/* HTMLGen.c
** HTML GENERATOR
**
** (c) COPYRIGHT MIT 1995.
** Please first read the full copyright statement in the file COPYRIGH.
** @(#) $Id: HTMLGen.c,v 2.45 1999/02/22 22:10:11 frystyk Exp $
**
** This version of the HTML object sends HTML markup to the output stream.
**
** Bugs: Line wrapping is not done at all.
** All data handled as PCDATA.
** Should convert old XMP, LISTING and PLAINTEXT to PRE.
**
** It is not obvious to me right now whether the HEAD should be generated
** from the incomming data or the anchor. Currently it is from the former
** which is cleanest. TBL
**
** HISTORY:
** 8 Jul 94 FM Insulate free() from _free structure element.
**
*/
/* Library include files */
#include "wwwsys.h"
#include "HTUtils.h"
#include "HTMLPDTD.h"
#include "HTStruct.h"
#include "HTFormat.h"
#include "HTMLGen.h" /* Implemented here */
#define BUFFER_SIZE 80 /* Line buffer attempts to make neat breaks */
#define MAX_CLEANNESS 10
#define PUT_CHAR(c) (*me->target->isa->put_character)(me->target, c)
#define PUT_STR(s) (*me->target->isa->put_string)(me->target, s)
#define PUT_BLOCK(s,l) (*me->target->isa->put_block)(me->target, s, l)
/* HTML Generator Object */
struct _HTStream {
const HTStreamClass * isa;
HTStream * target;
};
struct _HTStructured {
const HTStructuredClass * isa;
HTStream * target;
const SGML_dtd * dtd;
BOOL seven_bit; /* restrict output */
char buffer[BUFFER_SIZE+1];
char * write_pointer;
char * line_break [MAX_CLEANNESS+1];
int cleanness;
BOOL overflowed;
BOOL delete_line_break_char[MAX_CLEANNESS+1];
char preformatted;
};
/* OUTPUT FUNCTIONS
**
** These function output the finished SGML stream doing the
** line wrap
*/
/* Flush Buffer
** ------------
*/
PRIVATE void flush_breaks (HTStructured * me)
{
int i;
for (i=0; i<= MAX_CLEANNESS; i++) {
me->line_break[i] = NULL;
}
}
PRIVATE int HTMLGen_flush (HTStructured * me)
{
PUT_BLOCK(me->buffer, me->write_pointer - me->buffer);
me->write_pointer = me->buffer;
flush_breaks(me);
me->cleanness = 0;
return HT_OK;
}
/* Weighted optional line break
**
** We keep track of all the breaks for when we chop the line
*/
PRIVATE void allow_break (HTStructured * me, int new_cleanness, BOOL dlbc)
{
me->line_break[new_cleanness] =
dlbc ? me->write_pointer - 1 /* Point to space */
: me->write_pointer ; /* point to gap */
me->delete_line_break_char[new_cleanness] = dlbc;
if (new_cleanness >= me->cleanness)
me->cleanness = new_cleanness;
}
/* Character handling
** ------------------
**
** The tricky bits are the line break handling. This attempts
** to synchrononise line breaks on sentence or phrase ends. This
** is important if one stores SGML files in a line-oriented code
** repository, so that if a small change is made, line ends don't
** shift in a ripple-through to apparently change a large part of the
** file. We give extra "cleanness" to spaces appearing directly
** after periods (full stops), [semi]colons and commas.
** This should make the source files easier to read and modify
** by hand, too, though this is not a primary design consideration. TBL
*/
PRIVATE char delims[] = ",;:."; /* @@ english bias */
PRIVATE int HTMLGen_output_character (HTStructured * me, char c)
{
*me->write_pointer++ = c;
if (c=='\n') { /* Newlines */
if (me->preformatted) {
HTMLGen_flush(me);
return HT_OK;
} else {
me->write_pointer[-1] = c = ' '; /* Treat same as space */
}
}
/* Figure our whether we can break at this point
*/
if ((!me->preformatted && c==' ')) {
int new_cleanness = 1;
if (me->write_pointer > (me->buffer + 1)) {
char * p;
p = strchr(delims, me->write_pointer[-2]);
if (p) new_cleanness = p - delims + 4;
}
allow_break(me, new_cleanness, YES);
}
/* Flush buffer out when full, or whenever the line is over
the nominal maximum and we can break at all
*/
if (me->write_pointer >= me->buffer + BUFFER_SIZE-1
|| (me->overflowed && me->cleanness)) {
if (me->cleanness) {
char line_break_char = me->line_break[me->cleanness][0];
char * saved = me->line_break[me->cleanness];
if (me->delete_line_break_char[me->cleanness]) saved++;
me->line_break[me->cleanness][0] = '\n';
PUT_BLOCK(me->buffer, me->line_break[me->cleanness]-me->buffer+1);
me->line_break[me->cleanness][0] = line_break_char;
{ /* move next line in */
char * p=saved;
char *q;
for(q=me->buffer; p < me->write_pointer; )
*q++ = *p++;
}
me->cleanness = 0;
/* Now we have to check whether ther are any perfectly good breaks
** which weren't good enough for the last line but may be
** good enough for the next
*/
{
int i;
for(i=0; i <= MAX_CLEANNESS; i++) {
if (me->line_break[i] > saved) {
me->line_break[i] = me->line_break[i] -
(saved-me->buffer);
me->cleanness = i;
} else {
me->line_break[i] = NULL;
}
}
}
me->write_pointer = me->write_pointer - (saved-me->buffer);
me->overflowed = NO;
} else { /* No break- just output with no newline */
PUT_BLOCK(me->buffer, me->write_pointer - me->buffer);
me->write_pointer = me->buffer;
flush_breaks(me);
me->overflowed = YES;
}
}
return HT_OK;
}
/* String handling
** ---------------
*/
PRIVATE int HTMLGen_output_string (HTStructured * me, const char* s)
{
while (*s)
HTMLGen_output_character(me, *s++);
return HT_OK;
}
/* INPUT FUNCTIONS
**
** These take data from the structured stream. In the input
** stream, entities are in raw form. The seven_bit flag controls
** whether the ISO Latin-1 charactrs are represented in SGML entity
** form. This is only recommended for viewing on older non-latin-1
** capable equipment, or for mailing for example.
**
** Bug: assumes local encoding is ISO!
*/
PRIVATE int HTMLGen_put_character (HTStructured * me, char c)
{
if (c=='&') HTMLGen_output_string(me, "&");
else if (c=='<') HTMLGen_output_string(me, "<");
else if (me->seven_bit && ((unsigned char)c > 127)) {
char temp[8];
sprintf(temp, "&%d;", c);
HTMLGen_output_string(me, temp);
} else
HTMLGen_output_character(me, c);
return HT_OK;
}
PRIVATE int HTMLGen_put_string (HTStructured * me, const char* s)
{
while (*s)
HTMLGen_put_character(me, *s++);
return HT_OK;
}
PRIVATE int HTMLGen_write (HTStructured * me, const char* b, int l)
{
while (l-- > 0)
HTMLGen_put_character(me, *b++);
return HT_OK;
}
/* Start Element
** -------------
**
** Within the opening tag, there may be spaces
** and the line may be broken at these spaces.
*/
PRIVATE void HTMLGen_start_element (
HTStructured * me,
int element_number,
const BOOL* present,
const char ** value)
{
int i;
HTTag * tag = &me->dtd->tags[element_number];
/* Control line breaks allowed within tag! */
int was_preformatted = me->preformatted; /* save state */
me->preformatted = 1; /* Can break between attributes */
HTMLGen_output_character(me, '<');
HTMLGen_output_string(me, tag->name);
if (present) for (i=0; i< tag->number_of_attributes; i++) {
if (present[i]) {
HTMLGen_output_character(me, ' ');
allow_break(me, 1, YES);
HTMLGen_output_string(me, tag->attributes[i].name);
if (value[i]) {
HTMLGen_output_string(me, "=\"");
HTMLGen_output_string(me, value[i]);
HTMLGen_output_character(me, '"');
}
}
}
me->preformatted = was_preformatted; /* Restore state */
/* Nested PRE is no more a problem! */
if (element_number == HTML_PRE)
me->preformatted++;
HTMLGen_output_character(me, '>');
/* Here is a funny one. In PRE, newlines are significant, except of
course for one after the which is ignored. This means that
we MUST put in a dummy one after the to protect any real newline
within the pre section.
However, *within* a PRE section, although we can break after
(for example) emphasis start tags, it will probably confuse some
parsers so we won't.*/
if (element_number == HTML_PRE) {
HTMLGen_output_character(me, '\n');
} else if (!me->preformatted &&
tag->contents != SGML_EMPTY) { /* can break after element start */
allow_break(me, 3, NO);
}
}
/* End Element
** -----------
**
** The rules for insertring CR LF into SGML are weird, strict, and
** nonintitive.
** See comment also about PRE above.
*/
PRIVATE void HTMLGen_end_element (HTStructured * me, int element_number)
{
if (element_number == HTML_PRE) {
HTMLGen_output_character(me, '\n');
} else if (!me->preformatted) { /* can break before element end */
allow_break(me, 1, NO);
}
HTMLGen_output_string(me, "dtd->tags[element_number].name);
HTMLGen_output_character(me, '>'); /* NO break after. TBL 940501 */
if (element_number == HTML_PRE && me->preformatted)
me->preformatted--;
}
/* Expanding entities
** ------------------
**
*/
PRIVATE void HTMLGen_put_entity (HTStructured * me, int entity_number)
{
HTMLGen_output_character(me, '&');
HTMLGen_output_string(me, me->dtd->entity_names[entity_number]);
HTMLGen_output_character(me, ';');
}
/* Free an object
** --------------
**
*/
PRIVATE int HTMLGen_free (HTStructured * me)
{
HTMLGen_flush(me);
PUT_CHAR('\n');
(*me->target->isa->_free)(me->target);
HT_FREE(me);
return HT_OK;
}
PRIVATE int PlainToHTML_free (HTStructured * me)
{
HTMLGen_end_element(me, HTML_PRE);
HTMLGen_end_element(me, HTML_BODY);
HTMLGen_end_element(me, HTML_HTML);
HTMLGen_free(me);
return HT_OK;
}
PRIVATE int HTMLGen_abort (HTStructured * me, HTList * e)
{
HTMLGen_free(me);
return HT_ERROR;
}
PRIVATE int PlainToHTML_abort (HTStructured * me, HTList * e)
{
PlainToHTML_free(me);
return HT_ERROR;
}
/* Structured Object Class
** -----------------------
*/
PRIVATE const HTStructuredClass HTMLGeneration = /* As opposed to print etc */
{
"text/html",
HTMLGen_flush,
HTMLGen_free,
HTMLGen_abort,
HTMLGen_put_character, HTMLGen_put_string, HTMLGen_write,
HTMLGen_start_element, HTMLGen_end_element,
HTMLGen_put_entity
};
/* Subclass-specific Methods
** -------------------------
*/
PUBLIC HTStructured* HTMLGenerator (HTRequest * request,
void * param,
HTFormat input_format,
HTFormat output_format,
HTStream * output_stream)
{
HTStructured* me;
if ((me = (HTStructured *) HT_CALLOC(1, sizeof(HTStructured))) == NULL)
HT_OUTOFMEM("HTMLGenerator");
me->isa = &HTMLGeneration;
me->dtd = HTML_dtd();
if ((me->target = HTStreamStack(WWW_HTML, output_format, output_stream,
request, YES)) == NULL) {
HTTRACE(STREAM_TRACE, "HTMLGen..... Can't convert to media type\n");
HT_FREE(me);
me->target = HTErrorStream();
}
me->write_pointer = me->buffer;
flush_breaks(me);
return me;
}
/* Stream Object Class
** -------------------
**
** This object just converts a plain text stream into HTML
** It is officially a structured stream but only the stream bits exist.
** This is just the easiest way of typecasting all the routines.
*/
PRIVATE const HTStructuredClass PlainToHTMLConversion =
{
"plaintexttoHTML",
HTMLGen_flush,
PlainToHTML_free, /* HTMLGen_free, Henrik 03/03-94 */
PlainToHTML_abort,
HTMLGen_put_character,
HTMLGen_put_string,
HTMLGen_write,
NULL, /* Structured stuff */
NULL,
NULL
};
/* HTConverter from plain text to HTML Stream
** ------------------------------------------
**
** Changed by henrik 03/03-94, so no more core dumps etc. (I hope!!!)
*/
PUBLIC HTStream* HTPlainToHTML (HTRequest * request,
void * param,
HTFormat input_format,
HTFormat output_format,
HTStream * output_stream)
{
BOOL present[MAX_ATTRIBUTES]; /* Flags: attribute is present? */
const char *value[MAX_ATTRIBUTES]; /* malloc'd strings or NULL if none */
HTStructured* me;
if ((me = (HTStructured *) HT_CALLOC(1,sizeof(*me))) == NULL)
HT_OUTOFMEM("PlainToHTML");
memset((void *) present, '\0', MAX_ATTRIBUTES);
memset((void *) value, '\0', MAX_ATTRIBUTES*sizeof(char *));
me->isa = (HTStructuredClass*) &PlainToHTMLConversion;
me->dtd = HTML_dtd();
me->target = output_stream;
me->write_pointer = me->buffer;
flush_breaks(me);
if (me->target) {
HTMLGen_start_element(me, HTML_HTML, present, value);
HTMLGen_start_element(me, HTML_BODY, present, value);
HTMLGen_start_element(me, HTML_PRE, present, value);
}
return (HTStream*) me;
}
/* A safe version for making 7-bit restricted HTML
** Beware that thsi makes it horrible for the Scandinavians
** to actually read it.
** ehh - not horrible - THIS REALLY PISSES THEM OFF - Henrik ;-)
*/
PUBLIC HTStream* HTPlainTo7BitHTML (HTRequest * request,
void * param,
HTFormat input_format,
HTFormat output_format,
HTStream * output_stream)
{
HTStream* me = HTPlainToHTML(request,param,input_format,
output_format, output_stream);
((HTStructured*)me)->seven_bit = YES;
return me;
}