Add C solution

2 files changed, 543 insertions, 0 deletions

diff --git a/challenge-025/paulo-custodio/c/ch-2.c b/challenge-025/paulo-custodio/c/ch-2.c
new file mode 100644
index 0000000000..05cb7a86f6
--- /dev/null
+++ b/challenge-025/paulo-custodio/c/ch-2.c
@@ -0,0 +1,136 @@
+/*
+Challenge 025
+
+Task #2
+Create script to implement Chaocipher. Please checkout wiki page for more
+information.
+*/
+
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "utstring.h"
+
+#define LETTERS 26
+#define INIT_LEFT  "HXUCZVAMDSLKPEFJRIGTWOBNYQ"
+#define INIT_RIGHT "PTLNBQDEOYSFAVZKGJRIHWXUMC"
+
+struct crypt {
+    char left[LETTERS+1];
+    char right[LETTERS+1];
+};
+
+struct crypt crypt;
+
+void cat_substr(char* dest, const char* src, int start, int len) {
+    dest += strlen(dest);
+    src += start;
+    if (len < 0)
+        len = strlen(src);
+    strncpy(dest, src, len);
+    dest[len] = '\0';
+}
+
+void crypt_init(void) {
+    strcpy(crypt.left, INIT_LEFT);
+    strcpy(crypt.right, INIT_RIGHT);
+}
+
+void crypt_permute_alphapets(int pos) {
+    char temp[LETTERS+1];
+
+    // rotate left alphabet.
+    temp[0] = '\0';
+    cat_substr(temp, crypt.left, pos, -1);
+    cat_substr(temp, crypt.left, 0, pos);
+    strcpy(crypt.left, temp);
+
+    // permute left alphabet
+    temp[0] = '\0';
+    cat_substr(temp, crypt.left, 0, 1);
+    cat_substr(temp, crypt.left, 2, 12);
+    cat_substr(temp, crypt.left, 1, 1);
+    cat_substr(temp, crypt.left, 14, -1);
+    strcpy(crypt.left, temp);
+
+    // rotate right alphabet.
+    temp[0] = '\0';
+    cat_substr(temp, crypt.right, pos, -1);
+    cat_substr(temp, crypt.right, 0, pos);
+    strcpy(crypt.right, temp);
+
+    // permute left alphabet
+    temp[0] = '\0';
+    cat_substr(temp, crypt.right, 1, 25);
+    cat_substr(temp, crypt.right, 0, 1);
+    strcpy(crypt.right, temp);
+
+    temp[0] = '\0';
+    cat_substr(temp, crypt.right, 0, 2);
+    cat_substr(temp, crypt.right, 3, 11);
+    cat_substr(temp, crypt.right, 2, 1);
+    cat_substr(temp, crypt.right, 14, -1);
+    strcpy(crypt.right, temp);
+}
+
+int find_pos(char letter, const char* alphabet) {
+    const char* p = strchr(alphabet, toupper(letter));
+    if (p == NULL) {
+        fprintf(stderr, "Letter %c cannot be encoded\n", letter);
+        exit(EXIT_FAILURE);
+    }
+    return p - alphabet;
+}
+
+UT_string* crypt_encode(const char* text) {
+    UT_string* out;
+    utstring_new(out);
+
+    for (const char* p = text; *p != '\0'; p++) {
+        if (isalpha(*p)) {
+            int pos = find_pos(*p, crypt.right);
+            char code = crypt.left[pos];
+            utstring_printf(out, "%c", code);
+
+            crypt_permute_alphapets(pos);
+        }
+    }
+    return out;
+}
+
+UT_string* crypt_decode(const char* encoded) {
+    UT_string* out;
+    utstring_new(out);
+
+    for (const char* p = encoded; *p != '\0'; p++) {
+        if (isalpha(*p)) {
+            int pos = find_pos(*p, crypt.left);
+            char letter = crypt.right[pos];
+            utstring_printf(out, "%c", letter);
+
+            crypt_permute_alphapets(pos);
+        }
+    }
+    return out;
+}
+
+void exit_usage(void) {
+    fputs("usage: ch-2 encode|decode text\n", stderr);
+    exit(EXIT_FAILURE);
+}
+
+int main(int argc, char* argv[]) {
+    if (argc != 3)
+        exit_usage();
+    crypt_init();
+    UT_string* out;
+    if (strcmp(argv[1], "encode") == 0)
+        out = crypt_encode(argv[2]);
+    else if (strcmp(argv[1], "decode") == 0)
+        out = crypt_decode(argv[2]);
+    else
+        exit_usage();
+    printf("%s\n", utstring_body(out));
+    utstring_free(out);
+}
diff --git a/challenge-025/paulo-custodio/c/utstring.h b/challenge-025/paulo-custodio/c/utstring.h
new file mode 100644
index 0000000000..f0270fb632
--- /dev/null
+++ b/challenge-025/paulo-custodio/c/utstring.h
@@ -0,0 +1,407 @@
+/*
+Copyright (c) 2008-2022, Troy D. Hanson  https://troydhanson.github.io/uthash/
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* a dynamic string implementation using macros
+ */
+#ifndef UTSTRING_H
+#define UTSTRING_H
+
+#define UTSTRING_VERSION 2.3.0
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#ifdef __GNUC__
+#define UTSTRING_UNUSED __attribute__((__unused__))
+#else
+#define UTSTRING_UNUSED
+#endif
+
+#ifdef oom
+#error "The name of macro 'oom' has been changed to 'utstring_oom'. Please update your code."
+#define utstring_oom() oom()
+#endif
+
+#ifndef utstring_oom
+#define utstring_oom() exit(-1)
+#endif
+
+typedef struct {
+    char *d;  /* pointer to allocated buffer */
+    size_t n; /* allocated capacity */
+    size_t i; /* index of first unused byte */
+} UT_string;
+
+#define utstring_reserve(s,amt)                            \
+do {                                                       \
+  if (((s)->n - (s)->i) < (size_t)(amt)) {                 \
+    char *utstring_tmp = (char*)realloc(                   \
+      (s)->d, (s)->n + (amt));                             \
+    if (!utstring_tmp) {                                   \
+      utstring_oom();                                      \
+    }                                                      \
+    (s)->d = utstring_tmp;                                 \
+    (s)->n += (amt);                                       \
+  }                                                        \
+} while(0)
+
+#define utstring_init(s)                                   \
+do {                                                       \
+  (s)->n = 0; (s)->i = 0; (s)->d = NULL;                   \
+  utstring_reserve(s,100);                                 \
+  (s)->d[0] = '\0';                                        \
+} while(0)
+
+#define utstring_done(s)                                   \
+do {                                                       \
+  if ((s)->d != NULL) free((s)->d);                        \
+  (s)->n = 0;                                              \
+} while(0)
+
+#define utstring_free(s)                                   \
+do {                                                       \
+  utstring_done(s);                                        \
+  free(s);                                                 \
+} while(0)
+
+#define utstring_new(s)                                    \
+do {                                                       \
+  (s) = (UT_string*)malloc(sizeof(UT_string));             \
+  if (!(s)) {                                              \
+    utstring_oom();                                        \
+  }                                                        \
+  utstring_init(s);                                        \
+} while(0)
+
+#define utstring_renew(s)                                  \
+do {                                                       \
+   if (s) {                                                \
+     utstring_clear(s);                                    \
+   } else {                                                \
+     utstring_new(s);                                      \
+   }                                                       \
+} while(0)
+
+#define utstring_clear(s)                                  \
+do {                                                       \
+  (s)->i = 0;                                              \
+  (s)->d[0] = '\0';                                        \
+} while(0)
+
+#define utstring_bincpy(s,b,l)                             \
+do {                                                       \
+  utstring_reserve((s),(l)+1);                             \
+  if (l) memcpy(&(s)->d[(s)->i], b, l);                    \
+  (s)->i += (l);                                           \
+  (s)->d[(s)->i]='\0';                                     \
+} while(0)
+
+#define utstring_concat(dst,src)                                 \
+do {                                                             \
+  utstring_reserve((dst),((src)->i)+1);                          \
+  if ((src)->i) memcpy(&(dst)->d[(dst)->i], (src)->d, (src)->i); \
+  (dst)->i += (src)->i;                                          \
+  (dst)->d[(dst)->i]='\0';                                       \
+} while(0)
+
+#define utstring_len(s) ((s)->i)
+
+#define utstring_body(s) ((s)->d)
+
+UTSTRING_UNUSED static void utstring_printf_va(UT_string *s, const char *fmt, va_list ap) {
+   int n;
+   va_list cp;
+   for (;;) {
+#ifdef _WIN32
+      cp = ap;
+#else
+      va_copy(cp, ap);
+#endif
+      n = vsnprintf (&s->d[s->i], s->n-s->i, fmt, cp);
+      va_end(cp);
+
+      if ((n > -1) && ((size_t) n < (s->n-s->i))) {
+        s->i += n;
+        return;
+      }
+
+      /* Else try again with more space. */
+      if (n > -1) utstring_reserve(s,n+1); /* exact */
+      else utstring_reserve(s,(s->n)*2);   /* 2x */
+   }
+}
+#ifdef __GNUC__
+/* support printf format checking (2=the format string, 3=start of varargs) */
+static void utstring_printf(UT_string *s, const char *fmt, ...)
+  __attribute__ (( format( printf, 2, 3) ));
+#endif
+UTSTRING_UNUSED static void utstring_printf(UT_string *s, const char *fmt, ...) {
+   va_list ap;
+   va_start(ap,fmt);
+   utstring_printf_va(s,fmt,ap);
+   va_end(ap);
+}
+
+/*******************************************************************************
+ * begin substring search functions                                            *
+ ******************************************************************************/
+/* Build KMP table from left to right. */
+UTSTRING_UNUSED static void _utstring_BuildTable(
+    const char *P_Needle,
+    size_t P_NeedleLen,
+    long *P_KMP_Table)
+{
+    long i, j;
+
+    i = 0;
+    j = i - 1;
+    P_KMP_Table[i] = j;
+    while (i < (long) P_NeedleLen)
+    {
+        while ( (j > -1) && (P_Needle[i] != P_Needle[j]) )
+        {
+           j = P_KMP_Table[j];
+        }
+        i++;
+        j++;
+        if (i < (long) P_NeedleLen)
+        {
+            if (P_Needle[i] == P_Needle[j])
+            {
+                P_KMP_Table[i] = P_KMP_Table[j];
+            }
+            else
+            {
+                P_KMP_Table[i] = j;
+            }
+        }
+        else
+        {
+            P_KMP_Table[i] = j;
+        }
+    }
+
+    return;
+}
+
+
+/* Build KMP table from right to left. */
+UTSTRING_UNUSED static void _utstring_BuildTableR(
+    const char *P_Needle,
+    size_t P_NeedleLen,
+    long *P_KMP_Table)
+{
+    long i, j;
+
+    i = P_NeedleLen - 1;
+    j = i + 1;
+    P_KMP_Table[i + 1] = j;
+    while (i >= 0)
+    {
+        while ( (j < (long) P_NeedleLen) && (P_Needle[i] != P_Needle[j]) )
+        {
+           j = P_KMP_Table[j + 1];
+        }
+        i--;
+        j--;
+        if (i >= 0)
+        {
+            if (P_Needle[i] == P_Needle[j])
+            {
+                P_KMP_Table[i + 1] = P_KMP_Table[j + 1];
+            }
+            else
+            {
+                P_KMP_Table[i + 1] = j;
+            }
+        }
+        else
+        {
+            P_KMP_Table[i + 1] = j;
+        }
+    }
+
+    return;
+}
+
+
+/* Search data from left to right. ( Multiple search mode. ) */
+UTSTRING_UNUSED static long _utstring_find(
+    const char *P_Haystack,
+    size_t P_HaystackLen,
+    const char *P_Needle,
+    size_t P_NeedleLen,
+    long *P_KMP_Table)
+{
+    long i, j;
+    long V_FindPosition = -1;
+
+    /* Search from left to right. */
+    i = j = 0;
+    while ( (j < (int)P_HaystackLen) && (((P_HaystackLen - j) + i) >= P_NeedleLen) )
+    {
+        while ( (i > -1) && (P_Needle[i] != P_Haystack[j]) )
+        {
+            i = P_KMP_Table[i];
+        }
+        i++;
+        j++;
+        if (i >= (int)P_NeedleLen)
+        {
+            /* Found. */
+            V_FindPosition = j - i;
+            break;
+        }
+    }
+
+    return V_FindPosition;
+}
+
+
+/* Search data from right to left. ( Multiple search mode. ) */
+UTSTRING_UNUSED static long _utstring_findR(
+    const char *P_Haystack,
+    size_t P_HaystackLen,
+    const char *P_Needle,
+    size_t P_NeedleLen,
+    long *P_KMP_Table)
+{
+    long i, j;
+    long V_FindPosition = -1;
+
+    /* Search from right to left. */
+    j = (P_HaystackLen - 1);
+    i = (P_NeedleLen - 1);
+    while ( (j >= 0) && (j >= i) )
+    {
+        while ( (i < (int)P_NeedleLen) && (P_Needle[i] != P_Haystack[j]) )
+        {
+            i = P_KMP_Table[i + 1];
+        }
+        i--;
+        j--;
+        if (i < 0)
+        {
+            /* Found. */
+            V_FindPosition = j + 1;
+            break;
+        }
+    }
+
+    return V_FindPosition;
+}
+
+
+/* Search data from left to right. ( One time search mode. ) */
+UTSTRING_UNUSED static long utstring_find(
+    UT_string *s,
+    long P_StartPosition,   /* Start from 0. -1 means last position. */
+    const char *P_Needle,
+    size_t P_NeedleLen)
+{
+    long V_StartPosition;
+    long V_HaystackLen;
+    long *V_KMP_Table;
+    long V_FindPosition = -1;
+
+    if (P_StartPosition < 0)
+    {
+        V_StartPosition = s->i + P_StartPosition;
+    }
+    else
+    {
+        V_StartPosition = P_StartPosition;
+    }
+    V_HaystackLen = s->i - V_StartPosition;
+    if ( (V_HaystackLen >= (long) P_NeedleLen) && (P_NeedleLen > 0) )
+    {
+        V_KMP_Table = (long *)malloc(sizeof(long) * (P_NeedleLen + 1));
+        if (V_KMP_Table != NULL)
+        {
+            _utstring_BuildTable(P_Needle, P_NeedleLen, V_KMP_Table);
+
+            V_FindPosition = _utstring_find(s->d + V_StartPosition,
+                                            V_HaystackLen,
+                                            P_Needle,
+                                            P_NeedleLen,
+                                            V_KMP_Table);
+            if (V_FindPosition >= 0)
+            {
+                V_FindPosition += V_StartPosition;
+            }
+
+            free(V_KMP_Table);
+        }
+    }
+
+    return V_FindPosition;
+}
+
+
+/* Search data from right to left. ( One time search mode. ) */
+UTSTRING_UNUSED static long utstring_findR(
+    UT_string *s,
+    long P_StartPosition,   /* Start from 0. -1 means last position. */
+    const char *P_Needle,
+    size_t P_NeedleLen)
+{
+    long V_StartPosition;
+    long V_HaystackLen;
+    long *V_KMP_Table;
+    long V_FindPosition = -1;
+
+    if (P_StartPosition < 0)
+    {
+        V_StartPosition = s->i + P_StartPosition;
+    }
+    else
+    {
+        V_StartPosition = P_StartPosition;
+    }
+    V_HaystackLen = V_StartPosition + 1;
+    if ( (V_HaystackLen >= (long) P_NeedleLen) && (P_NeedleLen > 0) )
+    {
+        V_KMP_Table = (long *)malloc(sizeof(long) * (P_NeedleLen + 1));
+        if (V_KMP_Table != NULL)
+        {
+            _utstring_BuildTableR(P_Needle, P_NeedleLen, V_KMP_Table);
+
+            V_FindPosition = _utstring_findR(s->d,
+                                             V_HaystackLen,
+                                             P_Needle,
+                                             P_NeedleLen,
+                                             V_KMP_Table);
+
+            free(V_KMP_Table);
+        }
+    }
+
+    return V_FindPosition;
+}
+/*******************************************************************************
+ * end substring search functions                                              *
+ ******************************************************************************/
+
+#endif /* UTSTRING_H */