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Text::Markdown::Discount
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/* markdown: a C implementation of John Gruber's Markdown markup language.
*
* Copyright (C) 2007 David L Parsons.
* The redistribution terms are provided in the COPYRIGHT file that must
* be distributed with this source code.
*/
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <time.h>
#include <ctype.h>
#include "config.h"
#include "cstring.h"
#include "markdown.h"
#include "amalloc.h"
/* block-level tags for passing html blocks through the blender
*/
struct kw {
char *id;
int size;
int selfclose;
} ;
#define KW(x) { x, sizeof(x)-1, 0 }
#define SC(x) { x, sizeof(x)-1, 1 }
static struct kw blocktags[] = { KW("!--"), KW("STYLE"), KW("SCRIPT"),
KW("ADDRESS"), KW("BDO"), KW("BLOCKQUOTE"),
KW("CENTER"), KW("DFN"), KW("DIV"), KW("H1"),
KW("H2"), KW("H3"), KW("H4"), KW("H5"),
KW("H6"), KW("LISTING"), KW("NOBR"),
KW("UL"), KW("P"), KW("OL"), KW("DL"),
KW("PLAINTEXT"), KW("PRE"), KW("TABLE"),
KW("WBR"), KW("XMP"), SC("HR"), SC("BR"),
KW("IFRAME"), KW("MAP") };
#define SZTAGS (sizeof blocktags / sizeof blocktags[0])
#define MAXTAG 11 /* sizeof "BLOCKQUOTE" */
typedef int (*stfu)(const void*,const void*);
typedef ANCHOR(Paragraph) ParagraphRoot;
/* case insensitive string sort (for qsort() and bsearch() of block tags)
*/
static int
casort(struct kw *a, struct kw *b)
{
if ( a->size != b->size )
return a->size - b->size;
return strncasecmp(a->id, b->id, b->size);
}
/* case insensitive string sort for Footnote tags.
*/
int
__mkd_footsort(Footnote *a, Footnote *b)
{
int i;
char ac, bc;
if ( S(a->tag) != S(b->tag) )
return S(a->tag) - S(b->tag);
for ( i=0; i < S(a->tag); i++) {
ac = tolower(T(a->tag)[i]);
bc = tolower(T(b->tag)[i]);
if ( isspace(ac) && isspace(bc) )
continue;
if ( ac != bc )
return ac - bc;
}
return 0;
}
/* find the first blank character after position <i>
*/
static int
nextblank(Line *t, int i)
{
while ( (i < S(t->text)) && !isspace(T(t->text)[i]) )
++i;
return i;
}
/* find the next nonblank character after position <i>
*/
static int
nextnonblank(Line *t, int i)
{
while ( (i < S(t->text)) && isspace(T(t->text)[i]) )
++i;
return i;
}
/* find the first nonblank character on the Line.
*/
int
mkd_firstnonblank(Line *p)
{
return nextnonblank(p,0);
}
static int
blankline(Line *p)
{
return ! (p && (S(p->text) > p->dle) );
}
static Line *
skipempty(Line *p)
{
while ( p && (p->dle == S(p->text)) )
p = p->next;
return p;
}
void
___mkd_tidy(Cstring *t)
{
while ( S(*t) && isspace(T(*t)[S(*t)-1]) )
--S(*t);
}
static struct kw *
isopentag(Line *p)
{
int i=0, len;
struct kw key, *ret;
if ( !p ) return 0;
len = S(p->text);
if ( len < 3 || T(p->text)[0] != '<' )
return 0;
/* find how long the tag is so we can check to see if
* it's a block-level tag
*/
for ( i=1; i < len && T(p->text)[i] != '>'
&& T(p->text)[i] != '/'
&& !isspace(T(p->text)[i]); ++i )
;
key.id = T(p->text)+1;
key.size = i-1;
if ( ret = bsearch(&key, blocktags, SZTAGS, sizeof key, (stfu)casort))
return ret;
return 0;
}
typedef struct _flo {
Line *t;
int i;
} FLO;
static int
flogetc(FLO *f)
{
if ( f && f->t ) {
if ( f->i < S(f->t->text) )
return T(f->t->text)[f->i++];
f->t = f->t->next;
f->i = 0;
return flogetc(f);
}
return EOF;
}
static Line *
htmlblock(Paragraph *p, struct kw *tag)
{
Line *ret;
FLO f = { p->text, 0 };
int c;
int i, closing, depth=0;
if ( tag->selfclose || (tag->size >= MAXTAG) ) {
ret = f.t->next;
f.t->next = 0;
return ret;
}
while ( (c = flogetc(&f)) != EOF ) {
if ( c == '<' ) {
/* tag? */
c = flogetc(&f);
if ( c == '!' ) { /* comment? */
if ( flogetc(&f) == '-' && flogetc(&f) == '-' ) {
/* yes */
while ( (c = flogetc(&f)) != EOF ) {
if ( c == '-' && flogetc(&f) == '-'
&& flogetc(&f) == '>')
/* consumed whole comment */
break;
}
}
}
else {
if ( closing = (c == '/') ) c = flogetc(&f);
for ( i=0; i < tag->size; c=flogetc(&f) ) {
if ( tag->id[i++] != toupper(c) )
break;
}
if ( (i == tag->size) && !isalnum(c) ) {
depth = depth + (closing ? -1 : 1);
if ( depth == 0 ) {
while ( c != EOF && c != '>' ) {
/* consume trailing gunk in close tag */
c = flogetc(&f);
}
ret = f.t->next;
f.t->next = 0;
return ret;
}
}
}
}
}
return 0;
}
static Line *
comment(Paragraph *p)
{
Line *t, *ret;
for ( t = p->text; t ; t = t->next) {
if ( strstr(T(t->text), "-->") ) {
ret = t->next;
t->next = 0;
return ret;
}
}
return t;
}
/* tables look like
* header|header{|header}
* ------|------{|......}
* {body lines}
*/
static int
istable(Line *t)
{
char *p;
Line *dashes = t->next;
/* two lines, first must contain | */
if ( !(dashes && memchr(T(t->text), '|', S(t->text))) )
return 0;
/* second line must be only whitespace, |, -, or - */
for ( p = T(dashes->text)+S(dashes->text)-1; p >= T(dashes->text); --p)
if ( ! ((*p == '|') || (*p == ':') || (*p == '-') || isspace(*p)) )
return 0;
return 1;
}
/* footnotes look like ^<whitespace>{0,3}[stuff]: <content>$
*/
static int
isfootnote(Line *t)
{
int i;
if ( ( (i = t->dle) > 3) || (T(t->text)[i] != '[') )
return 0;
for ( ++i; i < S(t->text) ; ++i ) {
if ( T(t->text)[i] == '[' )
return 0;
else if ( T(t->text)[i] == ']' && T(t->text)[i+1] == ':' )
return 1;
}
return 0;
}
static int
isquote(Line *t)
{
return ( T(t->text)[0] == '>' );
}
static int
dashchar(char c)
{
return (c == '*') || (c == '-') || (c == '_');
}
static int
iscode(Line *t)
{
return (t->dle >= 4);
}
static int
ishr(Line *t)
{
int i, count=0;
char dash = 0;
char c;
if ( iscode(t) ) return 0;
for ( i = 0; i < S(t->text); i++) {
c = T(t->text)[i];
if ( (dash == 0) && dashchar(c) )
dash = c;
if ( c == dash ) ++count;
else if ( !isspace(c) )
return 0;
}
return (count >= 3);
}
static int
ishdr(Line *t, int *htyp)
{
int i;
/* first check for etx-style ###HEADER###
*/
/* leading run of `#`'s ?
*/
for ( i=0; T(t->text)[i] == '#'; ++i)
;
/* ANY leading `#`'s make this into an ETX header
*/
if ( i && (i < S(t->text) || i > 1) ) {
*htyp = ETX;
return 1;
}
/* then check for setext-style HEADER
* ======
*/
if ( t->next ) {
char *q = T(t->next->text);
if ( (*q == '=') || (*q == '-') ) {
for (i=1; i < S(t->next->text); i++)
if ( q[0] != q[i] )
return 0;
*htyp = SETEXT;
return 1;
}
}
return 0;
}
static int
isdefinition(Line *t)
{
#if DL_TAG_EXTENSION
return t && t->next
&& (S(t->text) > 2)
&& (t->dle == 0)
&& (T(t->text)[0] == '=')
&& (T(t->text)[S(t->text)-1] == '=')
&& ( (t->next->dle >= 4) || isdefinition(t->next) );
#else
return 0;
#endif
}
static int
islist(Line *t, int *trim)
{
int i, j;
char *q;
if ( iscode(t) || blankline(t) || ishdr(t,&i) || ishr(t) )
return 0;
if ( isdefinition(t) ) {
*trim = 4;
return DL;
}
if ( strchr("*-+", T(t->text)[t->dle]) && isspace(T(t->text)[t->dle+1]) ) {
i = nextnonblank(t, t->dle+1);
*trim = (i > 4) ? 4 : i;
return UL;
}
if ( (j = nextblank(t,t->dle)) > t->dle ) {
if ( T(t->text)[j-1] == '.' ) {
#if ALPHA_LIST
if ( (j == t->dle + 2) && isalpha(T(t->text)[t->dle]) ) {
j = nextnonblank(t,j);
*trim = j;
return AL;
}
#endif
strtoul(T(t->text)+t->dle, &q, 10);
if ( (q > T(t->text)+t->dle) && (q == T(t->text) + (j-1)) ) {
j = nextnonblank(t,j);
*trim = j;
return OL;
}
}
}
return 0;
}
static Line *
headerblock(Paragraph *pp, int htyp)
{
Line *ret = 0;
Line *p = pp->text;
int i, j;
switch (htyp) {
case SETEXT:
/* p->text is header, p->next->text is -'s or ='s
*/
pp->hnumber = (T(p->next->text)[0] == '=') ? 1 : 2;
ret = p->next->next;
___mkd_freeLine(p->next);
p->next = 0;
break;
case ETX:
/* p->text is ###header###, so we need to trim off
* the leading and trailing `#`'s
*/
for (i=0; (T(p->text)[i] == T(p->text)[0]) && (i < S(p->text)-1); i++)
;
pp->hnumber = i;
while ( (i < S(p->text)) && isspace(T(p->text)[i]) )
++i;
CLIP(p->text, 0, i);
for (j=S(p->text); (j > 1) && (T(p->text)[j-1] == '#'); --j)
;
while ( j && isspace(T(p->text)[j-1]) )
--j;
S(p->text) = j;
ret = p->next;
p->next = 0;
break;
}
return ret;
}
static Line *
codeblock(Paragraph *p)
{
Line *t = p->text, *r;
for ( ; t; t = r ) {
CLIP(t->text,0,4);
t->dle = mkd_firstnonblank(t);
if ( !( (r = skipempty(t->next)) && iscode(r)) ) {
___mkd_freeLineRange(t,r);
t->next = 0;
return r;
}
}
return t;
}
static int
centered(Line *first, Line *last)
{
if ( first&&last ) {
int len = S(last->text);
if ( (len > 2) && (strncmp(T(first->text), "->", 2) == 0)
&& (strncmp(T(last->text)+len-2, "<-", 2) == 0) ) {
CLIP(first->text, 0, 2);
S(last->text) -= 2;
return CENTER;
}
}
return 0;
}
static int
endoftextblock(Line *t, int toplevelblock)
{
int z;
if ( blankline(t)||isquote(t)||iscode(t)||ishdr(t,&z)||ishr(t) )
return 1;
/* HORRIBLE STANDARDS KLUDGE: Toplevel paragraphs eat absorb adjacent
* list items, but sublevel blocks behave properly.
*/
return toplevelblock ? 0 : islist(t,&z);
}
static Line *
textblock(Paragraph *p, int toplevel)
{
Line *t, *next;
for ( t = p->text; t ; t = next ) {
if ( ((next = t->next) == 0) || endoftextblock(next, toplevel) ) {
p->align = centered(p->text, t);
t->next = 0;
return next;
}
}
return t;
}
/* length of the id: or class: kind in a special div-not-quote block
*/
static int
szmarkerclass(char *p)
{
if ( strncasecmp(p, "id:", 3) == 0 )
return 3;
if ( strncasecmp(p, "class:", 6) == 0 )
return 6;
return 0;
}
/*
* check if the first line of a quoted block is the special div-not-quote
* marker %[kind:]name%
*/
static int
isdivmarker(Line *p, int start)
{
#if DIV_QUOTE
char *s = T(p->text);
int len = S(p->text);
int i;
if ( !(len && s[start] == '%' && s[len-1] == '%') ) return 0;
i = szmarkerclass(s+start+1)+start;
len -= start+1;
while ( ++i < len )
if ( !isalnum(s[i]) )
return 0;
return 1;
#else
return 0;
#endif
}
/*
* accumulate a blockquote.
*
* one sick horrible thing about blockquotes is that even though
* it just takes ^> to start a quote, following lines, if quoted,
* assume that the prefix is ``>''. This means that code needs
* to be indented *5* spaces from the leading '>', but *4* spaces
* from the start of the line. This does not appear to be
* documented in the reference implementation, but it's the
* way the markdown sample web form at Daring Fireball works.
*/
static Line *
quoteblock(Paragraph *p)
{
Line *t, *q;
int qp;
for ( t = p->text; t ; t = q ) {
if ( isquote(t) ) {
qp = (T(t->text)[1] == ' ') ? 2 : 1;
CLIP(t->text, 0, qp);
t->dle = mkd_firstnonblank(t);
}
q = skipempty(t->next);
if ( (q == 0) || ((q != t->next) && (!isquote(q) || isdivmarker(q,1))) ) {
___mkd_freeLineRange(t, q);
t = q;
break;
}
}
if ( isdivmarker(p->text,0) ) {
char *prefix = "class";
int i;
q = p->text;
p->text = p->text->next;
if ( (i = szmarkerclass(1+T(q->text))) == 3 )
/* and this would be an "%id:" prefix */
prefix="id";
if ( p->ident = malloc(4+strlen(prefix)+S(q->text)) )
sprintf(p->ident, "%s=\"%.*s\"", prefix, S(q->text)-(i+2),
T(q->text)+(i+1) );
___mkd_freeLine(q);
}
return t;
}
/*
* A table block starts with a table header (see istable()), and continues
* until EOF or a line that /doesn't/ contain a |.
*/
static Line *
tableblock(Paragraph *p)
{
Line *t, *q;
for ( t = p->text; t && (q = t->next); t = t->next ) {
if ( !memchr(T(q->text), '|', S(q->text)) ) {
t->next = 0;
return q;
}
}
return 0;
}
static Paragraph *Pp(ParagraphRoot *, Line *, int);
static Paragraph *compile(Line *, int, MMIOT *);
/*
* pull in a list block. A list block starts with a list marker and
* runs until the next list marker, the next non-indented paragraph,
* or EOF. You do not have to indent nonblank lines after the list
* marker, but multiple paragraphs need to start with a 4-space indent.
*/
static Line *
listitem(Paragraph *p, int indent)
{
Line *t, *q;
int clip = indent;
int z;
for ( t = p->text; t ; t = q) {
CLIP(t->text, 0, clip);
t->dle = mkd_firstnonblank(t);
if ( (q = skipempty(t->next)) == 0 ) {
___mkd_freeLineRange(t,q);
return 0;
}
/* after a blank line, the next block needs to start with a line
* that's indented 4 spaces, but after that the line doesn't
* need any indentation
*/
if ( q != t->next ) {
if (q->dle < indent) {
q = t->next;
t->next = 0;
return q;
}
indent = 4;
}
if ( (q->dle < indent) && (ishr(q) || islist(q,&z)) && !ishdr(q,&z) ) {
q = t->next;
t->next = 0;
return q;
}
clip = (q->dle > indent) ? indent : q->dle;
}
return t;
}
static Line *
listblock(Paragraph *top, int trim, MMIOT *f)
{
ParagraphRoot d = { 0, 0 };
Paragraph *p;
Line *q = top->text, *text, *label;
int isdl = (top->typ == DL),
para = 0,
ltype;
while (( text = q )) {
if ( top->typ == DL ) {
Line *lp;
for ( lp = label = text; lp ; lp = lp->next ) {
text = lp->next;
CLIP(lp->text, 0, 1);
S(lp->text)--;
if ( !isdefinition(lp->next) )
lp->next = 0;
}
}
else label = 0;
p = Pp(&d, text, LISTITEM);
text = listitem(p, trim);
p->down = compile(p->text, 0, f);
p->text = label;
if ( para && (top->typ != DL) && p->down ) p->down->align = PARA;
if ( !(q = skipempty(text)) || ((ltype = islist(q, &trim)) == 0)
|| (isdl != (ltype == DL)) )
break;
if ( para = (q != text) ) {
Line anchor;
anchor.next = text;
___mkd_freeLineRange(&anchor, q);
}
if ( para && (top->typ != DL) && p->down ) p->down->align = PARA;
}
top->text = 0;
top->down = T(d);
return text;
}
static int
tgood(char c)
{
switch (c) {
case '\'':
case '"': return c;
case '(': return ')';
}
return 0;
}
/*
* add a new (image or link) footnote to the footnote table
*/
static Line*
addfootnote(Line *p, MMIOT* f)
{
int j, i;
int c;
Line *np = p->next;
Footnote *foot = &EXPAND(*f->footnotes);
CREATE(foot->tag);
CREATE(foot->link);
CREATE(foot->title);
foot->height = foot->width = 0;
for (j=i=p->dle+1; T(p->text)[j] != ']'; j++)
EXPAND(foot->tag) = T(p->text)[j];
EXPAND(foot->tag) = 0;
S(foot->tag)--;
j = nextnonblank(p, j+2);
while ( (j < S(p->text)) && !isspace(T(p->text)[j]) )
EXPAND(foot->link) = T(p->text)[j++];
EXPAND(foot->link) = 0;
S(foot->link)--;
j = nextnonblank(p,j);
if ( T(p->text)[j] == '=' ) {
sscanf(T(p->text)+j, "=%dx%d", &foot->width, &foot->height);
while ( (j < S(p->text)) && !isspace(T(p->text)[j]) )
++j;
j = nextnonblank(p,j);
}
if ( (j >= S(p->text)) && np && np->dle && tgood(T(np->text)[np->dle]) ) {
___mkd_freeLine(p);
p = np;
np = p->next;
j = p->dle;
}
if ( (c = tgood(T(p->text)[j])) ) {
/* Try to take the rest of the line as a comment; read to
* EOL, then shrink the string back to before the final
* quote.
*/
++j; /* skip leading quote */
while ( j < S(p->text) )
EXPAND(foot->title) = T(p->text)[j++];
while ( S(foot->title) && T(foot->title)[S(foot->title)-1] != c )
--S(foot->title);
if ( S(foot->title) ) /* skip trailing quote */
--S(foot->title);
EXPAND(foot->title) = 0;
--S(foot->title);
}
___mkd_freeLine(p);
return np;
}
/*
* allocate a paragraph header, link it to the
* tail of the current document
*/
static Paragraph *
Pp(ParagraphRoot *d, Line *ptr, int typ)
{
Paragraph *ret = calloc(sizeof *ret, 1);
ret->text = ptr;
ret->typ = typ;
return ATTACH(*d, ret);
}
static Line*
consume(Line *ptr, int *eaten)
{
Line *next;
int blanks=0;
for (; ptr && blankline(ptr); ptr = next, blanks++ ) {
next = ptr->next;
___mkd_freeLine(ptr);
}
if ( ptr ) *eaten = blanks;
return ptr;
}
/*
* top-level compilation; break the document into
* style, html, and source blocks with footnote links
* weeded out.
*/
static Paragraph *
compile_document(Line *ptr, MMIOT *f)
{
ParagraphRoot d = { 0, 0 };
ANCHOR(Line) source = { 0, 0 };
Paragraph *p = 0;
struct kw *tag;
int eaten;
while ( ptr ) {
if ( !(f->flags & DENY_HTML) && (tag = isopentag(ptr)) ) {
/* If we encounter a html/style block, compile and save all
* of the cached source BEFORE processing the html/style.
*/
if ( T(source) ) {
E(source)->next = 0;
p = Pp(&d, 0, SOURCE);
p->down = compile(T(source), 1, f);
T(source) = E(source) = 0;
}
p = Pp(&d, ptr, strcmp(tag->id, "STYLE") == 0 ? STYLE : HTML);
if ( strcmp(tag->id, "!--") == 0 )
ptr = comment(p);
else
ptr = htmlblock(p, tag);
}
else if ( isfootnote(ptr) ) {
/* footnotes, like cats, sleep anywhere; pull them
* out of the input stream and file them away for
* later processing
*/
ptr = consume(addfootnote(ptr, f), &eaten);
}
else {
/* source; cache it up to wait for eof or the
* next html/style block
*/
ATTACH(source,ptr);
ptr = ptr->next;
}
}
if ( T(source) ) {
/* if there's any cached source at EOF, compile
* it now.
*/
E(source)->next = 0;
p = Pp(&d, 0, SOURCE);
p->down = compile(T(source), 1, f);
}
return T(d);
}
/*
* break a collection of markdown input into
* blocks of lists, code, html, and text to
* be marked up.
*/
static Paragraph *
compile(Line *ptr, int toplevel, MMIOT *f)
{
ParagraphRoot d = { 0, 0 };
Paragraph *p = 0;
Line *r;
int para = toplevel;
int blocks = 0;
int hdr_type, list_type, indent;
ptr = consume(ptr, &para);
while ( ptr ) {
if ( iscode(ptr) ) {
p = Pp(&d, ptr, CODE);
if ( f->flags & MKD_1_COMPAT) {
/* HORRIBLE STANDARDS KLUDGE: the first line of every block
* has trailing whitespace trimmed off.
*/
___mkd_tidy(&p->text->text);
}
ptr = codeblock(p);
}
else if ( ishr(ptr) ) {
p = Pp(&d, 0, HR);
r = ptr;
ptr = ptr->next;
___mkd_freeLine(r);
}
else if (( list_type = islist(ptr, &indent) )) {
p = Pp(&d, ptr, list_type);
ptr = listblock(p, indent, f);
}
else if ( isquote(ptr) ) {
p = Pp(&d, ptr, QUOTE);
ptr = quoteblock(p);
p->down = compile(p->text, 1, f);
p->text = 0;
}
else if ( ishdr(ptr, &hdr_type) ) {
p = Pp(&d, ptr, HDR);
ptr = headerblock(p, hdr_type);
}
else if ( istable(ptr) && !(f->flags & (STRICT|NOTABLES)) ) {
p = Pp(&d, ptr, TABLE);
ptr = tableblock(p);
}
else {
p = Pp(&d, ptr, MARKUP);
ptr = textblock(p, toplevel);
}
if ( (para||toplevel) && !p->align )
p->align = PARA;
blocks++;
para = toplevel || (blocks > 1);
ptr = consume(ptr, &para);
if ( para && !p->align )
p->align = PARA;
}
return T(d);
}
static void
initialize()
{
static int first = 1;
if ( first-- > 0 ) {
first = 0;
INITRNG(time(0));
qsort(blocktags, SZTAGS, sizeof blocktags[0], (stfu)casort);
}
}
/*
* the guts of the markdown() function, ripped out so I can do
* debugging.
*/
/*
* prepare and compile `text`, returning a Paragraph tree.
*/
int
mkd_compile(Document *doc, int flags)
{
if ( !doc )
return 0;
if ( doc->compiled )
return 1;
doc->compiled = 1;
memset(doc->ctx, 0, sizeof(MMIOT) );
doc->ctx->flags = flags & USER_FLAGS;
doc->ctx->base = doc->base;
CREATE(doc->ctx->in);
doc->ctx->footnotes = malloc(sizeof doc->ctx->footnotes[0]);
CREATE(*doc->ctx->footnotes);
initialize();
doc->code = compile_document(T(doc->content), doc->ctx);
qsort(T(*doc->ctx->footnotes), S(*doc->ctx->footnotes),
sizeof T(*doc->ctx->footnotes)[0],
(stfu)__mkd_footsort);
memset(&doc->content, 0, sizeof doc->content);
return 1;
}