Add methods to data extractor for extracting bytes and fixed length C strings.

Summary:
These modificaitons will be used in D74883.

Fixed length C strings can have trailing NULLs or sometimes spaces (BSD archive files), so the fixed length C string defaults to stripping trailing NULLs, but can have the arguments specify to remove one or more kinds of spaces if needed. This is used to extract fixed length C strings from ELF NOTEs in D74883.

Reviewers: labath, dblaikie, aprantl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74991

1 files changed, 15 insertions, 0 deletions

diff --git a/llvm/lib/Support/DataExtractor.cpp b/llvm/lib/Support/DataExtractor.cpp
index a98297c..3d19b4d 100644
--- a/llvm/lib/Support/DataExtractor.cpp
+++ b/llvm/lib/Support/DataExtractor.cpp
@@ -171,6 +171,21 @@ StringRef DataExtractor::getCStrRef(uint64_t *offset_ptr) const {
   return StringRef();
 }
 
+StringRef DataExtractor::getFixedLengthString(uint64_t *OffsetPtr,
+                                              uint64_t Length,
+                                              StringRef TrimChars) const {
+  StringRef Bytes(getBytes(OffsetPtr, Length));
+  return Bytes.trim(TrimChars);
+}
+
+StringRef DataExtractor::getBytes(uint64_t *OffsetPtr, uint64_t Length) const {
+  if (!isValidOffsetForDataOfSize(*OffsetPtr, Length))
+    return StringRef();
+  StringRef Result = Data.substr(*OffsetPtr, Length);
+  *OffsetPtr += Length;
+  return Result;
+}
+
 uint64_t DataExtractor::getULEB128(uint64_t *offset_ptr,
                                    llvm::Error *Err) const {
   assert(*offset_ptr <= Data.size());