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|
#[derive(Clone, Debug)]
pub struct JoshutoPageState {
pub start: usize,
pub end: usize,
}
impl JoshutoPageState {
pub fn update_page_state(
&mut self,
index: usize,
win_rows: i32,
vec_len: usize,
offset: usize,
) {
if self.end != self.start + win_rows as usize {
self.end = self.start + win_rows as usize;
}
if self.end > vec_len {
self.end = vec_len
}
if self.start + offset >= index {
self.start = if index as usize <= offset {
0
} else {
index as usize - offset
};
self.end = if self.start + win_rows as usize >= vec_len {
vec_len
} else {
self.start + win_rows as usize
};
self.start = if self.end <= win_rows as usize {
0
} else {
self.end - win_rows as usize
};
}
if self.end <= index + offset {
self.end = if index as usize + offset >= vec_len {
vec_len
} else {
index as usize + offset
};
self.start = if self.end <= win_rows as usize {
0
} else {
self.end - win_rows as usize
};
self.end = if self.start + win_rows as usize >= vec_len {
vec_len
} else {
self.start + win_rows as usize
};
}
}
}
impl std::default::Default for JoshutoPageState {
fn default() -> Self {
JoshutoPageState {
start: usize::default(),
end: usize::default(),
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn shorter_than_viewable_region() {
let mut page_state = JoshutoPageState::new();
let index = 5;
let win_rows = 37;
let vec_len = 12;
let offset = 6;
page_state.update_page_state(index, win_rows, vec_len, offset);
assert_eq!(0, page_state.start);
assert_eq!(12, page_state.end);
let index = 30;
let win_rows = 37;
let vec_len = 12;
let offset = 6;
page_state.update_page_state(index, win_rows, vec_len, offset);
assert_eq!(0, page_state.start);
assert_eq!(12, page_state.end);
}
#[test]
fn test_01() {
let mut page_state = JoshutoPageState::new();
let index = 3;
let win_rows = 25;
let vec_len = 40;
let offset = 6;
page_state.update_page_state(index, win_rows, vec_len, offset);
assert_eq!(0, page_state.start);
assert_eq!(25, page_state.end);
}
#[test]
fn test_02() {
let mut page_state = JoshutoPageState::new();
let index = 12;
let win_rows = 25;
let vec_len = 40;
let offset = 6;
page_state.update_page_state(index, win_rows, vec_len, offset);
assert_eq!(0, page_state.start);
assert_eq!(25, page_state.end);
}
#[test]
fn test_inside_top_offset() {
let mut page_state = JoshutoPageState::new();
page_state.start = 10;
let index = 12;
let win_rows = 25;
let vec_len = 40;
let offset = 6;
page_state.update_page_state(index, win_rows, vec_len, offset);
assert_eq!(6, page_state.start);
assert_eq!(31, page_state.end);
}
#[test]
fn test_inside_bottom_offset() {
let mut page_state = JoshutoPageState::new();
page_state.start = 36;
let index = 34;
let win_rows = 25;
let vec_len = 40;
let offset = 6;
page_state.update_page_state(index, win_rows, vec_len, offset);
assert_eq!(15, page_state.start);
assert_eq!(40, page_state.end);
}
#[test]
fn test_small_size() {
let mut page_state = JoshutoPageState::new();
let index = 3;
let win_rows = 6;
let vec_len = 6;
let offset = 6;
page_state.update_page_state(index, win_rows, vec_len, offset);
assert_eq!(0, page_state.start);
assert_eq!(6, page_state.end);
let index = 0;
let win_rows = 6;
let vec_len = 6;
let offset = 6;
page_state.update_page_state(index, win_rows, vec_len, offset);
assert_eq!(0, page_state.start);
assert_eq!(6, page_state.end);
let index = 6;
let win_rows = 6;
let vec_len = 6;
let offset = 6;
page_state.update_page_state(index, win_rows, vec_len, offset);
assert_eq!(0, page_state.start);
assert_eq!(6, page_state.end);
}
#[test]
fn test_negative() {
let mut page_state = JoshutoPageState::new();
page_state.start = 10;
page_state.end = 5;
let index = 7;
let win_rows = 30;
let vec_len = 35;
let offset = 6;
page_state.update_page_state(index, win_rows, vec_len, offset);
assert_eq!(1, page_state.start);
assert_eq!(31, page_state.end);
}
}
|
