141 lines
4.2 KiB
Markdown
141 lines
4.2 KiB
Markdown
# Buffer
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The `Napi::Buffer` class creates a projection of raw data that can be consumed by
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script.
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## Methods
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### New
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Allocates a new `Napi::Buffer` object with a given length.
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```cpp
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static Napi::Buffer<T> Napi::Buffer::New(napi_env env, size_t length);
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```
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- `[in] env`: The environment in which to create the `Napi::Buffer` object.
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- `[in] length`: The number of `T` elements to allocate.
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Returns a new `Napi::Buffer` object.
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### New
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Wraps the provided external data into a new `Napi::Buffer` object.
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The `Napi::Buffer` object does not assume ownership for the data and expects it to be
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valid for the lifetime of the object. Since the `Napi::Buffer` is subject to garbage
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collection this overload is only suitable for data which is static and never
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needs to be freed.
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```cpp
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static Napi::Buffer<T> Napi::Buffer::New(napi_env env, T* data, size_t length);
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```
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- `[in] env`: The environment in which to create the `Napi::Buffer` object.
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- `[in] data`: The pointer to the external data to expose.
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- `[in] length`: The number of `T` elements in the external data.
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Returns a new `Napi::Buffer` object.
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### New
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Wraps the provided external data into a new `Napi::Buffer` object.
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The `Napi::Buffer` object does not assume ownership for the data and expects it
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to be valid for the lifetime of the object. The data can only be freed once the
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`finalizeCallback` is invoked to indicate that the `Napi::Buffer` has been released.
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```cpp
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template <typename Finalizer>
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static Napi::Buffer<T> Napi::Buffer::New(napi_env env,
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T* data,
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size_t length,
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Finalizer finalizeCallback);
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```
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- `[in] env`: The environment in which to create the `Napi::Buffer` object.
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- `[in] data`: The pointer to the external data to expose.
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- `[in] length`: The number of `T` elements in the external data.
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- `[in] finalizeCallback`: The function to be called when the `Napi::Buffer` is
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destroyed. It must implement `operator()`, accept a `T*` (which is the
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external data pointer), and return `void`.
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Returns a new `Napi::Buffer` object.
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### New
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Wraps the provided external data into a new `Napi::Buffer` object.
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The `Napi::Buffer` object does not assume ownership for the data and expects it to be
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valid for the lifetime of the object. The data can only be freed once the
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`finalizeCallback` is invoked to indicate that the `Napi::Buffer` has been released.
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```cpp
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template <typename Finalizer, typename Hint>
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static Napi::Buffer<T> Napi::Buffer::New(napi_env env,
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T* data,
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size_t length,
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Finalizer finalizeCallback,
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Hint* finalizeHint);
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```
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- `[in] env`: The environment in which to create the `Napi::Buffer` object.
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- `[in] data`: The pointer to the external data to expose.
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- `[in] length`: The number of `T` elements in the external data.
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- `[in] finalizeCallback`: The function to be called when the `Napi::Buffer` is
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destroyed. It must implement `operator()`, accept a `T*` (which is the
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external data pointer) and `Hint*`, and return `void`.
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- `[in] finalizeHint`: The hint to be passed as the second parameter of the
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finalize callback.
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Returns a new `Napi::Buffer` object.
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### Copy
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Allocates a new `Napi::Buffer` object and copies the provided external data into it.
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```cpp
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static Napi::Buffer<T> Napi::Buffer::Copy(napi_env env, const T* data, size_t length);
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```
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- `[in] env`: The environment in which to create the `Napi::Buffer` object.
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- `[in] data`: The pointer to the external data to copy.
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- `[in] length`: The number of `T` elements in the external data.
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Returns a new `Napi::Buffer` object containing a copy of the data.
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### Constructor
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Initializes an empty instance of the `Napi::Buffer` class.
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```cpp
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Napi::Buffer::Buffer();
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```
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### Constructor
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Initializes the `Napi::Buffer` object using an existing Uint8Array.
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```cpp
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Napi::Buffer::Buffer(napi_env env, napi_value value);
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```
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- `[in] env`: The environment in which to create the `Napi::Buffer` object.
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- `[in] value`: The Uint8Array reference to wrap.
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### Data
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```cpp
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T* Napi::Buffer::Data() const;
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```
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Returns a pointer the external data.
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### Length
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```cpp
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size_t Napi::Buffer::Length() const;
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```
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Returns the number of `T` elements in the external data.
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