6 #include "posix-compat.h"
8 #include "../lib/arc4.h"
10 #define CHUNK_SIZE (63 * 1024) /* Max file size. */
11 #define CHUNK_CNT 16 /* 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-seq) 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. */
39 create ("buffer", CHUNK_SIZE);
40 for (i = 0; i < CHUNK_CNT; i++)
44 printf ("(page-merge-seq) sort chunk %zu\n", i);
46 /* Write this chunk to a file. */
51 printf ("(page-merge-seq) open() failed\n");
54 write (fd, buf1 + CHUNK_SIZE * i, CHUNK_SIZE);
57 /* Sort with subprocess. */
58 pid_t child = exec ("child-sort buffer");
61 printf ("(page-merge-seq) exec() failed\n");
64 if (join (child) != 123)
66 printf ("(page-merge-seq) join(exec()) returned bad value\n");
70 /* Read chunk back from file. */
74 printf ("(page-merge-seq) open() failed\n");
77 read (fd, buf1 + CHUNK_SIZE * i, CHUNK_SIZE);
82 /* Merge the sorted chunks in buf1 into a fully sorted buf2. */
86 unsigned char *mp[CHUNK_CNT];
91 printf ("(page-merge-seq) merge\n");
93 /* Initialize merge pointers. */
95 for (i = 0; i < CHUNK_CNT; i++)
96 mp[i] = buf1 + CHUNK_SIZE * i;
102 /* Find smallest value. */
104 for (i = 1; i < mp_left; i++)
105 if (*mp[i] < *mp[min])
108 /* Append value to buf2. */
111 /* Advance merge pointer.
112 Delete this chunk from the set if it's emptied. */
113 if ((++mp[min] - buf1) % CHUNK_SIZE == 0)
114 mp[min] = mp[--mp_left];
124 printf ("(page-merge-seq) verify\n");
127 for (hist_idx = 0; hist_idx < sizeof histogram / sizeof *histogram;
130 while (histogram[hist_idx]-- > 0)
132 if (buf2[buf_idx] != hist_idx)
134 printf ("(page-merge-seq) bad value %d in byte %zu\n",
135 buf2[buf_idx], buf_idx);
142 printf ("(page-merge-seq) success, buf_idx=%zu\n", buf_idx);
148 printf ("(page-merge-seq) begin\n");
153 printf ("(page-merge-seq) end\n");