1 files changed, 218 insertions, 0 deletions
diff --git a/llvm/lib/Support/DataExtractor.cpp b/llvm/lib/Support/DataExtractor.cpp
new file mode 100644
index 0000000000000..a98297cdb35f2
--- /dev/null
+++ b/llvm/lib/Support/DataExtractor.cpp
@@ -0,0 +1,218 @@
+//===-- DataExtractor.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Errc.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/SwapByteOrder.h"
+
+using namespace llvm;
+
+static void unexpectedEndReached(Error *E) {
+  if (E)
+    *E = createStringError(errc::illegal_byte_sequence,
+                           "unexpected end of data");
+}
+
+static bool isError(Error *E) { return E && *E; }
+
+template <typename T>
+static T getU(uint64_t *offset_ptr, const DataExtractor *de,
+              bool isLittleEndian, const char *Data, llvm::Error *Err) {
+  ErrorAsOutParameter ErrAsOut(Err);
+  T val = 0;
+  if (isError(Err))
+    return val;
+
+  uint64_t offset = *offset_ptr;
+  if (!de->isValidOffsetForDataOfSize(offset, sizeof(T))) {
+    unexpectedEndReached(Err);
+    return val;
+  }
+  std::memcpy(&val, &Data[offset], sizeof(val));
+  if (sys::IsLittleEndianHost != isLittleEndian)
+    sys::swapByteOrder(val);
+
+  // Advance the offset
+  *offset_ptr += sizeof(val);
+  return val;
+}
+
+template <typename T>
+static T *getUs(uint64_t *offset_ptr, T *dst, uint32_t count,
+                const DataExtractor *de, bool isLittleEndian, const char *Data,
+                llvm::Error *Err) {
+  ErrorAsOutParameter ErrAsOut(Err);
+  if (isError(Err))
+    return nullptr;
+
+  uint64_t offset = *offset_ptr;
+
+  if (!de->isValidOffsetForDataOfSize(offset, sizeof(*dst) * count)) {
+    unexpectedEndReached(Err);
+    return nullptr;
+  }
+  for (T *value_ptr = dst, *end = dst + count; value_ptr != end;
+       ++value_ptr, offset += sizeof(*dst))
+    *value_ptr = getU<T>(offset_ptr, de, isLittleEndian, Data, Err);
+  // Advance the offset
+  *offset_ptr = offset;
+  // Return a non-NULL pointer to the converted data as an indicator of
+  // success
+  return dst;
+}
+
+uint8_t DataExtractor::getU8(uint64_t *offset_ptr, llvm::Error *Err) const {
+  return getU<uint8_t>(offset_ptr, this, IsLittleEndian, Data.data(), Err);
+}
+
+uint8_t *
+DataExtractor::getU8(uint64_t *offset_ptr, uint8_t *dst, uint32_t count) const {
+  return getUs<uint8_t>(offset_ptr, dst, count, this, IsLittleEndian,
+                        Data.data(), nullptr);
+}
+
+uint8_t *DataExtractor::getU8(Cursor &C, uint8_t *Dst, uint32_t Count) const {
+  return getUs<uint8_t>(&C.Offset, Dst, Count, this, IsLittleEndian,
+                        Data.data(), &C.Err);
+}
+
+uint16_t DataExtractor::getU16(uint64_t *offset_ptr, llvm::Error *Err) const {
+  return getU<uint16_t>(offset_ptr, this, IsLittleEndian, Data.data(), Err);
+}
+
+uint16_t *DataExtractor::getU16(uint64_t *offset_ptr, uint16_t *dst,
+                                uint32_t count) const {
+  return getUs<uint16_t>(offset_ptr, dst, count, this, IsLittleEndian,
+                         Data.data(), nullptr);
+}
+
+uint32_t DataExtractor::getU24(uint64_t *offset_ptr) const {
+  uint24_t ExtractedVal =
+      getU<uint24_t>(offset_ptr, this, IsLittleEndian, Data.data(), nullptr);
+  // The 3 bytes are in the correct byte order for the host.
+  return ExtractedVal.getAsUint32(sys::IsLittleEndianHost);
+}
+
+uint32_t DataExtractor::getU32(uint64_t *offset_ptr, llvm::Error *Err) const {
+  return getU<uint32_t>(offset_ptr, this, IsLittleEndian, Data.data(), Err);
+}
+
+uint32_t *DataExtractor::getU32(uint64_t *offset_ptr, uint32_t *dst,
+                                uint32_t count) const {
+  return getUs<uint32_t>(offset_ptr, dst, count, this, IsLittleEndian,
+                         Data.data(), nullptr);
+}
+
+uint64_t DataExtractor::getU64(uint64_t *offset_ptr, llvm::Error *Err) const {
+  return getU<uint64_t>(offset_ptr, this, IsLittleEndian, Data.data(), Err);
+}
+
+uint64_t *DataExtractor::getU64(uint64_t *offset_ptr, uint64_t *dst,
+                                uint32_t count) const {
+  return getUs<uint64_t>(offset_ptr, dst, count, this, IsLittleEndian,
+                         Data.data(), nullptr);
+}
+
+uint64_t DataExtractor::getUnsigned(uint64_t *offset_ptr, uint32_t byte_size,
+                                    llvm::Error *Err) const {
+  switch (byte_size) {
+  case 1:
+    return getU8(offset_ptr, Err);
+  case 2:
+    return getU16(offset_ptr, Err);
+  case 4:
+    return getU32(offset_ptr, Err);
+  case 8:
+    return getU64(offset_ptr, Err);
+  }
+  llvm_unreachable("getUnsigned unhandled case!");
+}
+
+int64_t
+DataExtractor::getSigned(uint64_t *offset_ptr, uint32_t byte_size) const {
+  switch (byte_size) {
+  case 1:
+    return (int8_t)getU8(offset_ptr);
+  case 2:
+    return (int16_t)getU16(offset_ptr);
+  case 4:
+    return (int32_t)getU32(offset_ptr);
+  case 8:
+    return (int64_t)getU64(offset_ptr);
+  }
+  llvm_unreachable("getSigned unhandled case!");
+}
+
+const char *DataExtractor::getCStr(uint64_t *offset_ptr) const {
+  uint64_t offset = *offset_ptr;
+  StringRef::size_type pos = Data.find('\0', offset);
+  if (pos != StringRef::npos) {
+    *offset_ptr = pos + 1;
+    return Data.data() + offset;
+  }
+  return nullptr;
+}
+
+StringRef DataExtractor::getCStrRef(uint64_t *offset_ptr) const {
+  uint64_t Start = *offset_ptr;
+  StringRef::size_type Pos = Data.find('\0', Start);
+  if (Pos != StringRef::npos) {
+    *offset_ptr = Pos + 1;
+    return StringRef(Data.data() + Start, Pos - Start);
+  }
+  return StringRef();
+}
+
+uint64_t DataExtractor::getULEB128(uint64_t *offset_ptr,
+                                   llvm::Error *Err) const {
+  assert(*offset_ptr <= Data.size());
+  ErrorAsOutParameter ErrAsOut(Err);
+  if (isError(Err))
+    return 0;
+
+  const char *error;
+  unsigned bytes_read;
+  uint64_t result = decodeULEB128(
+      reinterpret_cast<const uint8_t *>(Data.data() + *offset_ptr), &bytes_read,
+      reinterpret_cast<const uint8_t *>(Data.data() + Data.size()), &error);
+  if (error) {
+    if (Err)
+      *Err = createStringError(errc::illegal_byte_sequence, error);
+    return 0;
+  }
+  *offset_ptr += bytes_read;
+  return result;
+}
+
+int64_t DataExtractor::getSLEB128(uint64_t *offset_ptr) const {
+  assert(*offset_ptr <= Data.size());
+
+  const char *error;
+  unsigned bytes_read;
+  int64_t result = decodeSLEB128(
+      reinterpret_cast<const uint8_t *>(Data.data() + *offset_ptr), &bytes_read,
+      reinterpret_cast<const uint8_t *>(Data.data() + Data.size()), &error);
+  if (error)
+    return 0;
+  *offset_ptr += bytes_read;
+  return result;
+}
+
+void DataExtractor::skip(Cursor &C, uint64_t Length) const {
+  ErrorAsOutParameter ErrAsOut(&C.Err);
+  if (isError(&C.Err))
+    return;
+
+  if (isValidOffsetForDataOfSize(C.Offset, Length))
+    C.Offset += Length;
+  else
+    unexpectedEndReached(&C.Err);
+}