股票市场HEX字符串解码异常排查：结果与预期不符求助

待解码的HEX字符串：

34 00 01 31 24 05 00 00 2C 00 41 50 DE C1 28 05 00 00 00 C4 C9 67 02 42 
64 00 00 00 45 41 42 4C 2E 4F 30 30 30 30 20 20 50 62 25 00 00 01 20 10 
27 00 80 00

文档定义的字段规则 #

• Length：偏移0，长度2，小端（Little-Endian）编码的16位无符号整数
• MessageType：偏移2，长度1，单个ASCII字符字节
• Nanosecond：偏移3，长度4，小端编码的32位无符号整数
• Order ID：偏移7，长度8，小端编码的64位无符号整数
• Side：偏移15，长度1，单个ASCII字符字节
• Quantity：偏移16，长度4，小端编码的32位无符号整数
• Symbol：偏移20，长度12，左对齐、右侧补空格的标准ASCII字符
• Price：偏移32，长度4，带四位隐含小数的小端编码有符号32位整数
• Flags：偏移36，长度1，最多8个1位标志的字节（0位为最低有效位）
• Sub Book：偏移37，长度1，8位无符号整数
• SettlementType：偏移38，长度1，单个ASCII字符字节
• Interest Rate：偏移39，长度4，带四位隐含小数的小端编码有符号32位整数
• Term：偏移43，长度1，8位无符号整数

我的Node.js解码代码 #

hexString = hexString.replace(/\s/g, '')

// Convert the hex pairs to a buffer
let buffer = Buffer.from(hexString, 'hex');
// Extract the various fields from the buffer
let length = buffer.readUInt16LE(0);
let messageType = buffer.toString('ascii', 2, 3);
let nanosecond = buffer.readUInt32LE(3);
let orderId = buffer.readBigUInt64LE (7);
let side = buffer.toString('ascii', 15, 16);
let quantity = buffer.readUInt32LE(16);
let symbol = buffer.toString('ascii', 20, 32).replace(/ /g, '');
let price = buffer.readInt32LE(32) / 10000.0;
let flags = buffer.toString('ascii', 36, 37);
let subBook = buffer.toString('ascii', 37, 38);
let settlementType = buffer.toString('ascii', 38, 39);
let interestRate = buffer.readInt32LE(39) / 10000.0;
let term = buffer.toString('ascii', 43, 44);

实际解码结果 #

> Length: 52
> MessageType: ☺
> Nanosecond: 336945
> Order ID: 2936872868291554304
> Side: ♣
> Quantity: 3288334336
> Symbol: Ig☻BdEABL
> Price: 80847.2366
> Flags: 0
> Sub Book: 0
> SettlementType:
> Interest Rate: 62720.0032
> Term:

预期输出结果 #

Length: 52
MessageType: "4"
Nanosecond: 588124
Order ID: 739452273724920
Side: "1"
Quantity: 100
Symbol: "EABL.O0000 Pb"
Price: 25.0
Flags: " "
Sub Book: " "
SettlementType: " "
Interest Rate: 0.0
Term: " "

问题 #

我首次处理此类数据，实际解码结果与预期差异极大，想请教问题出在哪？是解码逻辑错误、文档理解偏差还是编码器问题？烦请帮忙排查。

内容的提问来源于stack exchange，提问作者Kinyua James