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Usage of std::buffer

std::buffer provides variable byte buffers and generic buffers.

import​

import("std::buffer::types");
import("std::buffer::alloc");
import("std::buffer::read");
import("std::buffer::write");

1. Byte Buffer (Buffer)​

Create/Add/Modify​

fun main() {
 var buf: Buffer = buffer_new(128);

 buffer_append_str(&buf, "GET /health\n");
 buffer_push(&buf, 0);

 var first: u8 = buffer_at(buf, 0);
 var ok: bool = buffer_set(&buf, 0, 80); // 'P'

 buffer_free(&buf);
}

Core Functions​

fun buffer_new(capacity: i64) -> Buffer
fun buffer_reserve(buf: ptr<Buffer>, required_cap: i64) -> i64
fun buffer_push(buf: ptr<Buffer>, value: u8) -> i64
fun buffer_append(buf: ptr<Buffer>, src: ptr<u8>, size: i64) -> i64
fun buffer_append_str(buf: ptr<Buffer>, s: str) -> i64
fun buffer_at(buf: Buffer, index: i64) -> u8
fun buffer_set(buf: ptr<Buffer>, index: i64, value: u8) -> bool
fun buffer_free(buf: ptr<Buffer>) -> i64

2. Generic Buffer (TypedBuffer<T>)​

Wave does not have type inference, so type arguments must be specified.

fun main() {
 var nums: TypedBuffer<i32> = tbuffer_new<i32>(4, 16); // elem_size=4

 tbuffer_push<i32>(&nums, 10);
 tbuffer_push<i32>(&nums, 20);

 var out: i32 = 0;
 var got: bool = tbuffer_at<i32>(nums, 1, &out); // out = 20

 tbuffer_free<i32>(&nums);
}

Core Functions​

fun tbuffer_new<T>(elem_size: i64, initial_cap: i64) -> TypedBuffer<T>
fun tbuffer_reserve<T>(buf: ptr<TypedBuffer<T>>, required_len: i64) -> i64
fun tbuffer_push<T>(buf: ptr<TypedBuffer<T>>, value: T) -> i64
fun tbuffer_at<T>(buf: TypedBuffer<T>, index: i64, out_value: ptr<T>) -> bool
fun tbuffer_set<T>(buf: ptr<TypedBuffer<T>>, index: i64, value: T) -> bool
fun tbuffer_free<T>(buf: ptr<TypedBuffer<T>>) -> i64

Note:

  • elem_size must be set accurately by the caller.
  • Out-of-range access returns false or the default value (buffer_at returns 0).