Prepare wpiutil for merge into allwpilib.

wpiutil/src/main/native/include/support/raw_istream.h

@@ -0,0 +1,115 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2015-2018 FIRST. All Rights Reserved.                        */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_RAW_ISTREAM_H_
+#define WPIUTIL_SUPPORT_RAW_ISTREAM_H_
+
+#include <algorithm>
+#include <cstddef>
+#include <system_error>
+
+#include "llvm/SmallVector.h"
+#include "llvm/StringRef.h"
+#include "llvm/Twine.h"
+
+namespace wpi {
+
+class raw_istream {
+ public:
+  raw_istream() = default;
+  virtual ~raw_istream() = default;
+
+  raw_istream& read(char& c) {
+    read_impl(&c, 1);
+    return *this;
+  }
+
+  raw_istream& read(unsigned char& c) {
+    read_impl(&c, 1);
+    return *this;
+  }
+
+  raw_istream& read(signed char& c) {
+    read_impl(&c, 1);
+    return *this;
+  }
+
+  raw_istream& read(void* data, size_t len) {
+    read_impl(data, len);
+    return *this;
+  }
+
+  size_t readsome(void* data, size_t len) {
+    size_t readlen = std::min(in_avail(), len);
+    if (readlen == 0) return 0;
+    read_impl(data, readlen);
+    return readlen;
+  }
+
+  // Read a line from an input stream (up to a maximum length).
+  // The returned buffer will contain the trailing \n (unless the maximum length
+  // was reached).  \r's are stripped from the buffer.
+  // @param buf Buffer for output
+  // @param maxLen Maximum length
+  // @return Line
+  llvm::StringRef getline(llvm::SmallVectorImpl<char>& buf, int maxLen);
+
+  virtual void close() = 0;
+  virtual size_t in_avail() const = 0;
+
+  bool has_error() const { return m_error; }
+  void clear_error() { m_error = false; }
+
+  raw_istream(const raw_istream&) = delete;
+  raw_istream& operator=(const raw_istream&) = delete;
+
+ protected:
+  void error_detected() { m_error = true; }
+
+ private:
+  virtual void read_impl(void* data, size_t len) = 0;
+
+  bool m_error = false;
+};
+
+class raw_mem_istream : public raw_istream {
+ public:
+  explicit raw_mem_istream(llvm::StringRef mem);
+  raw_mem_istream(const char* mem, size_t len) : m_cur(mem), m_left(len) {}
+  void close() override;
+  size_t in_avail() const override;
+
+ private:
+  void read_impl(void* data, size_t len) override;
+
+  const char* m_cur;
+  size_t m_left;
+};
+
+class raw_fd_istream : public raw_istream {
+ public:
+  raw_fd_istream(const llvm::Twine& filename, std::error_code& ec,
+                 size_t bufSize = 4096);
+  raw_fd_istream(int fd, bool shouldClose, size_t bufSize = 4096);
+  ~raw_fd_istream() override;
+  void close() override;
+  size_t in_avail() const override;
+
+ private:
+  void read_impl(void* data, size_t len) override;
+
+  char* m_buf;
+  char* m_cur;
+  char* m_end;
+  size_t m_bufSize;
+  int m_fd;
+  bool m_shouldClose;
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_RAW_ISTREAM_H_