node_buffer.h

// Copyright Joyent, Inc. and other Node contributors.
//
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// 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,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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// USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SRC_NODE_BUFFER_H_
#define SRC_NODE_BUFFER_H_

#include "node.h"
#include "v8.h"

namespace node {

namespace Buffer {

static const size_t kMaxLength = v8::Uint8Array::kMaxLength;

typedef void (*FreeCallback)(char* data, void* hint);

NODE_EXTERN bool HasInstance(v8::Local<v8::Value> val);
NODE_EXTERN bool HasInstance(v8::Local<v8::Object> val);
NODE_EXTERN char* Data(v8::Local<v8::Value> val);
NODE_EXTERN char* Data(v8::Local<v8::Object> val);
NODE_EXTERN size_t Length(v8::Local<v8::Value> val);
NODE_EXTERN size_t Length(v8::Local<v8::Object> val);

// public constructor - data is copied
NODE_EXTERN v8::MaybeLocal<v8::Object> Copy(v8::Isolate* isolate,
                                            const char* data,
                                            size_t len);

// public constructor
NODE_EXTERN v8::MaybeLocal<v8::Object> New(v8::Isolate* isolate, size_t length);

// public constructor from string
NODE_EXTERN v8::MaybeLocal<v8::Object> New(v8::Isolate* isolate,
                                           v8::Local<v8::String> string,
                                           enum encoding enc = UTF8);

// public constructor - data is used, callback is passed data on object gc
NODE_EXTERN v8::MaybeLocal<v8::Object> New(v8::Isolate* isolate,
                                           char* data,
                                           size_t length,
                                           FreeCallback callback,
                                           void* hint);

// public constructor - data is used.
NODE_EXTERN v8::MaybeLocal<v8::Object> New(v8::Isolate* isolate,
                                           char* data,
                                           size_t len);

// Creates a Buffer instance over an existing ArrayBuffer.
NODE_EXTERN v8::MaybeLocal<v8::Uint8Array> New(v8::Isolate* isolate,
                                               v8::Local<v8::ArrayBuffer> ab,
                                               size_t byte_offset,
                                               size_t length);

// This is verbose to be explicit with inline commenting
static inline bool IsWithinBounds(size_t off, size_t len, size_t max) {
  // Asking to seek too far into the buffer
  // check to avoid wrapping in subsequent subtraction
  if (off > max)
    return false;

  // Asking for more than is left over in the buffer
  if (max - off < len)
    return false;

  // Otherwise we're in bounds
  return true;
}

}  // namespace Buffer
}  // namespace node

#endif  // SRC_NODE_BUFFER_H_