reading_data.go

package main

import (
    "bytes"
    "encoding/binary"
    "fmt"
)

/**
 * basically just grab a subsection of the buffer
 */
func ReadData(msg *MessageBuffer, length int) []byte {
    start := msg.index
    msg.index += length
    return msg.buffer[start:msg.index]
}

/**
 * Keep building a string until we hit a null
 */
func ReadString(msg *MessageBuffer) string {
    var buffer bytes.Buffer

    // find the next null (terminates the string)
    for i:=0; msg.buffer[msg.index]!=0; i++ {
        // we hit the end without finding a null
        if msg.index == len(msg.buffer) {
            break;
        }

        buffer.WriteString(string(msg.buffer[msg.index]))
        msg.index++
    }

    msg.index++
    return buffer.String()
}

/**
 * Read 4 bytes as a Long
 */
func ReadLong(msg *MessageBuffer) int32 {
    var tmp struct {
        Value int32
    }

    r := bytes.NewReader(msg.buffer[msg.index:])
    if err := binary.Read(r, binary.LittleEndian, &tmp); err != nil {
        fmt.Println("binary.Read failed:", err)
    }

    msg.index += 4
    return tmp.Value
}

/**
 * Read two bytes as a Short
 */
func ReadShort(msg *MessageBuffer) int16 {
    var tmp struct {
        Value int16
    }

    r := bytes.NewReader(msg.buffer[msg.index:])
    if err := binary.Read(r, binary.LittleEndian, &tmp); err != nil {
        fmt.Println("binary.Read failed:", err)
    }

    msg.index += 2
    return tmp.Value
}

// for consistency
func ReadByte(msg *MessageBuffer) byte {
    val := byte(msg.buffer[msg.index])
    msg.index++
    return val
}