Lucas
19049d2472
Don't set color and return the index instead. This allows also using it for background. Sprinkle a couple of '-nr --' for 'print' calls. Add the fnv1 variant.
84 lines
1.5 KiB
Bash
84 lines
1.5 KiB
Bash
function _color_hash_djb2
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{
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local c h s
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s=$1
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h=${2:-5381}
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while (( ${#s} > 0 )); do
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c=0x${s%${s#??}}
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s=${s#??}
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h=$(( ((($h << 5) + $h) ^ $c) & 0xffff ))
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done
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print -nr -- $h
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}
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function _color_hash_fnv1
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{
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local c h s
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s=$1
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h=${2:-2166136261}
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while (( ${#s} > 0 )); do
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c=0x${s%${s#??}}
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s=${s#??}
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h=$(( (($h << 24) + ($h << 8) +
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($h << 7) + ($h << 4) + ($h << 1) + $h) & 0xffffffff ))
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h=$(( $h ^ $c ))
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done
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# xor-fold to 16 bits
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print -nr -- $(( ($h >> 16) ^ ($h & 0xffff) ))
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}
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function _color_hash_fnv1a
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{
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local c h s
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s=$1
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h=${2:-2166136261}
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while (( ${#s} > 0 )); do
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c=0x${s%${s#??}}
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s=${s#??}
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h=$(( $h ^ $c ))
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h=$(( (($h << 24) + ($h << 8) +
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($h << 7) + ($h << 4) + ($h << 1) + $h) & 0xffffffff ))
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done
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# xor-fold to 16 bits
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print -nr -- $(( ($h >> 16) ^ ($h & 0xffff) ))
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}
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function color_hash
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{
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local bright impl flag h n s
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bright=false
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impl=_color_hash_fnv1a
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while getopts bi: flag; do
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case $flag in
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b) bright=true ;;
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i) if [[ $OPTARG != @(djb2|fnv1|fnv1a) ]]; then
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return 1
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fi
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impl=_color_hash_$OPTARG
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;;
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*) return 1 ;;
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esac
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done
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shift $(($OPTIND - 1))
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h=
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s=$(print -nr -- "$1" | od -A n -t x1 | tr -d '[:space:]*')
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while :; do
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h=$($impl "$s" $h)
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# Avoid modulo bias.
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(( $h >= 4 )) && break
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done
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h=$(( $h % 12 ))
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if $bright; then
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# $h < 6 ? 8 + 1 + $h : 8 + 1 + $h - 6
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n=$(( $h + ($h < 6 ? 9 : 3) ))
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else
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# $h < 6 ? 1 + $h : 8 + 1 + $h - 6
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n=$(( $h + ($h < 6 ? 1 : 3) ))
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fi
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print -nr -- "$n"
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}
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