6 #include "posix-compat.h"
8 #include "../lib/arc4.h"
10 #define CHUNK_SIZE (63 * 1024) /* Max file size. */
11 #define CHUNK_CNT 8 /* Number of chunks. */
12 #define DATA_SIZE (CHUNK_CNT * CHUNK_SIZE) /* Buffer size. */
14 unsigned char buf1[DATA_SIZE], buf2[DATA_SIZE];
15 size_t histogram[256];
17 /* Initialize buf1 with random data,
18 then count the number of instances of each value within it. */
25 printf ("(page-merge-par) init\n");
27 arc4_init (&arc4, "foobar", 6);
28 arc4_crypt (&arc4, buf1, sizeof buf1);
29 for (i = 0; i < sizeof buf1; i++)
33 /* Sort each chunk of buf1 using a subprocess. */
37 pid_t children[CHUNK_CNT];
40 for (i = 0; i < CHUNK_CNT; i++)
46 printf ("(page-merge-par) sort chunk %zu\n", i);
48 /* Write this chunk to a file. */
49 snprintf (fn, sizeof fn, "buf%zu", i);
50 create (fn, CHUNK_SIZE);
54 printf ("(page-merge-par) open() failed\n");
57 write (fd, buf1 + CHUNK_SIZE * i, CHUNK_SIZE);
60 /* Sort with subprocess. */
61 snprintf (cmd, sizeof cmd, "child-sort %s", fn);
62 children[i] = exec (cmd);
63 if (children[i] == -1)
65 printf ("(page-merge-par) exec() failed\n");
70 for (i = 0; i < CHUNK_CNT; i++)
75 if (join (children[i]) != 123)
77 printf ("(page-merge-par) join(exec()) returned bad value\n");
81 /* Read chunk back from file. */
82 snprintf (fn, sizeof fn, "buf%zu", i);
86 printf ("(page-merge-par) open() failed\n");
89 read (fd, buf1 + CHUNK_SIZE * i, CHUNK_SIZE);
94 /* Merge the sorted chunks in buf1 into a fully sorted buf2. */
98 unsigned char *mp[CHUNK_CNT];
103 printf ("(page-merge-par) merge\n");
105 /* Initialize merge pointers. */
107 for (i = 0; i < CHUNK_CNT; i++)
108 mp[i] = buf1 + CHUNK_SIZE * i;
114 /* Find smallest value. */
116 for (i = 1; i < mp_left; i++)
117 if (*mp[i] < *mp[min])
120 /* Append value to buf2. */
123 /* Advance merge pointer.
124 Delete this chunk from the set if it's emptied. */
125 if ((++mp[min] - buf1) % CHUNK_SIZE == 0)
126 mp[min] = mp[--mp_left];
136 printf ("(page-merge-par) verify\n");
139 for (hist_idx = 0; hist_idx < sizeof histogram / sizeof *histogram;
142 while (histogram[hist_idx]-- > 0)
144 if (buf2[buf_idx] != hist_idx)
146 printf ("(page-merge-par) bad value %d in byte %zu\n",
147 buf2[buf_idx], buf_idx);
154 printf ("(page-merge-par) success, buf_idx=%zu\n", buf_idx);
160 printf ("(page-merge-par) begin\n");
165 printf ("(page-merge-par) end\n");