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Extract gwilym_encoding into its own file

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Gwilym Inzani 2024-04-03 10:35:05 +01:00
parent 51de2ffa60
commit 219fc1e0bc
2 changed files with 94 additions and 78 deletions
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91
agb-addr2line/src/gwilym_encoding.rs Normal file
View file

@ -0,0 +1,91 @@
use std::{slice::ChunksExact, sync::OnceLock};
const ALPHABET: &[u8] = b"0123456789=ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz";
// pub fn encode_16(input: u16) -> [u8; 3] {
// let input = input as usize;
// [
// ALPHABET[input >> (16 - 5)],
// ALPHABET[(input >> (16 - 10)) & 0b11111],
// ALPHABET[input & 0b111111],
// ]
// }
// pub fn encode_32(input: u32) -> [u8; 6] {
// let input = input as usize;
// let output_16 = encode_16(input as u16);
// [
// ALPHABET[(input >> (32 - 5)) | 0b100000],
// ALPHABET[(input >> (32 - 10)) & 0b11111],
// ALPHABET[(input >> (32 - 16)) & 0b111111],
// output_16[0],
// output_16[1],
// output_16[2],
// ]
// }
pub fn gwilym_decode(input: &str) -> anyhow::Result<GwilymDecodeIter<'_>> {
GwilymDecodeIter::new(input)
}
pub struct GwilymDecodeIter<'a> {
chunks: ChunksExact<'a, u8>,
}
impl<'a> GwilymDecodeIter<'a> {
fn new(input: &'a str) -> anyhow::Result<Self> {
let Some((input, version)) = input.rsplit_once('v') else {
anyhow::bail!("Does not contain version");
};
if version != "1" {
anyhow::bail!("Only version 1 is supported");
}
if input.len() % 3 != 0 {
anyhow::bail!("Input string must have length a multiple of 3");
}
Ok(Self {
chunks: input.as_bytes().chunks_exact(3),
})
}
}
impl<'a> Iterator for GwilymDecodeIter<'a> {
type Item = u32;
fn next(&mut self) -> Option<Self::Item> {
let Some(chunk) = self.chunks.next() else {
return None;
};
let value = decode_chunk(chunk);
if value & (1 << 17) != 0 {
return Some(self.next().unwrap_or(0) | (value << 16));
}
Some(value | 0x0800_0000)
}
}
fn decode_chunk(chunk: &[u8]) -> u32 {
let a = get_value_for_char(chunk[0]);
let b = get_value_for_char(chunk[1]);
let c = get_value_for_char(chunk[2]);
(a << (16 - 5)) | (b << (16 - 10)) | c
}
fn get_value_for_char(input: u8) -> u32 {
static REVERSE_ALHPABET: OnceLock<[u8; 128]> = OnceLock::new();
REVERSE_ALHPABET.get_or_init(|| {
let mut result = [0; 128];
for (i, &c) in ALPHABET.iter().enumerate() {
result[c as usize] = i as u8;
}
result
})[input as usize] as u32
}

81
agb-addr2line/src/main.rs
View file

@ -10,6 +10,8 @@ use addr2line::{gimli, object};
use clap::Parser; use clap::Parser;
use colored::Colorize; use colored::Colorize;
mod gwilym_encoding;
#[derive(Parser, Debug)] #[derive(Parser, Debug)]
#[command(version, about, long_about = None)] #[command(version, about, long_about = None)]
struct Args { struct Args {
@ -48,7 +50,7 @@ fn main() -> anyhow::Result<()> {
let ctx = addr2line::Context::new(&object)?; let ctx = addr2line::Context::new(&object)?;
for (i, address) in gwilym_encoding::decode(&cli.dump)?.into_iter().enumerate() { for (i, address) in gwilym_encoding::gwilym_decode(&cli.dump)?.enumerate() {
print_address(&ctx, i, address.into(), modification_time)?; print_address(&ctx, i, address.into(), modification_time)?;
} }
@ -179,80 +181,3 @@ fn is_interesting_function(function_name: &str, path: &str) -> bool {
true true
} }
mod gwilym_encoding {
use std::sync::OnceLock;
const ALPHABET: &[u8] = b"0123456789=ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz";
// pub fn encode_16(input: u16) -> [u8; 3] {
// let input = input as usize;
// [
// ALPHABET[input >> (16 - 5)],
// ALPHABET[(input >> (16 - 10)) & 0b11111],
// ALPHABET[input & 0b111111],
// ]
// }
// pub fn encode_32(input: u32) -> [u8; 6] {
// let input = input as usize;
// let output_16 = encode_16(input as u16);
// [
// ALPHABET[(input >> (32 - 5)) | 0b100000],
// ALPHABET[(input >> (32 - 10)) & 0b11111],
// ALPHABET[(input >> (32 - 16)) & 0b111111],
// output_16[0],
// output_16[1],
// output_16[2],
// ]
// }
pub fn decode(input: &str) -> anyhow::Result<Vec<u32>> {
let Some((input, version)) = input.rsplit_once('v') else {
anyhow::bail!("Does not contain version");
};
if version != "1" {
anyhow::bail!("Only version 1 is supported");
}
let mut result = vec![];
let mut previous_value = None;
for chunk in input.as_bytes().chunks_exact(3) {
let value = decode_chunk(chunk);
if value & (1 << 17) != 0 {
previous_value = Some(value << 16);
} else if let Some(upper_bits) = previous_value {
result.push(upper_bits | value);
previous_value = None;
} else {
result.push(value | 0x0800_0000);
}
}
Ok(result)
}
fn decode_chunk(chunk: &[u8]) -> u32 {
let a = get_value_for_char(chunk[0]);
let b = get_value_for_char(chunk[1]);
let c = get_value_for_char(chunk[2]);
(a << (16 - 5)) | (b << (16 - 10)) | c
}
fn get_value_for_char(input: u8) -> u32 {
static REVERSE_ALHPABET: OnceLock<[u8; 128]> = OnceLock::new();
REVERSE_ALHPABET.get_or_init(|| {
let mut result = [0; 128];
for (i, &c) in ALPHABET.iter().enumerate() {
result[c as usize] = i as u8;
}
result
})[input as usize] as u32
}
}