From 87a1547478d67e345a003e4f77563f8ef0ef6a37 Mon Sep 17 00:00:00 2001
From: Dimitri Lozeve <dimitri@lozeve.com>
Date: Wed, 10 Jun 2020 17:59:32 +0200
Subject: [PATCH] Fix base64 decoding and decipher single-char xor

---
 src/ex06/main.c | 19 +++++++++++++++----
 src/utils.c     |  6 +-----
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/src/ex06/main.c b/src/ex06/main.c
index 3515bca..ac36e17 100644
--- a/src/ex06/main.c
+++ b/src/ex06/main.c
@@ -40,7 +40,15 @@ int main(int argc, char *argv[]) {
   }
 
   char input[BUF_SIZE] = {'\0'};
-  size_t nread = fread(input, 1, BUF_SIZE, fp);
+  int c;
+  size_t nread = 0;
+  while ((c = fgetc(fp)) != EOF) {
+    if (c == '\n' || c == '\r') { // ignore newlines
+      continue;
+    }
+    input[nread] = c;
+    nread++;
+  }
   if (nread == 0) {
     printf("Cannot read any character from file %s\n", filename);
     return EXIT_FAILURE;
@@ -82,11 +90,14 @@ int main(int argc, char *argv[]) {
 
   char key[keysize];
   for (size_t j = 0; j < keysize; ++j) {
-    printf("Guessing key character %2zu: ", j);
     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\n", key);
+
+  for (size_t i = 0; i < len; ++i) {
+    printf("%c", buf[i] ^ key[i % keysize]);
+  }
+  putchar('\n');
 
   return EXIT_SUCCESS;
 }
diff --git a/src/utils.c b/src/utils.c
index 4889d4c..97f577e 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -1,7 +1,6 @@
 #include "utils.h"
 #include <ctype.h>
 #include <math.h>
-#include <stdio.h>
 #include <string.h>
 
 unsigned char hex_to_byte(const char c) {
@@ -82,6 +81,7 @@ double frequency_score(size_t len, const char buf[static len]) {
       0.0673, 0.0894, 0.0268, 0.0106, 0.0183, 0.0019, 0.0172, 0.0011,
       // space
       0.19182};
+
   // static const double english_freqs[27] = {
   //     // A-Z
   //     0.08167, 0.01492, 0.02782, 0.04253, 0.12702, 0.02228, 0.02015, 0.06094,
@@ -137,14 +137,10 @@ char best_single_char_xor_key(size_t len, unsigned char buf[static len]) {
       cur[i] = buf[i] ^ c;
     }
     double score = frequency_score(len, cur);
-    //printf("current character: %c, current score: %f\n", c, score);
     if (score < min_score) {
       min_score = score;
       key = c;
     }
-    if (isfinite(min_score)) {
-      printf("current best character: %c, current best score: %f\n", key, min_score);
-    }
   }
 
   return key;