Generalize bug fix from OpenXRay#1512

src/Common/PlatformLinux.inl

@@ -429,7 +429,7 @@ inline int _rmdir(const char *path)
 }
 #define _write write
 #define _strupr strupr
-#define _read read
+#define _read xr_read
 #define _set_new_handler std::set_new_handler
 #define _finite isfinite
 inline int _mkdir(const char *dir) { return mkdir(dir, S_IRWXU); }
@@ -1108,3 +1108,29 @@ inline tm* localtime_safe(const time_t *time, struct tm* result){ return localti
 #define xr_strerror(errno, buffer, bufferSize) strerror_r(errno, buffer, sizeof(buffer))
 
 using xrpid_t = pid_t;
+
+// This is a drop-in replacement for calls to linux 'read' function. We use this because unlike other OSes
+// Linux 'read' function can return less then the requested number of bytes and then needs to be called multiple times.
+// Apart from this, it behaves exactly as you would expect and matches the other OSes implementation.
+// See also: https://www.man7.org/linux/man-pages/man2/read.2.html
+inline ssize_t xr_read(int file_handle, void *buffer, size_t count)
+{
+    ssize_t total_r_bytes = 0;
+    do
+    {
+        const ssize_t r_bytes =
+            read(file_handle, reinterpret_cast<u8*>(buffer) + total_r_bytes, count - total_r_bytes);
+
+        // Check for error
+        if (r_bytes == -1)
+            return -1;
+
+        // Check for EOF otherwise we would loop indefinitely
+        if (r_bytes == 0)
+            return total_r_bytes;
+
+        total_r_bytes += r_bytes;
+    } while (static_cast<size_t>(total_r_bytes) < count);
+
+    return total_r_bytes;
+}

src/xrCore/FS.cpp

@@ -134,22 +134,8 @@ void* FileDownload(pcstr file_name, const int& file_handle, size_t& file_size)
     VERIFY(file_size != 0);
     void* buffer = xr_malloc(file_size);
 
-#ifdef XR_PLATFORM_LINUX
-    size_t total_r_bytes = 0;
-    do
-    {
-        const ssize_t r_bytes =
-            _read(file_handle, reinterpret_cast<u8*>(buffer) + total_r_bytes, file_size - total_r_bytes);
-        R_ASSERT3(r_bytes > 0, "Can't read from file : ", file_name);
-
-        total_r_bytes += r_bytes;
-    } while (total_r_bytes < file_size);
-#elif defined(XR_PLATFORM_WINDOWS) || defined(XR_PLATFORM_BSD) || defined(XR_PLATFORM_APPLE)
-    int total_r_bytes = _read(file_handle, buffer, file_size);
-#else
-#   error Select or add implementation for your platform
-#endif
-    R_ASSERT3(total_r_bytes == file_size, "Can't read from file : ", file_name);
+    const ssize_t r_bytes = _read(file_handle, buffer, file_size);
+    R_ASSERT3(r_bytes > 0 && static_cast<size_t>(r_bytes) == file_size, "Can't read from file : ", file_name);
 
     // file_size = r_bytes;
 

src/xrCore/LocatorAPI.cpp

@@ -339,14 +339,14 @@ IReader* open_chunk(int fd, u32 ID, pcstr archiveName, size_t archiveSize, bool
 
     while (true)
     {
-        read_byte = ::read(fd, &dwType, 4);
+        read_byte = _read(fd, &dwType, 4);
         if (read_byte == -1)
             return nullptr;
         else if (read_byte == 0)
             return nullptr;
 
         u32 tempSize = 0;
-        read_byte = ::read(fd, &tempSize, 4);
+        read_byte = _read(fd, &tempSize, 4);
         dwSize = tempSize;
         if (read_byte == -1)
             return nullptr;
@@ -356,7 +356,7 @@ IReader* open_chunk(int fd, u32 ID, pcstr archiveName, size_t archiveSize, bool
         if ((dwType & ~CFS_CompressMark) == ID)
         {
             u8* src_data = xr_alloc<u8>(dwSize);
-            read_byte = ::read(fd, src_data, dwSize);
+            read_byte = _read(fd, src_data, dwSize);
 
             VERIFY(read_byte == dwSize);
             if (dwType & CFS_CompressMark)