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Avoid an if in the hot loop

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Kovid Goyal 2021-03-20 21:19:31 +05:30
parent c8b5289a34
commit 8755197b73
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GPG Key ID: 06BC317B515ACE7C
1 changed files with 21 additions and 17 deletions
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38
src/calibre/srv/fast_css_transform.cpp
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@ -737,6 +737,7 @@ class TokenQueue {
class Parser { class Parser {
private: private:
enum class ParseState : unsigned { enum class ParseState : unsigned {
normal,
escape, escape,
comment, comment,
string, string,
@ -843,6 +844,7 @@ class Parser {
// }}} // }}}
// testing stream contents {{{ // testing stream contents {{{
void pop_state() { if (states.size() > 1) states.pop(); }
void rewind_output() { token_queue.rewind_output(); } void rewind_output() { token_queue.rewind_output(); }
void write_to_output(const char32_t what) { token_queue.write_to_output(what); } void write_to_output(const char32_t what) { token_queue.write_to_output(what); }
void reconsume() { input.rewind(); rewind_output(); } void reconsume() { input.rewind(); rewind_output(); }
@ -893,9 +895,9 @@ class Parser {
void handle_escape() { void handle_escape() {
if (!escape_buf_pos) { if (!escape_buf_pos) {
if (ch == '\n') { reconsume(); states.pop(); return; } if (ch == '\n') { reconsume(); pop_state(); return; }
if (!is_hex_digit(ch)) { if (!is_hex_digit(ch)) {
states.pop(); pop_state();
token_queue.add_char(ch); token_queue.add_char(ch);
return; return;
} }
@ -905,7 +907,7 @@ class Parser {
if (is_hex_digit(ch) && escape_buf_pos < 6) { escape_buf[escape_buf_pos++] = (char)ch; return; } if (is_hex_digit(ch) && escape_buf_pos < 6) { escape_buf[escape_buf_pos++] = (char)ch; return; }
if (is_whitespace(ch)) return; // a single whitespace character is absorbed into escape if (is_whitespace(ch)) return; // a single whitespace character is absorbed into escape
reconsume(); reconsume();
states.pop(); pop_state();
escape_buf[escape_buf_pos] = 0; escape_buf[escape_buf_pos] = 0;
long kch = strtol(escape_buf, NULL, 16); long kch = strtol(escape_buf, NULL, 16);
if (kch > 0 && !is_surrogate(kch)) token_queue.add_char(kch); if (kch > 0 && !is_surrogate(kch)) token_queue.add_char(kch);
@ -925,7 +927,7 @@ class Parser {
if (peek() == '\n') input.next(); if (peek() == '\n') input.next();
else enter_escape_mode(); else enter_escape_mode();
} }
else if (ch == end_string_with) states.pop(); else if (ch == end_string_with) pop_state();
else token_queue.add_char(ch); else token_queue.add_char(ch);
} // }}} } // }}}
@ -937,7 +939,7 @@ class Parser {
void handle_comment() { void handle_comment() {
token_queue.add_char(ch); token_queue.add_char(ch);
if (ch == '/' && prev_ch == '*') states.pop(); if (ch == '/' && prev_ch == '*') pop_state();
} // }}} } // }}}
// hash {{{ // hash {{{
@ -951,7 +953,7 @@ class Parser {
else if (has_valid_escape()) enter_escape_mode(); else if (has_valid_escape()) enter_escape_mode();
else { else {
reconsume(); reconsume();
states.pop(); pop_state();
} }
} }
@ -967,18 +969,18 @@ class Parser {
void handle_number() { void handle_number() {
if (is_digit(ch)) { token_queue.add_char(ch); return; } if (is_digit(ch)) { token_queue.add_char(ch); return; }
if (ch == '.' && is_digit(peek())) { states.pop(); enter_digits_mode(); return; } if (ch == '.' && is_digit(peek())) { pop_state(); enter_digits_mode(); return; }
if ((ch == 'e' || ch == 'E')) { if ((ch == 'e' || ch == 'E')) {
char32_t next = peek(); char32_t next = peek();
if (is_digit(next) || ((next == '+' || next == '-') && is_digit(peek(1)))) { if (is_digit(next) || ((next == '+' || next == '-') && is_digit(peek(1)))) {
token_queue.add_char(input.next()); token_queue.add_char(input.next()); token_queue.add_char(input.next()); token_queue.add_char(input.next());
states.pop(); pop_state();
enter_digits_mode(); enter_digits_mode();
return; return;
} }
} }
reconsume(); reconsume();
states.pop(); pop_state();
if (has_identifier_next()) { enter_dimension_mode(); } if (has_identifier_next()) { enter_dimension_mode(); }
} // }}} } // }}}
@ -991,7 +993,7 @@ class Parser {
if (is_digit(ch)) { token_queue.add_char(ch); } if (is_digit(ch)) { token_queue.add_char(ch); }
else { else {
reconsume(); reconsume();
states.pop(); pop_state();
if (has_identifier_next()) { enter_dimension_mode(); } if (has_identifier_next()) { enter_dimension_mode(); }
} }
} // }}} } // }}}
@ -1006,7 +1008,7 @@ class Parser {
if (is_name(ch)) { token_queue.add_char(ch); return; } if (is_name(ch)) { token_queue.add_char(ch); return; }
if (has_valid_escape()) { enter_escape_mode(); return; } if (has_valid_escape()) { enter_escape_mode(); return; }
reconsume(); reconsume();
states.pop(); pop_state();
} // }}} } // }}}
// ident {{{ // ident {{{
@ -1026,7 +1028,7 @@ class Parser {
return; return;
} }
reconsume(); reconsume();
states.pop(); pop_state();
} // }}} } // }}}
// url {{{ // url {{{
@ -1037,9 +1039,9 @@ class Parser {
void handle_url_start() { void handle_url_start() {
if (is_whitespace(ch)) return; if (is_whitespace(ch)) return;
if (starting_string()) { states.pop(); end_string_with = ch; states.push(ParseState::url_string); return; } if (starting_string()) { pop_state(); end_string_with = ch; states.push(ParseState::url_string); return; }
if (ch == ')') { states.pop(); return; } if (ch == ')') { pop_state(); return; }
states.pop(); states.push(ParseState::url); pop_state(); states.push(ParseState::url);
} }
void handle_url_string() { void handle_url_string() {
@ -1057,7 +1059,7 @@ class Parser {
} }
void exit_url_mode(bool trim=false) { void exit_url_mode(bool trim=false) {
states.pop(); pop_state();
if (trim) token_queue.trim_trailing_whitespace(); if (trim) token_queue.trim_trailing_whitespace();
} }
// }}} // }}}
@ -1146,8 +1148,9 @@ class Parser {
void dispatch_current_char() { void dispatch_current_char() {
write_to_output(ch); write_to_output(ch);
if (!states.size()) { handle_normal(); return; }
switch (states.top()) { switch (states.top()) {
case ParseState::normal:
handle_normal(); break;
case ParseState::comment: case ParseState::comment:
handle_comment(); break; handle_comment(); break;
case ParseState::escape: case ParseState::escape:
@ -1185,6 +1188,7 @@ class Parser {
escape_buf_pos(0), token_queue(PyUnicode_GET_LENGTH(src), url_callback), input(src) escape_buf_pos(0), token_queue(PyUnicode_GET_LENGTH(src), url_callback), input(src)
{ {
if (is_declaration) push_block_type(); else push_block_type(true, true, true, true); if (is_declaration) push_block_type(); else push_block_type(true, true, true, true);
states.push(ParseState::normal);
} }
void parse(std::u32string &result) { void parse(std::u32string &result) {