1 files changed, 112 insertions, 0 deletions
diff --git a/tensorflow/core/lib/io/inputbuffer.cc b/tensorflow/core/lib/io/inputbuffer.cc
new file mode 100644
index 0000000000..8fa245a546
--- /dev/null
+++ b/tensorflow/core/lib/io/inputbuffer.cc
@@ -0,0 +1,112 @@
+#include "tensorflow/core/lib/io/inputbuffer.h"
+#include "tensorflow/core/lib/core/errors.h"
+
+namespace tensorflow {
+namespace io {
+
+InputBuffer::InputBuffer(RandomAccessFile* file, size_t buffer_bytes)
+    : file_(file),
+      file_pos_(0),
+      size_(buffer_bytes),
+      buf_(new char[size_]),
+      pos_(buf_),
+      limit_(buf_) {}
+
+InputBuffer::~InputBuffer() {
+  delete file_;
+  delete[] buf_;
+}
+
+Status InputBuffer::FillBuffer() {
+  StringPiece data;
+  Status s = file_->Read(file_pos_, size_, &data, buf_);
+  if (data.data() != buf_) {
+    memmove(buf_, data.data(), data.size());
+  }
+  pos_ = buf_;
+  limit_ = pos_ + data.size();
+  file_pos_ += data.size();
+  return s;
+}
+
+Status InputBuffer::ReadLine(string* result) {
+  result->clear();
+  int i;
+  Status s;
+  for (i = 0;; i++) {
+    if (pos_ == limit_) {
+      // Get more data into buffer
+      s = FillBuffer();
+      if (limit_ == buf_) {
+        break;
+      }
+    }
+    char c = *pos_++;
+    if (c == '\n') {
+      // We don't append the '\n' to *result
+      return Status::OK();
+    }
+    *result += c;
+  }
+  if (errors::IsOutOfRange(s) && !result->empty()) {
+    return Status::OK();
+  }
+  return s;
+}
+
+Status InputBuffer::ReadNBytes(int64 bytes_to_read, string* result) {
+  result->clear();
+  if (bytes_to_read < 0) {
+    return errors::InvalidArgument("Can't read a negative number of bytes: ",
+                                   bytes_to_read);
+  }
+  result->reserve(bytes_to_read);
+  Status s;
+  while (result->size() < static_cast<size_t>(bytes_to_read)) {
+    if (pos_ == limit_) {
+      // Get more data into buffer
+      s = FillBuffer();
+      if (limit_ == buf_) {
+        break;
+      }
+    }
+    const int64 bytes_to_copy =
+        std::min<int64>(limit_ - pos_, bytes_to_read - result->size());
+    result->insert(result->size(), pos_, bytes_to_copy);
+    pos_ += bytes_to_copy;
+  }
+  if (errors::IsOutOfRange(s) &&
+      (result->size() == static_cast<size_t>(bytes_to_read))) {
+    return Status::OK();
+  }
+  return s;
+}
+
+Status InputBuffer::SkipNBytes(int64 bytes_to_skip) {
+  if (bytes_to_skip < 0) {
+    return errors::InvalidArgument("Can only skip forward, not ",
+                                   bytes_to_skip);
+  }
+  int64 bytes_skipped = 0;
+  Status s;
+  while (bytes_skipped < bytes_to_skip) {
+    if (pos_ == limit_) {
+      // Get more data into buffer
+      s = FillBuffer();
+      if (limit_ == buf_) {
+        break;
+      }
+    }
+    const int64 bytes_to_advance =
+        std::min<int64>(limit_ - pos_, bytes_to_skip - bytes_skipped);
+    bytes_skipped += bytes_to_advance;
+    pos_ += bytes_to_advance;
+  }
+  if (errors::IsOutOfRange(s) && bytes_skipped == bytes_to_skip) {
+    return Status::OK();
+  }
+  return s;
+}
+
+}  // namespace io
+}  // namespace tensorflow