Implement read support for intel hex files, some ObjectFileReader refactoring

src/file.rs

@@ -2,6 +2,7 @@ extern crate object;
 
 use std::fs::File;
 use std::io::prelude::*;
+use std::iter::repeat;
 use std::path::Path;
 use std::path::PathBuf;
 
@@ -29,7 +30,9 @@ struct IhexWriter;
 struct BinWriter;
 
 struct ElfReader;
-struct IhexReader;
+struct IhexReader {
+    file_contents: String,
+}
 struct BinReader {
     filesize: usize,
     file: File,
@@ -47,12 +50,12 @@ impl MemoryFileType {
             _ => None,
         }
     }
-    pub fn read_object_file(
+    pub fn object_file_reader(
         filename: &PathBuf,
     ) -> Result<Box<dyn ObjectFileReader>, std::io::Error> {
         match MemoryFileType::type_from_filename(filename.to_str().unwrap_or("")) {
             Some(MemoryFileType::Elf) => unimplemented!(),
-            Some(MemoryFileType::Ihex) => unimplemented!(),
+            Some(MemoryFileType::Ihex) => IhexReader::new(filename),
             Some(MemoryFileType::Bin) => BinReader::new(filename),
             None => {
                 warn!("Can't determine an appropriate output type based on filename {}, reading as raw binary", filename.to_str().unwrap_or("<invalid utf-8>"));
@@ -85,21 +88,10 @@ pub trait ObjectFileReader {
     fn new(file: &PathBuf) -> Result<Box<dyn ObjectFileReader>, std::io::Error>
     where
         Self: Sized;
-    fn len(&self) -> usize;
-    /// Set buf's contents to the object file's first `text` section, up to `size` bytes
-    fn read_first(
-        &mut self,
-        buf: &mut Vec<u8>,
-        size: Option<u32>,
-    ) -> Result<(), Box<dyn std::error::Error>>;
-    /// Set buf's contents to the object file's contents, starting from LMA `addr`` to a maximum of `size` bytes,
-    /// or to the end of the section containing `addr`
-    fn read_at(
-        &mut self,
-        buf: &mut Vec<u8>,
-        addr: u32,
-        size: Option<u32>,
-    ) -> Result<(), Box<dyn std::error::Error>>;
+    /// Return the base address and entire data of `text` sections in the object file,
+    /// copied into a Vec<u8>. This will allocate the necessary space for the entire memory
+    /// map of the `text` sections, which in some cases is probably a horrible idea.
+    fn read_all(&mut self, size: Option<u32>) -> Result<Vec<u8>, Box<dyn std::error::Error>>;
 }
 
 /// An object that can write a block of memory to a file
@@ -252,36 +244,68 @@ impl ObjectFileReader for BinReader {
         let filesize = file.metadata()?.len().try_into().unwrap();
         Ok(Box::new(BinReader { file, filesize }))
     }
-    fn len(&self) -> usize {
-        self.filesize
-    }
-    fn read_at(
-        &mut self,
-        buf: &mut Vec<u8>,
-        addr: u32,
-        size: Option<u32>,
-    ) -> Result<(), Box<dyn std::error::Error>> {
-        if addr as usize > self.filesize {
-            return Err("Can't read past the end of the file!".into());
-        }
 
-        let size = std::cmp::min(
-            size.unwrap_or(self.filesize as u32 - addr) as usize,
-            self.filesize as usize - addr as usize,
-        );
-
-        self.file.seek(std::io::SeekFrom::Start(addr.into()))?;
-        buf.resize(size as usize, 0);
-        Ok(self.file.read_exact(buf)?)
-    }
-    fn read_first(
-        &mut self,
-        buf: &mut Vec<u8>,
-        size: Option<u32>,
-    ) -> Result<(), Box<dyn std::error::Error>> {
+    fn read_all(&mut self, size: Option<u32>) -> Result<Vec<u8>, Box<dyn std::error::Error>> {
         // The casting here is a bit janky...
         let size = std::cmp::min(size.unwrap_or(self.filesize as u32) as usize, self.filesize);
-        buf.resize(size as usize, 0);
-        Ok(self.file.read_exact(buf)?)
+        let mut buf = Vec::from_iter(std::iter::repeat(0).take(size));
+        self.file.read_exact(&mut buf)?;
+
+        Ok(buf)
+    }
+}
+
+impl ObjectFileReader for IhexReader {
+    fn new(file: &PathBuf) -> Result<Box<dyn ObjectFileReader>, std::io::Error>
+    where
+        Self: Sized,
+    {
+        // Parse the entire file up front, since we need it for len() anyway. Only store the parsed sections.
+        let file_contents = std::fs::read_to_string(file)?;
+
+        Ok(Box::new(IhexReader { file_contents }))
+    }
+    fn read_all(&mut self, size: Option<u32>) -> Result<Vec<u8>, Box<dyn std::error::Error>> {
+        let reader = ihex::Reader::new(&self.file_contents);
+        let mut cur_base = 0;
+        let mut data = Vec::new();
+        for rec in reader {
+            if let Ok(record) = rec {
+                match record {
+                    ihex::Record::ExtendedLinearAddress(a) => {
+                        cur_base = (a as u32) << 16;
+                        debug!(
+                            "ihex: Got ExtendedLinearAddress, new base: {:08x}",
+                            (a as u32) << 16
+                        );
+                    }
+                    // Entry point address is not useful for a flash tool, but it is emitted by objcopy etc. so we need to support/ignore it
+                    ihex::Record::StartSegmentAddress { .. }
+                    | ihex::Record::StartLinearAddress(_) => (),
+
+                    ihex::Record::Data { offset, mut value } => {
+                        let record_base = cur_base + (offset as u32);
+                        if (data.len() as u32) < record_base {
+                            debug!("Extending vec by {} to take up slack space", (record_base as usize) - data.len());
+                            data.extend(repeat(0xff).take((record_base as usize) - data.len()));
+                        }
+                        data.append(&mut value);
+                    }
+                    ihex::Record::EndOfFile => continue,
+                    _ => unimplemented!(
+                        "Only I32HEX format files are supported. We don't support record type {:?}",
+                        record
+                    ),
+                }
+            } else {
+                return Err(std::io::Error::new(
+                    std::io::ErrorKind::InvalidData,
+                    rec.unwrap_err().to_string(),
+                )
+                .into());
+            }
+        }
+
+        Ok(data)
     }
 }

src/main.rs

@@ -117,12 +117,9 @@ impl ObjectFileType {
             Self::Elf => MemoryFileType::Elf.mem_writer(),
         }
     }
-    fn file_reader(
-        &self,
-        filename: &PathBuf,
-    ) -> Result<Box<dyn ObjectFileReader>, std::io::Error> {
+    fn file_reader(&self, filename: &PathBuf) -> Result<Box<dyn ObjectFileReader>, std::io::Error> {
         match self {
-            Self::Auto => MemoryFileType::read_object_file(filename),
+            Self::Auto => MemoryFileType::object_file_reader(filename),
             _ => unimplemented!(),
         }
     }