Struct AllocatedRange

Source

pub struct AllocatedRange { /* private fields */ }

Expand description

Allocated file range

已分配的文件范围

Represents a valid range [start, end) allocated through RangeAllocator. This type can only be created through the allocator, guaranteeing that all ranges are non-overlapping.

表示通过 RangeAllocator 分配的有效范围 [start, end)。此类型只能通过分配器创建，保证所有范围不重叠。

§Range Format

Uses half-open interval [start, end):

start: Inclusive start position
end: Exclusive end position

For example: AllocatedRange { start: 0, end: 10 } represents bytes 0-9 (10 bytes total)

§范围格式

使用左闭右开区间 [start, end)：

start: 包含的起始位置
end: 不包含的结束位置

例如：AllocatedRange { start: 0, end: 10 } 表示字节 0-9（共 10 字节）

§Safety Guarantees

start is always ≤ end
Can only be created through the allocator, preventing overlaps
Provides immutable access, preventing modification

§安全性保证

start 总是小于等于 end
只能通过分配器创建，防止重叠
提供不可变访问，防止修改

§Examples

let (file, mut allocator) = MmapFile::create_default(&path, NonZeroU64::new(ALIGNMENT).unwrap())?;
let range = allocator.allocate(NonZeroU64::new(ALIGNMENT).unwrap()).unwrap();

// Get range information (4K aligned)
// 获取范围信息（4K对齐）
assert_eq!(range.start(), 0);
assert_eq!(range.end(), ALIGNMENT);
assert_eq!(range.len(), ALIGNMENT);

let (start, end) = range.as_range_tuple();
assert_eq!(start, 0);
assert_eq!(end, ALIGNMENT);

Implementations§

Source §

impl AllocatedRange

Source

pub fn start(&self) -> u64

Get the start position

获取起始位置

§Returns

The start position of the range (inclusive)

§返回值

返回范围的起始位置（包含）

Source

pub fn end(&self) -> u64

Get the end position

获取结束位置

§Returns

The end position of the range (exclusive)

§返回值

返回范围的结束位置（不包含）

Source

pub fn len(&self) -> u64

Get the length of the range in bytes

获取范围的长度（字节数）

Source

pub fn is_empty(&self) -> bool

Check if the range is empty

检查范围是否为空

Source

pub fn split_at_align_up(&self, pos: u64) -> SplitUpResult

Split the range at the given relative position with 4K upper alignment

在给定相对位置以4K上对齐方式拆分范围

The split point is calculated as align_up(start + pos).

分割点计算为 align_up(start + pos)。

§Parameters

pos: Relative offset from the start of the range.

§Returns

SplitUpResult::Split { low, high }: Successfully split into [start, split) and [split, end)
SplitUpResult::Low: Only low range exists (split point >= end)
SplitUpResult::OutOfBounds: Position exceeds range length (pos > len)

§参数

pos: 从范围起始位置开始的相对偏移量。

§返回值

SplitUpResult::Split { low, high }: 成功拆分为 [start, split) 和 [split, end)
SplitUpResult::Low: 仅存在低范围（分割点 >= end）
SplitUpResult::OutOfBounds: 位置超出范围长度 (pos > len)

§Examples

let range = AllocatedRange::from_range_unchecked(0, 8192);
match range.split_at_align_up(100) {
    SplitUpResult::Split { low, high } => {
        assert_eq!(low.end(), 4096);  // Aligned up from 100
        assert_eq!(high.start(), 4096);
    }
    _ => panic!("expected split"),
}

Source

pub fn split_at_align_down(&self, pos: u64) -> SplitDownResult

Split the range at the given relative position with 4K lower alignment

在给定相对位置以4K下对齐方式拆分范围

The split point is calculated as align_down(start + pos).

分割点计算为 align_down(start + pos)。

§Parameters

pos: Relative offset from the start of the range.

§Returns

SplitDownResult::Split { low, high }: Successfully split into [start, split) and [split, end)
SplitDownResult::High: Only high range exists (split point <= start)
SplitDownResult::OutOfBounds: Position exceeds range length (pos > len)

§参数

pos: 从范围起始位置开始的相对偏移量。

§返回值

SplitDownResult::Split { low, high }: 成功拆分为 [start, split) 和 [split, end)
SplitDownResult::High: 仅存在高范围（分割点 <= start）
SplitDownResult::OutOfBounds: 位置超出范围长度 (pos > len)

§Examples

let range = AllocatedRange::from_range_unchecked(0, 8192);
match range.split_at_align_down(5000) {
    SplitDownResult::Split { low, high } => {
        assert_eq!(low.end(), 4096);  // Aligned down from 5000
        assert_eq!(high.start(), 4096);
    }
    _ => panic!("expected split"),
}