rustao 0.2.0

Rust SDK for the AO protocol on Arweave
Documentation 
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use base64::{engine::general_purpose::URL_SAFE_NO_PAD, Engine as _};
use sha2::{Digest, Sha256};

/// Encode bytes to base64url (no padding).
pub fn base64url_encode(data: &[u8]) -> String {
    URL_SAFE_NO_PAD.encode(data)
}

/// Decode a base64url string to bytes (handles missing padding).
pub fn base64url_decode(s: &str) -> Result<Vec<u8>, base64::DecodeError> {
    URL_SAFE_NO_PAD.decode(s)
}

/// SHA‑256 hash.
pub fn sha256(data: &[u8]) -> Vec<u8> {
    Sha256::digest(data).to_vec()
}

/// Write an LEB128 varint to a buffer.
pub fn write_varint(buf: &mut Vec<u8>, mut value: u64) {
    loop {
        let mut byte = (value & 0x7F) as u8;
        value >>= 7;
        if value != 0 {
            byte |= 0x80;
        }
        buf.push(byte);
        if value == 0 {
            break;
        }
    }
}

/// Read an LEB128 varint from a slice, starting at `pos`.
/// Returns (value, new_pos).
pub fn read_varint(data: &[u8], mut pos: usize) -> Result<(u64, usize), String> {
    let mut value = 0u64;
    let mut shift = 0;
    loop {
        if pos >= data.len() {
            return Err("unexpected end of data".to_string());
        }
        let byte = data[pos];
        pos += 1;
        value |= ((byte & 0x7F) as u64) << shift;
        shift += 7;
        if (byte & 0x80) == 0 {
            break;
        }
        if shift >= 64 {
            return Err("varint too long".to_string());
        }
    }
    Ok((value, pos))
}

/// Number of bytes needed to encode a varint.
pub fn len_varint(mut value: u64) -> usize {
    if value == 0 {
        return 1;
    }
    let mut len = 0;
    while value > 0 {
        value >>= 7;
        len += 1;
    }
    len
}