tiny.machine.profile.capacity

1const std = @import("std");2const profile = @import("root.zig");34/// The ten bounded resources one profile pins, so a caller names one to ask for5/// its bound: instances, checkpoint candidates, admissions, request records, event6/// records, and the byte bounds for terminal, entropy, semantic, effect-request,7/// and effect-result payloads.8pub const Capacity = enum(u8) {9    instances,10    checkpoint_candidates,11    admissions,12    request_records,13    event_records,14    terminal_bytes,15    entropy_bytes,16    semantic_bytes,17    effect_request_bytes,18    effect_result_bytes,19};2021/// A requested value per bounded resource, held as one fixed array with a getter22/// and a setter so a caller fills one in to have a whole set of requests checked23/// at once. Every value starts at zero.24pub const Usage = struct {25    values: [std.meta.tags(Capacity).len]u32 = @splat(0),2627    pub fn get(self: Usage, kind: Capacity) u32 {28        return self.values[@backingInt(kind)];29    }3031    pub fn set(self: *Usage, kind: Capacity, value: u32) void {32        self.values[@backingInt(kind)] = value;33    }34};3536/// Returns the contract's bound for one resource, so a caller sizes a buffer before37/// asking for anything. Each bound is read straight from the contract, either from38/// a limit field or from the transport sizes.39pub fn capacity(value: profile.Profile, kind: Capacity) u32 {40    return switch (kind) {41        .instances => value.contract.instance_limit,42        .checkpoint_candidates => value.contract.checkpoint_candidate_limit,43        .admissions => value.contract.admission_limit,44        .request_records => value.contract.transport.request_records,45        .event_records => value.contract.transport.event_records,46        .terminal_bytes => value.contract.transport.terminal_bytes,47        .entropy_bytes => value.contract.transport.entropy_bytes,48        .semantic_bytes => value.contract.transport.semantic_bytes,49        .effect_request_bytes => value.contract.transport.effect_request_bytes,50        .effect_result_bytes => value.contract.transport.effect_result_bytes,51    };52}5354/// Checks the profile first, then refuses a request larger than the bound that profile55/// sets, so a caller checks a whole request set before committing to it. Every one56/// of the ten resources is checked, and the first one over its bound rejects.57pub fn usage(value: profile.Profile, requested: Usage) profile.Error!void {58    try profile.validate(value);59    for (std.meta.tags(Capacity)) |kind| {60        if (requested.get(kind) > capacity(value, kind)) {61            return error.CapacityExceeded;62        }63    }64}6566/// Checks the profile first, then refuses a geometry unequal to the one the contract67/// pins, so a caller proves its own memory layout matches the profile before constructing68/// an instance. The comparison covers all four fields, so a changed vCPU count,69/// page size, base address, or byte count rejects.70pub fn geometry(value: profile.Profile, requested: profile.Geometry) profile.Error!void {71    try profile.validate(value);72    if (!std.meta.eql(value.contract.geometry, requested)) {73        return error.IncompatibleGeometry;74    }75}

1pub const capacity = @import("capacity.zig");