Module vec 

Growable arrays backed by leased fabric memory.

This module provides two array types:

• FabricVec<T> stores elements in fixed-size slots within a single memory lease. When the lease is full, grow() acquires additional leases and chains them together. The push() method calls grow() automatically.

• VarFabricVec<T> stores variable-size elements using an index+heap layout. The index region holds fixed-size (offset, len) entries that point into a heap region where the actual serialized data lives. This avoids wasting space when element sizes vary widely.

FabricVec memory layout

Offset 0:  [header]  len: u64 (8 bytes) | capacity: u64 (8 bytes) | stride: u64 (8 bytes)
Offset 24: [data]    element 0 (stride bytes) | element 1 | ...

Each element slot is stride bytes wide, determined at construction time. Within each slot, the first 4 bytes store the serialized element length as a little-endian u32, followed by the postcard-serialized bytes. Variable-size types must fit within stride - 4 serialized bytes; exceeding it returns FabricError::CapacityExceeded.

When a FabricVec grows, additional leases are acquired and stored in an overflow chain. Elements in overflow regions are addressed by computing which region contains the target index.

VarFabricVec memory layout

Offset 0:  [header]       len: u64 (8) | index_cap: u64 (8) | heap_size: u64 (8) | heap_used: u64 (8)
Offset 32: [index region] entry 0 (12 bytes: offset u64 + len u32) | entry 1 | ...
After index: [heap region] variable-length serialized data packed contiguously

Examples

use grafos_collections::vec::FabricVec;
use grafos_std::mem::MemBuilder;

let lease = MemBuilder::new().min_bytes(4096).acquire()?;
let mut v: FabricVec<u32> = FabricVec::new(lease, 16)?;

v.push(&10)?;
v.push(&20)?;
assert_eq!(v.get(0)?, 10);
assert_eq!(v.pop()?, Some(20));

Structs

FabricVec

A growable array stored in leased fabric memory.

FabricVecIter

Iterator over elements of a FabricVec.

VarFabricVec

A vector that stores variable-size elements in leased fabric memory.

VarFabricVecIter

Iterator over elements of a VarFabricVec.