utils.cpp

#include "utils.h"
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <cstdint>
#include <vector>
#include <climits>

namespace Utils {

Stats computeStats(const std::string& originalText,
                   const std::string& bits,
                   const std::unordered_map<unsigned char, std::string>& codes) {
    Stats s;
    s.originalBytes   = originalText.size();
    s.compressedBytes = (bits.size() + 7) / 8;   // ceiling division
    s.compressionRatio = s.originalBytes > 0
        ? (double)s.compressedBytes / s.originalBytes
        : 0.0;
    s.spaceSaving = (1.0 - s.compressionRatio) * 100.0;
    s.uniqueChars = codes.size();

    size_t minLen = SIZE_MAX, maxLen = 0;
    for (auto& [ch, code] : codes) {
        if (code.size() < minLen) { minLen = code.size(); s.shortestCode = code; }
        if (code.size() > maxLen) { maxLen = code.size(); s.longestCode  = code; }
    }
    return s;
}

void printStats(const Stats& s) {
    std::cout << "\n--- Compression Stats ---\n";
    std::cout << "  Original size   : " << s.originalBytes   << " bytes\n";
    std::cout << "  Compressed size : " << s.compressedBytes << " bytes\n";
    std::cout << std::fixed << std::setprecision(2);
    std::cout << "  Compression ratio: " << s.compressionRatio << "\n";
    std::cout << "  Space saving     : " << s.spaceSaving << "%\n";
    std::cout << "  Unique chars     : " << s.uniqueChars << "\n";
    std::cout << "  Shortest code    : " << s.shortestCode << " (" << s.shortestCode.size() << " bits)\n";
    std::cout << "  Longest code     : " << s.longestCode  << " (" << s.longestCode.size()  << " bits)\n";
    std::cout << "-------------------------\n\n";
}

void printCodes(const std::unordered_map<unsigned char, std::string>& codes) {
    // Sort by code length for readability
    std::vector<std::pair<unsigned char, std::string>> sorted(codes.begin(), codes.end());
    std::sort(sorted.begin(), sorted.end(),
        [](auto& a, auto& b){ return a.second.size() < b.second.size(); });

    std::cout << "\n--- Huffman Codes ---\n";
    std::cout << std::left << std::setw(10) << "Char"
              << std::setw(8)  << "ASCII"
              << "Code\n";
    std::cout << std::string(40, '-') << "\n";
    for (auto& [ch, code] : sorted) {
        std::string display;
        if      (ch == '\n') display = "\\n";
        else if (ch == '\t') display = "\\t";
        else if (ch == ' ')  display = "SPACE";
        else                 display = std::string(1, (char)ch);
        std::cout << std::left << std::setw(10) << display
                  << std::setw(8) << (int)ch
                  << code << "\n";
    }
    std::cout << "---------------------\n\n";
}

} // namespace Utils