192 lines
4.0 KiB
Bash
192 lines
4.0 KiB
Bash
#!/usr/bin/env bash
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# int.sh - int conversion functions, and other numeric functions
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# int2varint(int)
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function int2varint() {
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# very proud of my implementation; haven't seen anyone use a modulo for this ;p
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local a
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local b
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local c
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local out
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out=$(printf '%02x' "$1")
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if [[ $1 -lt 128 ]]; then
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:
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elif [[ $1 -lt 16384 ]]; then
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a=$(($1%128))
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b=$(($1/128))
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out=$(printf "%02x" $((a+128)))$(printf "%02x" $b)
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elif [[ $1 -lt $((128*128*128)) ]]; then
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a=$(($1%128))
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c=$((($1/128)%128))
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b=$(($1/16384))
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out=$(printf "%02x" $((a+128)))$(printf "%02x" $((c+128)))$(printf "%02x" $b)
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fi
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echo -n "$out"
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}
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# varint2int() <<< varint
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function varint2int() {
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local x
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local uwu
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local out
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out=""
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x=1
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while true; do
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uwu=$(dd count=1 bs=1 status=none | xxd -p)
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out=$((out+((0x$uwu&127)*x)))
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x=$((x*128))
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if [[ $((0x$uwu>>7)) == 0 ]]; then
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break
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fi
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done
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echo -n "$out"
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}
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# decode_position(Position)
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# https://wiki.vg/Protocol#Position
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function decode_position() {
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x=$((0x$1 >> 38))
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y=$((0x$1 & 0xFFF))
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z=$(((0x$1 >> 12) & 0x3FFFFFF))
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[[ $x -gt 33554431 ]] && x=$((x-67108864))
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[[ $y -gt 2047 ]] && y=$((y-4095))
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[[ $z -gt 33554431 ]] && z=$((z-67108864))
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}
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# encode_position(x, y, z)
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function encode_position() {
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local x
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local y
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local z
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x=$1
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y=$2
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z=$3
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[[ $x -lt 33554433 ]] && x=$((x+67108864))
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[[ $y -lt 2049 ]] && y=$((y+4095))
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[[ $z -lt 33554433 ]] && z=$((z+67108864))
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printf "%016x" $((((x & 0x3FFFFFF)<<38) | ((z & 0x3FFFFFF)<<12) | (y & 0xFFF)))
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}
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# packet_len(packet)
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function packet_len() {
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int2varint $((($(echo -n "$1" | wc -c)+1)))
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}
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# hexpacket_len(hexpacket)
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function hexpacket_len() {
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int2varint $((($(echo -n "$1" | unhex | wc -c)+1)))
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}
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# str_len(string)
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function str_len() {
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int2varint $(echo -n "$1" | wc -c)
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}
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# hexstrl_len(hexstring)
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function hexstr_len() {
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int2varint $(echo -n "$1" | unhex | wc -c)
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}
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# hex2bin(hexstring)
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function hex2bin() {
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# \o/
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echo -n "$1" | sed -E 's/0/0000/g;s/1/0001/g;s/2/0010/g;s/3/0011/g;s/4/0100/g;s/5/0101/g;s/6/0110/g;s/7/0111/g;s/8/1000/g;s/9/1001/g;s/a/1010/g;s/b/1011/g;s/c/1100/g;s/d/1101/g;s/e/1110/g;s/f/1111/g'
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}
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# from_ieee754(hexstring)
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# this works only on ints
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function from_ieee754() {
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local sign
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local exponent
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local asdf
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local exponent_
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local val
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val=$(hex2bin "$1")
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sign=$(cut -c 1 <<< $val)
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exponent=$(cut -c 2-12 <<< $val)
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asdf=$(cut -c 13- <<< $val | sed -E 's/./,&/g;s/,//' | tr -d '\n' | awk -F , \
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'{
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power_count=-1
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x=0;
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for(i=1; i<=NF; i++) {
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x=(x + ($i * (2 ** power_count)))
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power_count=power_count-1;
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}
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print(x+1)
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}')
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exponent_=$((2#$exponent))
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if [[ $sign == 0 ]]; then
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echo "$asdf $exponent_" | awk '{print (int($1 * (2 ** ($2 - 1023))))}'
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else
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echo "$asdf $exponent_" | awk '{print -(int($1 * (2 ** ($2 - 1023))))}'
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fi
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}
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# to_ieee754(number)
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# this works only on ints
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function to_ieee754() {
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local n
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local m
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local i
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local sign
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local mantissa
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n=$1
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m=2
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i=0
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sign=0
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if [[ $n -lt 0 ]]; then
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n=$((n-2*n))
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sign=1
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fi
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while true; do
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if [[ $n -lt $((m*2)) ]]; then
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break
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fi
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i=$((i+1))
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m=$((m*2))
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done
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# we need to lie and tell Bash that this string is decimal, even though it's binary
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# otherwise, it will interpret this as octal
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# shh, nobody tell Bash
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mantissa=$(printf "1%010d" $((10#$(hex2bin $(printf "%x" $i)))))
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# leading zeroes kept screwing me over, I'm hardcoding 1 and -1.. and 0
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if [[ $n == -1 ]]; then
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printf "bff0000000000000"
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elif [[ $n == 1 ]]; then
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printf "3ff0000000000000"
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elif [[ $n == 0 ]]; then
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printf "0000000000000000"
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else
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res=$sign$mantissa$(printf "%0$((i+1))d" $(hex2bin $(printf "%x" $((n-m))) | sed -E 's/^0*//'))
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printf "%x" $((2#$res$(repeat $((64-$(echo -n $res | wc -c))) 0)))
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fi
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}
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# to_short(number)
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function to_short() {
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if [[ $1 -lt 0 && $1 -gt -32769 ]]; then
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printf "%04x" $(($1+65536))
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elif [[ $1 -lt 32768 && $1 -gt -1 ]]; then
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printf "%04x" $1
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elif [[ $1 -lt -32768 ]]; then
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printf "8000"
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elif [[ $1 -gt 32767 ]]; then
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printf "7FFF"
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fi
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}
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