1 files changed, 142 insertions, 0 deletions
diff --git a/third_party/rust/goblin/src/strtab.rs b/third_party/rust/goblin/src/strtab.rs
new file mode 100644
index 0000000000..a40d6c9ae5
--- /dev/null
+++ b/third_party/rust/goblin/src/strtab.rs
@@ -0,0 +1,142 @@
+//! A byte-offset based string table.
+//! Commonly used in ELF binaries, Unix archives, and even PE binaries.
+
+use core::ops::Index;
+use core::slice;
+use core::str;
+use core::fmt;
+use scroll::{ctx, Pread};
+if_alloc! {
+    use crate::error;
+    use crate::alloc::vec::Vec;
+}
+
+/// A common string table format which is indexed by byte offsets (and not
+/// member index). Constructed using [`parse`](#method.parse)
+/// with your choice of delimiter. Please be careful.
+pub struct Strtab<'a> {
+    bytes: &'a[u8],
+    delim: ctx::StrCtx,
+}
+
+#[inline(always)]
+fn get_str(offset: usize, bytes: &[u8], delim: ctx::StrCtx) -> scroll::Result<&str> {
+    bytes.pread_with::<&str>(offset, delim)
+}
+
+impl<'a> Strtab<'a> {
+    /// Construct a new strtab with `bytes` as the backing string table, using `delim` as the delimiter between entries
+    pub fn new (bytes: &'a [u8], delim: u8) -> Self {
+        Strtab { delim: ctx::StrCtx::Delimiter(delim), bytes }
+    }
+    /// Construct a strtab from a `ptr`, and a `size`, using `delim` as the delimiter
+    pub unsafe fn from_raw(ptr: *const u8, size: usize, delim: u8) -> Strtab<'a> {
+        Strtab { delim: ctx::StrCtx::Delimiter(delim), bytes: slice::from_raw_parts(ptr, size) }
+    }
+    #[cfg(feature = "alloc")]
+    /// Parses a strtab from `bytes` at `offset` with `len` size as the backing string table, using `delim` as the delimiter
+    pub fn parse(bytes: &'a [u8], offset: usize, len: usize, delim: u8) -> error::Result<Strtab<'a>> {
+        let (end, overflow) = offset.overflowing_add(len);
+        if overflow || end > bytes.len () {
+            return Err(error::Error::Malformed(format!("Strtable size ({}) + offset ({}) is out of bounds for {} #bytes. Overflowed: {}", len, offset, bytes.len(), overflow)));
+        }
+        Ok(Strtab { bytes: &bytes[offset..end], delim: ctx::StrCtx::Delimiter(delim) })
+    }
+    #[cfg(feature = "alloc")]
+    /// Converts the string table to a vector, with the original `delim` used to separate the strings
+    pub fn to_vec(&self) -> error::Result<Vec<&'a str>> {
+        let len = self.bytes.len();
+        let mut strings = Vec::with_capacity(len);
+        let mut i = 0;
+        while i < len {
+            let string = self.get(i).unwrap()?;
+            i = i + string.len() + 1;
+            strings.push(string);
+        }
+        Ok(strings)
+    }
+    /// Safely parses and gets a str reference from the backing bytes starting at byte `offset`.
+    /// If the index is out of bounds, `None` is returned.
+    /// Requires `feature = "alloc"`
+    #[cfg(feature = "alloc")]
+    pub fn get(&self, offset: usize) -> Option<error::Result<&'a str>> {
+        if offset >= self.bytes.len() {
+            None
+        } else {
+            Some(get_str(offset, self.bytes, self.delim).map_err(core::convert::Into::into))
+        }
+    }
+    /// Gets a str reference from the backing bytes starting at byte `offset`.
+    /// If the index is out of bounds, `None` is returned. Panics if bytes are invalid UTF-8.
+    pub fn get_unsafe(&self, offset: usize) -> Option<&'a str> {
+        if offset >= self.bytes.len() {
+            None
+        } else {
+            Some(get_str(offset, self.bytes, self.delim).unwrap())
+        }
+    }
+}
+
+impl<'a> fmt::Debug for Strtab<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("Strtab")
+            .field("delim", &self.delim)
+            .field("bytes", &str::from_utf8(self.bytes))
+            .finish()
+    }
+}
+
+impl<'a> Default for Strtab<'a> {
+    fn default() -> Strtab<'a> {
+        Strtab { bytes: &[], delim: ctx::StrCtx::default() }
+    }
+}
+
+impl<'a> Index<usize> for Strtab<'a> {
+    type Output = str;
+    /// Gets str reference at starting at byte `offset`.
+    /// **NB**: this will panic if the underlying bytes are not valid utf8, or the offset is invalid
+    #[inline(always)]
+    fn index(&self, offset: usize) -> &Self::Output {
+        // This can't delegate to get() because get() requires #[cfg(features = "alloc")]
+        // It's also slightly less useful than get() because the lifetime -- specified by the Index
+        // trait -- matches &self, even though we could return &'a instead
+        get_str(offset, self.bytes, self.delim).unwrap()
+    }
+}
+
+#[test]
+fn as_vec_no_final_null() {
+    let bytes = b"\0printf\0memmove\0busta";
+    let strtab = unsafe { Strtab::from_raw(bytes.as_ptr(), bytes.len(), 0x0) };
+    let vec = strtab.to_vec().unwrap();
+    assert_eq!(vec.len(), 4);
+    assert_eq!(vec, vec!["", "printf", "memmove", "busta"]);
+}
+
+#[test]
+fn as_vec_no_first_null_no_final_null() {
+    let bytes = b"printf\0memmove\0busta";
+    let strtab = unsafe { Strtab::from_raw(bytes.as_ptr(), bytes.len(), 0x0) };
+    let vec = strtab.to_vec().unwrap();
+    assert_eq!(vec.len(), 3);
+    assert_eq!(vec, vec!["printf", "memmove", "busta"]);
+}
+
+#[test]
+fn to_vec_final_null() {
+    let bytes = b"\0printf\0memmove\0busta\0";
+    let strtab = unsafe { Strtab::from_raw(bytes.as_ptr(), bytes.len(), 0x0) };
+    let vec = strtab.to_vec().unwrap();
+    assert_eq!(vec.len(), 4);
+    assert_eq!(vec, vec!["", "printf", "memmove", "busta"]);
+}
+
+#[test]
+fn to_vec_newline_delim() {
+    let bytes = b"\nprintf\nmemmove\nbusta\n";
+    let strtab = unsafe { Strtab::from_raw(bytes.as_ptr(), bytes.len(), b'\n') };
+    let vec = strtab.to_vec().unwrap();
+    assert_eq!(vec.len(), 4);
+    assert_eq!(vec, vec!["", "printf", "memmove", "busta"]);
+}