Change the way the hamming function handles its arguments length

src/ex06/main.c

@@ -19,7 +19,7 @@ double normalized_edit_distance(unsigned int keysize,
 
   double avg_dist = 0;
   for (size_t i = 0; i < blocks_count - 1; ++i) {
-    avg_dist += hamming(blocks[i], blocks[i + 1]) / (double)keysize;
+    avg_dist += hamming(keysize, blocks[i], blocks[i + 1]) / (double)keysize;
   }
 
   return avg_dist / ((double)blocks_count - 1.0);
@@ -60,7 +60,7 @@ int main(int argc, char *argv[]) {
 
   unsigned int keysize = 40;
   double min_edit_dist = INFINITY;
-  for (unsigned int i = 30; i > 1; --i) {
+  for (unsigned int i = 40; i > 1; --i) {
     double edit_dist = normalized_edit_distance(i, buf, len / i);
     if (edit_dist < min_edit_dist) {
       min_edit_dist = edit_dist;
@@ -86,7 +86,7 @@ int main(int argc, char *argv[]) {
     key[j] = best_single_char_xor_key(blocks_count, blocks[j]);
     printf("%c\n", key[j]);
   }
-  printf("key: %s\n", key);
+  //printf("key: %s\n", key);
 
   return EXIT_SUCCESS;
 }

src/utils.c

@@ -4,19 +4,6 @@
 #include <string.h>
 #include <stdio.h>
 
-#define min(a, b)                                                              \
-  ({                                                                           \
-    __typeof__(a) _a = (a);                                                    \
-    __typeof__(b) _b = (b);                                                    \
-    _a > _b ? _b : _a;                                                         \
-  })
-
-#define max(a, b)                                                              \
-  ({                                                                           \
-    __typeof__(a) _a = (a);                                                    \
-    __typeof__(b) _b = (b);                                                    \
-    _a > _b ? _a : _b;                                                         \
-  })
 
 unsigned char hex_to_byte(const char c) {
   if (isdigit(c)) {
@@ -121,12 +108,9 @@ double frequency_score(size_t len, const char buf[static len]) {
   return chi2;
 }
 
-unsigned int hamming(const char s1[static 1], const char s2[static 1]) {
+unsigned int hamming(size_t len, const char s1[static len], const char s2[static len]) {
-  unsigned int len1 = strlen(s1);
-  unsigned int len2 = strlen(s2);
-
   unsigned int res = 0;
-  for (size_t i = 0; i < min(len1, len2); ++i) {
+  for (size_t i = 0; i < len; ++i) {
     unsigned int n = s1[i] ^ s2[i];
     while (n) {
       res += n & 1;

src/utils.h

@@ -8,7 +8,7 @@ size_t hex_to_bytes(unsigned char out[static 1], const char hex[static 1]);
 char *bytes_to_base64(char out[static 4], const unsigned char in[static 3], size_t len);
 size_t base64_to_bytes(unsigned char out[static 3], const char in[static 4]);
 double frequency_score(size_t len, const char buf[static len]);
-unsigned int hamming(const char s1[static 1], const char s2[static 1]);
+unsigned int hamming(size_t len, const char s1[static len], const char s2[static len]);
 char best_single_char_xor_key(size_t len, unsigned char buf[static len]);
 
 #endif /* UTILS_H */

tests/main.c

@@ -83,7 +83,7 @@ static MunitResult test_hamming(const MunitParameter params[], void *data) {
   (void)params;
   (void)data;
 
-  assert_int(hamming("this is a test", "wokka wokka!!!"), ==, 37);
+  assert_int(hamming(14, "this is a test", "wokka wokka!!!"), ==, 37);
 
   return MUNIT_OK;
 }