parquet_variant/
variant.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18pub use self::decimal::{VariantDecimal16, VariantDecimal4, VariantDecimal8};
19pub use self::list::VariantList;
20pub use self::metadata::{VariantMetadata, EMPTY_VARIANT_METADATA, EMPTY_VARIANT_METADATA_BYTES};
21pub use self::object::VariantObject;
22
23// Publically export types used in the API
24pub use half::f16;
25pub use uuid::Uuid;
26
27use crate::decoder::{
28    self, get_basic_type, get_primitive_type, VariantBasicType, VariantPrimitiveType,
29};
30use crate::path::{VariantPath, VariantPathElement};
31use crate::utils::{first_byte_from_slice, fits_precision, slice_from_slice};
32use std::ops::Deref;
33
34use arrow_schema::ArrowError;
35use chrono::{DateTime, NaiveDate, NaiveDateTime, NaiveTime, Timelike, Utc};
36
37mod decimal;
38mod list;
39mod metadata;
40mod object;
41
42const MAX_SHORT_STRING_BYTES: usize = 0x3F;
43
44/// A Variant [`ShortString`]
45///
46/// This implementation is a zero cost wrapper over `&str` that ensures
47/// the length of the underlying string is a valid Variant short string (63 bytes or less)
48#[derive(Debug, Clone, Copy, PartialEq)]
49pub struct ShortString<'a>(pub(crate) &'a str);
50
51impl<'a> ShortString<'a> {
52    /// Attempts to interpret `value` as a variant short string value.
53    ///
54    /// # Errors
55    ///
56    /// Returns an error if  `value` is longer than the maximum allowed length
57    /// of a Variant short string (63 bytes).
58    pub fn try_new(value: &'a str) -> Result<Self, ArrowError> {
59        if value.len() > MAX_SHORT_STRING_BYTES {
60            return Err(ArrowError::InvalidArgumentError(format!(
61                "value is larger than {MAX_SHORT_STRING_BYTES} bytes"
62            )));
63        }
64
65        Ok(Self(value))
66    }
67
68    /// Returns the underlying Variant short string as a &str
69    pub fn as_str(&self) -> &'a str {
70        self.0
71    }
72}
73
74impl<'a> From<ShortString<'a>> for &'a str {
75    fn from(value: ShortString<'a>) -> Self {
76        value.0
77    }
78}
79
80impl<'a> TryFrom<&'a str> for ShortString<'a> {
81    type Error = ArrowError;
82
83    fn try_from(value: &'a str) -> Result<Self, Self::Error> {
84        Self::try_new(value)
85    }
86}
87
88impl AsRef<str> for ShortString<'_> {
89    fn as_ref(&self) -> &str {
90        self.0
91    }
92}
93
94impl Deref for ShortString<'_> {
95    type Target = str;
96
97    fn deref(&self) -> &Self::Target {
98        self.0
99    }
100}
101
102/// Represents a [Parquet Variant]
103///
104/// The lifetimes `'m` and `'v` are for metadata and value buffers, respectively.
105///
106/// # Background
107///
108/// The [specification] says:
109///
110/// The Variant Binary Encoding allows representation of semi-structured data
111/// (e.g. JSON) in a form that can be efficiently queried by path. The design is
112/// intended to allow efficient access to nested data even in the presence of
113/// very wide or deep structures.
114///
115/// Another motivation for the representation is that (aside from metadata) each
116/// nested Variant value is contiguous and self-contained. For example, in a
117/// Variant containing an Array of Variant values, the representation of an
118/// inner Variant value, when paired with the metadata of the full variant, is
119/// itself a valid Variant.
120///
121/// When stored in Parquet files, Variant fields can also be *shredded*. Shredding
122/// refers to extracting some elements of the variant into separate columns for
123/// more efficient extraction/filter pushdown. The [Variant Shredding
124/// specification] describes the details of shredding Variant values as typed
125/// Parquet columns.
126///
127/// A Variant represents a type that contains one of:
128///
129/// * Primitive: A type and corresponding value (e.g. INT, STRING)
130///
131/// * Array: An ordered list of Variant values
132///
133/// * Object: An unordered collection of string/Variant pairs (i.e. key/value
134///   pairs). An object may not contain duplicate keys.
135///
136/// # Encoding
137///
138/// A Variant is encoded with 2 binary values, the value and the metadata. The
139/// metadata stores a header and an optional dictionary of field names which are
140/// referred to by offset in the value. The value is a binary representation of
141/// the actual data, and varies depending on the type.
142///
143/// # Design Goals
144///
145/// The design goals of the Rust API are as follows:
146/// 1. Speed / Zero copy access (no `clone`ing is required)
147/// 2. Safety
148/// 3. Follow standard Rust conventions
149///
150/// [Parquet Variant]: https://github.com/apache/parquet-format/blob/master/VariantEncoding.md
151/// [specification]: https://github.com/apache/parquet-format/blob/master/VariantEncoding.md
152/// [Variant Shredding specification]: https://github.com/apache/parquet-format/blob/master/VariantShredding.md
153///
154/// # Examples:
155///
156/// ## Creating `Variant` from Rust Types
157/// ```
158/// use parquet_variant::Variant;
159/// // variants can be directly constructed
160/// let variant = Variant::Int32(123);
161/// // or constructed via `From` impls
162/// assert_eq!(variant, Variant::from(123i32));
163/// ```
164/// ## Creating `Variant` from metadata and value
165/// ```
166/// # use parquet_variant::{Variant, VariantMetadata};
167/// let metadata = [0x01, 0x00, 0x00];
168/// let value = [0x09, 0x48, 0x49];
169/// // parse the header metadata
170/// assert_eq!(
171///   Variant::from("HI"),
172///   Variant::new(&metadata, &value)
173/// );
174/// ```
175///
176/// ## Using `Variant` values
177/// ```
178/// # use parquet_variant::Variant;
179/// # let variant = Variant::Int32(123);
180/// // variants can be used in match statements like normal enums
181/// match variant {
182///   Variant::Int32(i) => println!("Integer: {}", i),
183///   Variant::String(s) => println!("String: {}", s),
184///   _ => println!("Other variant"),
185/// }
186/// ```
187///
188/// # Validation
189///
190/// Every instance of variant is either _valid_ or _invalid_. depending on whether the
191/// underlying bytes are a valid encoding of a variant value (see below).
192///
193/// Instances produced by [`Self::try_new`], [`Self::try_new_with_metadata`], or [`Self::with_full_validation`]
194/// are fully _validated_. They always contain _valid_ data, and infallible accesses such as
195/// iteration and indexing are panic-free. The validation cost is `O(m + v)` where `m` and
196/// `v` are the number of bytes in the metadata and value buffers, respectively.
197///
198/// Instances produced by [`Self::new`] and [`Self::new_with_metadata`] are _unvalidated_ and so
199/// they may contain either _valid_ or _invalid_ data. Infallible accesses to variant objects and
200/// arrays, such as iteration and indexing will panic if the underlying bytes are _invalid_, and
201/// fallible alternatives are provided as panic-free alternatives. [`Self::with_full_validation`] can also be
202/// used to _validate_ an _unvalidated_ instance, if desired.
203///
204/// _Unvalidated_ instances can be constructed in constant time. This can be useful if the caller
205/// knows the underlying bytes were already validated previously, or if the caller intends to
206/// perform a small number of (fallible) accesses to a large variant value.
207///
208/// A _validated_ variant value guarantees that the associated [metadata] and all nested [object]
209/// and [array] values are _valid_. Primitive variant subtypes are always _valid_ by construction.
210///
211/// # Safety
212///
213/// Even an _invalid_ variant value is still _safe_ to use in the Rust sense. Accessing it with
214/// infallible methods may cause panics but will never lead to undefined behavior.
215///
216/// [metadata]: VariantMetadata#Validation
217/// [object]: VariantObject#Validation
218/// [array]: VariantList#Validation
219#[derive(Clone, PartialEq)]
220pub enum Variant<'m, 'v> {
221    /// Primitive type: Null
222    Null,
223    /// Primitive (type_id=1): INT(8, SIGNED)
224    Int8(i8),
225    /// Primitive (type_id=1): INT(16, SIGNED)
226    Int16(i16),
227    /// Primitive (type_id=1): INT(32, SIGNED)
228    Int32(i32),
229    /// Primitive (type_id=1): INT(64, SIGNED)
230    Int64(i64),
231    /// Primitive (type_id=1): DATE
232    Date(NaiveDate),
233    /// Primitive (type_id=1): TIMESTAMP(isAdjustedToUTC=true, MICROS)
234    TimestampMicros(DateTime<Utc>),
235    /// Primitive (type_id=1): TIMESTAMP(isAdjustedToUTC=false, MICROS)
236    TimestampNtzMicros(NaiveDateTime),
237    /// Primitive (type_id=1): TIMESTAMP(isAdjustedToUTC=true, NANOS)
238    TimestampNanos(DateTime<Utc>),
239    /// Primitive (type_id=1): TIMESTAMP(isAdjustedToUTC=false, NANOS)
240    TimestampNtzNanos(NaiveDateTime),
241    /// Primitive (type_id=1): DECIMAL(precision, scale) 32-bits
242    Decimal4(VariantDecimal4),
243    /// Primitive (type_id=1): DECIMAL(precision, scale) 64-bits
244    Decimal8(VariantDecimal8),
245    /// Primitive (type_id=1): DECIMAL(precision, scale) 128-bits
246    Decimal16(VariantDecimal16),
247    /// Primitive (type_id=1): FLOAT
248    Float(f32),
249    /// Primitive (type_id=1): DOUBLE
250    Double(f64),
251    /// Primitive (type_id=1): BOOLEAN (true)
252    BooleanTrue,
253    /// Primitive (type_id=1): BOOLEAN (false)
254    BooleanFalse,
255    // Note: only need the *value* buffer for these types
256    /// Primitive (type_id=1): BINARY
257    Binary(&'v [u8]),
258    /// Primitive (type_id=1): STRING
259    String(&'v str),
260    /// Primitive (type_id=1): TIME(isAdjustedToUTC=false, MICROS)
261    Time(NaiveTime),
262    /// Primitive (type_id=1): UUID
263    Uuid(Uuid),
264    /// Short String (type_id=2): STRING
265    ShortString(ShortString<'v>),
266    // need both metadata & value
267    /// Object (type_id=3): N/A
268    Object(VariantObject<'m, 'v>),
269    /// Array (type_id=4): N/A
270    List(VariantList<'m, 'v>),
271}
272
273// We don't want this to grow because it could hurt performance of a frequently-created type.
274const _: () = crate::utils::expect_size_of::<Variant>(80);
275
276impl<'m, 'v> Variant<'m, 'v> {
277    /// Attempts to interpret a metadata and value buffer pair as a new `Variant`.
278    ///
279    /// The instance is fully [validated].
280    ///
281    /// # Example
282    /// ```
283    /// use parquet_variant::{Variant, VariantMetadata};
284    /// let metadata = [0x01, 0x00, 0x00];
285    /// let value = [0x09, 0x48, 0x49];
286    /// // parse the header metadata
287    /// assert_eq!(
288    ///   Variant::from("HI"),
289    ///   Variant::try_new(&metadata, &value).unwrap()
290    /// );
291    /// ```
292    ///
293    /// [validated]: Self#Validation
294    pub fn try_new(metadata: &'m [u8], value: &'v [u8]) -> Result<Self, ArrowError> {
295        let metadata = VariantMetadata::try_new(metadata)?;
296        Self::try_new_with_metadata(metadata, value)
297    }
298
299    /// Attempts to interpret a metadata and value buffer pair as a new `Variant`.
300    ///
301    /// The instance is [unvalidated].
302    ///
303    /// # Example
304    /// ```
305    /// use parquet_variant::{Variant, VariantMetadata};
306    /// let metadata = [0x01, 0x00, 0x00];
307    /// let value = [0x09, 0x48, 0x49];
308    /// // parse the header metadata
309    /// assert_eq!(
310    ///   Variant::from("HI"),
311    ///   Variant::new(&metadata, &value)
312    /// );
313    /// ```
314    ///
315    /// [unvalidated]: Self#Validation
316    pub fn new(metadata: &'m [u8], value: &'v [u8]) -> Self {
317        let metadata = VariantMetadata::try_new_with_shallow_validation(metadata)
318            .expect("Invalid variant metadata");
319        Self::try_new_with_metadata_and_shallow_validation(metadata, value)
320            .expect("Invalid variant data")
321    }
322
323    /// Create a new variant with existing metadata.
324    ///
325    /// The instance is fully [validated].
326    ///
327    /// # Example
328    /// ```
329    /// # use parquet_variant::{Variant, VariantMetadata};
330    /// let metadata = [0x01, 0x00, 0x00];
331    /// let value = [0x09, 0x48, 0x49];
332    /// // parse the header metadata first
333    /// let metadata = VariantMetadata::new(&metadata);
334    /// assert_eq!(
335    ///   Variant::from("HI"),
336    ///   Variant::try_new_with_metadata(metadata, &value).unwrap()
337    /// );
338    /// ```
339    ///
340    /// [validated]: Self#Validation
341    pub fn try_new_with_metadata(
342        metadata: VariantMetadata<'m>,
343        value: &'v [u8],
344    ) -> Result<Self, ArrowError> {
345        Self::try_new_with_metadata_and_shallow_validation(metadata, value)?.with_full_validation()
346    }
347
348    /// Similar to [`Self::try_new_with_metadata`], but [unvalidated].
349    ///
350    /// [unvalidated]: Self#Validation
351    pub fn new_with_metadata(metadata: VariantMetadata<'m>, value: &'v [u8]) -> Self {
352        Self::try_new_with_metadata_and_shallow_validation(metadata, value)
353            .expect("Invalid variant")
354    }
355
356    // The actual constructor, which only performs shallow (constant-time) validation.
357    fn try_new_with_metadata_and_shallow_validation(
358        metadata: VariantMetadata<'m>,
359        value: &'v [u8],
360    ) -> Result<Self, ArrowError> {
361        let value_metadata = first_byte_from_slice(value)?;
362        let value_data = slice_from_slice(value, 1..)?;
363        let new_self = match get_basic_type(value_metadata) {
364            VariantBasicType::Primitive => match get_primitive_type(value_metadata)? {
365                VariantPrimitiveType::Null => Variant::Null,
366                VariantPrimitiveType::Int8 => Variant::Int8(decoder::decode_int8(value_data)?),
367                VariantPrimitiveType::Int16 => Variant::Int16(decoder::decode_int16(value_data)?),
368                VariantPrimitiveType::Int32 => Variant::Int32(decoder::decode_int32(value_data)?),
369                VariantPrimitiveType::Int64 => Variant::Int64(decoder::decode_int64(value_data)?),
370                VariantPrimitiveType::Decimal4 => {
371                    let (integer, scale) = decoder::decode_decimal4(value_data)?;
372                    Variant::Decimal4(VariantDecimal4::try_new(integer, scale)?)
373                }
374                VariantPrimitiveType::Decimal8 => {
375                    let (integer, scale) = decoder::decode_decimal8(value_data)?;
376                    Variant::Decimal8(VariantDecimal8::try_new(integer, scale)?)
377                }
378                VariantPrimitiveType::Decimal16 => {
379                    let (integer, scale) = decoder::decode_decimal16(value_data)?;
380                    Variant::Decimal16(VariantDecimal16::try_new(integer, scale)?)
381                }
382                VariantPrimitiveType::Float => Variant::Float(decoder::decode_float(value_data)?),
383                VariantPrimitiveType::Double => {
384                    Variant::Double(decoder::decode_double(value_data)?)
385                }
386                VariantPrimitiveType::BooleanTrue => Variant::BooleanTrue,
387                VariantPrimitiveType::BooleanFalse => Variant::BooleanFalse,
388                VariantPrimitiveType::Date => Variant::Date(decoder::decode_date(value_data)?),
389                VariantPrimitiveType::TimestampMicros => {
390                    Variant::TimestampMicros(decoder::decode_timestamp_micros(value_data)?)
391                }
392                VariantPrimitiveType::TimestampNtzMicros => {
393                    Variant::TimestampNtzMicros(decoder::decode_timestampntz_micros(value_data)?)
394                }
395                VariantPrimitiveType::TimestampNanos => {
396                    Variant::TimestampNanos(decoder::decode_timestamp_nanos(value_data)?)
397                }
398                VariantPrimitiveType::TimestampNtzNanos => {
399                    Variant::TimestampNtzNanos(decoder::decode_timestampntz_nanos(value_data)?)
400                }
401                VariantPrimitiveType::Uuid => Variant::Uuid(decoder::decode_uuid(value_data)?),
402                VariantPrimitiveType::Binary => {
403                    Variant::Binary(decoder::decode_binary(value_data)?)
404                }
405                VariantPrimitiveType::String => {
406                    Variant::String(decoder::decode_long_string(value_data)?)
407                }
408                VariantPrimitiveType::Time => Variant::Time(decoder::decode_time_ntz(value_data)?),
409            },
410            VariantBasicType::ShortString => {
411                Variant::ShortString(decoder::decode_short_string(value_metadata, value_data)?)
412            }
413            VariantBasicType::Object => Variant::Object(
414                VariantObject::try_new_with_shallow_validation(metadata, value)?,
415            ),
416            VariantBasicType::Array => Variant::List(VariantList::try_new_with_shallow_validation(
417                metadata, value,
418            )?),
419        };
420        Ok(new_self)
421    }
422
423    /// True if this variant instance has already been [validated].
424    ///
425    /// [validated]: Self#Validation
426    pub fn is_fully_validated(&self) -> bool {
427        match self {
428            Variant::List(list) => list.is_fully_validated(),
429            Variant::Object(obj) => obj.is_fully_validated(),
430            _ => true,
431        }
432    }
433
434    /// Recursively validates this variant value, ensuring that infallible access will not panic due
435    /// to invalid bytes.
436    ///
437    /// Variant leaf values are always valid by construction, but [objects] and [arrays] can be
438    /// constructed in unvalidated (and potentially invalid) state.
439    ///
440    /// If [`Self::is_fully_validated`] is true, validation is a no-op. Otherwise, the cost is `O(m + v)`
441    /// where `m` and `v` are the sizes of metadata and value buffers, respectively.
442    ///
443    /// [objects]: VariantObject#Validation
444    /// [arrays]: VariantList#Validation
445    pub fn with_full_validation(self) -> Result<Self, ArrowError> {
446        use Variant::*;
447        match self {
448            List(list) => list.with_full_validation().map(List),
449            Object(obj) => obj.with_full_validation().map(Object),
450            _ => Ok(self),
451        }
452    }
453
454    /// Converts this variant to `()` if it is null.
455    ///
456    /// Returns `Some(())` for null variants,
457    /// `None` for non-null variants.
458    ///
459    /// # Examples
460    ///
461    /// ```
462    /// use parquet_variant::Variant;
463    ///
464    /// // you can extract `()` from a null variant
465    /// let v1 = Variant::from(());
466    /// assert_eq!(v1.as_null(), Some(()));
467    ///
468    /// // but not from other variants
469    /// let v2 = Variant::from("hello!");
470    /// assert_eq!(v2.as_null(), None);
471    /// ```
472    pub fn as_null(&self) -> Option<()> {
473        matches!(self, Variant::Null).then_some(())
474    }
475
476    /// Converts this variant to a `bool` if possible.
477    ///
478    /// Returns `Some(bool)` for boolean variants,
479    /// `None` for non-boolean variants.
480    ///
481    /// # Examples
482    ///
483    /// ```
484    /// use parquet_variant::Variant;
485    ///
486    /// // you can extract a bool from the true variant
487    /// let v1 = Variant::from(true);
488    /// assert_eq!(v1.as_boolean(), Some(true));
489    ///
490    /// // and the false variant
491    /// let v2 = Variant::from(false);
492    /// assert_eq!(v2.as_boolean(), Some(false));
493    ///
494    /// // but not from other variants
495    /// let v3 = Variant::from("hello!");
496    /// assert_eq!(v3.as_boolean(), None);
497    /// ```
498    pub fn as_boolean(&self) -> Option<bool> {
499        match self {
500            Variant::BooleanTrue => Some(true),
501            Variant::BooleanFalse => Some(false),
502            _ => None,
503        }
504    }
505
506    /// Converts this variant to a `NaiveDate` if possible.
507    ///
508    /// Returns `Some(NaiveDate)` for date variants,
509    /// `None` for non-date variants.
510    ///
511    /// # Examples
512    ///
513    /// ```
514    /// use parquet_variant::Variant;
515    /// use chrono::NaiveDate;
516    ///
517    /// // you can extract a NaiveDate from a date variant
518    /// let date = NaiveDate::from_ymd_opt(2025, 4, 12).unwrap();
519    /// let v1 = Variant::from(date);
520    /// assert_eq!(v1.as_naive_date(), Some(date));
521    ///
522    /// // but not from other variants
523    /// let v2 = Variant::from("hello!");
524    /// assert_eq!(v2.as_naive_date(), None);
525    /// ```
526    pub fn as_naive_date(&self) -> Option<NaiveDate> {
527        if let Variant::Date(d) = self {
528            Some(*d)
529        } else {
530            None
531        }
532    }
533
534    /// Converts this variant to a `DateTime<Utc>` if possible.
535    ///
536    /// Returns `Some(DateTime<Utc>)` for timestamp variants,
537    /// `None` for non-timestamp variants.
538    ///
539    /// # Examples
540    ///
541    /// ```
542    /// use parquet_variant::Variant;
543    /// use chrono::NaiveDate;
544    ///
545    /// // you can extract a DateTime<Utc> from a UTC-adjusted variant
546    /// let datetime = NaiveDate::from_ymd_opt(2025, 4, 16).unwrap().and_hms_milli_opt(12, 34, 56, 780).unwrap().and_utc();
547    /// let v1 = Variant::from(datetime);
548    /// assert_eq!(v1.as_datetime_utc(), Some(datetime));
549    /// let datetime_nanos = NaiveDate::from_ymd_opt(2025, 8, 14).unwrap().and_hms_nano_opt(12, 33, 54, 123456789).unwrap().and_utc();
550    /// let v2 = Variant::from(datetime_nanos);
551    /// assert_eq!(v2.as_datetime_utc(), Some(datetime_nanos));
552    ///
553    /// // but not from other variants
554    /// let v3 = Variant::from("hello!");
555    /// assert_eq!(v3.as_datetime_utc(), None);
556    /// ```
557    pub fn as_datetime_utc(&self) -> Option<DateTime<Utc>> {
558        match *self {
559            Variant::TimestampMicros(d) | Variant::TimestampNanos(d) => Some(d),
560            _ => None,
561        }
562    }
563
564    /// Converts this variant to a `NaiveDateTime` if possible.
565    ///
566    /// Returns `Some(NaiveDateTime)` for timestamp variants,
567    /// `None` for non-timestamp variants.
568    ///
569    /// # Examples
570    ///
571    /// ```
572    /// use parquet_variant::Variant;
573    /// use chrono::NaiveDate;
574    ///
575    /// // you can extract a NaiveDateTime from a non-UTC-adjusted variant
576    /// let datetime = NaiveDate::from_ymd_opt(2025, 4, 16).unwrap().and_hms_milli_opt(12, 34, 56, 780).unwrap();
577    /// let v1 = Variant::from(datetime);
578    /// assert_eq!(v1.as_naive_datetime(), Some(datetime));
579    ///
580    /// // or a UTC-adjusted variant
581    /// let datetime = NaiveDate::from_ymd_opt(2025, 4, 16).unwrap().and_hms_nano_opt(12, 34, 56, 123456789).unwrap();
582    /// let v2 = Variant::from(datetime);
583    /// assert_eq!(v2.as_naive_datetime(), Some(datetime));
584    ///
585    /// // but not from other variants
586    /// let v3 = Variant::from("hello!");
587    /// assert_eq!(v3.as_naive_datetime(), None);
588    /// ```
589    pub fn as_naive_datetime(&self) -> Option<NaiveDateTime> {
590        match *self {
591            Variant::TimestampNtzMicros(d) | Variant::TimestampNtzNanos(d) => Some(d),
592            _ => None,
593        }
594    }
595
596    /// Converts this variant to a `&[u8]` if possible.
597    ///
598    /// Returns `Some(&[u8])` for binary variants,
599    /// `None` for non-binary variants.
600    ///
601    /// # Examples
602    ///
603    /// ```
604    /// use parquet_variant::Variant;
605    ///
606    /// // you can extract a byte slice from a binary variant
607    /// let data = b"hello!";
608    /// let v1 = Variant::Binary(data);
609    /// assert_eq!(v1.as_u8_slice(), Some(data.as_slice()));
610    ///
611    /// // but not from other variant types
612    /// let v2 = Variant::from(123i64);
613    /// assert_eq!(v2.as_u8_slice(), None);
614    /// ```
615    pub fn as_u8_slice(&'v self) -> Option<&'v [u8]> {
616        if let Variant::Binary(d) = self {
617            Some(d)
618        } else {
619            None
620        }
621    }
622
623    /// Converts this variant to a `&str` if possible.
624    ///
625    /// Returns `Some(&str)` for string variants (both regular and short strings),
626    /// `None` for non-string variants.
627    ///
628    /// # Examples
629    ///
630    /// ```
631    /// use parquet_variant::Variant;
632    ///
633    /// // you can extract a string from string variants
634    /// let s = "hello!";
635    /// let v1 = Variant::from(s);
636    /// assert_eq!(v1.as_string(), Some(s));
637    ///
638    /// // but not from other variants
639    /// let v2 = Variant::from(123i64);
640    /// assert_eq!(v2.as_string(), None);
641    /// ```
642    pub fn as_string(&'v self) -> Option<&'v str> {
643        match self {
644            Variant::String(s) | Variant::ShortString(ShortString(s)) => Some(s),
645            _ => None,
646        }
647    }
648
649    /// Converts this variant to a `uuid hyphenated string` if possible.
650    ///
651    /// Returns `Some(String)` for UUID variants, `None` for non-UUID variants.
652    ///
653    /// # Examples
654    ///
655    /// ```
656    /// use parquet_variant::Variant;
657    ///
658    /// // You can extract a UUID from a UUID variant
659    /// let s = uuid::Uuid::parse_str("67e55044-10b1-426f-9247-bb680e5fe0c8").unwrap();
660    /// let v1 = Variant::Uuid(s);
661    /// assert_eq!(s, v1.as_uuid().unwrap());
662    /// assert_eq!("67e55044-10b1-426f-9247-bb680e5fe0c8", v1.as_uuid().unwrap().to_string());
663    ///
664    /// //but not from other variants
665    /// let v2 = Variant::from(1234);
666    /// assert_eq!(None, v2.as_uuid())
667    /// ```
668    pub fn as_uuid(&self) -> Option<Uuid> {
669        match self {
670            Variant::Uuid(u) => Some(*u),
671            _ => None,
672        }
673    }
674
675    /// Converts this variant to an `i8` if possible.
676    ///
677    /// Returns `Some(i8)` for integer variants that fit in `i8` range,
678    /// `None` for non-integer variants or values that would overflow.
679    ///
680    /// # Examples
681    ///
682    /// ```
683    /// use parquet_variant::Variant;
684    ///
685    /// // you can read an int64 variant into an i8 if it fits
686    /// let v1 = Variant::from(123i64);
687    /// assert_eq!(v1.as_int8(), Some(123i8));
688    ///
689    /// // but not if it would overflow
690    /// let v2 = Variant::from(1234i64);
691    /// assert_eq!(v2.as_int8(), None);
692    ///
693    /// // or if the variant cannot be cast into an integer
694    /// let v3 = Variant::from("hello!");
695    /// assert_eq!(v3.as_int8(), None);
696    /// ```
697    pub fn as_int8(&self) -> Option<i8> {
698        match *self {
699            Variant::Int8(i) => Some(i),
700            Variant::Int16(i) => i.try_into().ok(),
701            Variant::Int32(i) => i.try_into().ok(),
702            Variant::Int64(i) => i.try_into().ok(),
703            Variant::Decimal4(d) if d.scale() == 0 => d.integer().try_into().ok(),
704            Variant::Decimal8(d) if d.scale() == 0 => d.integer().try_into().ok(),
705            Variant::Decimal16(d) if d.scale() == 0 => d.integer().try_into().ok(),
706            _ => None,
707        }
708    }
709
710    /// Converts this variant to an `i16` if possible.
711    ///
712    /// Returns `Some(i16)` for integer variants that fit in `i16` range,
713    /// `None` for non-integer variants or values that would overflow.
714    ///
715    /// # Examples
716    ///
717    /// ```
718    /// use parquet_variant::Variant;
719    ///
720    /// // you can read an int64 variant into an i16 if it fits
721    /// let v1 = Variant::from(123i64);
722    /// assert_eq!(v1.as_int16(), Some(123i16));
723    ///
724    /// // but not if it would overflow
725    /// let v2 = Variant::from(123456i64);
726    /// assert_eq!(v2.as_int16(), None);
727    ///
728    /// // or if the variant cannot be cast into an integer
729    /// let v3 = Variant::from("hello!");
730    /// assert_eq!(v3.as_int16(), None);
731    /// ```
732    pub fn as_int16(&self) -> Option<i16> {
733        match *self {
734            Variant::Int8(i) => Some(i.into()),
735            Variant::Int16(i) => Some(i),
736            Variant::Int32(i) => i.try_into().ok(),
737            Variant::Int64(i) => i.try_into().ok(),
738            Variant::Decimal4(d) if d.scale() == 0 => d.integer().try_into().ok(),
739            Variant::Decimal8(d) if d.scale() == 0 => d.integer().try_into().ok(),
740            Variant::Decimal16(d) if d.scale() == 0 => d.integer().try_into().ok(),
741            _ => None,
742        }
743    }
744
745    /// Converts this variant to an `i32` if possible.
746    ///
747    /// Returns `Some(i32)` for integer variants that fit in `i32` range,
748    /// `None` for non-integer variants or values that would overflow.
749    ///
750    /// # Examples
751    ///
752    /// ```
753    /// use parquet_variant::Variant;
754    ///
755    /// // you can read an int64 variant into an i32 if it fits
756    /// let v1 = Variant::from(123i64);
757    /// assert_eq!(v1.as_int32(), Some(123i32));
758    ///
759    /// // but not if it would overflow
760    /// let v2 = Variant::from(12345678901i64);
761    /// assert_eq!(v2.as_int32(), None);
762    ///
763    /// // or if the variant cannot be cast into an integer
764    /// let v3 = Variant::from("hello!");
765    /// assert_eq!(v3.as_int32(), None);
766    /// ```
767    pub fn as_int32(&self) -> Option<i32> {
768        match *self {
769            Variant::Int8(i) => Some(i.into()),
770            Variant::Int16(i) => Some(i.into()),
771            Variant::Int32(i) => Some(i),
772            Variant::Int64(i) => i.try_into().ok(),
773            Variant::Decimal4(d) if d.scale() == 0 => Some(d.integer()),
774            Variant::Decimal8(d) if d.scale() == 0 => d.integer().try_into().ok(),
775            Variant::Decimal16(d) if d.scale() == 0 => d.integer().try_into().ok(),
776            _ => None,
777        }
778    }
779
780    /// Converts this variant to an `i64` if possible.
781    ///
782    /// Returns `Some(i64)` for integer variants that fit in `i64` range,
783    /// `None` for non-integer variants or values that would overflow.
784    ///
785    /// # Examples
786    ///
787    /// ```
788    /// use parquet_variant::Variant;
789    ///
790    /// // you can read an int64 variant into an i64
791    /// let v1 = Variant::from(123i64);
792    /// assert_eq!(v1.as_int64(), Some(123i64));
793    ///
794    /// // but not a variant that cannot be cast into an integer
795    /// let v2 = Variant::from("hello!");
796    /// assert_eq!(v2.as_int64(), None);
797    /// ```
798    pub fn as_int64(&self) -> Option<i64> {
799        match *self {
800            Variant::Int8(i) => Some(i.into()),
801            Variant::Int16(i) => Some(i.into()),
802            Variant::Int32(i) => Some(i.into()),
803            Variant::Int64(i) => Some(i),
804            Variant::Decimal4(d) if d.scale() == 0 => Some(d.integer().into()),
805            Variant::Decimal8(d) if d.scale() == 0 => Some(d.integer()),
806            Variant::Decimal16(d) if d.scale() == 0 => d.integer().try_into().ok(),
807            _ => None,
808        }
809    }
810
811    fn generic_convert_unsigned_primitive<T>(&self) -> Option<T>
812    where
813        T: TryFrom<i8> + TryFrom<i16> + TryFrom<i32> + TryFrom<i64> + TryFrom<i128>,
814    {
815        match *self {
816            Variant::Int8(i) => i.try_into().ok(),
817            Variant::Int16(i) => i.try_into().ok(),
818            Variant::Int32(i) => i.try_into().ok(),
819            Variant::Int64(i) => i.try_into().ok(),
820            Variant::Decimal4(d) if d.scale() == 0 => d.integer().try_into().ok(),
821            Variant::Decimal8(d) if d.scale() == 0 => d.integer().try_into().ok(),
822            Variant::Decimal16(d) if d.scale() == 0 => d.integer().try_into().ok(),
823            _ => None,
824        }
825    }
826
827    /// Converts this variant to a `u8` if possible.
828    ///
829    /// Returns `Some(u8)` for integer variants that fit in `u8`
830    /// `None` for non-integer variants or values that would overflow.
831    ///
832    /// # Examples
833    ///
834    /// ```
835    ///  use parquet_variant::{Variant, VariantDecimal4};
836    ///
837    ///  // you can read an int64 variant into an u8
838    ///  let v1 = Variant::from(123i64);
839    ///  assert_eq!(v1.as_u8(), Some(123u8));
840    ///
841    ///  // or a Decimal4 with scale 0 into u8
842    ///  let d = VariantDecimal4::try_new(26, 0).unwrap();
843    ///  let v2 = Variant::from(d);
844    ///  assert_eq!(v2.as_u8(), Some(26u8));
845    ///
846    ///  // but not a variant that can't fit into the range
847    ///  let v3 = Variant::from(-1);
848    ///  assert_eq!(v3.as_u8(), None);
849    ///
850    ///  // not a variant that decimal with scale not equal to zero
851    ///  let d = VariantDecimal4::try_new(1, 2).unwrap();
852    ///  let v4 = Variant::from(d);
853    ///  assert_eq!(v4.as_u8(), None);
854    ///
855    ///  // or not a variant that cannot be cast into an integer
856    ///  let v5 = Variant::from("hello!");
857    ///  assert_eq!(v5.as_u8(), None);
858    /// ```
859    pub fn as_u8(&self) -> Option<u8> {
860        self.generic_convert_unsigned_primitive::<u8>()
861    }
862
863    /// Converts this variant to an `u16` if possible.
864    ///
865    /// Returns `Some(u16)` for integer variants that fit in `u16`
866    /// `None` for non-integer variants or values that would overflow.
867    ///
868    /// # Examples
869    ///
870    /// ```
871    ///  use parquet_variant::{Variant, VariantDecimal4};
872    ///
873    ///  // you can read an int64 variant into an u16
874    ///  let v1 = Variant::from(123i64);
875    ///  assert_eq!(v1.as_u16(), Some(123u16));
876    ///
877    ///  // or a Decimal4 with scale 0 into u8
878    ///  let d = VariantDecimal4::try_new(u16::MAX as i32, 0).unwrap();
879    ///  let v2 = Variant::from(d);
880    ///  assert_eq!(v2.as_u16(), Some(u16::MAX));
881    ///
882    ///  // but not a variant that can't fit into the range
883    ///  let v3 = Variant::from(-1);
884    ///  assert_eq!(v3.as_u16(), None);
885    ///
886    ///  // not a variant that decimal with scale not equal to zero
887    ///  let d = VariantDecimal4::try_new(1, 2).unwrap();
888    ///  let v4 = Variant::from(d);
889    ///  assert_eq!(v4.as_u16(), None);
890    ///
891    ///  // or not a variant that cannot be cast into an integer
892    ///  let v5 = Variant::from("hello!");
893    ///  assert_eq!(v5.as_u16(), None);
894    /// ```
895    pub fn as_u16(&self) -> Option<u16> {
896        self.generic_convert_unsigned_primitive::<u16>()
897    }
898
899    /// Converts this variant to an `u32` if possible.
900    ///
901    /// Returns `Some(u32)` for integer variants that fit in `u32`
902    /// `None` for non-integer variants or values that would overflow.
903    ///
904    /// # Examples
905    ///
906    /// ```
907    ///  use parquet_variant::{Variant, VariantDecimal8};
908    ///
909    ///  // you can read an int64 variant into an u32
910    ///  let v1 = Variant::from(123i64);
911    ///  assert_eq!(v1.as_u32(), Some(123u32));
912    ///
913    ///  // or a Decimal4 with scale 0 into u8
914    ///  let d = VariantDecimal8::try_new(u32::MAX as i64, 0).unwrap();
915    ///  let v2 = Variant::from(d);
916    ///  assert_eq!(v2.as_u32(), Some(u32::MAX));
917    ///
918    ///  // but not a variant that can't fit into the range
919    ///  let v3 = Variant::from(-1);
920    ///  assert_eq!(v3.as_u32(), None);
921    ///
922    ///  // not a variant that decimal with scale not equal to zero
923    ///  let d = VariantDecimal8::try_new(1, 2).unwrap();
924    ///  let v4 = Variant::from(d);
925    ///  assert_eq!(v4.as_u32(), None);
926    ///
927    ///  // or not a variant that cannot be cast into an integer
928    ///  let v5 = Variant::from("hello!");
929    ///  assert_eq!(v5.as_u32(), None);
930    /// ```
931    pub fn as_u32(&self) -> Option<u32> {
932        self.generic_convert_unsigned_primitive::<u32>()
933    }
934
935    /// Converts this variant to an `u64` if possible.
936    ///
937    /// Returns `Some(u64)` for integer variants that fit in `u64`
938    /// `None` for non-integer variants or values that would overflow.
939    ///
940    /// # Examples
941    ///
942    /// ```
943    ///  use parquet_variant::{Variant, VariantDecimal16};
944    ///
945    ///  // you can read an int64 variant into an u64
946    ///  let v1 = Variant::from(123i64);
947    ///  assert_eq!(v1.as_u64(), Some(123u64));
948    ///
949    ///  // or a Decimal16 with scale 0 into u8
950    ///  let d = VariantDecimal16::try_new(u64::MAX as i128, 0).unwrap();
951    ///  let v2 = Variant::from(d);
952    ///  assert_eq!(v2.as_u64(), Some(u64::MAX));
953    ///
954    ///  // but not a variant that can't fit into the range
955    ///  let v3 = Variant::from(-1);
956    ///  assert_eq!(v3.as_u64(), None);
957    ///
958    ///  // not a variant that decimal with scale not equal to zero
959    /// let d = VariantDecimal16::try_new(1, 2).unwrap();
960    ///  let v4 = Variant::from(d);
961    ///  assert_eq!(v4.as_u64(), None);
962    ///
963    ///  // or not a variant that cannot be cast into an integer
964    ///  let v5 = Variant::from("hello!");
965    ///  assert_eq!(v5.as_u64(), None);
966    /// ```
967    pub fn as_u64(&self) -> Option<u64> {
968        self.generic_convert_unsigned_primitive::<u64>()
969    }
970
971    /// Converts this variant to tuple with a 4-byte unscaled value if possible.
972    ///
973    /// Returns `Some((i32, u8))` for decimal variants where the unscaled value
974    /// fits in `i32` range,
975    /// `None` for non-decimal variants or decimal values that would overflow.
976    ///
977    /// # Examples
978    ///
979    /// ```
980    /// use parquet_variant::{Variant, VariantDecimal4, VariantDecimal8};
981    ///
982    /// // you can extract decimal parts from smaller or equally-sized decimal variants
983    /// let v1 = Variant::from(VariantDecimal4::try_new(1234_i32, 2).unwrap());
984    /// assert_eq!(v1.as_decimal4(), VariantDecimal4::try_new(1234_i32, 2).ok());
985    ///
986    /// // and from larger decimal variants if they fit
987    /// let v2 = Variant::from(VariantDecimal8::try_new(1234_i64, 2).unwrap());
988    /// assert_eq!(v2.as_decimal4(), VariantDecimal4::try_new(1234_i32, 2).ok());
989    ///
990    /// // but not if the value would overflow i32
991    /// let v3 = Variant::from(VariantDecimal8::try_new(12345678901i64, 2).unwrap());
992    /// assert_eq!(v3.as_decimal4(), None);
993    ///
994    /// // or if the variant is not a decimal
995    /// let v4 = Variant::from("hello!");
996    /// assert_eq!(v4.as_decimal4(), None);
997    /// ```
998    pub fn as_decimal4(&self) -> Option<VariantDecimal4> {
999        match *self {
1000            Variant::Int8(i) => i32::from(i).try_into().ok(),
1001            Variant::Int16(i) => i32::from(i).try_into().ok(),
1002            Variant::Int32(i) => i.try_into().ok(),
1003            Variant::Int64(i) => i32::try_from(i).ok()?.try_into().ok(),
1004            Variant::Decimal4(decimal4) => Some(decimal4),
1005            Variant::Decimal8(decimal8) => decimal8.try_into().ok(),
1006            Variant::Decimal16(decimal16) => decimal16.try_into().ok(),
1007            _ => None,
1008        }
1009    }
1010
1011    /// Converts this variant to tuple with an 8-byte unscaled value if possible.
1012    ///
1013    /// Returns `Some((i64, u8))` for decimal variants where the unscaled value
1014    /// fits in `i64` range,
1015    /// `None` for non-decimal variants or decimal values that would overflow.
1016    ///
1017    /// # Examples
1018    ///
1019    /// ```
1020    /// use parquet_variant::{Variant, VariantDecimal4, VariantDecimal8, VariantDecimal16};
1021    ///
1022    /// // you can extract decimal parts from smaller or equally-sized decimal variants
1023    /// let v1 = Variant::from(VariantDecimal4::try_new(1234_i32, 2).unwrap());
1024    /// assert_eq!(v1.as_decimal8(), VariantDecimal8::try_new(1234_i64, 2).ok());
1025    ///
1026    /// // and from larger decimal variants if they fit
1027    /// let v2 = Variant::from(VariantDecimal16::try_new(1234_i128, 2).unwrap());
1028    /// assert_eq!(v2.as_decimal8(), VariantDecimal8::try_new(1234_i64, 2).ok());
1029    ///
1030    /// // but not if the value would overflow i64
1031    /// let v3 = Variant::from(VariantDecimal16::try_new(2e19 as i128, 2).unwrap());
1032    /// assert_eq!(v3.as_decimal8(), None);
1033    ///
1034    /// // or if the variant is not a decimal
1035    /// let v4 = Variant::from("hello!");
1036    /// assert_eq!(v4.as_decimal8(), None);
1037    /// ```
1038    pub fn as_decimal8(&self) -> Option<VariantDecimal8> {
1039        match *self {
1040            Variant::Int8(i) => i64::from(i).try_into().ok(),
1041            Variant::Int16(i) => i64::from(i).try_into().ok(),
1042            Variant::Int32(i) => i64::from(i).try_into().ok(),
1043            Variant::Int64(i) => i.try_into().ok(),
1044            Variant::Decimal4(decimal4) => Some(decimal4.into()),
1045            Variant::Decimal8(decimal8) => Some(decimal8),
1046            Variant::Decimal16(decimal16) => decimal16.try_into().ok(),
1047            _ => None,
1048        }
1049    }
1050
1051    /// Converts this variant to tuple with a 16-byte unscaled value if possible.
1052    ///
1053    /// Returns `Some((i128, u8))` for decimal variants where the unscaled value
1054    /// fits in `i128` range,
1055    /// `None` for non-decimal variants or decimal values that would overflow.
1056    ///
1057    /// # Examples
1058    ///
1059    /// ```
1060    /// use parquet_variant::{Variant, VariantDecimal16, VariantDecimal4};
1061    ///
1062    /// // you can extract decimal parts from smaller or equally-sized decimal variants
1063    /// let v1 = Variant::from(VariantDecimal4::try_new(1234_i32, 2).unwrap());
1064    /// assert_eq!(v1.as_decimal16(), VariantDecimal16::try_new(1234_i128, 2).ok());
1065    ///
1066    /// // but not if the variant is not a decimal
1067    /// let v2 = Variant::from("hello!");
1068    /// assert_eq!(v2.as_decimal16(), None);
1069    /// ```
1070    pub fn as_decimal16(&self) -> Option<VariantDecimal16> {
1071        match *self {
1072            Variant::Int8(i) => i128::from(i).try_into().ok(),
1073            Variant::Int16(i) => i128::from(i).try_into().ok(),
1074            Variant::Int32(i) => i128::from(i).try_into().ok(),
1075            Variant::Int64(i) => i128::from(i).try_into().ok(),
1076            Variant::Decimal4(decimal4) => Some(decimal4.into()),
1077            Variant::Decimal8(decimal8) => Some(decimal8.into()),
1078            Variant::Decimal16(decimal16) => Some(decimal16),
1079            _ => None,
1080        }
1081    }
1082
1083    /// Converts this variant to an `f16` if possible.
1084    ///
1085    /// Returns `Some(f16)` for floating point values, and integers with up to 11 bits of
1086    /// precision. `None` otherwise.
1087    ///
1088    /// # Example
1089    ///
1090    /// ```
1091    /// use parquet_variant::Variant;
1092    /// use half::f16;
1093    ///
1094    /// // you can extract an f16 from a float variant
1095    /// let v1 = Variant::from(std::f32::consts::PI);
1096    /// assert_eq!(v1.as_f16(), Some(f16::from_f32(std::f32::consts::PI)));
1097    ///
1098    /// // and from a double variant (with loss of precision to nearest f16)
1099    /// let v2 = Variant::from(std::f64::consts::PI);
1100    /// assert_eq!(v2.as_f16(), Some(f16::from_f64(std::f64::consts::PI)));
1101    ///
1102    /// // and from integers with no more than 11 bits of precision
1103    /// let v3 = Variant::from(2047);
1104    /// assert_eq!(v3.as_f16(), Some(f16::from_f32(2047.0)));
1105    ///
1106    /// // but not from other variants
1107    /// let v4 = Variant::from("hello!");
1108    /// assert_eq!(v4.as_f16(), None);
1109    pub fn as_f16(&self) -> Option<f16> {
1110        match *self {
1111            Variant::Float(i) => Some(f16::from_f32(i)),
1112            Variant::Double(i) => Some(f16::from_f64(i)),
1113            Variant::Int8(i) => Some(i.into()),
1114            Variant::Int16(i) if fits_precision::<11>(i) => Some(f16::from_f32(i as _)),
1115            Variant::Int32(i) if fits_precision::<11>(i) => Some(f16::from_f32(i as _)),
1116            Variant::Int64(i) if fits_precision::<11>(i) => Some(f16::from_f32(i as _)),
1117            _ => None,
1118        }
1119    }
1120
1121    /// Converts this variant to an `f32` if possible.
1122    ///
1123    /// Returns `Some(f32)` for floating point values, and integer values with up to 24 bits of
1124    /// precision.  `None` otherwise.
1125    ///
1126    /// # Examples
1127    ///
1128    /// ```
1129    /// use parquet_variant::Variant;
1130    ///
1131    /// // you can extract an f32 from a float variant
1132    /// let v1 = Variant::from(std::f32::consts::PI);
1133    /// assert_eq!(v1.as_f32(), Some(std::f32::consts::PI));
1134    ///
1135    /// // and from a double variant (with loss of precision to nearest f32)
1136    /// let v2 = Variant::from(std::f64::consts::PI);
1137    /// assert_eq!(v2.as_f32(), Some(std::f32::consts::PI));
1138    ///
1139    /// // and from integers with no more than 24 bits of precision
1140    /// let v3 = Variant::from(16777215i64);
1141    /// assert_eq!(v3.as_f32(), Some(16777215.0));
1142    ///
1143    /// // but not from other variants
1144    /// let v4 = Variant::from("hello!");
1145    /// assert_eq!(v4.as_f32(), None);
1146    /// ```
1147    #[allow(clippy::cast_possible_truncation)]
1148    pub fn as_f32(&self) -> Option<f32> {
1149        match *self {
1150            Variant::Float(i) => Some(i),
1151            Variant::Double(i) => Some(i as f32),
1152            Variant::Int8(i) => Some(i.into()),
1153            Variant::Int16(i) => Some(i.into()),
1154            Variant::Int32(i) if fits_precision::<24>(i) => Some(i as _),
1155            Variant::Int64(i) if fits_precision::<24>(i) => Some(i as _),
1156            _ => None,
1157        }
1158    }
1159
1160    /// Converts this variant to an `f64` if possible.
1161    ///
1162    /// Returns `Some(f64)` for floating point values, and integer values with up to 53 bits of
1163    /// precision.  `None` otherwise.
1164    ///
1165    /// # Examples
1166    ///
1167    /// ```
1168    /// use parquet_variant::Variant;
1169    ///
1170    /// // you can extract an f64 from a float variant
1171    /// let v1 = Variant::from(std::f32::consts::PI);
1172    /// assert_eq!(v1.as_f64(), Some(std::f32::consts::PI as f64));
1173    ///
1174    /// // and from a double variant
1175    /// let v2 = Variant::from(std::f64::consts::PI);
1176    /// assert_eq!(v2.as_f64(), Some(std::f64::consts::PI));
1177    ///
1178    /// // and from integers with no more than 53 bits of precision
1179    /// let v3 = Variant::from(9007199254740991i64);
1180    /// assert_eq!(v3.as_f64(), Some(9007199254740991.0));
1181    ///
1182    /// // but not from other variants
1183    /// let v4 = Variant::from("hello!");
1184    /// assert_eq!(v4.as_f64(), None);
1185    /// ```
1186    pub fn as_f64(&self) -> Option<f64> {
1187        match *self {
1188            Variant::Float(i) => Some(i.into()),
1189            Variant::Double(i) => Some(i),
1190            Variant::Int8(i) => Some(i.into()),
1191            Variant::Int16(i) => Some(i.into()),
1192            Variant::Int32(i) => Some(i.into()),
1193            Variant::Int64(i) if fits_precision::<53>(i) => Some(i as _),
1194            _ => None,
1195        }
1196    }
1197
1198    /// Converts this variant to an `Object` if it is an [`VariantObject`].
1199    ///
1200    /// Returns `Some(&VariantObject)` for object variants,
1201    /// `None` for non-object variants.
1202    ///
1203    /// See [`Self::get_path`] to dynamically traverse objects
1204    ///
1205    /// # Examples
1206    /// ```
1207    /// # use parquet_variant::{Variant, VariantBuilder, VariantObject};
1208    /// # let (metadata, value) = {
1209    /// # let mut builder = VariantBuilder::new();
1210    /// #   let mut obj = builder.new_object();
1211    /// #   obj.insert("name", "John");
1212    /// #   obj.finish();
1213    /// #   builder.finish()
1214    /// # };
1215    /// // object that is {"name": "John"}
1216    ///  let variant = Variant::new(&metadata, &value);
1217    /// // use the `as_object` method to access the object
1218    /// let obj = variant.as_object().expect("variant should be an object");
1219    /// assert_eq!(obj.get("name"), Some(Variant::from("John")));
1220    /// ```
1221    pub fn as_object(&'m self) -> Option<&'m VariantObject<'m, 'v>> {
1222        if let Variant::Object(obj) = self {
1223            Some(obj)
1224        } else {
1225            None
1226        }
1227    }
1228
1229    /// If this is an object and the requested field name exists, retrieves the corresponding field
1230    /// value. Otherwise, returns None.
1231    ///
1232    /// This is shorthand for [`Self::as_object`] followed by [`VariantObject::get`].
1233    ///
1234    /// # Examples
1235    /// ```
1236    /// # use parquet_variant::{Variant, VariantBuilder, VariantObject};
1237    /// # let mut builder = VariantBuilder::new();
1238    /// # let mut obj = builder.new_object();
1239    /// # obj.insert("name", "John");
1240    /// # obj.finish();
1241    /// # let (metadata, value) = builder.finish();
1242    /// // object that is {"name": "John"}
1243    ///  let variant = Variant::new(&metadata, &value);
1244    /// // use the `get_object_field` method to access the object
1245    /// let obj = variant.get_object_field("name");
1246    /// assert_eq!(obj, Some(Variant::from("John")));
1247    /// let obj = variant.get_object_field("foo");
1248    /// assert!(obj.is_none());
1249    /// ```
1250    pub fn get_object_field(&self, field_name: &str) -> Option<Self> {
1251        match self {
1252            Variant::Object(object) => object.get(field_name),
1253            _ => None,
1254        }
1255    }
1256
1257    /// Converts this variant to a `List` if it is a [`VariantList`].
1258    ///
1259    /// Returns `Some(&VariantList)` for list variants,
1260    /// `None` for non-list variants.
1261    ///
1262    /// See [`Self::get_path`] to dynamically traverse lists
1263    ///
1264    /// # Examples
1265    /// ```
1266    /// # use parquet_variant::{Variant, VariantBuilder, VariantList};
1267    /// # let (metadata, value) = {
1268    /// # let mut builder = VariantBuilder::new();
1269    /// #   let mut list = builder.new_list();
1270    /// #   list.append_value("John");
1271    /// #   list.append_value("Doe");
1272    /// #   list.finish();
1273    /// #   builder.finish()
1274    /// # };
1275    /// // list that is ["John", "Doe"]
1276    /// let variant = Variant::new(&metadata, &value);
1277    /// // use the `as_list` method to access the list
1278    /// let list = variant.as_list().expect("variant should be a list");
1279    /// assert_eq!(list.len(), 2);
1280    /// assert_eq!(list.get(0).unwrap(), Variant::from("John"));
1281    /// assert_eq!(list.get(1).unwrap(), Variant::from("Doe"));
1282    /// ```
1283    pub fn as_list(&'m self) -> Option<&'m VariantList<'m, 'v>> {
1284        if let Variant::List(list) = self {
1285            Some(list)
1286        } else {
1287            None
1288        }
1289    }
1290
1291    /// Converts this variant to a `NaiveTime` if possible.
1292    ///
1293    /// Returns `Some(NaiveTime)` for `Variant::Time`,
1294    /// `None` for non-Time variants.
1295    ///
1296    /// # Example
1297    ///
1298    /// ```
1299    /// use chrono::NaiveTime;
1300    /// use parquet_variant::Variant;
1301    ///
1302    /// // you can extract a `NaiveTime` from a `Variant::Time`
1303    /// let time = NaiveTime::from_hms_micro_opt(1, 2, 3, 4).unwrap();
1304    /// let v1 = Variant::from(time);
1305    /// assert_eq!(Some(time), v1.as_time_utc());
1306    ///
1307    /// // but not from other variants.
1308    /// let v2 = Variant::from("Hello");
1309    /// assert_eq!(None, v2.as_time_utc());
1310    /// ```
1311    pub fn as_time_utc(&'m self) -> Option<NaiveTime> {
1312        if let Variant::Time(time) = self {
1313            Some(*time)
1314        } else {
1315            None
1316        }
1317    }
1318
1319    /// If this is a list and the requested index is in bounds, retrieves the corresponding
1320    /// element. Otherwise, returns None.
1321    ///
1322    /// This is shorthand for [`Self::as_list`] followed by [`VariantList::get`].
1323    ///
1324    /// # Examples
1325    /// ```
1326    /// # use parquet_variant::{Variant, VariantBuilder, VariantList};
1327    /// # let mut builder = VariantBuilder::new();
1328    /// # let mut list = builder.new_list();
1329    /// # list.append_value("John");
1330    /// # list.append_value("Doe");
1331    /// # list.finish();
1332    /// # let (metadata, value) = builder.finish();
1333    /// // list that is ["John", "Doe"]
1334    /// let variant = Variant::new(&metadata, &value);
1335    /// // use the `get_list_element` method to access the list
1336    /// assert_eq!(variant.get_list_element(0), Some(Variant::from("John")));
1337    /// assert_eq!(variant.get_list_element(1), Some(Variant::from("Doe")));
1338    /// assert!(variant.get_list_element(2).is_none());
1339    /// ```
1340    pub fn get_list_element(&self, index: usize) -> Option<Self> {
1341        match self {
1342            Variant::List(list) => list.get(index),
1343            _ => None,
1344        }
1345    }
1346
1347    /// Return the metadata dictionary associated with this variant value.
1348    pub fn metadata(&self) -> &VariantMetadata<'m> {
1349        match self {
1350            Variant::Object(VariantObject { metadata, .. })
1351            | Variant::List(VariantList { metadata, .. }) => metadata,
1352            _ => &EMPTY_VARIANT_METADATA,
1353        }
1354    }
1355
1356    /// Return a new Variant with the path followed.
1357    ///
1358    /// If the path is not found, `None` is returned.
1359    ///
1360    /// # Example
1361    /// ```
1362    /// # use parquet_variant::{Variant, VariantBuilder, VariantObject, VariantPath};
1363    /// # let mut builder = VariantBuilder::new();
1364    /// # let mut obj = builder.new_object();
1365    /// # let mut list = obj.new_list("foo");
1366    /// # list.append_value("bar");
1367    /// # list.append_value("baz");
1368    /// # list.finish();
1369    /// # obj.finish();
1370    /// # let (metadata, value) = builder.finish();
1371    /// // given a variant like `{"foo": ["bar", "baz"]}`
1372    /// let variant = Variant::new(&metadata, &value);
1373    /// // Accessing a non existent path returns None
1374    /// assert_eq!(variant.get_path(&VariantPath::from("non_existent")), None);
1375    /// // Access obj["foo"]
1376    /// let path = VariantPath::from("foo");
1377    /// let foo = variant.get_path(&path).expect("field `foo` should exist");
1378    /// assert!(foo.as_list().is_some(), "field `foo` should be a list");
1379    /// // Access foo[0]
1380    /// let path = VariantPath::from(0);
1381    /// let bar = foo.get_path(&path).expect("element 0 should exist");
1382    /// // bar is a string
1383    /// assert_eq!(bar.as_string(), Some("bar"));
1384    /// // You can also access nested paths
1385    /// let path = VariantPath::from("foo").join(0);
1386    /// assert_eq!(variant.get_path(&path).unwrap(), bar);
1387    /// ```
1388    pub fn get_path(&self, path: &VariantPath) -> Option<Variant<'_, '_>> {
1389        path.iter()
1390            .try_fold(self.clone(), |output, element| match element {
1391                VariantPathElement::Field { name } => output.get_object_field(name),
1392                VariantPathElement::Index { index } => output.get_list_element(*index),
1393            })
1394    }
1395}
1396
1397impl From<()> for Variant<'_, '_> {
1398    fn from((): ()) -> Self {
1399        Variant::Null
1400    }
1401}
1402
1403impl From<bool> for Variant<'_, '_> {
1404    fn from(value: bool) -> Self {
1405        match value {
1406            true => Variant::BooleanTrue,
1407            false => Variant::BooleanFalse,
1408        }
1409    }
1410}
1411
1412impl From<i8> for Variant<'_, '_> {
1413    fn from(value: i8) -> Self {
1414        Variant::Int8(value)
1415    }
1416}
1417
1418impl From<i16> for Variant<'_, '_> {
1419    fn from(value: i16) -> Self {
1420        Variant::Int16(value)
1421    }
1422}
1423
1424impl From<i32> for Variant<'_, '_> {
1425    fn from(value: i32) -> Self {
1426        Variant::Int32(value)
1427    }
1428}
1429
1430impl From<i64> for Variant<'_, '_> {
1431    fn from(value: i64) -> Self {
1432        Variant::Int64(value)
1433    }
1434}
1435
1436impl From<u8> for Variant<'_, '_> {
1437    fn from(value: u8) -> Self {
1438        // if it fits in i8, use that, otherwise use i16
1439        if let Ok(value) = i8::try_from(value) {
1440            Variant::Int8(value)
1441        } else {
1442            Variant::Int16(i16::from(value))
1443        }
1444    }
1445}
1446
1447impl From<u16> for Variant<'_, '_> {
1448    fn from(value: u16) -> Self {
1449        // if it fits in i16, use that, otherwise use i32
1450        if let Ok(value) = i16::try_from(value) {
1451            Variant::Int16(value)
1452        } else {
1453            Variant::Int32(i32::from(value))
1454        }
1455    }
1456}
1457impl From<u32> for Variant<'_, '_> {
1458    fn from(value: u32) -> Self {
1459        // if it fits in i32, use that, otherwise use i64
1460        if let Ok(value) = i32::try_from(value) {
1461            Variant::Int32(value)
1462        } else {
1463            Variant::Int64(i64::from(value))
1464        }
1465    }
1466}
1467
1468impl From<u64> for Variant<'_, '_> {
1469    fn from(value: u64) -> Self {
1470        // if it fits in i64, use that, otherwise use Decimal16
1471        if let Ok(value) = i64::try_from(value) {
1472            Variant::Int64(value)
1473        } else {
1474            // u64 max is 18446744073709551615, which fits in i128
1475            Variant::Decimal16(VariantDecimal16::try_new(i128::from(value), 0).unwrap())
1476        }
1477    }
1478}
1479
1480impl From<VariantDecimal4> for Variant<'_, '_> {
1481    fn from(value: VariantDecimal4) -> Self {
1482        Variant::Decimal4(value)
1483    }
1484}
1485
1486impl From<VariantDecimal8> for Variant<'_, '_> {
1487    fn from(value: VariantDecimal8) -> Self {
1488        Variant::Decimal8(value)
1489    }
1490}
1491
1492impl From<VariantDecimal16> for Variant<'_, '_> {
1493    fn from(value: VariantDecimal16) -> Self {
1494        Variant::Decimal16(value)
1495    }
1496}
1497
1498impl From<half::f16> for Variant<'_, '_> {
1499    fn from(value: half::f16) -> Self {
1500        Variant::Float(value.into())
1501    }
1502}
1503
1504impl From<f32> for Variant<'_, '_> {
1505    fn from(value: f32) -> Self {
1506        Variant::Float(value)
1507    }
1508}
1509
1510impl From<f64> for Variant<'_, '_> {
1511    fn from(value: f64) -> Self {
1512        Variant::Double(value)
1513    }
1514}
1515
1516impl From<NaiveDate> for Variant<'_, '_> {
1517    fn from(value: NaiveDate) -> Self {
1518        Variant::Date(value)
1519    }
1520}
1521
1522impl From<DateTime<Utc>> for Variant<'_, '_> {
1523    fn from(value: DateTime<Utc>) -> Self {
1524        if value.nanosecond() % 1000 > 0 {
1525            Variant::TimestampNanos(value)
1526        } else {
1527            Variant::TimestampMicros(value)
1528        }
1529    }
1530}
1531
1532impl From<NaiveDateTime> for Variant<'_, '_> {
1533    fn from(value: NaiveDateTime) -> Self {
1534        if value.nanosecond() % 1000 > 0 {
1535            Variant::TimestampNtzNanos(value)
1536        } else {
1537            Variant::TimestampNtzMicros(value)
1538        }
1539    }
1540}
1541
1542impl<'v> From<&'v [u8]> for Variant<'_, 'v> {
1543    fn from(value: &'v [u8]) -> Self {
1544        Variant::Binary(value)
1545    }
1546}
1547
1548impl From<NaiveTime> for Variant<'_, '_> {
1549    fn from(value: NaiveTime) -> Self {
1550        Variant::Time(value)
1551    }
1552}
1553
1554impl From<Uuid> for Variant<'_, '_> {
1555    fn from(value: Uuid) -> Self {
1556        Variant::Uuid(value)
1557    }
1558}
1559
1560impl<'v> From<&'v str> for Variant<'_, 'v> {
1561    fn from(value: &'v str) -> Self {
1562        if value.len() > MAX_SHORT_STRING_BYTES {
1563            Variant::String(value)
1564        } else {
1565            Variant::ShortString(ShortString(value))
1566        }
1567    }
1568}
1569
1570impl TryFrom<(i32, u8)> for Variant<'_, '_> {
1571    type Error = ArrowError;
1572
1573    fn try_from(value: (i32, u8)) -> Result<Self, Self::Error> {
1574        Ok(Variant::Decimal4(VariantDecimal4::try_new(
1575            value.0, value.1,
1576        )?))
1577    }
1578}
1579
1580impl TryFrom<(i64, u8)> for Variant<'_, '_> {
1581    type Error = ArrowError;
1582
1583    fn try_from(value: (i64, u8)) -> Result<Self, Self::Error> {
1584        Ok(Variant::Decimal8(VariantDecimal8::try_new(
1585            value.0, value.1,
1586        )?))
1587    }
1588}
1589
1590impl TryFrom<(i128, u8)> for Variant<'_, '_> {
1591    type Error = ArrowError;
1592
1593    fn try_from(value: (i128, u8)) -> Result<Self, Self::Error> {
1594        Ok(Variant::Decimal16(VariantDecimal16::try_new(
1595            value.0, value.1,
1596        )?))
1597    }
1598}
1599
1600// helper to print <invalid> instead of "<invalid>" in debug mode when a VariantObject or VariantList contains invalid values.
1601struct InvalidVariant;
1602
1603impl std::fmt::Debug for InvalidVariant {
1604    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
1605        write!(f, "<invalid>")
1606    }
1607}
1608
1609// helper to print binary data in hex format in debug mode, as space-separated hex byte values.
1610struct HexString<'a>(&'a [u8]);
1611
1612impl<'a> std::fmt::Debug for HexString<'a> {
1613    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
1614        if let Some((first, rest)) = self.0.split_first() {
1615            write!(f, "{:02x}", first)?;
1616            for b in rest {
1617                write!(f, " {:02x}", b)?;
1618            }
1619        }
1620        Ok(())
1621    }
1622}
1623
1624impl std::fmt::Debug for Variant<'_, '_> {
1625    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
1626        match self {
1627            Variant::Null => write!(f, "Null"),
1628            Variant::BooleanTrue => write!(f, "BooleanTrue"),
1629            Variant::BooleanFalse => write!(f, "BooleanFalse"),
1630            Variant::Int8(v) => f.debug_tuple("Int8").field(v).finish(),
1631            Variant::Int16(v) => f.debug_tuple("Int16").field(v).finish(),
1632            Variant::Int32(v) => f.debug_tuple("Int32").field(v).finish(),
1633            Variant::Int64(v) => f.debug_tuple("Int64").field(v).finish(),
1634            Variant::Float(v) => f.debug_tuple("Float").field(v).finish(),
1635            Variant::Double(v) => f.debug_tuple("Double").field(v).finish(),
1636            Variant::Decimal4(d) => f.debug_tuple("Decimal4").field(d).finish(),
1637            Variant::Decimal8(d) => f.debug_tuple("Decimal8").field(d).finish(),
1638            Variant::Decimal16(d) => f.debug_tuple("Decimal16").field(d).finish(),
1639            Variant::Date(d) => f.debug_tuple("Date").field(d).finish(),
1640            Variant::TimestampMicros(ts) => f.debug_tuple("TimestampMicros").field(ts).finish(),
1641            Variant::TimestampNtzMicros(ts) => {
1642                f.debug_tuple("TimestampNtzMicros").field(ts).finish()
1643            }
1644            Variant::TimestampNanos(ts) => f.debug_tuple("TimestampNanos").field(ts).finish(),
1645            Variant::TimestampNtzNanos(ts) => f.debug_tuple("TimestampNtzNanos").field(ts).finish(),
1646            Variant::Binary(bytes) => write!(f, "Binary({:?})", HexString(bytes)),
1647            Variant::String(s) => f.debug_tuple("String").field(s).finish(),
1648            Variant::Time(s) => f.debug_tuple("Time").field(s).finish(),
1649            Variant::ShortString(s) => f.debug_tuple("ShortString").field(s).finish(),
1650            Variant::Uuid(uuid) => f.debug_tuple("Uuid").field(&uuid).finish(),
1651            Variant::Object(obj) => {
1652                let mut map = f.debug_map();
1653                for res in obj.iter_try() {
1654                    match res {
1655                        Ok((k, v)) => map.entry(&k, &v),
1656                        Err(_) => map.entry(&InvalidVariant, &InvalidVariant),
1657                    };
1658                }
1659                map.finish()
1660            }
1661            Variant::List(arr) => {
1662                let mut list = f.debug_list();
1663                for res in arr.iter_try() {
1664                    match res {
1665                        Ok(v) => list.entry(&v),
1666                        Err(_) => list.entry(&InvalidVariant),
1667                    };
1668                }
1669                list.finish()
1670            }
1671        }
1672    }
1673}
1674
1675#[cfg(test)]
1676mod tests {
1677
1678    use super::*;
1679
1680    #[test]
1681    fn test_empty_variant_will_fail() {
1682        let metadata = VariantMetadata::try_new(&[1, 0, 0]).unwrap();
1683
1684        let err = Variant::try_new_with_metadata(metadata, &[]).unwrap_err();
1685
1686        assert!(matches!(
1687            err,
1688            ArrowError::InvalidArgumentError(ref msg) if msg == "Received empty bytes"));
1689    }
1690
1691    #[test]
1692    fn test_construct_short_string() {
1693        let short_string = ShortString::try_new("norm").expect("should fit in short string");
1694        assert_eq!(short_string.as_str(), "norm");
1695
1696        let long_string = "a".repeat(MAX_SHORT_STRING_BYTES + 1);
1697        let res = ShortString::try_new(&long_string);
1698        assert!(res.is_err());
1699    }
1700
1701    #[test]
1702    fn test_variant_decimal_conversion() {
1703        let decimal4 = VariantDecimal4::try_new(1234_i32, 2).unwrap();
1704        let variant = Variant::from(decimal4);
1705        assert_eq!(variant.as_decimal4(), Some(decimal4));
1706
1707        let decimal8 = VariantDecimal8::try_new(12345678901_i64, 2).unwrap();
1708        let variant = Variant::from(decimal8);
1709        assert_eq!(variant.as_decimal8(), Some(decimal8));
1710
1711        let decimal16 = VariantDecimal16::try_new(123456789012345678901234567890_i128, 2).unwrap();
1712        let variant = Variant::from(decimal16);
1713        assert_eq!(variant.as_decimal16(), Some(decimal16));
1714    }
1715
1716    #[test]
1717    fn test_variant_all_subtypes_debug() {
1718        use crate::VariantBuilder;
1719
1720        let mut builder = VariantBuilder::new();
1721
1722        // Create a root object that contains one of every variant subtype
1723        let mut root_obj = builder.new_object();
1724
1725        // Add primitive types
1726        root_obj.insert("null", ());
1727        root_obj.insert("boolean_true", true);
1728        root_obj.insert("boolean_false", false);
1729        root_obj.insert("int8", 42i8);
1730        root_obj.insert("int16", 1234i16);
1731        root_obj.insert("int32", 123456i32);
1732        root_obj.insert("int64", 1234567890123456789i64);
1733        root_obj.insert("float", 1.234f32);
1734        root_obj.insert("double", 1.23456789f64);
1735
1736        // Add date and timestamp types
1737        let date = chrono::NaiveDate::from_ymd_opt(2024, 12, 25).unwrap();
1738        root_obj.insert("date", date);
1739
1740        let timestamp_utc = chrono::NaiveDate::from_ymd_opt(2024, 12, 25)
1741            .unwrap()
1742            .and_hms_milli_opt(15, 30, 45, 123)
1743            .unwrap()
1744            .and_utc();
1745        root_obj.insert("timestamp_micros", Variant::TimestampMicros(timestamp_utc));
1746
1747        let timestamp_ntz = chrono::NaiveDate::from_ymd_opt(2024, 12, 25)
1748            .unwrap()
1749            .and_hms_milli_opt(15, 30, 45, 123)
1750            .unwrap();
1751        root_obj.insert(
1752            "timestamp_ntz_micros",
1753            Variant::TimestampNtzMicros(timestamp_ntz),
1754        );
1755
1756        let timestamp_nanos_utc = chrono::NaiveDate::from_ymd_opt(2025, 8, 15)
1757            .unwrap()
1758            .and_hms_nano_opt(12, 3, 4, 123456789)
1759            .unwrap()
1760            .and_utc();
1761        root_obj.insert(
1762            "timestamp_nanos",
1763            Variant::TimestampNanos(timestamp_nanos_utc),
1764        );
1765
1766        let timestamp_ntz_nanos = chrono::NaiveDate::from_ymd_opt(2025, 8, 15)
1767            .unwrap()
1768            .and_hms_nano_opt(12, 3, 4, 123456789)
1769            .unwrap();
1770        root_obj.insert(
1771            "timestamp_ntz_nanos",
1772            Variant::TimestampNtzNanos(timestamp_ntz_nanos),
1773        );
1774
1775        // Add decimal types
1776        let decimal4 = VariantDecimal4::try_new(1234i32, 2).unwrap();
1777        root_obj.insert("decimal4", decimal4);
1778
1779        let decimal8 = VariantDecimal8::try_new(123456789i64, 3).unwrap();
1780        root_obj.insert("decimal8", decimal8);
1781
1782        let decimal16 = VariantDecimal16::try_new(123456789012345678901234567890i128, 4).unwrap();
1783        root_obj.insert("decimal16", decimal16);
1784
1785        // Add binary and string types
1786        let binary_data = b"\x01\x02\x03\x04\xde\xad\xbe\xef";
1787        root_obj.insert("binary", binary_data.as_slice());
1788
1789        let long_string =
1790            "This is a long string that exceeds the short string limit and contains emoji 🦀";
1791        root_obj.insert("string", long_string);
1792        root_obj.insert("short_string", "Short string with emoji 🎉");
1793        let time = NaiveTime::from_hms_micro_opt(1, 2, 3, 4).unwrap();
1794        root_obj.insert("time", time);
1795
1796        // Add uuid
1797        let uuid = Uuid::parse_str("67e55044-10b1-426f-9247-bb680e5fe0c8").unwrap();
1798        root_obj.insert("uuid", Variant::Uuid(uuid));
1799
1800        // Add nested object
1801        let mut nested_obj = root_obj.new_object("nested_object");
1802        nested_obj.insert("inner_key1", "inner_value1");
1803        nested_obj.insert("inner_key2", 999i32);
1804        nested_obj.finish();
1805
1806        // Add list with mixed types
1807        let mut mixed_list = root_obj.new_list("mixed_list");
1808        mixed_list.append_value(1i32);
1809        mixed_list.append_value("two");
1810        mixed_list.append_value(true);
1811        mixed_list.append_value(4.0f32);
1812        mixed_list.append_value(());
1813
1814        // Add nested list inside the mixed list
1815        let mut nested_list = mixed_list.new_list();
1816        nested_list.append_value("nested");
1817        nested_list.append_value(10i8);
1818        nested_list.finish();
1819
1820        mixed_list.finish();
1821
1822        root_obj.finish();
1823
1824        let (metadata, value) = builder.finish();
1825        let variant = Variant::try_new(&metadata, &value).unwrap();
1826
1827        // Test Debug formatter (?)
1828        let debug_output = format!("{:?}", variant);
1829
1830        // Verify that the debug output contains all the expected types
1831        assert!(debug_output.contains("\"null\": Null"));
1832        assert!(debug_output.contains("\"boolean_true\": BooleanTrue"));
1833        assert!(debug_output.contains("\"boolean_false\": BooleanFalse"));
1834        assert!(debug_output.contains("\"int8\": Int8(42)"));
1835        assert!(debug_output.contains("\"int16\": Int16(1234)"));
1836        assert!(debug_output.contains("\"int32\": Int32(123456)"));
1837        assert!(debug_output.contains("\"int64\": Int64(1234567890123456789)"));
1838        assert!(debug_output.contains("\"float\": Float(1.234)"));
1839        assert!(debug_output.contains("\"double\": Double(1.23456789"));
1840        assert!(debug_output.contains("\"date\": Date(2024-12-25)"));
1841        assert!(debug_output.contains("\"timestamp_micros\": TimestampMicros("));
1842        assert!(debug_output.contains("\"timestamp_ntz_micros\": TimestampNtzMicros("));
1843        assert!(debug_output.contains("\"timestamp_nanos\": TimestampNanos("));
1844        assert!(debug_output.contains("\"timestamp_ntz_nanos\": TimestampNtzNanos("));
1845        assert!(debug_output.contains("\"decimal4\": Decimal4("));
1846        assert!(debug_output.contains("\"decimal8\": Decimal8("));
1847        assert!(debug_output.contains("\"decimal16\": Decimal16("));
1848        assert!(debug_output.contains("\"binary\": Binary(01 02 03 04 de ad be ef)"));
1849        assert!(debug_output.contains("\"string\": String("));
1850        assert!(debug_output.contains("\"short_string\": ShortString("));
1851        assert!(debug_output.contains("\"uuid\": Uuid(67e55044-10b1-426f-9247-bb680e5fe0c8)"));
1852        assert!(debug_output.contains("\"time\": Time(01:02:03.000004)"));
1853        assert!(debug_output.contains("\"nested_object\":"));
1854        assert!(debug_output.contains("\"mixed_list\":"));
1855
1856        let expected = r#"{"binary": Binary(01 02 03 04 de ad be ef), "boolean_false": BooleanFalse, "boolean_true": BooleanTrue, "date": Date(2024-12-25), "decimal16": Decimal16(VariantDecimal16 { integer: 123456789012345678901234567890, scale: 4 }), "decimal4": Decimal4(VariantDecimal4 { integer: 1234, scale: 2 }), "decimal8": Decimal8(VariantDecimal8 { integer: 123456789, scale: 3 }), "double": Double(1.23456789), "float": Float(1.234), "int16": Int16(1234), "int32": Int32(123456), "int64": Int64(1234567890123456789), "int8": Int8(42), "mixed_list": [Int32(1), ShortString(ShortString("two")), BooleanTrue, Float(4.0), Null, [ShortString(ShortString("nested")), Int8(10)]], "nested_object": {"inner_key1": ShortString(ShortString("inner_value1")), "inner_key2": Int32(999)}, "null": Null, "short_string": ShortString(ShortString("Short string with emoji 🎉")), "string": String("This is a long string that exceeds the short string limit and contains emoji 🦀"), "time": Time(01:02:03.000004), "timestamp_micros": TimestampMicros(2024-12-25T15:30:45.123Z), "timestamp_nanos": TimestampNanos(2025-08-15T12:03:04.123456789Z), "timestamp_ntz_micros": TimestampNtzMicros(2024-12-25T15:30:45.123), "timestamp_ntz_nanos": TimestampNtzNanos(2025-08-15T12:03:04.123456789), "uuid": Uuid(67e55044-10b1-426f-9247-bb680e5fe0c8)}"#;
1857        assert_eq!(debug_output, expected);
1858
1859        // Test alternate Debug formatter (#?)
1860        let alt_debug_output = format!("{:#?}", variant);
1861        let expected = r#"{
1862    "binary": Binary(01 02 03 04 de ad be ef),
1863    "boolean_false": BooleanFalse,
1864    "boolean_true": BooleanTrue,
1865    "date": Date(
1866        2024-12-25,
1867    ),
1868    "decimal16": Decimal16(
1869        VariantDecimal16 {
1870            integer: 123456789012345678901234567890,
1871            scale: 4,
1872        },
1873    ),
1874    "decimal4": Decimal4(
1875        VariantDecimal4 {
1876            integer: 1234,
1877            scale: 2,
1878        },
1879    ),
1880    "decimal8": Decimal8(
1881        VariantDecimal8 {
1882            integer: 123456789,
1883            scale: 3,
1884        },
1885    ),
1886    "double": Double(
1887        1.23456789,
1888    ),
1889    "float": Float(
1890        1.234,
1891    ),
1892    "int16": Int16(
1893        1234,
1894    ),
1895    "int32": Int32(
1896        123456,
1897    ),
1898    "int64": Int64(
1899        1234567890123456789,
1900    ),
1901    "int8": Int8(
1902        42,
1903    ),
1904    "mixed_list": [
1905        Int32(
1906            1,
1907        ),
1908        ShortString(
1909            ShortString(
1910                "two",
1911            ),
1912        ),
1913        BooleanTrue,
1914        Float(
1915            4.0,
1916        ),
1917        Null,
1918        [
1919            ShortString(
1920                ShortString(
1921                    "nested",
1922                ),
1923            ),
1924            Int8(
1925                10,
1926            ),
1927        ],
1928    ],
1929    "nested_object": {
1930        "inner_key1": ShortString(
1931            ShortString(
1932                "inner_value1",
1933            ),
1934        ),
1935        "inner_key2": Int32(
1936            999,
1937        ),
1938    },
1939    "null": Null,
1940    "short_string": ShortString(
1941        ShortString(
1942            "Short string with emoji 🎉",
1943        ),
1944    ),
1945    "string": String(
1946        "This is a long string that exceeds the short string limit and contains emoji 🦀",
1947    ),
1948    "time": Time(
1949        01:02:03.000004,
1950    ),
1951    "timestamp_micros": TimestampMicros(
1952        2024-12-25T15:30:45.123Z,
1953    ),
1954    "timestamp_nanos": TimestampNanos(
1955        2025-08-15T12:03:04.123456789Z,
1956    ),
1957    "timestamp_ntz_micros": TimestampNtzMicros(
1958        2024-12-25T15:30:45.123,
1959    ),
1960    "timestamp_ntz_nanos": TimestampNtzNanos(
1961        2025-08-15T12:03:04.123456789,
1962    ),
1963    "uuid": Uuid(
1964        67e55044-10b1-426f-9247-bb680e5fe0c8,
1965    ),
1966}"#;
1967        assert_eq!(alt_debug_output, expected);
1968    }
1969}