1 files changed, 92 insertions, 0 deletions
diff --git a/tensorflow/core/lib/io/path.cc b/tensorflow/core/lib/io/path.cc
new file mode 100644
index 0000000000..1359ded0f0
--- /dev/null
+++ b/tensorflow/core/lib/io/path.cc
@@ -0,0 +1,92 @@
+#include "tensorflow/core/lib/io/path.h"
+#include "tensorflow/core/lib/strings/strcat.h"
+
+namespace tensorflow {
+namespace io {
+
+string JoinPath(StringPiece part1, StringPiece part2) {
+  string result;
+
+  StringPiece paths[2] = {part1, part2};
+  for (StringPiece path : paths) {
+    if (path.empty()) continue;
+
+    if (result.empty()) {
+      result = path.ToString();
+      continue;
+    }
+
+    if (result[result.size() - 1] == '/') {
+      if (IsAbsolutePath(path)) {
+        strings::StrAppend(&result, path.substr(1));
+      } else {
+        strings::StrAppend(&result, path);
+      }
+    } else {
+      if (IsAbsolutePath(path)) {
+        strings::StrAppend(&result, path);
+      } else {
+        strings::StrAppend(&result, "/", path);
+      }
+    }
+  }
+
+  return result;
+}
+
+namespace internal {
+
+// Return the parts of the path, split on the final "/".  If there is no
+// "/" in the path, the first part of the output is empty and the second
+// is the input. If the only "/" in the path is the first character, it is
+// the first part of the output.
+std::pair<StringPiece, StringPiece> SplitPath(StringPiece path) {
+  auto pos = path.rfind('/');
+
+  // Handle the case with no '/' in 'path'.
+  if (pos == StringPiece::npos)
+    return std::make_pair(StringPiece(path.data(), 0), path);
+
+  // Handle the case with a single leading '/' in 'path'.
+  if (pos == 0)
+    return std::make_pair(StringPiece(path.data(), 1),
+                          StringPiece(path.data() + 1, path.size() - 1));
+
+  return std::make_pair(
+      StringPiece(path.data(), pos),
+      StringPiece(path.data() + pos + 1, path.size() - (pos + 1)));
+}
+
+// Return the parts of the basename of path, split on the final ".".
+// If there is no "." in the basename or "." is the final character in the
+// basename, the second value will be empty.
+std::pair<StringPiece, StringPiece> SplitBasename(StringPiece path) {
+  path = Basename(path);
+
+  auto pos = path.rfind('.');
+  if (pos == StringPiece::npos)
+    return std::make_pair(path, StringPiece(path.data() + path.size(), 0));
+  return std::make_pair(
+      StringPiece(path.data(), pos),
+      StringPiece(path.data() + pos + 1, path.size() - (pos + 1)));
+}
+}  // namespace internal
+
+bool IsAbsolutePath(StringPiece path) {
+  return !path.empty() && path[0] == '/';
+}
+
+StringPiece Dirname(StringPiece path) {
+  return internal::SplitPath(path).first;
+}
+
+StringPiece Basename(StringPiece path) {
+  return internal::SplitPath(path).second;
+}
+
+StringPiece Extension(StringPiece path) {
+  return internal::SplitBasename(path).second;
+}
+
+}  // namespace io
+}  // namespace tensorflow