MultiMarkdown-6/Sources/libMultiMarkdown/token_pairs.c
2017-03-11 13:20:17 -05:00

253 lines
6.6 KiB
C

/**
MultiMarkdown 6 -- Lightweight markup processor to produce HTML, LaTeX, and more.
@file token_pairs.c
@brief Allow for pairing certain tokens together (e.g. '[' and ']') to create
more meaningful token trees.
@author Fletcher T. Penney
@bug
**/
/*
Copyright © 2016 - 2017 Fletcher T. Penney.
The `MultiMarkdown 6` project is released under the MIT License..
GLibFacade.c and GLibFacade.h are from the MultiMarkdown v4 project:
https://github.com/fletcher/MultiMarkdown-4/
MMD 4 is released under both the MIT License and GPL.
CuTest is released under the zlib/libpng license. See CuTest.c for the text
of the license.
## The MIT License ##
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "stack.h"
#include "token.h"
#include "token_pairs.h"
/// Create a new token pair engine
token_pair_engine * token_pair_engine_new(void) {
token_pair_engine * e = malloc(sizeof(token_pair_engine));
if (e) {
unsigned short empty[kMaxTokenTypes] = {0};
unsigned short empty2[kMaxTokenTypes][kMaxTokenTypes] = {{0}};
memcpy(e->can_open_pair, empty, sizeof(unsigned short) * kMaxTokenTypes);
memcpy(e->can_close_pair, empty, sizeof(unsigned short) * kMaxTokenTypes);
memcpy(e->pair_type, empty2, sizeof(unsigned short) * kMaxTokenTypes * kMaxTokenTypes);
memcpy(e->empty_allowed, empty, sizeof(unsigned short) * kMaxTokenTypes);
memcpy(e->match_len, empty, sizeof(unsigned short) * kMaxTokenTypes);
memcpy(e->should_prune, empty, sizeof(unsigned short) * kMaxTokenTypes);
}
return e;
}
/// Free existing token pair engine
void token_pair_engine_free(token_pair_engine * e) {
if (e == NULL)
return;
free(e);
}
/// Add a new pairing configuration to a token pair engine
void token_pair_engine_add_pairing(token_pair_engine * e, unsigned short open_type, unsigned short close_type,
unsigned short pair_type, int options) {
// \todo: This needs to be more sophisticated
e->can_open_pair[open_type] = 1;
e->can_close_pair[close_type] = 1;
(e->pair_type)[open_type][close_type] = pair_type;
if (options & PAIRING_ALLOW_EMPTY)
e->empty_allowed[pair_type] = true;
if (options & PAIRING_MATCH_LENGTH)
e->match_len[pair_type] = true;
if (options & PAIRING_PRUNE_MATCH)
e->should_prune[pair_type] = true;
}
/// Mate opener and closer together
void token_pair_mate(token * a, token * b) {
if (a == NULL | b == NULL)
return;
a->mate = b;
a->unmatched = false;
b->mate = a;
b->unmatched = false;
}
/// Search a token's childen for matching pairs
void token_pairs_match_pairs_inside_token(token * parent, token_pair_engine * e, stack * s, unsigned short depth) {
// Avoid stack overflow in "pathologic" input
if (depth == kMaxPairRecursiveDepth)
return;
// Walk the child chain
token * walker = parent->child;
// Counter
size_t start_counter = s->size;
size_t i; // We're sharing one stack, so any opener earlier than this belongs to a parent
token * peek;
unsigned short pair_type;
unsigned int opener_count[kMaxTokenTypes] = {0}; // Keep track of which token types are on the stack
while (walker != NULL) {
if (walker->child) {
token_pairs_match_pairs_inside_token(walker, e, s, depth + 1);
}
// Is this a closer?
if (walker->can_close && e->can_close_pair[walker->type] && walker->unmatched ) {
i = s->size;
// Do we even have a valid opener in the stack?
// It's only worth checking if the stack is beyond a certain size
if (i > start_counter + kLargeStackThreshold) {
for (int j = 0; j < kMaxTokenTypes; ++j)
{
if (opener_count[j]) {
if (e->pair_type[j][walker->type])
goto close;
}
}
// No opener available for this as closer
goto open;
}
close:
// Find matching opener for this closer
while (i > start_counter) {
peek = stack_peek_index(s, i - 1);
pair_type = e->pair_type[peek->type][walker->type];
if (pair_type) {
if (!e->empty_allowed[pair_type]) {
// Make sure they aren't consecutive tokens
if ((peek->next == walker) &&
(peek->start + peek->len == walker->start)) {
// i--;
i = start_counter; // In this situation, we can't use this token as a closer
continue;
}
}
if (e->match_len[pair_type]) {
// Lengths must match
if (peek->len != walker->len) {
i--;
continue;
}
}
token_pair_mate(peek, walker);
// Clear portion of stack between opener and closer as they are now unavailable for mating
while (s->size > (i - 1)) {
peek = stack_pop(s);
opener_count[peek->type]--;
}
#ifndef NDEBUG
fprintf(stderr, "stack now sized %lu\n", s->size);
#endif
// Prune matched section
if (e->should_prune[pair_type]) {
if (peek->prev == NULL) {
walker = token_prune_graft(peek, walker, e->pair_type[peek->type][walker->type]);
parent->child = walker;
} else {
walker = token_prune_graft(peek, walker, e->pair_type[peek->type][walker->type]);
}
}
break;
}
#ifndef NDEBUG
else {
fprintf(stderr, "token type %d failed to match stack element\n", walker->type);
}
#endif
i--;
}
}
open:
// Is this an opener?
if (walker->can_open && e->can_open_pair[walker->type] && walker->unmatched) {
stack_push(s, walker);
opener_count[walker->type]++;
#ifndef NDEBUG
fprintf(stderr, "push token type %d to stack (%lu elements)\n", walker->type, s->size);
#endif
}
walker = walker->next;
}
#ifndef NDEBUG
fprintf(stderr, "token stack has %lu elements (of %lu)\n", s->size, s->capacity);
#endif
// Remove unused tokens from stack and return to parent
s->size = start_counter;
}