os_read, ui misc

src/os/os_win32.c

@@ -108,6 +108,34 @@ fn os_write_t os_write(s8_t path, s8_t content) {
     return result;
 }
 
+// @todo: improve to return error codes
+fn s8_t os_read(ma_arena_t *arena, s8_t path) {
+    s8_t result = {0};
+    ma_temp_t scratch = ma_begin_scratch1(arena);
+    s16_t path16 = s16_from_s8(scratch.arena, path);
+    HANDLE handle = CreateFileW(path16.str, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+    if (handle != INVALID_HANDLE_VALUE) {
+        LARGE_INTEGER file_size;
+        if (GetFileSizeEx(handle, &file_size)) {
+            if (file_size.QuadPart != 0) {
+                result.len = file_size.QuadPart;
+                result.str = ma_push_array(arena, char, result.len + 1);
+                assert(result.len == (i64)(DWORD)result.len);
+                DWORD read;
+                if (ReadFile(handle, result.str, (DWORD)result.len, &read, NULL)) { // @todo: can only read 32 byte size files?
+                    if (read == result.len) {
+                        result.str[result.len] = 0;
+                    }
+                }
+
+            }
+        }
+        CloseHandle(handle);
+    }
+    ma_end_scratch(scratch);
+    return result;
+}
+
 typedef struct w32_file_iter_t w32_file_iter_t;
 struct w32_file_iter_t {
     HANDLE           handle;