span.h File Reference

Value-type views that fold the SDK's recurring argument shapes into single parameters, keeping every function at <=3 args without a calling cost: More...

#include "common/platform/sys/syscall.h"

Go to the source code of this file.

Data Structures
struct	wired_span
	Read-only view of a byte range. More...
struct	wired_mspan
	Mutable view of a byte range. More...
struct	wired_obuf
	Growing output buffer view for variable-length results. More...

Functions
static wired_span	wired_span_of (const u8 *p, usz n)
	Make a read-only span over p[0..n).
static wired_mspan	wired_mspan_of (u8 *p, usz n)
	Make a mutable span over p[0..n).
static wired_obuf	obuf_of (u8 *p, usz cap)
	Make an output buffer over p[0..cap) with len starting at 0.

Detailed Description

Value-type views that fold the SDK's recurring argument shapes into single parameters, keeping every function at <=3 args without a calling cost:

(const u8 *p, usz n) -> wired_span (by value: 16 bytes, two (u8 *p, usz n) -> wired_mspan registers under SysV, the same as the loose pair) (u8 *out, usz cap, usz *out_len)-> wired_obuf * (one register instead of three; callee fills .len)

These are views, not owners: a span never copies and never frees. The caller's buffer must stay alive for as long as the span (or anything the span was handed to) is in use. Build them with the wired_span_of / wired_mspan_of / obuf_of constructors below.

Function Documentation

obuf_of()

wired_obuf obuf_of ( u8 * p, usz cap )

inlinestatic

Make an output buffer over p[0..cap) with len starting at 0.

The buffer borrows p; the storage must outlive every use of the returned value. Pass its address to the producing call and read .len afterwards: wired_obuf ob = obuf_of(buf, sizeof buf); ... use ob.len.

Parameters

p	caller-provided storage
cap	capacity of p in bytes

Returns

the buffer view with len = 0

wired_mspan_of()

wired_mspan wired_mspan_of ( u8 * p, usz n )

inlinestatic

Make a mutable span over p[0..n).

The span borrows p; the buffer must outlive every use of the returned value. Example: wired_mspan out = wired_mspan_of(key, sizeof key);

Parameters

p	first byte of the writable range
n	number of writable bytes

Returns

the view as a value type

wired_span_of()

wired_span wired_span_of ( const u8 * p, usz n )

inlinestatic

Make a read-only span over p[0..n).

The span borrows p; the buffer must outlive every use of the returned value. Example: wired_span msg = wired_span_of(buf, buf_len);

Parameters

p	first byte of the range (may be 0 when n is 0)
n	number of readable bytes

Returns

the view as a value type