6 #include "posix-compat.h"
8 #include "../lib/arc4.h"
10 /* This is the max file size for an older version of the Pintos
11 file system that had 126 direct blocks each pointing to a
12 single disk sector. We could raise it now. */
13 #define CHUNK_SIZE (126 * 512)
14 #define CHUNK_CNT 16 /* Number of chunks. */
15 #define DATA_SIZE (CHUNK_CNT * CHUNK_SIZE) /* Buffer size. */
17 unsigned char buf1[DATA_SIZE], buf2[DATA_SIZE];
18 size_t histogram[256];
20 /* Initialize buf1 with random data,
21 then count the number of instances of each value within it. */
28 printf ("page-merge-seq) init\n");
30 arc4_init (&arc4, "foobar", 6);
31 arc4_crypt (&arc4, buf1, sizeof buf1);
32 for (i = 0; i < sizeof buf1; i++)
36 /* Sort each chunk of buf1 using a subprocess. */
42 create ("buffer", CHUNK_SIZE);
43 for (i = 0; i < CHUNK_CNT; i++)
47 printf ("(page-merge-seq) sort chunk %zu\n", i);
49 /* Write this chunk to a file. */
54 printf ("(page-merge-seq) open() failed\n");
57 write (fd, buf1 + CHUNK_SIZE * i, CHUNK_SIZE);
60 /* Sort with subprocess. */
61 pid_t child = exec ("child-sort buffer");
64 printf ("(page-merge-seq) exec() failed\n");
67 if (wait (child) != 123)
69 printf ("(page-merge-seq) wait(exec()) returned bad value\n");
73 /* Read chunk back from file. */
77 printf ("(page-merge-seq) open() failed\n");
80 read (fd, buf1 + CHUNK_SIZE * i, CHUNK_SIZE);
85 /* Merge the sorted chunks in buf1 into a fully sorted buf2. */
89 unsigned char *mp[CHUNK_CNT];
94 printf ("(page-merge-seq) merge\n");
96 /* Initialize merge pointers. */
98 for (i = 0; i < CHUNK_CNT; i++)
99 mp[i] = buf1 + CHUNK_SIZE * i;
105 /* Find smallest value. */
107 for (i = 1; i < mp_left; i++)
108 if (*mp[i] < *mp[min])
111 /* Append value to buf2. */
114 /* Advance merge pointer.
115 Delete this chunk from the set if it's emptied. */
116 if ((++mp[min] - buf1) % CHUNK_SIZE == 0)
117 mp[min] = mp[--mp_left];
127 printf ("(page-merge-seq) verify\n");
130 for (hist_idx = 0; hist_idx < sizeof histogram / sizeof *histogram;
133 while (histogram[hist_idx]-- > 0)
135 if (buf2[buf_idx] != hist_idx)
137 printf ("(page-merge-seq) bad value %d in byte %zu\n",
138 buf2[buf_idx], buf_idx);
145 printf ("(page-merge-seq) success, buf_idx=%zu\n", buf_idx);
151 printf ("(page-merge-seq) begin\n");
156 printf ("(page-merge-seq) end\n");