[2sem] pb21 done

2sem/programming basics/21/prac_qt/dbmanager.cpp

@@ -0,0 +1,207 @@
+// pb_21_100.cpp
+// Горбацевич Андрей
+#include <iostream>
+#include <fstream>
+#include <vector>
+#include <iomanip>
+#include <cstring>
+#include <QtCore/QTextStream>
+
+namespace nuark {
+    class DB_record {
+        std::string surname = "";
+        unsigned short age = 0;
+        std::string city = "";
+        enum scholarship {
+            HI_ED = 0, SC_ED = 1, SV_RD = 2
+        } scs = SV_RD;
+
+    public:
+        DB_record() = default;
+
+        void load_txt(std::istream &ist) {
+            ist >> this->surname;
+            if (this->surname.length() > 32) {
+                this->surname = this->surname.substr(0, 32);
+            }
+            ist >> this->age;
+            ist >> this->city;
+            if (this->city.length() > 32) {
+                this->city = this->city.substr(0, 32);
+            }
+            {
+                std::string comp_str;
+                ist >> comp_str;
+                if (comp_str[0] == '"') {
+                    std::string sub_comp_str;
+                    ist >> sub_comp_str;
+                    comp_str += " " + sub_comp_str;
+                }
+                if (comp_str == "higher") {
+                    this->scs = HI_ED;
+                }
+                else if (comp_str == "secondary") {
+                    this->scs = SC_ED;
+                }
+                else if (comp_str == "\"secondary vocational\"") {
+                    this->scs = SV_RD;
+                }
+            }
+        }
+
+        void load_bin(std::istream &ist) {
+            struct wrapper {
+                char _surname[32];
+                unsigned short _age;
+                char _city[32];
+                scholarship _scs;
+            } wr{};
+            ist.read(reinterpret_cast<char*>(&wr), sizeof(wrapper));
+
+            this->surname = std::string(wr._surname);
+            this->age = wr._age;
+            this->city = std::string(wr._city);
+            this->scs = wr._scs;
+        }
+
+        void save_bin(std::ostream &ost) const {
+            struct wrapper {
+                char _surname[32];
+                unsigned short _age;
+                char _city[32];
+                scholarship _scs;
+            } wr{};
+            std::strcpy(wr._surname, this->surname.c_str());
+            wr._age = this->age;
+            std::strcpy(wr._city, this->city.c_str());
+            wr._scs = this->scs;
+
+            ost.write(reinterpret_cast<char*>(&wr), sizeof(wrapper));
+        }
+
+        static void print_table_head(QTextStream &ost) {
+            auto ss = std::stringstream();
+            ss.setf(std::ios::left);
+            ss << std::string(102, '=') << std::endl;
+            ss << std::setw(34) << "| surname";
+            ss << std::setw(8) << " | age";
+            ss << std::setw(35) << " | city";
+            ss << std::setw(23) << " | scholarship" << " |\n";
+            ss << std::string(102, '=') << std::endl;
+
+            ost << ss.str().c_str();
+        }
+
+        void print_table_row(QTextStream &ost) const {
+            auto ss = std::stringstream();
+            ss.setf(std::ios::left);
+            ss << "| " << std::setw(32) << this->surname;
+            ss << " | " << std::setw(5) << this->age;
+            ss << " | " << std::setw(32) << this->city;
+            ss << " | " << std::setw(20);
+            switch (this->scs) {
+                case HI_ED:
+                    ss << "higher";
+                    break;
+                case SC_ED:
+                    ss << "secondary";
+                    break;
+                case SV_RD:
+                    ss << "secondary vocational";
+                    break;
+            }
+            ss << " |\n";
+            auto t = ss.str();
+            ost << ss.str().c_str();
+        }
+
+        bool validate() {
+            return this->surname.length() > 0 && this->age > 0 && this->city.length() > 0;
+        }
+    };
+
+    struct DBManager {
+        typedef std::vector<DB_record> Database;
+
+        std::size_t print_table(const Database &data, QTextStream &ost) {
+            std::size_t c = 0;
+            DB_record::print_table_head(ost);
+            for (const auto& rec : data) {
+                rec.print_table_row(ost);
+                c++;
+            }
+            return c;
+        }
+
+        std::size_t load_txt(Database &data, std::istream &ist) {
+            std::size_t c = 0;
+            while (!ist.fail() && !ist.eof()) {
+                DB_record record{};
+                record.load_txt(ist);
+                if (record.validate()) {
+                    data.push_back(record);
+                    c++;
+                }
+            }
+            return c;
+        }
+
+        std::size_t load_bin(Database &data, std::istream &ist) {
+            std::size_t c = 0;
+            while (!ist.fail() && !ist.eof()) {
+                DB_record record{};
+                record.load_bin(ist);
+                if (record.validate()) {
+                    data.push_back(record);
+                    c++;
+                }
+            }
+            return c;
+        }
+
+        std::size_t save_bin(const Database &data, std::ostream &ost) {
+            std::size_t c = 0;
+            for (const auto& rec : data) {
+                rec.save_bin(ost);
+                c++;
+            }
+            return c;
+        }
+
+        void first_mode(const QString &path_in, const QString &path_out, QTextStream &stream) {
+            std::ifstream ist(path_in.toStdString());
+            std::ofstream ost(path_out.toStdString(), std::ios::binary);
+            if (!ist.is_open())
+            {
+                stream << "Unable to open `" << path_in << "`\n";
+            }
+            else {
+                Database db;
+                std::size_t trrc = load_txt(db, ist);
+                stream << "Read " << trrc << " rows from txt\n";
+                std::size_t prc = print_table(db, stream);
+                stream << "Print " << prc << " rows from db\n";
+                std::size_t brwc = save_bin(db, ost);
+                stream << "Write " << brwc << " rows to bin\n";
+            }
+            ist.close();
+            ost.close();
+        }
+
+        void second_mode(const QString &path_in, QTextStream &stream) {
+            std::ifstream ist(path_in.toStdString(), std::ios::binary);
+            if (!ist.is_open())
+            {
+                stream << "Unable to open `" << path_in << "`\n";
+            }
+            else {
+                Database db;
+                std::size_t brrc = load_bin(db, ist);
+                stream << "Read " << brrc << " rows from bin\n";
+                std::size_t prc = print_table(db, stream);
+                stream << "Print " << prc << " rows from db\n";
+            }
+            ist.close();
+        }
+    };
+}