550 lines
15 KiB
Nim
550 lines
15 KiB
Nim
# SPDX-License-Identifier: ISC
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import base64, endians, json, hashes, sets, streams, tables
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import bigints
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type
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PreserveKind* = enum
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pkBoolean, pkFloat, pkDouble, pkSignedInteger, pkBigInteger, pkString,
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pkByteString, pkSymbol, pkRecord, pkSequence, pkSet, pkDictionary, pkEmbedded
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Preserve*[T] {.acyclic.} = object
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## Type that stores a Preserves value.
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## ``T`` is the domain-specific type of "embedded" values, otherwise ``void``.
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case kind*: PreserveKind
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of pkBoolean:
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bool*: bool
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of pkFloat:
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float*: float32
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of pkDouble:
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double*: float64
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of pkSignedInteger:
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int*: BiggestInt
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of pkBigInteger:
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bigint*: BigInt
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of pkString:
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string*: string
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of pkByteString:
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bytes*: seq[byte]
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of pkSymbol:
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symbol*: string
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of pkRecord:
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record*: seq[Preserve[T]] # record[0] is the label
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of pkSequence:
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seq*: seq[Preserve[T]]
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of pkSet:
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set*: HashSet[Preserve[T]]
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of pkDictionary:
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dict*: Table[Preserve[T], Preserve[T]]
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of pkEmbedded:
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embedded*: T
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proc `$`*[T](prs: Preserve[T]): string =
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case prs.kind:
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of pkBoolean:
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case prs.bool
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of false: result = "#f"
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of true: result = "#t"
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of pkFloat:
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result = $prs.float & "f"
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of pkDouble:
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result = $prs.double
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of pkSignedInteger:
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result = $prs.int
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of pkBigInteger:
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result = $prs.bigint
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of pkString:
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result = escapeJson(prs.string)
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of pkByteString:
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result.add("#[")
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result.add(base64.encode(prs.bytes))
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result.add(']')
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of pkSymbol:
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result.add(escapeJsonUnquoted(prs.symbol))
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of pkRecord:
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result.add('<')
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for val in prs.record:
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result.add(' ')
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result.add($val)
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result.add('>')
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of pkSequence:
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result.add('[')
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for i, val in prs.seq:
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if i > 0:
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result.add(' ')
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result.add($val)
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result.add(']')
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of pkSet:
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result.add("#{")
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for val in prs.set:
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result.add($val)
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result.add(' ')
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if result.len > 1:
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result.setLen(result.high)
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result.add('}')
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of pkDictionary:
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result.add('{')
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for (key, value) in prs.dict.pairs:
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result.add($key)
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result.add(" :")
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result.add($value)
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result.add(' ')
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if result.len > 1:
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result.setLen(result.high)
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result.add('}')
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of pkEmbedded:
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when not T is void:
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$prs.embedded
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proc toPreserve*(b: bool): Preserve[void] =
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Preserve[void](kind: pkBoolean, bool: b)
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proc toPreserve*(n: SomeInteger): Preserve[void] =
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Preserve[void](kind: pkSignedInteger, int: n.BiggestInt)
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proc toPreserve*(n: BigInt): Preserve[void] =
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if initBigInt(low(BiggestInt)) < n and n < initBigInt(high(BiggestInt)):
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var tmp: BiggestUint
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for limb in n.limbs:
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tmp = (tmp shl 32) or limb
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if Negative in n.flags:
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tmp = (not tmp) + 1
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result = Preserve[void](kind: pkSignedInteger, int: cast[BiggestInt](tmp))
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else:
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result = Preserve[void](kind: pkBigInteger, bigint: n)
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proc toPreserve*(s: string): Preserve[void] =
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Preserve[void](kind: pkString, string: s)
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proc symbol*[T](s: string): Preserve[void] {.inline.} =
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## Symbol constructor.
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Preserve[T](kind: pkSymbol, symbol: s)
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proc record*[T](label: Preserve[T], args: varargs[Preserve[T]]): Preserve[T] =
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## Record constructor.
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result = Preserve[T](kind: pkRecord, record: newSeqOfCap(1+args.len))
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result.record.add(label)
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for arg in args: result.record.add(arg)
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proc record*[T](label: string, args: varargs[Preserve[T]]): Preserve[T] {.inline.} =
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## Record constructor that converts ``label`` to a symbol.
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record(symbol[T](label), args)
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proc label*[T](prs: Preserve[T]): Preserve[T] {.inline.} =
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## Return the label of a record value.
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prs.record[0]
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proc arity*[T](prs: Preserve[T]): int {.inline.} =
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## Return the number of fields in a record value.
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pred(prs.record.len)
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proc fields*[T](prs: Preserve[T]): seq[Preserve[T]] {.inline.} =
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## Return the fields of a record value.
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prs.record[1..prs.record.high]
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iterator fields*[T](prs: Preserve[T]): Preserve[T] =
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## Iterate the fields of a record value.
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for i in 1..prs.record.high: yield prs.record[i]
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iterator setItems*[T](prs: Preserve[T]): Preserve[T] =
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for v in prs.set.keys: yield v
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proc `<`(x, y: string | seq[byte]): bool =
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for i in 0 .. min(x.high, y.high):
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if x[i] < y[i]:
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return true
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x.len < y.len
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proc `<`*[T](x, y: Preserve[T]): bool =
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if x.kind != y.kind:
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if x.kind == pkSignedInteger and y.kind == pkBigInteger:
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result = x.int < y.bigint
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elif x.kind == pkBigInteger and y.kind == pkSignedInteger:
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result = x.bigint < y.int
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else:
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result = x.kind < y.kind
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else:
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case x.kind
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of pkBoolean:
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result = (not x.bool) and y.bool
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of pkSignedInteger:
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result = x.int < y.int
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of pkBigInteger:
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result = x.bigint < y.bigint
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of pkString:
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result = x.string < y.string
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of pkByteString:
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result = x.bytes < y.bytes
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of pkSymbol:
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result = x.symbol < y.symbol
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else:
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discard
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proc `==`*[T](x, y: Preserve[T]): bool =
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if x.kind == y.kind:
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case x.kind
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of pkBoolean:
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result = x.bool == y.bool
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of pkFloat:
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result = x.float == y.float
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of pkDouble:
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result = x.double == y.double
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of pkSignedInteger:
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result = x.int == y.int
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of pkBigInteger:
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result = x.bigint == y.bigint
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of pkString:
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result = x.string == y.string
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of pkByteString:
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result = x.bytes == y.bytes
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of pkSymbol:
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result = x.symbol == y.symbol
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of pkRecord:
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for i, val in x.record:
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if y.record[i] != val: return false
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result = true
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of pkSequence:
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for i, val in x.seq:
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if y.seq[i] != val: return false
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result = true
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of pkSet:
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for val in x.set:
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if not y.set.contains(val): return false
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for val in y.set:
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if not x.set.contains(val): return false
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result = true
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of pkDictionary:
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for (key, val) in x.dict.pairs:
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if y.dict[key] != val: return false
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result = true
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of pkEmbedded:
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when not T is void:
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result = x.embedded == y.embedded
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proc hash*[T](prs: Preserve[T]): Hash =
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var h = hash(prs.kind.int)
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case prs.kind
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of pkBoolean:
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h = h !& hash(prs.bool)
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of pkFloat:
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h = h !& hash(prs.float)
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of pkDouble:
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h = h !& hash(prs.double)
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of pkSignedInteger:
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h = h !& hash(prs.int)
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of pkBigInteger:
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h = h !& hash(prs.bigint.flags)
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h = h !& hash(prs.bigint)
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of pkString:
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h = h !& hash(prs.string)
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of pkByteString:
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h = h !& hash(prs.bytes)
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of pkSymbol:
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h = h !& hash(prs.symbol)
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of pkRecord:
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for val in prs.record:
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h = h !& hash(val)
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of pkSequence:
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for val in prs.seq:
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h = h !& hash(val)
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of pkSet:
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for val in prs.set:
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h = h !& hash(val)
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of pkDictionary:
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for (key, val) in prs.dict.pairs:
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h = h !& hash(val)
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of pkEmbedded:
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when not T is void:
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h = h !& hash(prs.embedded)
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!$h
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proc writeVarint(s: Stream; n: int) =
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var n = n
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while true:
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let c = int8(n and 0x7f)
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n = n shr 7
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if n == 0:
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s.write((char)c.char)
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break
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else:
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s.write((char)c or 0x80)
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proc readVarint(s: Stream): int =
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var shift: int
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while shift < (9*8):
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let c = s.readChar.int
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result = result or ((c and 0x7f) shl shift)
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if (c and 0x80) == 0:
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break
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shift.inc 7
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proc write*[T](str: Stream; prs: Preserve[T]) =
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case prs.kind:
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of pkBoolean:
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case prs.bool
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of false: str.write(0x80'u8)
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of true: str.write(0x81'u8)
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of pkFloat:
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str.write(0x82'u8)
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when system.cpuEndian == bigEndian:
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str.write(prs.float)
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else:
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var be: float32
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swapEndian32(be.addr, prs.float.unsafeAddr)
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str.write(be)
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of pkDouble:
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str.write(0x83'u8)
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when system.cpuEndian == bigEndian:
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str.write(prs.double)
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else:
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var be: float64
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swapEndian64(be.addr, prs.double.unsafeAddr)
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str.write(be)
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of pkSignedInteger:
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if (-3 <= prs.int) and (prs.int <= 12):
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str.write(0x90'i8 or int8(if prs.int < 0: prs.int + 16 else: prs.int))
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else:
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var bitCount = 1'u8
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if prs.int < 0:
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while ((not prs.int) shr bitCount) != 0:
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inc(bitCount)
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else:
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while (prs.int shr bitCount) != 0:
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inc(bitCount)
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var byteCount = (bitCount + 8) div 8
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str.write(0xa0'u8 or (byteCount - 1))
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proc write(n: uint8; i: BiggestInt) =
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if n > 0:
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write(n.pred, i shr 8)
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str.write(i.uint8)
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write(byteCount, prs.int)
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of pkBigInteger:
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doAssert(Negative notin prs.bigint.flags, "negative big integers not implemented")
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var bytes = newSeqOfCap[uint8](prs.bigint.limbs.len * 4)
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var begun = false
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for i in countdown(prs.bigint.limbs.high, 0):
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let limb = prs.bigint.limbs[i]
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for j in countdown(24, 0, 8):
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let b = uint8(limb shr j)
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begun = begun or (b != 0)
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if begun:
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bytes.add(b)
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if bytes.len <= 16:
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str.write(0xa0'u8 or bytes.high.uint8)
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else:
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str.write(0xb0'u8)
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str.writeVarint(bytes.len)
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str.write(cast[string](bytes))
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of pkString:
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str.write(0xb1'u8)
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str.writeVarint(prs.string.len)
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str.write(prs.string)
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of pkByteString:
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str.write(0xb2'u8)
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str.writeVarint(prs.bytes.len)
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str.write(prs.bytes)
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of pkSymbol:
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str.write(0xb3'u8)
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str.writeVarint(prs.symbol.len)
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str.write(prs.symbol)
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of pkRecord:
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str.write(0xb4'u8)
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for val in prs.record:
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str.write(val)
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str.write(0x84'u8)
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of pkSequence:
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str.write(0xb5'u8)
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for e in prs.seq:
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str.write(e)
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str.write(0x84'u8)
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of pkSet:
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str.write(0xb6'u8)
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for val in prs.set.items:
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str.write(val)
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str.write(0x84'u8)
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of pkDictionary:
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str.write(0xb7'u8)
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for (key, value) in prs.dict.pairs:
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str.write(key)
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str.write(value)
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str.write(0x84'u8)
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of pkEmbedded:
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when not T is void:
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str.write(0x86'u8)
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str.write(prs.embedded)
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proc parsePreserve*(s: Stream): Preserve[void] =
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proc assertStream(check: bool) =
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if not check:
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raise newException(ValueError, "invalid Preserves stream")
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const endMarker = 0x84
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let tag = s.readUint8()
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case tag
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of 0x80: result = Preserve[void](kind: pkBoolean, bool: false)
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of 0x81: result = Preserve[void](kind: pkBoolean, bool: true)
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of 0x82:
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when system.cpuEndian == bigEndian:
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result = Preserve[void](kind: pkFloat, float: s.readFloat32())
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else:
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result = Preserve[void](kind: pkFloat)
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var be = s.readFloat32()
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swapEndian32(result.float.addr, be.addr)
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of 0x83:
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when system.cpuEndian == bigEndian:
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result = Preserve[void](kind: pkDouble, double: s.readFloat64())
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else:
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result = Preserve[void](kind: pkDouble)
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var be = s.readFloat64()
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swapEndian64(result.double.addr, be.addr)
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of 0x84:
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assertStream(false)
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of 0xb1:
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result = Preserve[void](kind: pkString)
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let len = s.readVarint()
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result.string = s.readStr(len)
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of 0xb2:
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result = Preserve[void](kind: pkByteString)
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let len = s.readVarint()
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result.bytes = cast[seq[byte]](s.readStr(len))
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of 0xb3:
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let len = s.readVarint()
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result = symbol[void](s.readStr(len))
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of 0xb4:
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result = Preserve[void](kind: pkRecord)
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while s.peekUint8() != endMarker:
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result.record.add(s.parsePreserve())
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discard s.readUint8()
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assertStream(result.record.len > 0)
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of 0xb5:
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result = Preserve[void](kind: pkSequence)
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while s.peekUint8() != endMarker:
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result.seq.add(s.parsePreserve())
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discard s.readUint8()
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of 0xb6:
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result = Preserve[void](kind: pkSet)
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while s.peekUint8() != endMarker:
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let val = s.parsePreserve()
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result.set.incl(val)
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discard s.readUint8()
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of 0xb7:
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result = Preserve[void](kind: pkDictionary)
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while s.peekUint8() != endMarker:
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let key = s.parsePreserve()
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let val = s.parsePreserve()
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result.dict[key] = val
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discard s.readUint8()
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of 0xb0:
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let len = s.readVarint()
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result = Preserve[void](kind: pkBigInteger)
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for _ in 1..len:
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result.bigint = (result.bigint shl 8) + s.readUint8().int32
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else:
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case 0xf0 and tag
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of 0x90:
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var n = tag.BiggestInt
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result = Preserve[void](kind: pkSignedInteger,
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int: n - (if n > 0x9c: 0xa0 else: 0x90))
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of 0xa0:
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let len = (tag.int and 0x0f) + 1
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if len <= 8:
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result = Preserve[void](kind: pkSignedInteger, int: s.readUint8().BiggestInt)
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if (result.int and 0x80) != 0: result.int.dec(0x100)
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for i in 1..<len:
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result.int = (result.int shl 8) or s.readUint8().BiggestInt
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else:
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result = Preserve[void](kind: pkBigInteger)
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for i in 0..<len:
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result.bigint = (result.bigint shl 8) + s.readUint8().int32
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else:
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assertStream(false)
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proc toPreserve*(js: JsonNode): Preserve[void] =
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case js.kind
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of JString:
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result = js.str.toPreserve
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of JInt:
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result = Preserve[void](kind: pkSignedInteger, int: js.num)
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of JFloat:
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result = Preserve[void](kind: pkDouble, double: js.fnum)
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of JBool:
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result = case js.bval
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of false: symbol[void]"false"
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of true: symbol[void]"true"
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of JNull:
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result = symbol[void]"null"
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of JObject:
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result = Preserve[void](kind: pkDictionary)
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for key, val in js.fields.pairs:
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result.dict[key.toPreserve] = val.toPreserve
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of JArray:
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result = Preserve[void](kind: pkSequence, seq: newSeq[Preserve[void]](
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js.elems.len))
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for i, e in js.elems:
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result.seq[i] = e.toPreserve
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proc toJson*[T](prs: Preserve[T]): JsonNode =
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case prs.kind:
|
|
of pkBoolean:
|
|
result = newJBool(prs.bool)
|
|
of pkFloat:
|
|
result = newJFloat(prs.float)
|
|
of pkDouble:
|
|
result = newJFloat(prs.double)
|
|
of pkSignedInteger:
|
|
result = newJInt(prs.int)
|
|
of pkBigInteger:
|
|
raise newException(ValueError, "cannot convert big integer to JSON")
|
|
of pkString:
|
|
result = newJString(prs.string)
|
|
of pkByteString:
|
|
raise newException(ValueError, "cannot convert bytes to JSON")
|
|
of pkSymbol:
|
|
case prs.symbol
|
|
of "false":
|
|
result = newJBool(false)
|
|
of "true":
|
|
result = newJBool(true)
|
|
of "null":
|
|
result = newJNull()
|
|
else:
|
|
raise newException(ValueError, "cannot convert symbol to JSON")
|
|
of pkRecord:
|
|
raise newException(ValueError, "cannot convert record to JSON")
|
|
of pkSequence:
|
|
result = newJArray()
|
|
for val in prs.seq:
|
|
result.add(val.toJSON)
|
|
of pkSet:
|
|
raise newException(ValueError, "cannot convert set to JSON")
|
|
of pkDictionary:
|
|
result = newJObject()
|
|
for (key, val) in prs.dict.pairs:
|
|
if key.kind != pkString:
|
|
raise newException(ValueError, "cannot convert non-string dictionary key to JSON")
|
|
result[key.string] = val.toJson
|
|
of pkEmbedded:
|
|
raise newException(ValueError, "cannot convert embedded value to JSON")
|
|
|
|
type Record* = object
|
|
## Type of a preserves record type.
|
|
label*: string
|
|
arity*: Natural
|
|
|
|
proc init*[T](rec: Record, fields: varargs[Preserve[T]]): Preserve[T] =
|
|
## Initialize a new record value.
|
|
assert(fields.len == rec.arity)
|
|
record(rec.label, fields)
|
|
|
|
proc isClassOf*[T](rec: Record, val: Preserve[T]): bool =
|
|
## Compare the label and arity of ``val`` to the record type ``rec``.
|
|
if val.kind == pkRecord:
|
|
let label = val.label
|
|
if label.kind == pkSymbol:
|
|
result = label.symbol == rec.label and rec.arity == val.arity
|
|
|
|
proc classOf*[T](val: Preserve[T]): Record =
|
|
## Derive the ``Record`` type of ``val``.
|
|
if val.kind != pkRecord or val.label.kind == pkSymbol:
|
|
raise newException(ValueError, "cannot derive class of non-record value")
|
|
Record(label: val.label.symbol, arity: val.arity)
|