initial commit

os_utils.cc

@@ -0,0 +1,149 @@
+//
+// Created on 2024-05-17.
+//
+
+#include "os_utils.h"
+
+#include "utf_convert.h"
+
+#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__)
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <cerrno>
+#include <cstring>
+
+bool ReadFile(std::string_view path, std::vector<uint8_t>& out, size_t maxSize, int& errorCode) {
+    if (maxSize == 0) {
+        errorCode = -EINVAL;
+        return false;
+    }
+    int fd = open(std::string(path).c_str(), O_RDONLY);
+    if (fd < 0) {
+        errorCode = -errno;
+        return false;
+    }
+    struct stat64 st{};
+    if (fstat64(fd, &st) < 0) {
+        close(fd);
+        errorCode = -errno;
+        return false;
+    }
+    if (st.st_size > maxSize) {
+        close(fd);
+        errorCode = -EOVERFLOW;
+        return false;
+    }
+    out.resize(st.st_size);
+    ssize_t remaining = st.st_size;
+    ssize_t read = 0;
+    uint8_t* ptr = out.data();
+    while (remaining > 0) {
+        read = ::read(fd, ptr, remaining);
+        if (read < 0) {
+            close(fd);
+            errorCode = -errno;
+            return false;
+        }
+        remaining -= read;
+        ptr += read;
+    }
+    close(fd);
+    return true;
+
+}
+
+bool WriteFile(std::string_view path, std::span<const uint8_t> data, int& errorCode) {
+    int fd = open(std::string(path).c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0644);
+    if (fd < 0) {
+        errorCode = -errno;
+        return false;
+    }
+    ssize_t remaining = data.size_bytes();
+    ssize_t written = 0;
+    const uint8_t* ptr = data.data();
+    while (remaining > 0) {
+        written = ::write(fd, ptr, remaining);
+        if (written < 0) {
+            close(fd);
+            errorCode = -errno;
+            return false;
+        }
+        remaining -= written;
+        ptr += written;
+    }
+    close(fd);
+    return true;
+}
+
+#include <cwchar>
+
+
+std::string GetErrorMsg(int errorCode) {
+    return strerror(std::abs(errorCode));
+}
+
+#elif defined(_WIN32)
+
+#include <windows.h>
+
+bool ReadFile(std::string_view path, std::vector<uint8_t>& out, size_t maxSize, int& errorCode) {
+    std::wstring wpath = utfcvt::UTF8ToWide(path);
+    HANDLE hFile = CreateFileW(wpath.c_str(), GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING,
+                               FILE_ATTRIBUTE_NORMAL, nullptr);
+    if (hFile == INVALID_HANDLE_VALUE) {
+        errorCode = -(int) GetLastError();
+        return false;
+    }
+    LARGE_INTEGER fileSize;
+    if (!GetFileSizeEx(hFile, &fileSize)) {
+        CloseHandle(hFile);
+        errorCode = -(int) GetLastError();
+        return false;
+    }
+    if (fileSize.QuadPart > maxSize) {
+        CloseHandle(hFile);
+        errorCode = -ERROR_FILE_TOO_LARGE;
+        return false;
+    }
+    out.resize(fileSize.QuadPart);
+    DWORD bytesRead = 0;
+    if (!ReadFile(hFile, out.data(), fileSize.LowPart, &bytesRead, nullptr)) {
+        CloseHandle(hFile);
+        errorCode = -(int) GetLastError();
+        return false;
+    }
+    CloseHandle(hFile);
+    return true;
+}
+
+bool WriteFile(std::string_view path, std::span<const uint8_t> data, int& errorCode) {
+    std::wstring wpath = utfcvt::UTF8ToWide(path);
+    HANDLE hFile = CreateFileW(wpath.c_str(), GENERIC_WRITE, 0, nullptr, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, nullptr);
+    if (hFile == INVALID_HANDLE_VALUE) {
+        errorCode = -(int) GetLastError();
+        return false;
+    }
+    DWORD bytesWritten = 0;
+    if (!WriteFile(hFile, data.data(), (DWORD) data.size_bytes(), &bytesWritten, nullptr)) {
+        CloseHandle(hFile);
+        errorCode = -(int) GetLastError();
+        return false;
+    }
+    CloseHandle(hFile);
+    return true;
+}
+
+std::string GetErrorMsg(int errorCode) {
+    LPWSTR msgBuf = nullptr;
+    FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+                   nullptr, errorCode, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPWSTR) &msgBuf, 0, nullptr);
+    std::wstring msg(msgBuf);
+    LocalFree(msgBuf);
+    return utfcvt::WideToUTF8(msg);
+}
+
+#else
+#error "Unsupported platform"
+#endif