From 6aa9095865017c06a61f0cb10c1f1231a89b761c Mon Sep 17 00:00:00 2001
From: Benjamin Barenblat <bbaren@mit.edu>
Date: Sun, 21 Feb 2016 19:23:11 -0500
Subject: Implement fgetattr and read

---
 src/posix_extras.cc | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

(limited to 'src/posix_extras.cc')

diff --git a/src/posix_extras.cc b/src/posix_extras.cc
index 7529251..ac6e3b2 100644
--- a/src/posix_extras.cc
+++ b/src/posix_extras.cc
@@ -16,9 +16,11 @@
 
 #include <array>
 #include <cerrno>
+#include <cstdint>
 #include <experimental/optional>
 #include <stdexcept>
 #include <system_error>
+#include <vector>
 
 #include <dirent.h>
 #include <fcntl.h>
@@ -101,6 +103,22 @@ File File::OpenAt(const char* const path, const int flags,
   return result;
 }
 
+std::vector<std::uint8_t> File::Read(off_t offset, size_t bytes) const {
+  std::vector<std::uint8_t> result(bytes, 0);
+  size_t cursor = 0;
+  ssize_t bytes_read;
+  while (0 < (bytes_read = pread(fd_, result.data() + cursor, bytes, offset))) {
+    cursor += static_cast<size_t>(bytes_read);
+    offset += bytes_read;
+    bytes -= static_cast<size_t>(bytes_read);
+  }
+  if (bytes_read == -1) {
+    throw SystemError();
+  }
+  result.resize(cursor);
+  return result;
+}
+
 void File::UnlinkAt(const char* const path) const {
   if (path[0] == '/') {
     throw std::invalid_argument("absolute path");
-- 
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