node/src/node_crypto_bio.h

// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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// USE OR OTHER DEALINGS IN THE SOFTWARE.

#include "openssl/bio.h"
#include <assert.h>

namespace node {

class NodeBIO {
 public:
  static inline BIO_METHOD* GetMethod() {
    return &method_;
  }

  static int New(BIO* bio);
  static int Free(BIO* bio);
  static int Read(BIO* bio, char* out, int len);
  static int Write(BIO* bio, const char* data, int len);
  static int Puts(BIO* bio, const char* str);
  static int Gets(BIO* bio, char* out, int size);
  static long Ctrl(BIO* bio, int cmd, long num, void* ptr);

 protected:
  static const size_t kBufferLength = 16 * 1024;

  class Buffer {
   public:
    Buffer() : read_pos_(0), write_pos_(0), next_(NULL) {
    }

    size_t read_pos_;
    size_t write_pos_;
    Buffer* next_;
    char data_[kBufferLength];
  };

  NodeBIO() : length_(0), read_head_(&head_), write_head_(&head_) {
    // Loop head
    head_.next_ = &head_;
  }

  ~NodeBIO();

  // Read `len` bytes maximum into `out`, return actual number of read bytes
  size_t Read(char* out, size_t size);

  // Memory optimization:
  // Deallocate children of write head's child if they're empty
  void FreeEmpty();

  // Find first appearance of `delim` in buffer or `limit` if `delim`
  // wasn't found.
  size_t IndexOf(char delim, size_t limit);

  // Discard all available data
  void Reset();

  // Put `len` bytes from `data` into buffer
  void Write(const char* data, size_t size);

  // Return size of buffer in bytes
  size_t inline Length() {
    return length_;
  }

  static inline NodeBIO* FromBIO(BIO* bio) {
    assert(bio->ptr != NULL);
    return static_cast<NodeBIO*>(bio->ptr);
  }

  size_t length_;
  Buffer head_;
  Buffer* read_head_;
  Buffer* write_head_;

  static BIO_METHOD method_;
};

} // namespace node