use crate::escape_html;
use rapiddoc_core::{Error, ErrorCode};
#[derive(Debug, PartialEq, Eq)]
pub struct Metrics {
pub cells: usize,
pub blank: usize,
pub ocr_hits: usize,
}
impl Metrics {
pub fn non_blank(&self) -> usize {
self.cells - self.blank
}
}
pub struct Selection {
pub route: &'static str,
pub reason: &'static str,
pub wired: Metrics,
pub wireless: Metrics,
}
fn invalid(message: &str) -> Error {
Error {
code: ErrorCode::InvalidInput,
message: message.into(),
}
}
fn limited(message: &str) -> Error {
Error {
code: ErrorCode::ResourceLimit,
message: message.into(),
}
}
fn whitespace(c: char) -> bool {
c.is_whitespace() || matches!(c, '\u{001c}'..='\u{001f}')
}
fn visible(mut text: &str) -> Result<bool, Error> {
let mut result = false;
while let Some((_, after)) = text.split_once('&') {
let entity = ["amp;", "lt;", "gt;", "quot;", "#39;"]
.iter()
.find(|e| after.starts_with(**e))
.ok_or_else(|| invalid("候选 HTML 含非规范实体；请使用 Rust 表格输出器生成候选"))?;
result = true;
text = &after[entity.len()..];
}
Ok(result || text.chars().any(|c| !whitespace(c)))
}
fn attributes(attrs: &str) -> Result<(), Error> {
let mut seen = [false; 2];
for attr in attrs.split_ascii_whitespace() {
let (key, raw) = attr
.split_once('=')
.ok_or_else(|| invalid("候选单元格属性无效"))?;
let slot = match key {
"rowspan" => 0,
"colspan" => 1,
_ => return Err(invalid("候选单元格含未知属性")),
};
if std::mem::replace(&mut seen[slot], true) {
return Err(invalid("候选单元格属性重复"));
}
let raw = raw
.strip_prefix('"')
.and_then(|v| v.strip_suffix('"'))
.unwrap_or(raw);
let value = raw.parse::<usize>().ok().filter(|v| (1..=1000).contains(v));
if value.is_none() {
return Err(invalid("候选单元格跨度无效"));
}
}
Ok(())
}
pub fn metrics(mut html: &str) -> Result<Metrics, Error> {
if html.len() > rapiddoc_core::resources::limit(16_000_000) {
return Err(limited("表格候选 HTML 超过预算"));
}
let mut result = Metrics {
cells: 0,
blank: 0,
ocr_hits: 0,
};
let mut stack: Vec<String> = Vec::new();
let mut cell: Option<bool> = None;
let mut tables = 0;
while !html.is_empty() {
let (text, rest) = html.split_once('<').unwrap_or((html, ""));
let has_text = visible(text)?;
if let Some(v) = &mut cell {
*v |= has_text;
} else if has_text {
return Err(invalid("候选 HTML 的文字必须位于单元格内"));
}
if rest.is_empty() {
if html.ends_with('<') {
return Err(invalid("候选 HTML 标签未闭合"));
}
break;
}
let (raw, tail) = rest
.split_once('>')
.ok_or_else(|| invalid("候选 HTML 标签未闭合"))?;
if raw.len() > rapiddoc_core::resources::limit(128) {
return Err(invalid("候选 HTML 标签过长"));
}
let tag = raw.trim_ascii().to_ascii_lowercase();
html = tail;
if tag == "br" || tag == "br/" || tag == "br /" {
if cell.is_none() {
return Err(invalid("候选换行必须位于单元格内"));
}
continue;
}
if let Some(close) = tag.strip_prefix('/') {
if stack.pop().as_deref() != Some(close) {
return Err(invalid("候选 HTML 标签错位"));
}
if (close == "td" || close == "th")
&& !cell.take().ok_or_else(|| invalid("候选单元格未开始"))?
{
result.blank += 1;
}
continue;
}
let (name, attrs) = tag
.split_once(|c: char| c.is_ascii_whitespace())
.unwrap_or((&tag, ""));
let parent = stack.last().map(String::as_str).unwrap_or("");
let allowed = match name {
"html" => parent.is_empty(),
"body" => parent == "html" || parent.is_empty(),
"table" => matches!(parent, "" | "html" | "body") && tables == 0,
"thead" | "tbody" | "tfoot" => parent == "table",
"tr" => matches!(parent, "table" | "thead" | "tbody" | "tfoot"),
"td" | "th" => parent == "tr" && cell.is_none(),
_ => false,
};
if !allowed {
return Err(invalid("候选 HTML 含未知或错位标签"));
}
if name == "td" || name == "th" {
attributes(attrs)?;
result.cells += 1;
cell = Some(false);
} else if !attrs.is_empty() {
return Err(invalid("候选容器不允许属性"));
}
if name == "thead" {
result.cells += 1;
}
if result.cells > rapiddoc_core::resources::limit(100_000) {
return Err(limited("候选 HTML 单元格超过预算"));
}
if name == "table" {
tables += 1;
}
stack.push(name.to_owned());
}
if !stack.is_empty() || cell.is_some() {
return Err(invalid("候选 HTML 结构未闭合"));
}
Ok(result)
}
pub fn select(texts: &[String], wired_html: &str, wireless_html: &str) -> Result<Selection, Error> {
if texts.len() > rapiddoc_core::resources::limit(1000)
|| texts.iter().map(String::len).sum::<usize>() > rapiddoc_core::resources::limit(1_000_000)
|| wired_html.len().saturating_add(wireless_html.len())
> rapiddoc_core::resources::limit(16_000_000)
{
return Err(limited("表格选优输入超过预算"));
}
let mut wired = metrics(wired_html)?;
let mut wireless = metrics(wireless_html)?;
let mut remaining = rapiddoc_core::resources::limit(50_000_000usize);
for text in texts {
let text = escape_html(text);
for (html, m) in [(wired_html, &mut wired), (wireless_html, &mut wireless)] {
if !text.is_empty() && text.len() <= html.len() {
remaining = remaining
.checked_sub(html.len())
.ok_or_else(|| limited("表格文字命中工作量超过预算"))?;
}
m.ocr_hits += usize::from(html.contains(&text));
}
}
Ok(select_metrics(wired, wireless))
}
pub fn select_metrics(wired: Metrics, wireless: Metrics) -> Selection {
let wn = wired.non_blank();
let ln = wireless.non_blank();
let gap = wireless.cells as i64 - wired.cells as i64;
let scale = (wn as f64).sqrt().round_ties_even() as usize;
let (route, reason) = if wired.ocr_hits > wireless.ocr_hits && wn >= ln {
("wired", "wired_text_coverage")
} else if ln > wn && ln + 3 >= (wn + scale * 2).max(scale * (scale + 2)) {
("wireless", "wireless_scale")
} else if (0..=5).contains(&gap)
&& wired.cells <= (wireless.cells as f64 * 0.75).round_ties_even() as usize
{
("wireless", "wireless_cell_gap")
} else if gap == 0 && wired.cells <= 4 && wireless.ocr_hits >= wired.ocr_hits {
("wireless", "wireless_small_equal")
} else if wired.ocr_hits as f64 <= wireless.ocr_hits as f64 * 0.6 && wireless.ocr_hits >= 10 {
("wireless", "wireless_text_coverage")
} else {
("wired", "wired_default")
};
Selection {
route,
reason,
wired,
wireless,
}
}