From c80e4a85126a8a7b57bba679187d2d5acabab5df Mon Sep 17 00:00:00 2001 From: Jonathan Strong Date: Fri, 7 Oct 2022 21:46:32 -0400 Subject: [PATCH] initial commit --- .gitignore | 3 + Cargo.toml | 17 +++++ LICENSE | 18 +++++ README.md | 36 ++++++++++ src/lib.rs | 192 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 266 insertions(+) create mode 100644 .gitignore create mode 100644 Cargo.toml create mode 100644 LICENSE create mode 100644 README.md create mode 100644 src/lib.rs diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..1a1e473 --- /dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +/target +/Cargo.lock +*.swp diff --git a/Cargo.toml b/Cargo.toml new file mode 100644 index 0000000..55fe0d1 --- /dev/null +++ b/Cargo.toml @@ -0,0 +1,17 @@ +[package] +name = "deserialize-file-size" +version = "1.0.0" +edition = "2021" +authors = ["Jonathan Strong "] +description = "A serde helper function for deserializing file size input flexibly and robustly." +repository = "https://git.shipyard.rs/jstrong/deserialize-file-size" +keywords = ["serde", "deserialize", "human", "value formatting"] +readme = "README.md" +license = "MIT" + +[dependencies] +serde = { version = "1", features = ["derive"] } +byte-unit = "4.0.12" + +[dev-dependencies] +serde_json = "1" diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..a0eb8ed --- /dev/null +++ b/LICENSE @@ -0,0 +1,18 @@ +MIT License + +Copyright (c) 2022 Jonathan Strong +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. diff --git a/README.md b/README.md new file mode 100644 index 0000000..48e1c4a --- /dev/null +++ b/README.md @@ -0,0 +1,36 @@ +# deserialize-file-size + +A serde helper function for deserializing file size input +flexibly and robustly. + +Accepts either: + +1) a "human" size string, e.g. "1k", "5mb", "12GiB", etc. +2) an integer number of bytes + +## Example + +```rust +use serde::Deserialize; +use deserialize_file_size::deserialize_file_size; + +#[derive(Deserialize, Debug, PartialEq)] +struct FileSize { + #[serde(deserialize_with = "deserialize_file_size")] + sz: usize, +} + +let size_str = r#"{"sz": "42mb"}"#; +assert_eq!( + serde_json::from_str::(size_str).unwrap(), + FileSize { sz: 1024 * 1024 * 42 }, +); + +let int_bytes = r#"{"sz": 4096}"#; +assert_eq!( + serde_json::from_str::(int_bytes).unwrap(), + FileSize { sz: 4096 }, +); +``` + + diff --git a/src/lib.rs b/src/lib.rs new file mode 100644 index 0000000..28c8537 --- /dev/null +++ b/src/lib.rs @@ -0,0 +1,192 @@ +//! A serde helper function for deserializing file size input +//! flexibly and robustly. +//! +//! Accepts either: +//! +//! 1) a "human" size string, e.g. "1k", "5mb", "12GiB", etc. +//! 2) an integer number of bytes +//! +//! # Examples +//! +//! ``` +//! use serde::Deserialize; +//! use deserialize_file_size::deserialize_file_size; +//! +//! #[derive(Deserialize, Debug, PartialEq)] +//! struct FileSize { +//! #[serde(deserialize_with = "deserialize_file_size")] +//! sz: usize, +//! } +//! +//! let size_str = r#"{"sz": "42mb"}"#; +//! assert_eq!( +//! serde_json::from_str::(size_str).unwrap(), +//! FileSize { sz: 1024 * 1024 * 42 }, +//! ); +//! +//! let int_bytes = r#"{"sz": 4096}"#; +//! assert_eq!( +//! serde_json::from_str::(int_bytes).unwrap(), +//! FileSize { sz: 4096 }, +//! ); +//! ``` + +#![allow(clippy::single_char_pattern)] // annoying, who the f cares "a" vs 'a' + +use std::fmt; +use serde::de::{self, Visitor}; + +/// returns size in bytes if parsing is successful. note: units "k"/"kb", "m"/"mb", +/// and "g"/"gb" are converted to KiB, MiB, and GiB respectively. there are no 1000-based +/// file sizes as far as this implementation is concerned, 1024 is file size god. +pub fn parse_file_size(s: &str) -> Option { + let mut s = s.trim().to_string(); + s[..].make_ascii_lowercase(); + let s = if s.contains("ib") { + s + } else { + s.replace("kb", "k") // first truncate kb/mb/gb -> k/m/g + .replace("mb", "m") + .replace("gb", "g") + .replace("k", "kib") // then transform k/m/g -> kib/mib/gib + .replace("m", "mib") + .replace("g", "gib") + }; + + let bytes: u128 = byte_unit::Byte::from_str(&s) + .ok()? + .get_bytes(); + + usize::try_from(bytes).ok() +} + +/// A serde "deserialize_with" helper function for parsing a `usize` field +/// flexibly and robustly. +/// +/// Accepts input that is either: +/// +/// 1) a "human" size string, e.g. "10k", "42mb", "7GiB", etc. +/// 2) an integer number of bytes +/// +/// To make the point explicit, either `String`/`&str` or integer +/// (`visit_u64`-compatible) input is accepted. +/// +/// # Examples +/// +/// ``` +/// use serde::Deserialize; +/// use deserialize_file_size::deserialize_file_size; +/// +/// #[derive(Deserialize, Debug, PartialEq)] +/// struct FileSize { +/// #[serde(deserialize_with = "deserialize_file_size")] +/// sz: usize, +/// } +/// +/// let size_str = r#"{"sz": "42mb"}"#; +/// assert_eq!( +/// serde_json::from_str::(size_str).unwrap(), +/// FileSize { sz: 1024 * 1024 * 42 }, +/// ); +/// +/// let int_bytes = r#"{"sz": 4096}"#; +/// assert_eq!( +/// serde_json::from_str::(int_bytes).unwrap(), +/// FileSize { sz: 4096 }, +/// ); +/// ``` +pub fn deserialize_file_size<'de, D>(deserializer: D) -> Result + where D: serde::de::Deserializer<'de> +{ + struct SizeStringOrUsize; + + impl<'de> Visitor<'de> for SizeStringOrUsize { + type Value = usize; + + fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { + formatter.write_str("file size string or integer number of bytes") + } + + fn visit_str(self, value: &str) -> Result + where + E: de::Error, + { + match parse_file_size(value) { + Some(size) => Ok(size), + None => { + Err(serde::de::Error::custom(format!( + "parsing file size input '{}' failed; expected number followed \ + by human size abbreviation (e.g. 10k/5mb/15GiB) or integer number \ + of bytes", + value, + ))) + } + } + } + + fn visit_u64(self, value: u64) -> Result + where E: de::Error, + { + Ok(value as usize) + } + } + + deserializer.deserialize_any(SizeStringOrUsize) +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn check_file_size_parser_against_several_inputs() { + assert_eq!(parse_file_size("1k") , Some(1024)); + assert_eq!(parse_file_size("1kib") , Some(1024)); + assert_eq!(parse_file_size("1K") , Some(1024)); + assert_eq!(parse_file_size("1Kb") , Some(1024)); + assert_eq!(parse_file_size("1kb") , Some(1024)); + assert_eq!(parse_file_size("1 kb") , Some(1024)); + assert_eq!(parse_file_size("1 k") , Some(1024)); + assert_eq!(parse_file_size("1 kib") , Some(1024)); + + assert_eq!(parse_file_size("1m") , Some(1024 * 1024)); + assert_eq!(parse_file_size("1mib") , Some(1024 * 1024)); + assert_eq!(parse_file_size("1M") , Some(1024 * 1024)); + assert_eq!(parse_file_size("1Mb") , Some(1024 * 1024)); + assert_eq!(parse_file_size("1MB") , Some(1024 * 1024)); + assert_eq!(parse_file_size("1mb") , Some(1024 * 1024)); + assert_eq!(parse_file_size("1 MB") , Some(1024 * 1024)); + + assert_eq!(parse_file_size("1g") , Some(1024 * 1024 * 1024)); + assert_eq!(parse_file_size("1gib") , Some(1024 * 1024 * 1024)); + assert_eq!(parse_file_size("1G") , Some(1024 * 1024 * 1024)); + assert_eq!(parse_file_size("1Gb") , Some(1024 * 1024 * 1024)); + assert_eq!(parse_file_size("1gb") , Some(1024 * 1024 * 1024)); + assert_eq!(parse_file_size("1 gb") , Some(1024 * 1024 * 1024)); + assert_eq!(parse_file_size("1 g") , Some(1024 * 1024 * 1024)); + assert_eq!(parse_file_size("1 Gib") , Some(1024 * 1024 * 1024)); + + assert_eq!(parse_file_size("48G") , Some( 48 * 1024 * 1024 * 1024)); + assert_eq!(parse_file_size("96G") , Some( 96 * 1024 * 1024 * 1024)); + assert_eq!(parse_file_size("2G") , Some( 2 * 1024 * 1024 * 1024)); + assert_eq!(parse_file_size("128G"), Some(128 * 1024 * 1024 * 1024)); + } + + #[test] + fn check_deserialize_file_size() { + #[derive(serde::Deserialize)] + struct A { + #[serde(deserialize_with = "deserialize_file_size")] + sz: usize, + } + + assert_eq!( + serde_json::from_str::(r#"{"sz":"1mb"}"#).unwrap().sz, + 1024 * 1024, + ); + assert_eq!( + serde_json::from_str::(r#"{"sz":4096}"#).unwrap().sz, + 4096, + ); + } +}