cargo_openvm/
input.rs

1use std::{fs::read, path::PathBuf, str::FromStr};
2
3use eyre::Result;
4use openvm_sdk::{StdIn, F};
5use openvm_stark_backend::p3_field::FieldAlgebra;
6
7/// Input can be either:
8/// (1) one single hex string
9/// (2) A JSON file containing an array of hex strings.
10/// Each hex string (either in the file or the direct input) is either:
11/// - Hex strings of bytes, which is prefixed with 0x01
12/// - Hex strings of native field elements (represented as u32, little endian), prefixed with 0x02
13#[derive(Debug, Clone)]
14pub enum Input {
15    FilePath(PathBuf),
16    HexBytes(Vec<u8>),
17}
18
19impl FromStr for Input {
20    type Err = String;
21
22    fn from_str(s: &str) -> Result<Self, Self::Err> {
23        if let Ok(bytes) = decode_hex_string(s) {
24            Ok(Input::HexBytes(bytes))
25        } else if PathBuf::from(s).exists() {
26            Ok(Input::FilePath(PathBuf::from(s)))
27        } else {
28            Err("Input must be a valid file path or a hex string of even length.".to_string())
29        }
30    }
31}
32
33pub fn decode_hex_string(s: &str) -> Result<Vec<u8>> {
34    // Remove 0x prefix if present (exactly once)
35    let s = s.strip_prefix("0x").unwrap_or(s);
36    if s.len() % 2 != 0 {
37        return Err(eyre::eyre!("The hex string must be of even length"));
38    }
39    if !s.chars().all(|c| c.is_ascii_hexdigit()) {
40        return Err(eyre::eyre!("The hex string must consist of hex digits"));
41    }
42    if s.starts_with("02") {
43        if s.len() % 8 != 2 {
44            return Err(eyre::eyre!(
45                "If the hex value starts with 02, a whole number of 32-bit elements must follow"
46            ));
47        }
48    } else if !s.starts_with("01") {
49        return Err(eyre::eyre!("The hex value must start with 01 or 02"));
50    }
51    hex::decode(s).map_err(|e| eyre::eyre!("Invalid hex: {}", e))
52}
53
54pub fn read_bytes_into_stdin(stdin: &mut StdIn, bytes: &[u8]) -> Result<()> {
55    // should either write_bytes or write_field
56    match bytes.first() {
57        Some(0x01) => {
58            stdin.write_bytes(&bytes[1..]);
59            Ok(())
60        }
61        Some(0x02) => {
62            let data = &bytes[1..];
63            if data.len() % 4 != 0 {
64                return Err(eyre::eyre!(
65                    "Invalid input format: incorrect number of bytes"
66                ));
67            }
68            let mut fields = Vec::with_capacity(data.len() / 4);
69            for chunk in data.chunks_exact(4) {
70                let value = u32::from_le_bytes(chunk.try_into().unwrap());
71                fields.push(F::from_canonical_u32(value));
72            }
73            stdin.write_field(&fields);
74            Ok(())
75        }
76        _ => Err(eyre::eyre!(
77            "Invalid input format: the first byte must be 0x01 or 0x02"
78        )),
79    }
80}
81
82pub fn read_to_stdin(input: &Option<Input>) -> Result<StdIn> {
83    match input {
84        Some(Input::FilePath(path)) => {
85            let mut stdin = StdIn::default();
86            // read the json
87            let bytes = read(path)?;
88            let json: serde_json::Value = serde_json::from_slice(&bytes)?;
89            json["input"]
90                .as_array()
91                .ok_or_else(|| eyre::eyre!("Input must be an array under 'input' key"))?
92                .iter()
93                .try_for_each(|inner| {
94                    inner
95                        .as_str()
96                        .ok_or_else(|| eyre::eyre!("Each value must be a hex string"))
97                        .and_then(|s| match decode_hex_string(s) {
98                            Err(msg) => Err(eyre::eyre!("Invalid hex string: {}", msg)),
99                            Ok(bytes) => {
100                                read_bytes_into_stdin(&mut stdin, &bytes).expect("Fail: input validation accepted an input, but the deserialization rejected it");
101                                Ok(())
102                            }
103                        })
104                })?;
105
106            Ok(stdin)
107        }
108        Some(Input::HexBytes(bytes)) => {
109            let mut stdin = StdIn::default();
110            read_bytes_into_stdin(&mut stdin, bytes)?;
111            Ok(stdin)
112        }
113        None => Ok(StdIn::default()),
114    }
115}
cargo_openvm/input.rs

cargo_openvm/
input.rs
