ref: baf202e3cb0f6cb03e52c2af4fbc19406133b9e5
dir: /sys/src/cmd/html2ms.c/
#include <u.h>
#include <libc.h>
#include <ctype.h>
#include <bio.h>
typedef struct Tag Tag;
typedef struct Attr Attr;
typedef struct Text Text;
struct Attr {
char attr[64];
char val[256-64];
};
struct Tag {
Tag *up;
char tag[32];
Attr attr[16];
int nattr;
int opening;
int closing;
void (*close)(Text *, Tag *);
union {
void *aux;
int restore;
};
};
struct Text {
char* font;
int pre;
int pos;
int space;
int output;
int underline;
};
void eatwhite(void);
Tag *parsetext(Text *, Tag *);
int parsetag(Tag *);
int parseattr(Attr *);
Biobuf in, out;
void
emit(Text *text, char *fmt, ...)
{
va_list a;
if(text->pos > 0){
text->pos = 0;
Bputc(&out, '\n');
}
va_start(a, fmt);
Bvprint(&out, fmt, a);
va_end(a);
}
void
restoreoutput(Text *text, Tag *tag)
{
text->output = tag->restore;
}
void
ongarbage(Text *text, Tag *tag)
{
tag->restore = text->output;
tag->close = restoreoutput;
text->output = 0;
}
void
onp(Text *text, Tag *)
{
emit(text, ".LP\n");
}
void
restorepre(Text *text, Tag *tag)
{
text->pre = tag->restore;
emit(text, ".DE\n");
}
void
onpre(Text *text, Tag *tag)
{
tag->restore = text->pre;
tag->close = restorepre;
text->pre = 1;
emit(text, ".DS L\n");
}
void
onli(Text *text, Tag *tag)
{
if(tag->up && cistrcmp(tag->up->tag, "ol") == 0)
emit(text, ".IP\n");
else
emit(text, ".IP \\(bu\n");
if(tag->up)
tag->up->close = onp;
}
void
onh(Text *text, Tag *tag)
{
emit(text, ".SH %c\n", tag->tag[1]);
tag->close = onp;
}
void
onbr(Text *text, Tag *tag)
{
tag->closing = 1;
emit(text, ".br\n");
if(cistrcmp(tag->tag, "hr") == 0)
emit(text, "\\l'5i'\n.br\n");
}
void
restorefont(Text *text, Tag *tag)
{
text->font = tag->aux;
text->pos += Bprint(&out, "\\f%s", text->font);
}
void
onfont(Text *text, Tag *tag)
{
if(text->font == 0)
text->font = "R";
tag->aux = text->font;
tag->close = restorefont;
if(cistrcmp(tag->tag, "i") == 0)
text->font = "I";
else if(cistrcmp(tag->tag, "b") == 0)
text->font = "B";
text->pos += Bprint(&out, "\\f%s", text->font);
}
void
restoreunderline(Text *text, Tag *tag)
{
text->underline = tag->restore;
emit(text, "");
}
void
ona(Text *text, Tag *tag)
{
int i;
for(i=0; i<tag->nattr; i++)
if(cistrcmp(tag->attr[i].attr, "href") == 0)
break;
if(i == tag->nattr)
return;
tag->restore = text->underline;
tag->close = restoreunderline;
text->underline = 1;
}
struct {
char *tag;
void (*open)(Text *, Tag *);
} ontag[] = {
"a", ona,
"br", onbr,
"hr", onbr,
"b", onfont,
"i", onfont,
"p", onp,
"h1", onh,
"h2", onh,
"h3", onh,
"h4", onh,
"h5", onh,
"h6", onh,
"li", onli,
"pre", onpre,
"head", ongarbage,
"style", ongarbage,
"script", ongarbage,
};
void
eatwhite(void)
{
int c;
while((c = Bgetc(&in)) > 0){
if(strchr("\n\r\t ", c) == nil){
Bungetc(&in);
return;
}
}
}
void
parsecomment(void)
{
char buf[64];
int n, c;
n = 0;
eatwhite();
while((c = Bgetc(&in)) > 0){
if(c == '>')
return;
if(n == 0 && c == '-'){
while((c = Bgetc(&in)) > 0){
if(c == '-')
if(Bgetc(&in) == '-')
if(Bgetc(&in) == '>')
return;
}
}
if(n+1 < sizeof(buf)){
buf[n++] = c;
if(n != 7 || cistrncmp(buf, "[CDATA[", 7))
continue;
while((c = Bgetc(&in)) > 0){
if(c == ']'){
if(Bgetc(&in) == ']'){
if(Bgetc(&in) != '>')
Bungetc(&in);
return;
}
}
}
}
}
}
int
parseattr(Attr *a)
{
int q, c, n;
n = 0;
eatwhite();
while((c = Bgetc(&in)) > 0){
if(strchr("</>=?!", c)){
Bungetc(&in);
break;
}
if(strchr("\n\r\t ", c))
break;
if(n < sizeof(a->attr)-1)
a->attr[n++] = c;
}
if(n == 0)
return 0;
a->attr[n] = 0;
n = 0;
eatwhite();
if(Bgetc(&in) == '='){
eatwhite();
c = Bgetc(&in);
if(strchr("'\"", c)){
q = c;
while((c = Bgetc(&in)) > 0){
if(c == q)
break;
if(n < sizeof(a->val)-1)
a->val[n++] = c;
}
} else {
Bungetc(&in);
while((c = Bgetc(&in)) > 0){
if(strchr("\n\r\t </>?!", c)){
Bungetc(&in);
break;
}
if(n < sizeof(a->val)-1)
a->val[n++] = c;
}
}
} else
Bungetc(&in);
a->val[n] = 0;
return 1;
}
int
parsetag(Tag *t)
{
int n, c;
t->nattr = 0;
t->opening = 1;
t->closing = 0;
n = 0;
eatwhite();
while((c = Bgetc(&in)) > 0){
if(c == '>')
break;
if(strchr("\n\r\t ", c)){
if(parseattr(t->attr + t->nattr))
if(t->nattr < nelem(t->attr)-1)
t->nattr++;
continue;
}
if(n == 0 && strchr("?!", c)){
parsecomment();
return 0;
}
if(c == '/'){
if(n == 0){
t->opening = 0;
t->closing = 1;
} else
t->closing = 1;
continue;
}
if(n < sizeof(t->tag)-1)
t->tag[n++] = c;
}
t->tag[n] = 0;
return n > 0;
}
Rune
parserune(int c)
{
char buf[10];
int n;
Rune r;
n = 0;
if(c == '&'){
while((c = Bgetc(&in)) > 0){
if(strchr(";&</>\n\r\t ", c)){
if(c != ';')
Bungetc(&in);
if(n == 0)
return '&';
break;
}
if(n == sizeof(buf)-1)
break;
buf[n++] = c;
}
buf[n] = 0;
if(strcmp(buf, "lt") == 0)
return '<';
if(strcmp(buf, "gt") == 0)
return '>';
if(strcmp(buf, "quot") == 0)
return '"';
if(strcmp(buf, "amp") == 0)
return '&';
/* use tcs -f html to handle the rest. */
} else {
do {
buf[n++] = c;
if(fullrune(buf, n)){
chartorune(&r, buf);
return r;
}
if(n >= UTFmax)
break;
} while((c = Bgetc(&in)) > 0);
}
return 0xFFFD;
}
Rune
substrune(Rune r)
{
switch(r){
case 0x2019:
case 0x2018:
return '\'';
case 0x201c:
case 0x201d:
return '"';
default:
return r;
}
}
void
debugtag(Tag *tag, char *dbg)
{
if(1) return;
if(tag == nil)
return;
debugtag(tag->up, nil);
fprint(2, "%s %s%s", tag->tag, dbg ? dbg : " > ", dbg ? "\n" : "");
}
Tag*
parsetext(Text *text, Tag *tag)
{
Tag *rtag;
Rune r;
int c;
rtag = tag;
debugtag(tag, "open");
if(tag == nil || tag->closing == 0){
while((c = Bgetc(&in)) > 0){
if(c == '<'){
Tag t;
memset(&t, 0, sizeof(t));
if(parsetag(&t)){
if(t.opening){
t.up = tag;
for(c = 0; c < nelem(ontag); c++){
if(cistrcmp(t.tag, ontag[c].tag) == 0){
ontag[c].open(text, &t);
break;
}
}
rtag = parsetext(text, &t);
if(rtag == &t)
rtag = tag;
else
break;
} else if(t.closing){
while(rtag && cistrcmp(rtag->tag, t.tag))
rtag = rtag->up;
if(rtag == nil)
rtag = tag;
else
break;
}
}
continue;
}
if(!text->output)
continue;
r = substrune(parserune(c));
switch(r){
case '\n':
case '\r':
case ' ':
case '\t':
text->space = 1;
if(text->pre == 0)
continue;
default:
if(r == '\n' || r == '\r')
text->pos = 0;
if(text->space){
text->space = 0;
if(text->underline){
emit(text, ".UL ");
text->pos = 1;
} else if(text->pos >= 70){
text->pos = 0;
Bputc(&out, '\n');
} else if(text->pos > 0){
text->pos++;
Bputc(&out, ' ');
}
}
if(text->pos == 0 && r == '.')
text->pos += Bprint(&out, "\\&");
else if(r == '\\')
text->pos += Bprint(&out, "\\&\\");
else if(r == 0xA0){
r = ' ';
text->pos += Bprint(&out, "\\");
}
text->pos += Bprint(&out, "%C", r);
}
}
}
debugtag(tag, "close");
if(tag && tag->close)
tag->close(text, tag);
return rtag;
}
void
main(void)
{
Text text;
Binit(&in, 0, OREAD);
Binit(&out, 1, OWRITE);
memset(&text, 0, sizeof(text));
text.font = "R";
text.output = 1;
parsetext(&text, nil);
emit(&text, "\n");
}