Initial data commit

Task/Burrows-Wheeler-transform/C/burrows-wheeler-transform.c

@@ -0,0 +1,99 @@
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+const char STX = '\002', ETX = '\003';
+
+int compareStrings(const void *a, const void *b) {
+    char *aa = *(char **)a;
+    char *bb = *(char **)b;
+    return strcmp(aa, bb);
+}
+
+int bwt(const char *s, char r[]) {
+    int i, len = strlen(s) + 2;
+    char *ss, *str;
+    char **table;
+    if (strchr(s, STX) || strchr(s, ETX)) return 1;
+    ss = calloc(len + 1, sizeof(char));
+    sprintf(ss, "%c%s%c", STX, s, ETX);
+    table = malloc(len * sizeof(const char *));
+    for (i = 0; i < len; ++i) {
+        str = calloc(len + 1, sizeof(char));
+        strcpy(str, ss + i);
+        if (i > 0) strncat(str, ss, i);
+        table[i] = str;
+    }
+    qsort(table, len, sizeof(const char *), compareStrings);
+    for(i = 0; i < len; ++i) {
+        r[i] = table[i][len - 1];
+        free(table[i]);
+    }
+    free(table);
+    free(ss);
+    return 0;
+}
+
+void ibwt(const char *r, char s[]) {
+    int i, j, len = strlen(r);
+    char **table = malloc(len * sizeof(const char *));
+    for (i = 0; i < len; ++i) table[i] = calloc(len + 1, sizeof(char));
+    for (i = 0; i < len; ++i) {
+        for (j = 0; j < len; ++j) {
+            memmove(table[j] + 1, table[j], len);
+            table[j][0] = r[j];
+        }
+        qsort(table, len, sizeof(const char *), compareStrings);
+    }
+    for (i = 0; i < len; ++i) {
+        if (table[i][len - 1] == ETX) {
+            strncpy(s, table[i] + 1, len - 2);
+            break;
+        }
+    }
+    for (i = 0; i < len; ++i) free(table[i]);
+    free(table);
+}
+
+void makePrintable(const char *s, char t[]) {
+    strcpy(t, s);
+    for ( ; *t != '\0'; ++t) {
+        if (*t == STX) *t = '^';
+        else if (*t == ETX) *t = '|';
+    }
+}
+
+int main() {
+    int i, res, len;
+    char *tests[6], *t, *r, *s;
+    tests[0] = "banana";
+    tests[1] = "appellee";
+    tests[2] = "dogwood";
+    tests[3] = "TO BE OR NOT TO BE OR WANT TO BE OR NOT?";
+    tests[4] = "SIX.MIXED.PIXIES.SIFT.SIXTY.PIXIE.DUST.BOXES",
+    tests[5] = "\002ABC\003";
+    for (i = 0; i < 6; ++i) {
+        len = strlen(tests[i]);
+        t = calloc(len + 1, sizeof(char));
+        makePrintable(tests[i], t);
+        printf("%s\n", t);
+        printf(" --> ");
+        r = calloc(len + 3, sizeof(char));
+        res = bwt(tests[i], r);
+        if (res == 1) {
+            printf("ERROR: String can't contain STX or ETX\n");
+        }
+        else {
+            makePrintable(r, t);
+            printf("%s\n", t);
+        }
+        s = calloc(len + 1, sizeof(char));
+        ibwt(r, s);
+        makePrintable(s, t);
+        printf(" --> %s\n\n", t);
+        free(t);
+        free(r);
+        free(s);
+    }
+    return 0;
+}