_SZ_16MiB
@@ -25,70 +25,48 @@ static int
 test_memalloc(bfdev_memalloc_head_t *pool)
 {
     bfdev_memalloc_chunk_t *node;
-    void *result, *data;
+    void *result[TEST_LOOP];
     unsigned int count;
     size_t size;
     int retval;
 
-    DEFINE_RANDPOOL(rpool1);
-    DEFINE_RANDPOOL(rpool2);
     retval = -BFDEV_ENOERR;
-
     srand(time(NULL));
+
     for (count = 0; count < TEST_LOOP; ++count) {
         size = (unsigned int)rand() % (TEST_SIZE / TEST_LOOP);
-        result = bfdev_memalloc_alloc(pool, size);
-        if (!result) {
-            retval = BFDEV_ENOMEM;
-            goto failed;
-        }
-
-        retval = randpool_put(&rpool1, result);
-        if (retval)
-            goto failed;
-
-        memset(result, 0, size);
+        result[count] = bfdev_memalloc_alloc(pool, size);
+        if (!result[count])
+            return -BFDEV_ENOMEM;
+        memset(result[count], 0, size);
     }
 
+    bfdev_knuth(result, TEST_LOOP, sizeof(*result));
     for (count = 0; count < TEST_LOOP; ++count) {
-        data = randpool_get(&rpool1);
         size = (unsigned int)rand() % (TEST_SIZE / TEST_LOOP);
-        result = bfdev_memalloc_realloc(pool, data, size);
-        if (!result) {
-            retval = BFDEV_ENOMEM;
-            goto failed;
-        }
-
-        retval = randpool_put(&rpool2, result);
-        if (retval)
-            goto failed;
-
-        memset(result, 0, size);
+        result[count] = bfdev_memalloc_realloc(pool, result[count], size);
+        if (!result[count])
+            return -BFDEV_ENOMEM;
+        memset(result[count], 0, size);
     }
 
-    for (count = 0; count < TEST_LOOP; ++count) {
-        data = randpool_get(&rpool2);
-        bfdev_memalloc_free(pool, data);
-    }
+    bfdev_knuth(result, TEST_LOOP, sizeof(*result));
+    for (count = 0; count < TEST_LOOP; ++count)
+        bfdev_memalloc_free(pool, result[count]);
 
     node = bfdev_list_first_entry(&pool->block_list, bfdev_memalloc_chunk_t, block);
     if (node->usize != POOL_SIZE - sizeof(bfdev_memalloc_chunk_t)) {
         bfdev_log_err("free node size leak %#lx -> %#lx\n", (unsigned long)POOL_SIZE -
                       sizeof(bfdev_memalloc_chunk_t), (unsigned long)node->usize);
-        retval = -BFDEV_EFAULT;
-        goto failed;
+        return -BFDEV_EFAULT;
     }
 
     if (pool->avail != POOL_SIZE - sizeof(bfdev_memalloc_chunk_t)) {
         bfdev_log_err("total available leak %#lx -> %#lx\n", (unsigned long)POOL_SIZE -
                       sizeof(bfdev_memalloc_chunk_t), (unsigned long)pool->avail);
-        retval = -BFDEV_EFAULT;
-        goto failed;
+        return -BFDEV_EFAULT;
     }
 
-failed:
-    randpool_release(&rpool1, NULL, NULL);
-    randpool_release(&rpool2, NULL, NULL);
     return retval;
 }