static void
test_Window(TestBatchRunner *runner) {
String *test_filename = SSTR_WRAP_C("_fstest");
FSFileHandle *fh;
FileWindow *window = FileWindow_new();
uint32_t i;
S_remove(test_filename);
fh = FSFH_open(test_filename,
FH_CREATE | FH_WRITE_ONLY | FH_EXCLUSIVE);
for (i = 0; i < 1024; i++) {
FSFH_Write(fh, "foo ", 4);
}
if (!FSFH_Close(fh)) { RETHROW(INCREF(Err_get_error())); }
// Reopen for reading.
DECREF(fh);
fh = FSFH_open(test_filename, FH_READ_ONLY);
if (!fh) { RETHROW(INCREF(Err_get_error())); }
Err_set_error(NULL);
TEST_FALSE(runner, FSFH_Window(fh, window, -1, 4),
"Window() with a negative offset returns false");
TEST_TRUE(runner, Err_get_error() != NULL,
"Window() with a negative offset sets error");
Err_set_error(NULL);
TEST_FALSE(runner, FSFH_Window(fh, window, 4000, 1000),
"Window() past EOF returns false");
TEST_TRUE(runner, Err_get_error() != NULL,
"Window() past EOF sets error");
TEST_TRUE(runner, FSFH_Window(fh, window, 1021, 2),
"Window() returns true");
const char *buf = FileWindow_Get_Buf(window);
int64_t offset = FileWindow_Get_Offset(window);
TEST_TRUE(runner,
strncmp(buf - offset + 1021, "oo", 2) == 0,
"Window()");
TEST_TRUE(runner, FSFH_Release_Window(fh, window),
"Release_Window() returns true");
TEST_TRUE(runner, FileWindow_Get_Buf(window) == NULL,
"Release_Window() resets buf");
TEST_INT_EQ(runner, FileWindow_Get_Offset(window), 0,
"Release_Window() resets offset");
TEST_INT_EQ(runner, FileWindow_Get_Len(window), 0,
"Release_Window() resets len");
DECREF(window);
DECREF(fh);
S_remove(test_filename);
}
static INLINE int64_t
SI_tell(InStream *self) {
InStreamIVARS *const ivars = InStream_IVARS(self);
char *fw_buf = FileWindow_Get_Buf(ivars->window);
int64_t pos_in_buf = PTR_TO_I64(ivars->buf) - PTR_TO_I64(fw_buf);
return pos_in_buf + FileWindow_Get_Offset(ivars->window) - ivars->offset;
}
void
InStream_seek(InStream *self, int64_t target) {
InStreamIVARS *const ivars = InStream_IVARS(self);
FileWindow *const window = ivars->window;
char *fw_buf = FileWindow_Get_Buf(window);
int64_t fw_offset = FileWindow_Get_Offset(window);
int64_t fw_len = FileWindow_Get_Len(window);
int64_t virtual_window_top = fw_offset - ivars->offset;
int64_t virtual_window_end = virtual_window_top + fw_len;
if (target < 0) {
THROW(ERR, "Can't Seek '%o' to negative target %i64", ivars->filename,
target);
}
// Seek within window if possible.
else if (target >= virtual_window_top
&& target <= virtual_window_end
) {
ivars->buf = fw_buf - fw_offset + ivars->offset + target;
}
else if (target > ivars->len) {
THROW(ERR, "Can't Seek '%o' past EOF (%i64 > %i64)", ivars->filename,
target, ivars->len);
}
else {
// Target is outside window. Set all buffer and limit variables to
// NULL to trigger refill on the next read. Store the file position
// in the FileWindow's offset.
FH_Release_Window(ivars->file_handle, window);
ivars->buf = NULL;
ivars->limit = NULL;
FileWindow_Set_Offset(window, ivars->offset + target);
}
}
static void
S_fill(InStream *self, int64_t amount) {
InStreamIVARS *const ivars = InStream_IVARS(self);
FileWindow *const window = ivars->window;
const int64_t virtual_file_pos = SI_tell(self);
const int64_t real_file_pos = virtual_file_pos + ivars->offset;
const int64_t remaining = ivars->len - virtual_file_pos;
// Throw an error if the requested amount would take us beyond EOF.
if (amount > remaining) {
THROW(ERR, "Read past EOF of %o (pos: %u64 len: %u64 request: %u64)",
ivars->filename, virtual_file_pos, ivars->len, amount);
}
// Make the request.
if (FH_Window(ivars->file_handle, window, real_file_pos, amount)) {
char *fw_buf = FileWindow_Get_Buf(window);
int64_t fw_offset = FileWindow_Get_Offset(window);
int64_t fw_len = FileWindow_Get_Len(window);
char *const window_limit = fw_buf + fw_len;
ivars->buf = fw_buf
- fw_offset // theoretical start of real file
+ ivars->offset // top of virtual file
+ virtual_file_pos; // position within virtual file
ivars->limit = window_limit - ivars->buf > remaining
? ivars->buf + remaining
: window_limit;
}
else {
Err *error = Err_get_error();
CB_catf(Err_Get_Mess(error), " (%o)", ivars->filename);
RETHROW(INCREF(error));
}
}
