[MWRAPPER-123] hash string char-by-char for ksh implementations

[bmarwell]

AIX's ksh's printf %d implementation cannot handle full string input.

Thus, create the hash char-by-char. This is what the implementation would have done anyway.

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[rmannibucau]

ok for me but kind of yet another proof we don't want to have a shell script with any logic so I would move to a java/jsh or anything else script since wrapper will no more be used with older jvm version

[bmarwell]

ok for me but kind of yet another proof we don't want to have a shell script with any logic so I would move to a java/jsh or anything else script since wrapper will no more be used with older jvm version

100 %

I still don't like the subshell (| cut ). If anyone can come up with a better solution, let us know.

[slawekjaranowski]

My test:

hash_string() {
  str="${1:-}" h=0
  while [ -n "$str" ]; do
    c="${str%${str#?}}"
    h=$(( ( h * 31 + $(LC_CTYPE=C printf %d "'$c") ) % 4294967296 ))
    str="${str#?}"
  done
  printf %x\\n $h
}

@bmarwell can you try on AIX?

[bmarwell]

My test:

hash_string() {
  str="${1:-}" h=0
  while [ -n "$str" ]; do
    c="${str%${str#?}}"
    h=$(( ( h * 31 + $(LC_CTYPE=C printf %d "'$c") ) % 4294967296 ))
    str="${str#?}"
  done
  printf %x\\n $h
}

@bmarwell can you try on AIX?

sadly...

# vi test.sh
# ksh test.sh "https://reopsitory/repository/maven-central/org/apache/maven/apache-maven/3.9.6/apache-maven-3.9.6-bin.zip"
printf: 2589392689: A return value of a math subroutine is not within machine precision.
7fffffff

[slawekjaranowski]

just out of curiosity, what result will be:

echo 'T="abcde"; echo "${T#?}"' | bash  

echo 'T="abcde"; echo "${T%${T#?}}"' | bash

[bmarwell]

# echo 'T="abcde"; echo "${T#?}"' | bash
bcde

# echo 'T="abcde"; echo "${T%${T#?}}"' | bash
a

[slawekjaranowski]

# echo 'T="abcde"; echo "${T#?}"' | bash
bcde

# echo 'T="abcde"; echo "${T%${T#?}}"' | bash
a

I thought about test on AIX with ksh ...

[bmarwell]

# echo 'T="abcde"; echo "${T#?}"' | bash
bcde

# echo 'T="abcde"; echo "${T%${T#?}}"' | bash
a

I thought about test on AIX with ksh ...

# echo 'T="abcde"; echo "${T#?}"' | ksh
bcde

echo 'T="abcde"; echo "${T%${T#?}}"' | ksh
a

I think I know what you have in mind...

[bmarwell]

I think we can replace this

  # strings start with index 1
  idx=1

  # lt: skip line break at end
  while [ $idx -lt "$length" ]; do
    char=$( printf "%s" "$str" | cut -c $idx )
    h=$(( ( h * 31 + $(LC_CTYPE=C printf %d "'$char") ) % 4294967296 ))
    idx=$(( idx + 1 ))
  done

with this:

  while [ "$str" != "" ]; do
    char="${str%${str#?}}"
    h=$(( ( h * 31 + $(LC_CTYPE=C printf %d "'$char") ) % 4294967296 ))
    str="${str#?}"
  done