Parse mojo bytes and group by allocations

parsemojo.go

package main

import (
        "encoding/binary"
        "encoding/hex"
        "flag"
        "fmt"
        "log"
)

func main() {
        flag.Parse()
        input := flag.Arg(0)
        b, err := hex.DecodeString(input)
        if err != nil {
                panic(err)
        }

        for i := 0; i < len(b); {
                if i+4 > len(b) {
                        log.Fatalf("ERROR => Partial size in header")
                }
                if i+8 > len(b) {
                        log.Fatalf("ERROR => Partial elem count in header")
                }
                headSize := int(binary.LittleEndian.Uint32(b[i : i+4]))
                if headSize != 0 && headSize < 8 {
                        log.Fatalf("ERROR => Size was %v, but size must be a minimum of 8 in length for just the header.", headSize)
                }
                elemCount := binary.LittleEndian.Uint32(b[i+4 : i+8])
                if i+headSize > len(b) || i+8 > len(b) {
                        log.Fatalf("ERROR => Cannot perform full read (%v readable elements, but expected %v)", len(b)-i-1, headSize)
                }

                end := headSize
                if headSize == 0 {
                        end = 8
                }
                data := b[i+8 : i+end]
                padding := 8 - (end % 8)
                if padding == 8 {
                        padding = 0
                }
                fmt.Printf("%d\t[%d %d] % x (%d bytes padding)\n", i, headSize, elemCount, data, padding)

                i += end + padding
        }
}