From 4f9fe856a25ab29345b90e7725509e9ee38a37be Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:19:41 +0200 Subject: Adding upstream version 1.69.0+dfsg1. Signed-off-by: Daniel Baumann --- vendor/gimli-0.26.2/src/leb128.rs | 612 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 612 insertions(+) create mode 100644 vendor/gimli-0.26.2/src/leb128.rs (limited to 'vendor/gimli-0.26.2/src/leb128.rs') diff --git a/vendor/gimli-0.26.2/src/leb128.rs b/vendor/gimli-0.26.2/src/leb128.rs new file mode 100644 index 000000000..de81cfdcf --- /dev/null +++ b/vendor/gimli-0.26.2/src/leb128.rs @@ -0,0 +1,612 @@ +//! Read and write DWARF's "Little Endian Base 128" (LEB128) variable length +//! integer encoding. +//! +//! The implementation is a direct translation of the psuedocode in the DWARF 4 +//! standard's appendix C. +//! +//! Read and write signed integers: +//! +//! ``` +//! # #[cfg(all(feature = "read", feature = "write"))] { +//! use gimli::{EndianSlice, NativeEndian, leb128}; +//! +//! let mut buf = [0; 1024]; +//! +//! // Write to anything that implements `std::io::Write`. +//! { +//! let mut writable = &mut buf[..]; +//! leb128::write::signed(&mut writable, -12345).expect("Should write number"); +//! } +//! +//! // Read from anything that implements `gimli::Reader`. +//! let mut readable = EndianSlice::new(&buf[..], NativeEndian); +//! let val = leb128::read::signed(&mut readable).expect("Should read number"); +//! assert_eq!(val, -12345); +//! # } +//! ``` +//! +//! Or read and write unsigned integers: +//! +//! ``` +//! # #[cfg(all(feature = "read", feature = "write"))] { +//! use gimli::{EndianSlice, NativeEndian, leb128}; +//! +//! let mut buf = [0; 1024]; +//! +//! { +//! let mut writable = &mut buf[..]; +//! leb128::write::unsigned(&mut writable, 98765).expect("Should write number"); +//! } +//! +//! let mut readable = EndianSlice::new(&buf[..], NativeEndian); +//! let val = leb128::read::unsigned(&mut readable).expect("Should read number"); +//! assert_eq!(val, 98765); +//! # } +//! ``` + +const CONTINUATION_BIT: u8 = 1 << 7; +#[cfg(feature = "read-core")] +const SIGN_BIT: u8 = 1 << 6; + +#[inline] +fn low_bits_of_byte(byte: u8) -> u8 { + byte & !CONTINUATION_BIT +} + +#[inline] +#[allow(dead_code)] +fn low_bits_of_u64(val: u64) -> u8 { + let byte = val & u64::from(core::u8::MAX); + low_bits_of_byte(byte as u8) +} + +/// A module for reading signed and unsigned integers that have been LEB128 +/// encoded. +#[cfg(feature = "read-core")] +pub mod read { + use super::{low_bits_of_byte, CONTINUATION_BIT, SIGN_BIT}; + use crate::read::{Error, Reader, Result}; + + /// Read bytes until the LEB128 continuation bit is not set. + pub fn skip(r: &mut R) -> Result<()> { + loop { + let byte = r.read_u8()?; + if byte & CONTINUATION_BIT == 0 { + return Ok(()); + } + } + } + + /// Read an unsigned LEB128 number from the given `Reader` and + /// return it or an error if reading failed. + pub fn unsigned(r: &mut R) -> Result { + let mut result = 0; + let mut shift = 0; + + loop { + let byte = r.read_u8()?; + if shift == 63 && byte != 0x00 && byte != 0x01 { + return Err(Error::BadUnsignedLeb128); + } + + let low_bits = u64::from(low_bits_of_byte(byte)); + result |= low_bits << shift; + + if byte & CONTINUATION_BIT == 0 { + return Ok(result); + } + + shift += 7; + } + } + + /// Read an LEB128 u16 from the given `Reader` and + /// return it or an error if reading failed. + pub fn u16(r: &mut R) -> Result { + let byte = r.read_u8()?; + let mut result = u16::from(low_bits_of_byte(byte)); + if byte & CONTINUATION_BIT == 0 { + return Ok(result); + } + + let byte = r.read_u8()?; + result |= u16::from(low_bits_of_byte(byte)) << 7; + if byte & CONTINUATION_BIT == 0 { + return Ok(result); + } + + let byte = r.read_u8()?; + if byte > 0x03 { + return Err(Error::BadUnsignedLeb128); + } + result += u16::from(byte) << 14; + Ok(result) + } + + /// Read a signed LEB128 number from the given `Reader` and + /// return it or an error if reading failed. + pub fn signed(r: &mut R) -> Result { + let mut result = 0; + let mut shift = 0; + let size = 64; + let mut byte; + + loop { + byte = r.read_u8()?; + if shift == 63 && byte != 0x00 && byte != 0x7f { + return Err(Error::BadSignedLeb128); + } + + let low_bits = i64::from(low_bits_of_byte(byte)); + result |= low_bits << shift; + shift += 7; + + if byte & CONTINUATION_BIT == 0 { + break; + } + } + + if shift < size && (SIGN_BIT & byte) == SIGN_BIT { + // Sign extend the result. + result |= !0 << shift; + } + + Ok(result) + } +} + +/// A module for writing integers encoded as LEB128. +#[cfg(feature = "write")] +pub mod write { + use super::{low_bits_of_u64, CONTINUATION_BIT}; + use std::io; + + /// Write the given unsigned number using the LEB128 encoding to the given + /// `std::io::Write`able. Returns the number of bytes written to `w`, or an + /// error if writing failed. + pub fn unsigned(w: &mut W, mut val: u64) -> Result + where + W: io::Write, + { + let mut bytes_written = 0; + loop { + let mut byte = low_bits_of_u64(val); + val >>= 7; + if val != 0 { + // More bytes to come, so set the continuation bit. + byte |= CONTINUATION_BIT; + } + + let buf = [byte]; + w.write_all(&buf)?; + bytes_written += 1; + + if val == 0 { + return Ok(bytes_written); + } + } + } + + /// Return the size of the LEB128 encoding of the given unsigned number. + pub fn uleb128_size(mut val: u64) -> usize { + let mut size = 0; + loop { + val >>= 7; + size += 1; + if val == 0 { + return size; + } + } + } + + /// Write the given signed number using the LEB128 encoding to the given + /// `std::io::Write`able. Returns the number of bytes written to `w`, or an + /// error if writing failed. + pub fn signed(w: &mut W, mut val: i64) -> Result + where + W: io::Write, + { + let mut bytes_written = 0; + loop { + let mut byte = val as u8; + // Keep the sign bit for testing + val >>= 6; + let done = val == 0 || val == -1; + if done { + byte &= !CONTINUATION_BIT; + } else { + // Remove the sign bit + val >>= 1; + // More bytes to come, so set the continuation bit. + byte |= CONTINUATION_BIT; + } + + let buf = [byte]; + w.write_all(&buf)?; + bytes_written += 1; + + if done { + return Ok(bytes_written); + } + } + } + + /// Return the size of the LEB128 encoding of the given signed number. + pub fn sleb128_size(mut val: i64) -> usize { + let mut size = 0; + loop { + val >>= 6; + let done = val == 0 || val == -1; + val >>= 1; + size += 1; + if done { + return size; + } + } + } +} + +#[cfg(test)] +#[cfg(all(feature = "read", feature = "write"))] +mod tests { + use super::{low_bits_of_byte, low_bits_of_u64, read, write, CONTINUATION_BIT}; + use crate::endianity::NativeEndian; + use crate::read::{EndianSlice, Error, ReaderOffsetId}; + + trait ResultExt { + fn map_eof(self, input: &[u8]) -> Self; + } + + impl ResultExt for Result { + fn map_eof(self, input: &[u8]) -> Self { + match self { + Err(Error::UnexpectedEof(id)) => { + let id = ReaderOffsetId(id.0 - input.as_ptr() as u64); + Err(Error::UnexpectedEof(id)) + } + r => r, + } + } + } + + #[test] + fn test_low_bits_of_byte() { + for i in 0..127 { + assert_eq!(i, low_bits_of_byte(i)); + assert_eq!(i, low_bits_of_byte(i | CONTINUATION_BIT)); + } + } + + #[test] + fn test_low_bits_of_u64() { + for i in 0u64..127 { + assert_eq!(i as u8, low_bits_of_u64(1 << 16 | i)); + assert_eq!( + i as u8, + low_bits_of_u64(i << 16 | i | (u64::from(CONTINUATION_BIT))) + ); + } + } + + // Examples from the DWARF 4 standard, section 7.6, figure 22. + #[test] + fn test_read_unsigned() { + let buf = [2u8]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + 2, + read::unsigned(&mut readable).expect("Should read number") + ); + + let buf = [127u8]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + 127, + read::unsigned(&mut readable).expect("Should read number") + ); + + let buf = [CONTINUATION_BIT, 1]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + 128, + read::unsigned(&mut readable).expect("Should read number") + ); + + let buf = [1u8 | CONTINUATION_BIT, 1]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + 129, + read::unsigned(&mut readable).expect("Should read number") + ); + + let buf = [2u8 | CONTINUATION_BIT, 1]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + 130, + read::unsigned(&mut readable).expect("Should read number") + ); + + let buf = [57u8 | CONTINUATION_BIT, 100]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + 12857, + read::unsigned(&mut readable).expect("Should read number") + ); + } + + // Examples from the DWARF 4 standard, section 7.6, figure 23. + #[test] + fn test_read_signed() { + let buf = [2u8]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!(2, read::signed(&mut readable).expect("Should read number")); + + let buf = [0x7eu8]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!(-2, read::signed(&mut readable).expect("Should read number")); + + let buf = [127u8 | CONTINUATION_BIT, 0]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + 127, + read::signed(&mut readable).expect("Should read number") + ); + + let buf = [1u8 | CONTINUATION_BIT, 0x7f]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + -127, + read::signed(&mut readable).expect("Should read number") + ); + + let buf = [CONTINUATION_BIT, 1]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + 128, + read::signed(&mut readable).expect("Should read number") + ); + + let buf = [CONTINUATION_BIT, 0x7f]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + -128, + read::signed(&mut readable).expect("Should read number") + ); + + let buf = [1u8 | CONTINUATION_BIT, 1]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + 129, + read::signed(&mut readable).expect("Should read number") + ); + + let buf = [0x7fu8 | CONTINUATION_BIT, 0x7e]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + -129, + read::signed(&mut readable).expect("Should read number") + ); + } + + #[test] + fn test_read_signed_63_bits() { + let buf = [ + CONTINUATION_BIT, + CONTINUATION_BIT, + CONTINUATION_BIT, + CONTINUATION_BIT, + CONTINUATION_BIT, + CONTINUATION_BIT, + CONTINUATION_BIT, + CONTINUATION_BIT, + 0x40, + ]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + -0x4000_0000_0000_0000, + read::signed(&mut readable).expect("Should read number") + ); + } + + #[test] + fn test_read_unsigned_not_enough_data() { + let buf = [CONTINUATION_BIT]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + read::unsigned(&mut readable).map_eof(&buf), + Err(Error::UnexpectedEof(ReaderOffsetId(1))) + ); + } + + #[test] + fn test_read_signed_not_enough_data() { + let buf = [CONTINUATION_BIT]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + read::signed(&mut readable).map_eof(&buf), + Err(Error::UnexpectedEof(ReaderOffsetId(1))) + ); + } + + #[test] + fn test_write_unsigned_not_enough_space() { + let mut buf = [0; 1]; + let mut writable = &mut buf[..]; + match write::unsigned(&mut writable, 128) { + Err(e) => assert_eq!(e.kind(), std::io::ErrorKind::WriteZero), + otherwise => panic!("Unexpected: {:?}", otherwise), + } + } + + #[test] + fn test_write_signed_not_enough_space() { + let mut buf = [0; 1]; + let mut writable = &mut buf[..]; + match write::signed(&mut writable, 128) { + Err(e) => assert_eq!(e.kind(), std::io::ErrorKind::WriteZero), + otherwise => panic!("Unexpected: {:?}", otherwise), + } + } + + #[test] + fn dogfood_signed() { + fn inner(i: i64) { + let mut buf = [0u8; 1024]; + + { + let mut writable = &mut buf[..]; + write::signed(&mut writable, i).expect("Should write signed number"); + } + + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + let result = read::signed(&mut readable).expect("Should be able to read it back again"); + assert_eq!(i, result); + } + for i in -513..513 { + inner(i); + } + inner(core::i64::MIN); + } + + #[test] + fn dogfood_unsigned() { + for i in 0..1025 { + let mut buf = [0u8; 1024]; + + { + let mut writable = &mut buf[..]; + write::unsigned(&mut writable, i).expect("Should write signed number"); + } + + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + let result = + read::unsigned(&mut readable).expect("Should be able to read it back again"); + assert_eq!(i, result); + } + } + + #[test] + fn test_read_unsigned_overflow() { + let buf = [ + 2u8 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 1, + ]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert!(read::unsigned(&mut readable).is_err()); + } + + #[test] + fn test_read_signed_overflow() { + let buf = [ + 2u8 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 2 | CONTINUATION_BIT, + 1, + ]; + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert!(read::signed(&mut readable).is_err()); + } + + #[test] + fn test_read_multiple() { + let buf = [2u8 | CONTINUATION_BIT, 1u8, 1u8]; + + let mut readable = EndianSlice::new(&buf[..], NativeEndian); + assert_eq!( + read::unsigned(&mut readable).expect("Should read first number"), + 130u64 + ); + assert_eq!( + read::unsigned(&mut readable).expect("Should read first number"), + 1u64 + ); + } + + #[test] + fn test_read_u16() { + for (buf, val) in [ + (&[2][..], 2), + (&[0x7f][..], 0x7f), + (&[0x80, 1][..], 0x80), + (&[0x81, 1][..], 0x81), + (&[0x82, 1][..], 0x82), + (&[0xff, 0x7f][..], 0x3fff), + (&[0x80, 0x80, 1][..], 0x4000), + (&[0xff, 0xff, 1][..], 0x7fff), + (&[0xff, 0xff, 3][..], 0xffff), + ] + .iter() + { + let mut readable = EndianSlice::new(buf, NativeEndian); + assert_eq!(*val, read::u16(&mut readable).expect("Should read number")); + } + + for buf in [ + &[0x80][..], + &[0x80, 0x80][..], + &[0x80, 0x80, 4][..], + &[0x80, 0x80, 0x80, 3][..], + ] + .iter() + { + let mut readable = EndianSlice::new(buf, NativeEndian); + assert!(read::u16(&mut readable).is_err(), "{:?}", buf); + } + } +} -- cgit v1.2.3