diff options
Diffstat (limited to 'third_party/rust/base64-0.10.1/examples')
-rw-r--r-- | third_party/rust/base64-0.10.1/examples/make_tables.rs | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/third_party/rust/base64-0.10.1/examples/make_tables.rs b/third_party/rust/base64-0.10.1/examples/make_tables.rs new file mode 100644 index 0000000000..9f170c047a --- /dev/null +++ b/third_party/rust/base64-0.10.1/examples/make_tables.rs @@ -0,0 +1,116 @@ +use std::collections::HashMap; +use std::iter::Iterator; + +fn main() { + println!("pub const INVALID_VALUE: u8 = 255;"); + + // A-Z + let standard_alphabet: Vec<u8> = (0x41..0x5B) + // a-z + .chain(0x61..0x7B) + // 0-9 + .chain(0x30..0x3A) + // + + .chain(0x2B..0x2C) + // / + .chain(0x2F..0x30) + .collect(); + print_encode_table(&standard_alphabet, "STANDARD_ENCODE", 0); + print_decode_table(&standard_alphabet, "STANDARD_DECODE", 0); + + // A-Z + let url_alphabet: Vec<u8> = (0x41..0x5B) + // a-z + .chain(0x61..0x7B) + // 0-9 + .chain(0x30..0x3A) + // - + .chain(0x2D..0x2E) + // _s + .chain(0x5F..0x60) + .collect(); + print_encode_table(&url_alphabet, "URL_SAFE_ENCODE", 0); + print_decode_table(&url_alphabet, "URL_SAFE_DECODE", 0); + + // ./0123456789 + let crypt_alphabet: Vec<u8> = (b'.'..(b'9' + 1)) + // A-Z + .chain(b'A'..(b'Z' + 1)) + // a-z + .chain(b'a'..(b'z' + 1)) + .collect(); + print_encode_table(&crypt_alphabet, "CRYPT_ENCODE", 0); + print_decode_table(&crypt_alphabet, "CRYPT_DECODE", 0); +} + +fn print_encode_table(alphabet: &[u8], const_name: &str, indent_depth: usize) { + println!("#[cfg_attr(rustfmt, rustfmt_skip)]"); + println!( + "{:width$}pub const {}: &'static [u8; 64] = &[", + "", + const_name, + width = indent_depth + ); + + for (i, b) in alphabet.iter().enumerate() { + println!( + "{:width$}{}, // input {} (0x{:X}) => '{}' (0x{:X})", + "", + b, + i, + i, + String::from_utf8(vec![*b as u8]).unwrap(), + b, + width = indent_depth + 4 + ); + } + + println!("{:width$}];", "", width = indent_depth); +} + +fn print_decode_table(alphabet: &[u8], const_name: &str, indent_depth: usize) { + // map of alphabet bytes to 6-bit morsels + let mut input_to_morsel = HashMap::<u8, u8>::new(); + + // standard base64 alphabet bytes, in order + for (morsel, ascii_byte) in alphabet.iter().enumerate() { + // truncation cast is fine here + let _ = input_to_morsel.insert(*ascii_byte, morsel as u8); + } + + println!("#[cfg_attr(rustfmt, rustfmt_skip)]"); + println!( + "{:width$}pub const {}: &'static [u8; 256] = &[", + "", + const_name, + width = indent_depth + ); + for ascii_byte in 0..256 { + let (value, comment) = match input_to_morsel.get(&(ascii_byte as u8)) { + None => ( + "INVALID_VALUE".to_string(), + format!("input {} (0x{:X})", ascii_byte, ascii_byte), + ), + Some(v) => ( + format!("{}", *v), + format!( + "input {} (0x{:X} char '{}') => {} (0x{:X})", + ascii_byte, + ascii_byte, + String::from_utf8(vec![ascii_byte as u8]).unwrap(), + *v, + *v + ), + ), + }; + + println!( + "{:width$}{}, // {}", + "", + value, + comment, + width = indent_depth + 4 + ); + } + println!("{:width$}];", "", width = indent_depth); +} |