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rippled/include/xrpl/protocol/StructuredData.h
2026-09-11 22:58:58 -04:00

79 lines
2.6 KiB
C++

#pragma once
#include <xrpl/basics/Slice.h>
#include <cstddef>
#include <cstdint>
namespace xrpl {
/**
* Structural validation for MPTStructuredData schemas and data.
*
* A schema is a sequence of one-byte type codes describing a packed
* record layout. Data is the corresponding values packed back-to-back
* in schema order: big-endian integers, VL-prefixed str/bin (standard
* XRPL variable-length encoding, byte counts), arrays as a one-byte
* element count followed by that many elements, and tuples with no
* framing of their own (the markers exist only in the schema).
*
* These functions validate structure only. No values are materialized
* and no semantic checks are performed beyond the bool 0x00/0x01 rule.
*/
/**
* Schema type codes. Codes not listed here are reserved and malformed.
*/
enum class SchemaType : std::uint8_t {
boolean = 0x01, // 1 byte, 0x00 or 0x01
u8 = 0x02, // 1 byte
u16 = 0x03, // 2 bytes, big-endian
u32 = 0x04, // 4 bytes, big-endian
u64 = 0x05, // 8 bytes, big-endian
u128 = 0x06, // 16 bytes
u256 = 0x07, // 32 bytes
xfl = 0x08, // 8 bytes, XLS-17 floating point
account = 0x09, // 20 bytes, AccountID
currency = 0x0A, // 20 bytes, 160-bit currency code
h160 = 0x0B, // 20 bytes
h256 = 0x0C, // 32 bytes
pubkey = 0x0D, // 33 bytes, compressed public key
str = 0x0E, // VL prefix + UTF-8 bytes
bin = 0x0F, // VL prefix + opaque bytes
array = 0x20, // followed by one element type; data: count byte + elements
tupleOpen = 0x30,
tupleClose = 0x31,
};
/**
* Maximum array/tuple nesting depth a schema may declare.
*/
constexpr std::size_t kMaxSchemaDepth = 8;
/**
* Check that a schema is well-formed.
*
* Well-formed means: non-empty, no longer than kMaxSchemaLength, every
* code is a known SchemaType, every array code is followed by an
* element type, every tupleOpen has a matching tupleClose, and nesting
* does not exceed kMaxSchemaDepth.
*/
[[nodiscard]] bool
isWellFormedSchema(Slice schema);
/**
* Check that data decodes exactly against a well-formed schema.
*
* Walks both inputs with two cursors. Every field must be present at
* its declared width (VL-prefixed for str/bin), array counts must be
* consistent with the remaining input, and both cursors must end
* exactly exhausted: truncated data and trailing bytes both fail.
*
* The schema is re-validated during the walk, so a malformed schema
* returns false rather than misreading data.
*/
[[nodiscard]] bool
dataMatchesSchema(Slice schema, Slice data);
} // namespace xrpl