Module scan 

Byte-level scanning helpers ported from markmend/core/src/preprocess/utils.ts and pattern.ts. All positions are byte offsets into the original string.

ASCII needles are searched with memchr: in UTF-8, ASCII bytes never occur inside multi-byte chars, so the returned offsets are always char boundaries — safe to slice with.

Functions

append_before_trailing_whitespace

Append suffix before trailing whitespace.

count_of

memchr 版 count（ASCII needle：偏移天然边界，SIMD 加速）。

find_closed_code_block_ranges

/```[\s\S]*?```/g — all closed fenced code ranges [start, end).

find_inline_code_ranges

/[^\n]+/-style inline code ranges [start, end)` outside code blocks.

is_escaped_character

Odd number of preceding backslashes.

is_inside_unclosed_code_block

is_position_in_ranges

is_range_overlapping_ranges

Whether [start, end) overlaps any range.

is_underscore_inside_word

is_within_code_block

is_within_html_tag

Whether position is inside an unclosed HTML tag (<...>).

is_within_link_or_image_url

Whether position is inside ](...) of a link/image.

is_within_math_block

Whether position sits inside a $$ math span (or $ inline math when enabled).

is_ws

JS \s (without unicode flag): space, tab, newline, CR, FF, VT.

join_multiline_math

Fold every $$…$$ span that crosses a line break onto one line, leaving fenced code blocks alone.

js_trim

JS String.prototype.trim-ish (ASCII + unicode whitespace).

last_non_empty_line_index

Find last non-empty line index (JS findLastNonEmptyLineIndex).

last_paragraph

last_paragraph_range

Last paragraph = content after the last blank line. Returns (start_line_index, byte_offset_of_start).

mask_inline_code_markdown_markers

Mask * _ ~ inside inline code with spaces (offsets preserved).

mask_invalid_underscore_markers

Mask escaped / intraword underscore runs with spaces.

remove_math_blocks_from_text

Remove $$...$$ block math (and optionally $...$ inline math) spans.

remove_urls_from_text

Remove code blocks, HTML tags, and link/image URL bodies from text, so markdown markers inside URLs don’t get counted.

should_ignore_underscore_marker

trailing_ws_offset

Trailing whitespace run (/\s+$/), returns byte offset of the run start.