遍历字节数组以解析出各个长度 [英] Iterate over byte array to parse out individual lengths

问题描述

我正在通过Core Bluetooth（BLE）从硬件设备读取数据。我正在阅读的一种特性是压缩到单个值的结构。

I am reading data off of a hardware device through Core Bluetooth (BLE). One of the charecteristics I am reading is a struct compressed down to a single value. The struct as programmed to the board looks like this:

typedef struct
{
  uint8          id;
  uint32        dur;
  uint16        dis;
} record;

我要解析的大多数其他特征都是单一类型， uint8 ， uint32 ，依此类推。

Most of the other characteristics I am parsing are of a single type, uint8, uint32, so on.

如何循环遍历字节并进行解析每个单独的特征都是本机类型还是 NSString ？有没有一种方法可以遍历 NSData 对象的字节或子字符串？

How can I loop through the bytes and parse each individual characteristic either to native type or an NSString? Is there a way to iterate over the bytes or substring the NSData object?

NSData *data = [characteristic value]; // characteristic is of type CBCharacteristic
    NSUInteger len = data.length;
    Byte *bytes = (Byte *)[data bytes];
    for (Byte in bytes) { // no fast enumeration here, but the general intention is to iterate byte by byte
        // TODO: parse out uint8
        // TODO: parse out uint32
        // TODO: parse out uint16
    }

推荐答案

您可以执行类似的操作以从数据创建结构实例。

You can do something like this to create an instance of your struct from the data.

typedef struct
{
  uint8          id;
  uint32        dur;
  uint16        dis;
} record;

@implementation YourClass (DataRetrieval)
- (void)process:(CBCharacteristic *)characteristic {
  record r;
  [[characteristic value] getBytes:&r length:sizeof(r)];
  // r.id
  // r.dur
  // r.dis
}
@end

这篇关于遍历字节数组以解析出各个长度的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！