Homework 4 - Task 2 - [Phone database]

homework_4/CMakeLists.txt

@@ -3,3 +3,4 @@ project(homework_4)
 set(homeworkName "${PROJECT_NAME}")
 
 add_subdirectory(task_1)
+add_subdirectory(task_2)

homework_4/README.md

@@ -1,3 +1,5 @@
 # Homework 4
 
 [Task 1. Binary representation](/homework_4/task_1)
+
+[Task 2. Phone database](/homework_4/task_2)

homework_4/task_2/.gitignore

@@ -0,0 +1 @@
+phoneDatabase

homework_4/task_2/CMakeLists.txt

@@ -0,0 +1,9 @@
+project("${homeworkName}_task_2")
+
+add_library(phoneBook database.c personEntry.c)
+
+add_executable(${PROJECT_NAME} main.c)
+target_link_libraries(${PROJECT_NAME} phoneBook)
+
+add_executable(${PROJECT_NAME}_test test.c)
+target_link_libraries(${PROJECT_NAME}_test phoneBook)

homework_4/task_2/database.c

@@ -0,0 +1,149 @@
+#include "database.h"
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define DB_SIGNATURE "#!hw_phonebook"
+#define DB_BEGIN "{{"
+#define DB_END "}}"
+
+Database *createDatabase() {
+    Database *database = malloc(sizeof(Database));
+    if (database == NULL) {
+        return NULL;
+    }
+    database->entriesCount = 0;
+
+    return database;
+}
+
+bool addEntry(Database *database, PersonEntry entry) {
+    if (database == NULL) {
+        return false;
+    }
+
+    // entries count cannot be more than DB_MAX_ENTRIES, but check this case too
+    if (database->entriesCount >= DB_MAX_ENTRIES) {
+        return false;
+    }
+
+    database->entries[database->entriesCount] = entry;
+    ++database->entriesCount;
+    return true;
+}
+
+#pragma region Save/Load
+
+bool saveDatabase(FILE *stream, Database *database) {
+    if (stream == NULL) {
+        return false;
+    }
+
+    if (database == NULL) {
+        return false;
+    }
+
+    fprintf(stream, "%s\n", DB_SIGNATURE);
+    fprintf(stream, "%s\n", DB_BEGIN);
+
+    for (int i = 0; i < database->entriesCount; ++i) {
+        PersonEntry entry = database->entries[i];
+        fprintf(stream, "%s\n", entry.personName);
+        fprintf(stream, "%s\n", entry.phoneNumber);
+    }
+
+    fprintf(stream, "%s\n", DB_END);
+
+    return true;
+}
+
+// reads line and sets first '\n' to '\0'
+bool tryReadLine(char *buffer, int count, FILE *file) {
+    if (fgets(buffer, count, file) == NULL || feof(file)) {
+        return false;
+    }
+
+    for (int i = 0; i < count; ++i) {
+        if (buffer[i] == '\n') {
+            buffer[i] = '\0';
+            break;
+        }
+    }
+
+    return true;
+}
+
+Database *loadDatabase(FILE *stream) {
+    if (stream == NULL) {
+        return NULL;
+    }
+
+    Database *database = createDatabase();
+
+    if (database == NULL) {
+        return NULL;
+    }
+
+    char buffer[256] = { 0 };
+
+    if (!tryReadLine(buffer, sizeof(buffer), stream) && strcmp(buffer, DB_SIGNATURE) != 0) {
+        return NULL;
+    }
+
+    if (!tryReadLine(buffer, sizeof(buffer), stream) && strcmp(buffer, DB_BEGIN) != 0) {
+        return NULL;
+    }
+
+    while (true) {
+        // person name or db end anchor
+        if (!tryReadLine(buffer, sizeof(buffer), stream)) {
+            return NULL;
+        }
+
+        if (strcmp(buffer, DB_END) == 0) {
+            break;
+        }
+
+        char *personName = strdup(buffer);
+        if (personName == NULL) {
+            return NULL;
+        }
+
+        // phone number
+        if (!tryReadLine(buffer, sizeof(buffer), stream)) {
+            return NULL;
+        }
+
+        PhoneNumber phoneNumber;
+        if (!tryParsePhoneNumber(buffer, &phoneNumber)) {
+            return NULL;
+        }
+
+        PersonEntry entry = {
+            .personName = personName,
+            .phoneNumber = phoneNumber
+        };
+
+        if (!addEntry(database, entry)) {
+            // no space left, not an error
+            break;
+        }
+    }
+
+    return database;
+}
+
+#pragma endregion
+
+void disposeDatabase(Database *database) {
+    if (database == NULL) {
+        return;
+    }
+
+    for (int i = 0; i < database->entriesCount; ++i) {
+        disposeEntry(&database->entries[i]);
+    }
+    free(database);
+}

homework_4/task_2/database.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stdio.h>
+
+#include "personEntry.h"
+
+#define DB_MAX_ENTRIES 100
+
+typedef struct {
+    int entriesCount;
+    PersonEntry entries[DB_MAX_ENTRIES];
+} Database;
+
+/// @brief Creates empty database
+/// @return `Database` if created successfully, `NULL` otherwise
+Database *createDatabase();
+
+/// @brief Adds a person entry to database
+/// @param database Pointer to database
+/// @param entry Entry to add
+/// @return `true` if added successfully, `false` otherwise (no space in database left)
+bool addEntry(Database *database, PersonEntry entry);
+
+/// @brief Saves database to specified stream
+/// @param stream Stream to save database to
+/// @param database Pointer to database
+/// @return `true` if saved successfully, `false` otherwise
+bool saveDatabase(FILE *stream, Database *database);
+
+/// @brief Loads database from specified file stream
+/// @param stream Stream to load database from
+/// @return `Database` if loaded successfully, `NULL` otherwise
+Database *loadDatabase(FILE *stream);
+
+/// @brief Disposes database and all of its entries
+/// @param database Database to dispose (can be `NULL`)
+void disposeDatabase(Database *database);