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allaun
4f7c554981
New modules in formal/SilverSight/: - Schema.lean: Schema class with 6 type instances - WireFormat.lean: WireFormat structure + Layout enum - ProductSchema.lean: Schema (α × β) instance - ProductWireFormat.lean: Row-major pair encoders - Receipt.lean: Receipt structure + GateType enum - Bind.lean: bindReceipt composition primitive Build: 3307 jobs, 0 errors (from Research Stack lake build SilverSight) All modules use Semantics.FixedPoint cross-project import.
74 lines
3.7 KiB
Text
74 lines
3.7 KiB
Text
import SilverSight.Schema
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namespace SilverSight
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open Semantics.FixedPoint
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-- ═══════════════════════════════════════════════════════════════════════════
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-- §1 Layout enum
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-- ═══════════════════════════════════════════════════════════════════════════
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/-- Layout describes how fields are arranged in a wire encoding.
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- `rowMajor`: fields stored in declaration order (a₀, a₁, …, b₀, b₁, …)
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- `columnar`: fields stored contiguously by field index (a₀, b₀, a₁, b₁, …) -/
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inductive Layout where
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| rowMajor
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| columnar
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deriving BEq, DecidableEq, Repr, Inhabited
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-- ═══════════════════════════════════════════════════════════════════════════
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-- §2 WireFormat structure
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-- ═══════════════════════════════════════════════════════════════════════════
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/-- A WireFormat certifies the encode/decode cycle for a type under a layout.
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The `encode_size` proof ensures every encoded value has exactly `Schema.byteSize α` bytes.
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The `roundTrip` proof ensures `decode (encode x) = some x` for all valid `x`. -/
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structure WireFormat (α : Type) [Schema α] (L : Layout) where
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encode : α → ByteArray
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decode : ByteArray → Option α
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encode_size : ∀ a : α, (encode a).size = Schema.byteSize α
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roundTrip : ∀ a : α, decode (encode a) = some a
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-- ═══════════════════════════════════════════════════════════════════════════
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-- §3 Basic WireFormat instances
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-- ═══════════════════════════════════════════════════════════════════════════
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/-- Encode a UInt8 as a single byte.
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Roundtrip: encoding then decoding recovers the original value. -/
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def uint8RowMajor : WireFormat UInt8 Layout.rowMajor where
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encode := fun u => ByteArray.mk #[u]
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decode := fun bs =>
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if h : bs.size = 1 then some (bs.get! 0)
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else none
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encode_size := by intro a; simp [ByteArray.size]
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roundTrip := by
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intro a
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simp only [ByteArray.size]
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have h1 : (ByteArray.mk #[a]).size = 1 := by simp [ByteArray.size]
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simp [h1]
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rfl
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#eval uint8RowMajor.encode 42 -- expected: ByteArray with single byte 42
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#eval uint8RowMajor.decode (uint8RowMajor.encode 42) -- expected: some 42
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/-- Encode a Bool as a single byte (0=false, 1=true).
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Uses revert + native_decide for the roundtrip proof since Bool is finite. -/
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def boolRowMajor : WireFormat Bool Layout.rowMajor where
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encode := fun b => ByteArray.mk #[if b then 1 else 0]
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decode := fun bs =>
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if h : bs.size = 1 then
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let b := bs.get! 0
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some (b != 0)
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else none
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encode_size := by intro a; simp [ByteArray.size]
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roundTrip := by
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intro a
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revert a
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native_decide
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#eval boolRowMajor.encode true -- expected: ByteArray with single byte 1
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#eval boolRowMajor.encode false -- expected: ByteArray with single byte 0
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#eval boolRowMajor.decode (boolRowMajor.encode true) -- expected: some true
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#eval boolRowMajor.decode (boolRowMajor.encode false) -- expected: some false
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end SilverSight
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