crypto_square: iteration 1

cpp/crypto-square/crypto_square.cpp

@@ -0,0 +1,87 @@
+#include "crypto_square.h"
+
+#include <algorithm>
+#include <cmath>
+
+namespace crypto_square {
+
+using namespace std;
+
+cipher::cipher(const string &text)
+{
+    text_.reserve(text.size());
+
+    for (auto ch : text) {
+
+        if (isalpha(ch) || isdigit(ch))
+            text_.push_back(tolower(ch));
+    }
+
+    text_.shrink_to_fit();
+
+    size_ = ceil(sqrt(text_.size()));
+}
+
+string cipher::normalize_plain_text() const
+{
+    return text_;
+}
+
+size_t cipher::size() const
+{
+    return size_;
+}
+
+cipher::segments_t cipher::plain_text_segments() const
+{
+    segments_t result;
+
+    const size_t s = size();
+
+    for (size_t i = 0; i < text_.size(); i += s)
+        result.push_back(text_.substr(i, s));
+
+    return result;
+}
+
+string cipher::cipher_text() const
+{
+    string result;
+    result.reserve(text_.size());
+
+    const segments_t segments = plain_text_segments();
+
+    for (size_t col = 0; col < size(); ++col) {
+
+        for (size_t row = 0; row < segments.size(); ++row) {
+
+            const string &segment = segments[row];
+
+            if (col >= segment.size())
+                continue;
+
+            result += segment[col];
+        }
+    }
+
+    return result;
+}
+
+string cipher::normalized_cipher_text() const
+{
+    string result;
+
+    const string text = cipher_text();
+    const size_t s = size();
+
+    for (size_t i = 0; i < text.size(); i += s) {
+
+        result += i ? " " : "";
+        result += text.substr(i, s);
+    }
+
+    return result;
+}
+
+
+}