From 6d0c863a428bf8f4ad4ca566f3d8a731f6f860b6 Mon Sep 17 00:00:00 2001
From: Peter Gerwinski <peter.gerwinski@hs-bochum.de>
Date: Thu, 5 May 2022 15:12:06 +0200
Subject: [PATCH] =?UTF-8?q?Aktualisiertes=20Testprogramm=20f=C3=BCr=20Hash?=
=?UTF-8?q?-Tabellen,=205.5.2022?=
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---
20220505/hash-map-test-02.c | 97 +++++++++++++++++++++++++++++++++
20220505/hash-map-test-03.c | 106 ++++++++++++++++++++++++++++++++++++
2 files changed, 203 insertions(+)
create mode 100644 20220505/hash-map-test-02.c
create mode 100644 20220505/hash-map-test-03.c
diff --git a/20220505/hash-map-test-02.c b/20220505/hash-map-test-02.c
new file mode 100644
index 0000000..7a69934
--- /dev/null
+++ b/20220505/hash-map-test-02.c
@@ -0,0 +1,97 @@
+#include <stdio.h>
+#include <errno.h>
+#include <error.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+const int ERROR = -1;
+const int size = 1117;
+const int bufsize = 100;
+
+int n[size]; // zunächst: alle 0
+const char *check[size]; // zunächst: alle NULL
+
+constexpr int hash (const char *name)
+{
+ // Cantor pairing function
+ uint8_t n0 = name ? name[0] : 0;
+ uint8_t n1 = n0 ? name[1] : 0;
+ uint8_t n2 = n1 ? name[2] : 0;
+ return ((n0 + n1) / 2 * (n0 + n1 + 1) + n2) % size;
+}
+
+void put_number (const char *name, int value)
+{
+ int idx = hash (name);
+ if (check[idx] && strcmp (check[idx], name) != 0)
+ fprintf (stderr, "occupied: %s = %d\n", name, value);
+ else
+ {
+ check[idx] = name;
+ n[idx] = value;
+ }
+}
+
+int get_number (const char *name)
+{
+ int value = ERROR;
+ int idx = hash (name);
+ if (check[idx] && strcmp (check[idx], name) == 0)
+ value = n[idx];
+ else
+ fprintf (stderr, "not found: %s\n", name);
+ return value;
+}
+
+static void read_data (FILE *f, char **name, int *value)
+{
+ int v;
+ char buffer[bufsize];
+ int bytes_read_1 = fscanf (f, "%d", &v);
+ char *bytes_read_2 = fgets (buffer, bufsize - 1, f);
+ int l = strlen (buffer);
+ if (l > 0 && buffer[l - 1] == '\n')
+ buffer[l - 1] = 0;
+ const char *n = buffer;
+ while (n[0] == ' ')
+ n++;
+ l = strlen (n);
+ if (l < 30)
+ printf ("l = %d, buffer = \"%s\", bytes_read_1 = %d, bytes_read_2 = %zx, errno = %d\n",
+ l, buffer, bytes_read_1, (size_t) bytes_read_2, errno);
+ if (*name == NULL)
+ *name = (char *) malloc (l);
+ strncpy (*name, n, l + 1);
+ *value = v;
+}
+
+int main (int argc, char **argv)
+{
+ const char *filename = "hash-test.dat";
+ if (argc > 1)
+ filename = argv[1];
+ FILE *f = fopen (filename, "r");
+ if (!f)
+ error (errno, errno, "cannot open file \"%s\"", filename);
+ while (!feof (f))
+ {
+ int value;
+ char *name = NULL;
+ read_data (f, &name, &value);
+ put_number (name, value);
+ }
+ rewind (f);
+ while (!feof (f))
+ {
+ int value;
+ char name[bufsize];
+ char *p = name;
+ read_data (f, &p, &value);
+ int v = get_number (name);
+ if (v != value)
+ printf ("%s: %d instead of %d\n", name, v, value);
+ }
+ fclose (f);
+ return 0;
+}
diff --git a/20220505/hash-map-test-03.c b/20220505/hash-map-test-03.c
new file mode 100644
index 0000000..06200c5
--- /dev/null
+++ b/20220505/hash-map-test-03.c
@@ -0,0 +1,106 @@
+#include <stdio.h>
+#include <errno.h>
+#include <error.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+const int ERROR = -1;
+const int size = 1117;
+const int bufsize = 100;
+
+int n[size]; // zunächst: alle 0
+const char *check[size]; // zunächst: alle NULL
+
+constexpr int hash (const char *name)
+{
+ // Cantor pairing function
+ uint8_t n0 = name ? name[0] : 0;
+ uint8_t n1 = n0 ? name[1] : 0;
+ uint8_t n2 = n1 ? name[2] : 0;
+ return ((n0 + n1) / 2 * (n0 + n1 + 1) + n2) % size;
+}
+
+void put_number (const char *name, int value)
+{
+ int idx = hash (name);
+ if (check[idx] && strcmp (check[idx], name) != 0)
+ fprintf (stderr, "occupied: %s = %d\n", name, value);
+ else
+ {
+ check[idx] = name;
+ n[idx] = value;
+ }
+}
+
+int get_number (const char *name)
+{
+ int value = ERROR;
+ int idx = hash (name);
+ if (check[idx] && strcmp (check[idx], name) == 0)
+ value = n[idx];
+ else
+ fprintf (stderr, "not found: %s\n", name);
+ return value;
+}
+
+static void read_data (FILE *f, char **name, int *value)
+{
+ int v;
+ char buffer[bufsize];
+ int bytes_read_1 = fscanf (f, "%d", &v);
+ char *bytes_read_2 = fgets (buffer, bufsize - 1, f);
+ if (bytes_read_1 <= 0 || bytes_read_2 == NULL)
+ {
+ *name = NULL;
+ *value = -1;
+ }
+ else
+ {
+ int l = strlen (buffer);
+ if (l > 0 && buffer[l - 1] == '\n')
+ buffer[l - 1] = 0;
+ const char *n = buffer;
+ while (n[0] == ' ')
+ n++;
+ l = strlen (n);
+ if (*name == NULL)
+ *name = (char *) malloc (l);
+ strncpy (*name, n, l + 1);
+ *value = v;
+ }
+}
+
+int main (int argc, char **argv)
+{
+ const char *filename = "hash-test.dat";
+ if (argc > 1)
+ filename = argv[1];
+ FILE *f = fopen (filename, "r");
+ if (!f)
+ error (errno, errno, "cannot open file \"%s\"", filename);
+ while (!feof (f))
+ {
+ int value;
+ char *name = NULL;
+ read_data (f, &name, &value);
+ if (value >= 0 && name)
+ put_number (name, value);
+ }
+ rewind (f);
+ while (!feof (f))
+ {
+ int value;
+ char name[bufsize];
+ char *p = name;
+ read_data (f, &p, &value);
+ if (value >= 0 && name)
+ {
+ int v = get_number (name);
+ if (v != value)
+ printf ("%s: %d instead of %d\n", name, v, value);
+ }
+ }
+ fclose (f);
+ return 0;
+}
--
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