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BufferStream.md 6.90 KB

# BufferStream<a name="ZH-CN_TOPIC_0000001055518082"></a>

## **Overview**<a name="section768519582093529"></a>

**Related Modules:**

[Format](Format.md)

**Description:**

Defines the function for reading stream data.

**Since:**

1.0

**Version:**

1.0

## **Summary**<a name="section931399633093529"></a>

## Data Fields<a name="pub-attribs"></a>

<a name="table1452526778093529"></a>
<table><thead align="left"><tr id="row1323234146093529"><th class="cellrowborder" valign="top" width="50%" id="mcps1.1.3.1.1"><p id="p441301631093529"><a name="p441301631093529"></a><a name="p441301631093529"></a>Variable Name</p>
</th>
<th class="cellrowborder" valign="top" width="50%" id="mcps1.1.3.1.2"><p id="p1552533267093529"><a name="p1552533267093529"></a><a name="p1552533267093529"></a>Description</p>
</th>
</tr>
</thead>
<tbody><tr id="row1997461826093529"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.1 "><p id="p1323546637093529"><a name="p1323546637093529"></a><a name="p1323546637093529"></a><a href="BufferStream.md#af0c4387f21bba2c1f02a5310daa95a00">ReadData</a> )(void *<a href="BufferStream.md#ae2019a77aba73fa96d5a716155c7fb7f">handle</a>, uint8_t *data, int32_t size, int32_t timeOutMs, <a href="Format.md#gacff079fdf8427c743f9197ea5be33a7f">DataFlags</a> *flags)</p>
</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.2 "><p id="p766582115093529"><a name="p766582115093529"></a><a name="p766582115093529"></a>int32_t(*&nbsp;</p>
<p id="p387230513093529"><a name="p387230513093529"></a><a name="p387230513093529"></a>Reads data from streams, save the data to the buffer pointed by <strong id="b1222491118093529"><a name="b1222491118093529"></a><a name="b1222491118093529"></a>data</strong> with the specified <strong id="b613371266093529"><a name="b613371266093529"></a><a name="b613371266093529"></a>size</strong>, and returns the size of the read data and type. </p>
</td>
</tr>
<tr id="row1216511084093529"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.1 "><p id="p1406357602093529"><a name="p1406357602093529"></a><a name="p1406357602093529"></a><a href="BufferStream.md#a24e47ffeb7e9c2a8e01f83ffb3a16407">GetReadableSize</a> )(const void *<a href="BufferStream.md#ae2019a77aba73fa96d5a716155c7fb7f">handle</a>)</p>
</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.2 "><p id="p1158899833093529"><a name="p1158899833093529"></a><a name="p1158899833093529"></a>int32_t(*&nbsp;</p>
<p id="p1204108019093529"><a name="p1204108019093529"></a><a name="p1204108019093529"></a>Obtains the size of data that can be read. </p>
</td>
</tr>
<tr id="row328899468093529"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.1 "><p id="p200010745093529"><a name="p200010745093529"></a><a name="p200010745093529"></a><a href="BufferStream.md#ae2019a77aba73fa96d5a716155c7fb7f">handle</a></p>
</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.2 "><p id="p697775831093529"><a name="p697775831093529"></a><a name="p697775831093529"></a>void *&nbsp;</p>
</td>
</tr>
</tbody>
</table>

## **Details**<a name="section1674721808093529"></a>

## **Field Documentation**<a name="section1513064537093529"></a>

## GetReadableSize<a name="a24e47ffeb7e9c2a8e01f83ffb3a16407"></a>

```
int32_t(* BufferStream::GetReadableSize) (const void *[handle](BufferStream.md#ae2019a77aba73fa96d5a716155c7fb7f))
```

**Description:**

Obtains the size of data that can be read.

Before reading data, you should call this function to check whether there is data to read.

**Parameters:**

<a name="table707523236093529"></a>
<table><thead align="left"><tr id="row1227170241093529"><th class="cellrowborder" valign="top" width="50%" id="mcps1.1.3.1.1"><p id="p612879636093529"><a name="p612879636093529"></a><a name="p612879636093529"></a>Name</p>
</th>
<th class="cellrowborder" valign="top" width="50%" id="mcps1.1.3.1.2"><p id="p809849653093529"><a name="p809849653093529"></a><a name="p809849653093529"></a>Description</p>
</th>
</tr>
</thead>
<tbody><tr id="row302141161093529"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.1 ">handle</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.2 ">Indicates the pointer to the context handle. </td>
</tr>
</tbody>
</table>

**Returns:**

Returns the size of the read data.

## handle<a name="ae2019a77aba73fa96d5a716155c7fb7f"></a>

```
void* BufferStream::handle
```

**Description:**

Context handle

## ReadData<a name="af0c4387f21bba2c1f02a5310daa95a00"></a>

```
int32_t(* BufferStream::ReadData) (void *[handle](BufferStream.md#ae2019a77aba73fa96d5a716155c7fb7f), uint8_t *data, int32_t size, int32_t timeOutMs, [DataFlags](Format.md#gacff079fdf8427c743f9197ea5be33a7f) *flags)
```

**Description:**

Reads data from streams, save the data to the buffer pointed by  **data**  with the specified  **size**, and returns the size of the read data and type.

**Parameters:**

<a name="table1931880739093529"></a>
<table><thead align="left"><tr id="row669909289093529"><th class="cellrowborder" valign="top" width="50%" id="mcps1.1.3.1.1"><p id="p335502138093529"><a name="p335502138093529"></a><a name="p335502138093529"></a>Name</p>
</th>
<th class="cellrowborder" valign="top" width="50%" id="mcps1.1.3.1.2"><p id="p1662677005093529"><a name="p1662677005093529"></a><a name="p1662677005093529"></a>Description</p>
</th>
</tr>
</thead>
<tbody><tr id="row1477108758093529"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.1 ">handle</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.2 ">Indicates the pointer to the context handle. </td>
</tr>
<tr id="row1593245296093529"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.1 ">data</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.2 ">Indicates the pointer to the buffer to store the read data. The memory is allocated by the caller. </td>
</tr>
<tr id="row1010827668093529"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.1 ">size</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.2 ">Indicates the size of the available buffer memory. </td>
</tr>
<tr id="row1225687994093529"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.1 ">timeOutMs</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.2 ">Indicates read operation wait time. The value <strong id="b99771570093529"><a name="b99771570093529"></a><a name="b99771570093529"></a>0</strong> means no wait time. </td>
</tr>
<tr id="row962851156093529"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.1 ">flags</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.1.3.1.2 ">Indicates the pointer to the type of the read data, see <a href="Format.md#gacff079fdf8427c743f9197ea5be33a7f">DataFlags</a>. </td>
</tr>
</tbody>
</table>

**Returns:**

Returns the size of the read data.

一键复制编辑原始数据按行查看历史

提交于 2020-09-08 10:08 . add OpenHarmony 1.0 baseline

BufferStream

Overview

Related Modules:

Description:

Defines the function for reading stream data.

Since:

1.0

Version:

1.0

Summary

Data Fields

Variable Name

Description

ReadData )(void *handle, uint8_t *data, int32_t size, int32_t timeOutMs, DataFlags *flags)

int32_t(*

Reads data from streams, save the data to the buffer pointed by data with the specified size, and returns the size of the read data and type.

GetReadableSize )(const void *handle)

int32_t(*

Obtains the size of data that can be read.

void *

Details

Field Documentation

GetReadableSize

int32_t(* BufferStream::GetReadableSize) (const void *[handle](BufferStream.md#ae2019a77aba73fa96d5a716155c7fb7f))

Description:

Obtains the size of data that can be read.

Before reading data, you should call this function to check whether there is data to read.

Parameters:

Name	Description
handle	Indicates the pointer to the context handle.

Returns:

Returns the size of the read data.

handle

void* BufferStream::handle

Description:

Context handle

ReadData

int32_t(* BufferStream::ReadData) (void *[handle](BufferStream.md#ae2019a77aba73fa96d5a716155c7fb7f), uint8_t *data, int32_t size, int32_t timeOutMs, [DataFlags](Format.md#gacff079fdf8427c743f9197ea5be33a7f) *flags)

Description:

Reads data from streams, save the data to the buffer pointed by data with the specified size, and returns the size of the read data and type.

Parameters:

Name	Description
handle	Indicates the pointer to the context handle.
data	Indicates the pointer to the buffer to store the read data. The memory is allocated by the caller.
size	Indicates the size of the available buffer memory.
timeOutMs	Indicates read operation wait time. The value 0 means no wait time.
flags	Indicates the pointer to the type of the read data, see DataFlags.

Returns:

Returns the size of the read data.

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