Make C++ file io more idiomatic

cplusplus/src/include/utils.hpp

@@ -1,105 +1,45 @@
 #pragma once
-#include <stdlib.h>
-#include <stdint.h>
-#include <inttypes.h>
-#include <string.h>
-#ifdef _WIN32
-#include <direct.h>
-#include <windows.h>
-#define PATH_SEPARATOR "\\"
-#else
-#include <libgen.h>
-#include <stdio.h>
-#include <unistd.h>
-#define PATH_SEPARATOR "/"
-#endif
 
-char* get_parent_directory(char* path, const uint32_t levels) {
-#ifdef _WIN32
-    static char drive[_MAX_DRIVE];
-    static char dir[_MAX_DIR];
-    _splitpath(path, drive, dir, NULL, NULL);
-    for (uint32_t i = 0; i < levels; ++i) {
-        size_t len = strlen(dir);
-        if (len > 1 && (dir[len - 1] == '\\' || dir[len - 1] == '/')) {
-            dir[len - 1] = '\0';
-        }
-        char* last_slash = strrchr(dir, '\\');
-        if (!last_slash) last_slash = strrchr(dir, '/');
-        if (last_slash) *last_slash = '\0';
-    }
-    static char parent_dir[_MAX_PATH];
-    snprintf(parent_dir, sizeof(parent_dir), "%s%s", drive, dir);
-    return parent_dir;
-#else
-    char* dir = dirname(path);
-    for (uint32_t i = 0; i < levels; ++i) {
-        dir = dirname(dir);
-        if (strcmp(dir, "/") == 0 || strcmp(dir, ".") == 0) {
-            break;
-        }
-    }
-    return dir;
-#endif
-}
+#include <cstdint>
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <stdexcept>
+#include <string>
+#include <vector>
 
-std::string get_data_file(const char *name) {
-    const char* start = __FILE__;
-#ifdef _WIN32
-    char absolute_path[MAX_PATH];
-    if (!_fullpath(absolute_path, start, MAX_PATH)) {
-        perror("_fullpath");
-        return NULL;
-    }
-#else
-   char* absolute_path = realpath(start, NULL);
-    if (!absolute_path) {
-        perror("realpath");
-        return NULL;
-    }
-#endif
-    char* parents_dir = get_parent_directory(absolute_path, 3);
-    const size_t p_len = strlen(parents_dir),
-    name_len = strlen(name);
-    char *file_path = (char *)malloc(p_len + name_len + 8);
-    memcpy(file_path, parents_dir, p_len);
-    memcpy(file_path + p_len, PATH_SEPARATOR "_data" PATH_SEPARATOR, 7);
-    memcpy(file_path + p_len + 7, name, name_len);
-    file_path[p_len + name_len + 7] = 0;
-    FILE* file = fopen(file_path, "r");
-#ifndef _WIN32
-    free(absolute_path);
-#endif
-//    free(parents_dir);
-    free(file_path);
-    if (!file) {
-        perror("fopen");
-        return NULL;
-    }
+namespace FileUtils {
+    std::filesystem::path FileUtils::get_parent_directory(const std::filesystem::path& path, uint32_t levels);
+    std::string get_data_file(const std::string& name);
+};
 
-    fseek(file, 0, SEEK_END);
-    size_t length = ftell(file);
-    fseek(file, 0, SEEK_SET);
+inline
+std::filesystem::path FileUtils::get_parent_directory(const std::filesystem::path& path, uint32_t levels) {
+    std::filesystem::path p(path);
+    for (uint32_t i = 0; i < levels && p.has_parent_path(); ++i)
+        p = p.parent_path();
+    return p.string();
+}
 
-    char* buffer = (char*)malloc(length + 1);
-    if (!buffer) {
-        perror("malloc");
-        fclose(file);
-        return NULL;
-    }
+std::string FileUtils::get_data_file(const std::string& name) {
+    try {
+        std::filesystem::path parent_dir = get_parent_directory(std::filesystem::path(__FILE__), 4);
+        std::filesystem::path file_path = parent_dir / "_data" / name;
 
-    const size_t ret_code = fread(buffer, 1, length, file);
-    if (ret_code != length) {
-        if (feof(file))
-            printf("Error reading %s: unexpected end of file, read %" PRIu64 " of %" PRIu64 " bytes expected\n", name, (uint64_t)ret_code, (uint64_t)length);
-        else if (ferror(file))
-            perror("Error reading data file");
-    }
+        std::ifstream file(file_path, std::ios::binary | std::ios::ate);
+        if (!file)
+            throw std::runtime_error("Failed to open file: " + file_path.string());
 
-    buffer[length] = 0;
-    fclose(file);
+        std::ifstream::pos_type file_size = file.tellg();
+        file.seekg(0, std::ios::beg);
 
-    std::string ret(buffer);
-    free(buffer);
-    return ret;
+        std::vector<char> buffer(static_cast<size_t>(file_size));
+        if (!file.read(buffer.data(), file_size))
+            throw std::runtime_error("Failed to read file: " + file_path.string());
+
+        return std::string(buffer.begin(), buffer.end());
+    } catch (const std::exception& e) {
+        std::cerr << e.what() << std::endl;
+        return {};
+    }
 }

cplusplus/src/p0022.cpp

@@ -22,7 +22,7 @@
 
 uint64_t p0022() {
     uint64_t answer = 0;
-    std::string fstring = get_data_file("p0022_names.txt");
+    std::string fstring = FileUtils::get_data_file("p0022_names.txt");
     const uint32_t name_count = 5163;
     std::vector<std::string> names(5163, "");
     size_t idx = 0, i = 0, pi = 0;

docs/src/cplusplus/lib/macros.rst

@@ -44,6 +44,6 @@ View source code :source:`cplusplus/src/include/macros.hpp`
 
 .. c:namespace-pop::
 
-.. literalinclude:: ../../../../cplusplus/src/include/macros.h
+.. literalinclude:: ../../../../cplusplus/src/include/macros.hpp
    :language: C++
    :linenos:

docs/src/cplusplus/lib/math.rst

@@ -30,6 +30,6 @@ Includes
 
 .. c:namespace-pop::
 
-.. literalinclude:: ../../../../cplusplus/src/include/math.h
+.. literalinclude:: ../../../../cplusplus/src/include/math.hpp
    :language: C++
    :linenos:

docs/src/cplusplus/lib/utils.rst

@@ -3,17 +3,17 @@ utils.hpp
 
 View source code :source:`cplusplus/src/include/utils.hpp`
 
-.. cpp:namespace-push:: utils
+.. cpp:namespace-push:: FileUtils
     
-.. cpp:function:: std::string get_data_file(const char *name)
+.. cpp:function:: std::string get_data_file(const std::string& name)
 
     Return a character array containing the whole contents of a file found in _data.
 
-.. cpp:function:: char *get_parent_directory(const char *name, const uint32_t levels)
+.. cpp:function:: std::filesystem::path get_parent_directory(const std::filesystem::path& path, uint32_t levels)
 
 .. cpp:namespace-pop::
 
-.. literalinclude:: ../../../../cplusplus/src/include/utils.h
+.. literalinclude:: ../../../../cplusplus/src/include/utils.hpp
    :language: C++
    :linenos: