bxstr

#!/bin/bash
## bxstrudel
function string:lenght {
	local input="$1"
	local total_width=0
	local char

	while IFS= read -rn1 char; do
		test -z "$char" && break 
		local cdp=$(printf '%d' "'${char}")
		((total_width += 1))
		# Check for double-width characters using Unicode ranges
		((
			(cdp >= 0x1100 && cdp <= 0x115F) ||
				(cdp >= 0x2E80 && cdp <= 0xA4CF) ||
				(cdp >= 0xAC00 && cdp <= 0xD7A3) ||
				(cdp >= 0xF900 && cdp <= 0xFAFF) ||
				(cdp >= 0xFE10 && cdp <= 0xFE6F) ||
				(cdp >= 0xFF00 && cdp <= 0xFF60) ||
				(cdp >= 0xFFE0 && cdp <= 0xFFE6) ||
				(cdp >= 0x1F300 && cdp <= 0x1F64F) ||
				(cdp >= 0x1F900 && cdp <= 0x1F9FF) ||
				(cdp >= 0x20000 && cdp <= 0x2FFFD) ||
				(cdp >= 0x30000 && cdp <= 0x3FFFD)
		)) &&
			((total_width += 1))
	done <<< "$input"

	echo "$total_width"
}
function string:sub {
	local input="$3"
    local start="$1"
    local end="$2"
    local width=0
    local char
    local output=""

    while IFS= read -rn1 char; do
        [[ -z "$char" ]] && break  # Stop processing when reaching the end

        # Get the Unicode codepoint of the character
        local ord=$(printf '%d' "'${char}")
        local char_width=1

        # Check for double-width characters
        if (( \
              (ord >= 0x1100 && ord <= 0x115F) || \
				  (ord >= 0x2E80 && ord <= 0xA4CF) || \
				  (ord >= 0xAC00 && ord <= 0xD7A3) || \
				  (ord >= 0xF900 && ord <= 0xFAFF) || \
				  (ord >= 0xFE10 && ord <= 0xFE6F) || \
				  (ord >= 0xFF00 && ord <= 0xFF60) || \
				  (ord >= 0xFFE0 && ord <= 0xFFE6) || \
				  (ord >= 0x1F300 && ord <= 0x1F64F) || \
				  (ord >= 0x1F900 && ord <= 0x1F9FF) || \
				  (ord >= 0x20000 && ord <= 0x2FFFD) || \
				  (ord >= 0x30000 && ord <= 0x3FFFD) \
           )); then
            char_width=2
        fi

        if (( width + char_width > end )); then
            break
        fi
        
        if (( width >= start )); then
            output+="$char"
        fi
        
        (( width += char_width ))
    done <<< "$input"

    echo "$output"
}

[[ "${BASH_SOURCE[0]}" = "${0}" ]] && string:sub "$@"