1 | use std::ops::{Add, RangeBounds, Sub}; |
2 | |
3 | use crate::{ |
4 | grid::config::Entity, |
5 | grid::records::{ExactRecords, Records}, |
6 | settings::object::{cell::EntityOnce, Object}, |
7 | }; |
8 | |
9 | use super::util::bounds_to_usize; |
10 | |
11 | /// Row denotes a set of cells on given rows on a [`Table`]. |
12 | /// |
13 | /// [`Table`]: crate::Table |
14 | #[derive (Debug)] |
15 | pub struct Rows<R> { |
16 | range: R, |
17 | } |
18 | |
19 | impl<R> Rows<R> { |
20 | /// Returns a new instance of [`Rows`] for a range of rows. |
21 | /// |
22 | /// If the boundaries are exceeded it may panic. |
23 | pub fn new(range: R) -> Self |
24 | where |
25 | R: RangeBounds<usize>, |
26 | { |
27 | Self { range } |
28 | } |
29 | |
30 | pub(crate) const fn get_range(&self) -> &R { |
31 | &self.range |
32 | } |
33 | } |
34 | |
35 | impl Rows<()> { |
36 | /// Returns a new instance of [`Rows`] with a single row. |
37 | /// |
38 | /// If the boundaries are exceeded it may panic. |
39 | pub const fn single(index: usize) -> Row { |
40 | Row { index } |
41 | } |
42 | |
43 | /// Returns a first row [`Object`]. |
44 | /// |
45 | /// If the table has 0 rows returns an empty set of cells. |
46 | pub const fn first() -> FirstRow { |
47 | FirstRow |
48 | } |
49 | |
50 | /// Returns a last row [`Object`]. |
51 | /// |
52 | /// If the table has 0 rows returns an empty set of cells. |
53 | pub const fn last() -> LastRow { |
54 | LastRow |
55 | } |
56 | } |
57 | |
58 | impl<I, R> Object<I> for Rows<R> |
59 | where |
60 | R: RangeBounds<usize>, |
61 | I: ExactRecords, |
62 | { |
63 | type Iter = RowsIter; |
64 | |
65 | fn cells(&self, records: &I) -> Self::Iter { |
66 | let start: Bound<&usize> = self.range.start_bound(); |
67 | let end: Bound<&usize> = self.range.end_bound(); |
68 | let max: usize = records.count_rows(); |
69 | let (x: usize, y: usize) = bounds_to_usize(left:start, right:end, count_elements:max); |
70 | |
71 | RowsIter::new(start:x, end:y) |
72 | } |
73 | } |
74 | |
75 | /// A row which is located by an offset from the first row. |
76 | #[derive (Debug, Clone, Copy)] |
77 | pub struct Row { |
78 | index: usize, |
79 | } |
80 | |
81 | impl<I> Object<I> for Row { |
82 | type Iter = EntityOnce; |
83 | |
84 | fn cells(&self, _: &I) -> Self::Iter { |
85 | EntityOnce::new(entity:Some(Entity::Row(self.index))) |
86 | } |
87 | } |
88 | |
89 | impl From<Row> for usize { |
90 | fn from(val: Row) -> Self { |
91 | val.index |
92 | } |
93 | } |
94 | |
95 | /// This structure represents the first row of a [`Table`]. |
96 | /// It's often contains headers data. |
97 | /// |
98 | /// [`Table`]: crate::Table |
99 | #[derive (Debug)] |
100 | pub struct FirstRow; |
101 | |
102 | impl<I> Object<I> for FirstRow |
103 | where |
104 | I: Records + ExactRecords, |
105 | { |
106 | type Iter = EntityOnce; |
107 | |
108 | fn cells(&self, records: &I) -> Self::Iter { |
109 | if records.count_columns() == 0 || records.count_rows() == 0 { |
110 | return EntityOnce::new(entity:None); |
111 | } |
112 | |
113 | EntityOnce::new(entity:Some(Entity::Row(0))) |
114 | } |
115 | } |
116 | |
117 | impl Add<usize> for FirstRow { |
118 | type Output = Row; |
119 | |
120 | fn add(self, rhs: usize) -> Self::Output { |
121 | Row { index: rhs } |
122 | } |
123 | } |
124 | |
125 | /// This structure represents the last row of a [`Table`]. |
126 | /// |
127 | /// [`Table`]: crate::Table |
128 | #[derive (Debug)] |
129 | pub struct LastRow; |
130 | |
131 | impl<I> Object<I> for LastRow |
132 | where |
133 | I: Records + ExactRecords, |
134 | { |
135 | type Iter = EntityOnce; |
136 | |
137 | fn cells(&self, records: &I) -> Self::Iter { |
138 | let count_rows: usize = records.count_rows(); |
139 | if records.count_columns() == 0 || count_rows == 0 { |
140 | return EntityOnce::new(entity:None); |
141 | } |
142 | |
143 | let row: usize = if count_rows == 0 { 0 } else { count_rows - 1 }; |
144 | |
145 | EntityOnce::new(entity:Some(Entity::Row(row))) |
146 | } |
147 | } |
148 | |
149 | impl Sub<usize> for LastRow { |
150 | type Output = LastRowOffset; |
151 | |
152 | fn sub(self, rhs: usize) -> Self::Output { |
153 | LastRowOffset { offset: rhs } |
154 | } |
155 | } |
156 | |
157 | /// A row which is located by an offset from the last row. |
158 | #[derive (Debug)] |
159 | pub struct LastRowOffset { |
160 | offset: usize, |
161 | } |
162 | |
163 | impl<I> Object<I> for LastRowOffset |
164 | where |
165 | I: Records + ExactRecords, |
166 | { |
167 | type Iter = EntityOnce; |
168 | |
169 | fn cells(&self, records: &I) -> Self::Iter { |
170 | let count_rows: usize = records.count_rows(); |
171 | if records.count_columns() == 0 || count_rows == 0 { |
172 | return EntityOnce::new(entity:None); |
173 | } |
174 | |
175 | let row: usize = if count_rows == 0 { 0 } else { count_rows - 1 }; |
176 | if self.offset > row { |
177 | return EntityOnce::new(entity:None); |
178 | } |
179 | |
180 | let row: usize = row - self.offset; |
181 | EntityOnce::new(entity:Some(Entity::Row(row))) |
182 | } |
183 | } |
184 | |
185 | /// An [`Iterator`] which goes goes over all rows of a [`Table`]. |
186 | /// |
187 | /// [`Table`]: crate::Table |
188 | #[derive (Debug)] |
189 | pub struct RowsIter { |
190 | start: usize, |
191 | end: usize, |
192 | } |
193 | |
194 | impl RowsIter { |
195 | const fn new(start: usize, end: usize) -> Self { |
196 | Self { start, end } |
197 | } |
198 | } |
199 | |
200 | impl Iterator for RowsIter { |
201 | type Item = Entity; |
202 | |
203 | fn next(&mut self) -> Option<Self::Item> { |
204 | if self.start >= self.end { |
205 | return None; |
206 | } |
207 | |
208 | let col: usize = self.start; |
209 | self.start += 1; |
210 | |
211 | Some(Entity::Row(col)) |
212 | } |
213 | } |
214 | |