, then the "x" tag follows the line breaks inserted * by the
tag). */
struct tag *last_tag_for_newline;
struct link_state_info link_state_info;
struct conv_table *convert_table;
/* Used for setting cache info from HTTP-EQUIV meta tags. */
struct cache_entry *cached;
int g_ctrl_num;
int subscript; /* Count stacked subscripts */
int supscript; /* Count stacked supscripts */
unsigned int empty_format:1;
unsigned int nobreak:1;
unsigned int nosearchable:1;
unsigned int nowrap:1; /* Activated/deactivated by SP_NOWRAP. */
};
static struct renderer_context renderer_context;
/* Prototypes */
static void line_break(struct html_context *);
static void put_chars(struct html_context *, unsigned char *, int);
#define X(x_) (part->box.x + (x_))
#define Y(y_) (part->box.y + (y_))
#define SPACES_GRANULARITY 0x7F
#define ALIGN_SPACES(x, o, n) mem_align_alloc(x, o, n, SPACES_GRANULARITY)
static inline void
set_screen_char_color(struct screen_char *schar,
color_T bgcolor, color_T fgcolor,
enum color_flags color_flags,
enum color_mode color_mode)
{
struct color_pair colors = INIT_COLOR_PAIR(bgcolor, fgcolor);
set_term_color(schar, &colors, color_flags, color_mode);
}
static int
realloc_line(struct html_context *html_context, struct document *document,
int y, int length)
{
struct screen_char *pos, *end;
struct line *line;
int orig_length;
if (!realloc_lines(document, y))
return -1;
line = &document->data[y];
orig_length = line->length;
if (length < orig_length)
return orig_length;
if (!ALIGN_LINE(&line->chars, line->length, length + 1))
return -1;
/* We cannot rely on the aligned allocation to clear the members for us
* since for line splitting we simply trim the length. Question is if
* it is better to to clear the line after the splitting or here. */
end = &line->chars[length];
end->data = ' ';
end->attr = 0;
set_screen_char_color(end, par_format.color.background, 0x0,
COLOR_ENSURE_CONTRAST, /* for bug 461 */
document->options.color_mode);
for (pos = &line->chars[line->length]; pos < end; pos++) {
copy_screen_chars(pos, end, 1);
}
line->length = length + 1;
return orig_length;
}
void
expand_lines(struct html_context *html_context, struct part *part,
int x, int y, int lines, color_T bgcolor)
{
int line;
assert(part && part->document);
if_assert_failed return;
if (!use_document_bg_colors(&part->document->options))
return;
par_format.color.background = bgcolor;
for (line = 0; line < lines; line++)
realloc_line(html_context, part->document, Y(y + line), X(x));
}
static inline int
realloc_spaces(struct part *part, int length)
{
if (length < part->spaces_len)
return 0;
if (!ALIGN_SPACES(&part->spaces, part->spaces_len, length))
return -1;
#ifdef CONFIG_UTF8
if (!ALIGN_SPACES(&part->char_width, part->spaces_len, length))
return -1;
#endif
part->spaces_len = length;
return 0;
}
#define LINE(y_) part->document->data[Y(y_)]
#define POS(x_, y_) LINE(y_).chars[X(x_)]
#define LEN(y_) int_max(LINE(y_).length - part->box.x, 0)
/* When we clear chars we want to preserve and use the background colors
* already in place else we could end up ``staining'' the background especial
* when drawing table cells. So make the cleared chars share the colors in
* place.
*
* This function does not update document.comb_x and document.comb_y.
* That is the caller's responsibility. */
static inline void
clear_hchars(struct html_context *html_context, int x, int y, int width,
struct screen_char *a)
{
struct part *part;
struct screen_char *pos, *end;
assert(html_context);
if_assert_failed return;
part = html_context->part;
assert(part && part->document && width > 0);
if_assert_failed return;
if (realloc_line(html_context, part->document, Y(y), X(x) + width - 1) < 0)
return;
assert(part->document->data);
if_assert_failed return;
pos = &POS(x, y);
end = pos + width - 1;
end->data = ' ';
end->attr = 0;
end->c = a->c;
while (pos < end)
copy_screen_chars(pos++, end, 1);
}
/* TODO: Merge parts with get_format_screen_char(). --jonas */
/* Allocates the required chars on the given line and returns the char at
* position (x, y) ready to be used as a template char. */
static inline struct screen_char *
get_frame_char(struct html_context *html_context, struct part *part,
int x, int y, unsigned char data,
color_T bgcolor, color_T fgcolor)
{
struct screen_char *template_;
assert(html_context);
if_assert_failed return NULL;
assert(part && part->document && x >= 0 && y >= 0);
if_assert_failed return NULL;
if (realloc_line(html_context, part->document, Y(y), X(x)) < 0)
return NULL;
assert(part->document->data);
if_assert_failed return NULL;
template_ = &POS(x, y);
template_->data = data;
template_->attr = SCREEN_ATTR_FRAME;
set_screen_char_color(template_, bgcolor, fgcolor,
part->document->options.color_flags,
part->document->options.color_mode);
return template_;
}
void
draw_frame_hchars(struct part *part, int x, int y, int width,
unsigned char data, color_T bgcolor, color_T fgcolor,
struct html_context *html_context)
{
struct screen_char *template_;
assert(width > 0);
if_assert_failed return;
template_ = get_frame_char(html_context, part, x + width - 1, y, data, bgcolor, fgcolor);
if (!template_) return;
/* The template char is the last we need to draw so only decrease @width. */
for (width -= 1; width; width--, x++) {
copy_screen_chars(&POS(x, y), template_, 1);
}
}
void
draw_frame_vchars(struct part *part, int x, int y, int height,
unsigned char data, color_T bgcolor, color_T fgcolor,
struct html_context *html_context)
{
struct screen_char *template_ = get_frame_char(html_context, part, x, y,
data, bgcolor, fgcolor);
if (!template_) return;
/* The template char is the first vertical char to be drawn. So
* copy it to the rest. */
for (height -= 1, y += 1; height; height--, y++) {
if (realloc_line(html_context, part->document, Y(y), X(x)) < 0)
return;
copy_screen_chars(&POS(x, y), template_, 1);
}
}
static inline struct screen_char *
get_format_screen_char(struct html_context *html_context,
enum link_state link_state)
{
static struct text_style ta_cache = INIT_TEXT_STYLE(-1, 0x0, 0x0);
static struct screen_char schar_cache;
if (memcmp(&ta_cache, &format.style, sizeof(ta_cache))) {
copy_struct(&ta_cache, &format.style);
struct text_style final_style = format.style;
get_screen_char_template(&schar_cache, html_context->options, final_style);
}
if (!!(schar_cache.attr & SCREEN_ATTR_UNSEARCHABLE)
^ !!renderer_context.nosearchable) {
schar_cache.attr ^= SCREEN_ATTR_UNSEARCHABLE;
}
if (link_state != LINK_STATE_NONE
&& !format.form
&& html_context->options->underline_links) {
schar_cache.attr |= SCREEN_ATTR_UNDERLINE;
}
return &schar_cache;
}
/* document.comb_x and document.comb_y exist only when CONFIG_COMBINE
* is defined. assert() does nothing if CONFIG_FASTMEM is defined. */
#if defined(CONFIG_COMBINE) && !defined(CONFIG_FASTMEM)
/** Assert that path->document->comb_x and part->document->comb_y
* refer to an allocated struct screen_char, or comb_x is -1.
*
* The CONFIG_COMBINE variant of set_hline() can update the
* screen_char.data at these coordinates. Sometimes, the coordinates
* have not been valid, and the update has corrupted memory. These
* assertions should catch that bug if it happens again.
*
* @post This function can leave ::assert_failed set, so the caller
* should use ::if_assert_failed, perhaps with discard_comb_x_y(). */
static void
assert_comb_x_y_ok(const struct document *document)
{
assert(document);
if (document->comb_x != -1) {
assert(document->comb_y >= 0);
assert(document->comb_y < document->height);
assert(document->comb_x >= 0);
assert(document->comb_x < document->data[document->comb_y].length);
}
}
#else
# define assert_comb_x_y_ok(document) ((void) 0)
#endif
#ifdef CONFIG_COMBINE
/** Discard any combining characters that have not yet been combined
* with to the previous base character. */
static void
discard_comb_x_y(struct document *document)
{
document->comb_x = -1;
document->comb_y = -1;
document->combi_length = 0;
}
#else
# define discard_comb_x_y(document) ((void) 0)
#endif
#ifdef CONFIG_COMBINE
static void
move_comb_x_y(struct part *part, int xf, int yf, int xt, int yt)
{
if (part->document->comb_x != -1
&& part->document->comb_y == Y(yf)
&& part->document->comb_x >= X(xf)) {
if (yt >= 0) {
part->document->comb_x += xt - xf;
part->document->comb_y += yt - yf;
} else
discard_comb_x_y(part->document);
}
}
#else
# define move_comb_x_y(part, xf, yf, xt, yt) ((void) 0)
#endif
#ifdef CONFIG_COMBINE
static void
set_comb_x_y(struct part *part, int x, int y)
{
struct document *document = part->document;
document->comb_x = X(x);
document->comb_y = Y(y);
assert_comb_x_y_ok(document);
if_assert_failed discard_comb_x_y(document);
}
#else
# define set_comb_x_y(part, x, y) ((void) 0)
#endif
#ifdef CONFIG_COMBINE
static void
put_combined(struct part *part, int x)
{
struct document *document = part->document;
if (document->combi_length) {
if (document->comb_x != -1) {
unicode_val_T prev = get_combined(document->combi, document->combi_length + 1);
assert_comb_x_y_ok(document);
if_assert_failed prev = UCS_NO_CHAR;
/* Make sure the combined character is not considered as
* a space. */
if (x)
part->spaces[x - 1] = 0;
if (prev != UCS_NO_CHAR)
document->data[document->comb_y]
.chars[document->comb_x].data = prev;
}
document->combi_length = 0;
}
}
#else
# define put_combined(part, x) ((void) 0)
#endif
#ifdef CONFIG_UTF8
/* First possibly do the format change and then find out what coordinates
* to use since sub- or superscript might change them */
static inline int
set_hline(struct html_context *html_context, unsigned char *chars, int charslen,
enum link_state link_state)
{
struct part *const part = html_context->part;
struct screen_char *const schar = get_format_screen_char(html_context,
link_state);
int x = part->cx;
const int y = part->cy;
const int x2 = x;
int len = charslen;
const int utf8 = html_context->options->utf8;
int orig_length;
assert(part);
if_assert_failed return len;
assert(charslen >= 0);
if (realloc_spaces(part, x + charslen))
return 0;
/* U+00AD SOFT HYPHEN characters in HTML documents are
* supposed to be displayed only if the word is broken at that
* point. ELinks currently does not use them, so it should
* not display them. If the input @chars is in UTF-8, then
* set_hline() discards the characters. If the input is in
* some other charset, then set_hline() does not know which
* byte that charset uses for U+00AD, so it cannot discard
* the characters; instead, the translation table used by
* convert_string() has already discarded the characters.
*
* Likewise, if the input @chars is in UTF-8, then it may
* contain U+00A0 NO-BREAK SPACE characters; but if the input
* is in some other charset, then the translation table
* has mapped those characters to NBSP_CHAR. */
if (part->document) {
struct document *const document = part->document;
assert_comb_x_y_ok(document);
if_assert_failed discard_comb_x_y(document);
/* Reallocate LINE(y).chars[] to large enough. The
* last parameter of realloc_line is the index of the
* last element to which we may want to write,
* i.e. one less than the required size of the array.
* Compute the required size by assuming that each
* byte of input will need at most one character cell.
* (All double-cell characters take up at least two
* bytes in UTF-8, and there are no triple-cell or
* wider characters.) However, if there already is an
* incomplete character in document->buf, then
* the first byte of input can result in a double-cell
* character, so we must reserve one extra element. */
orig_length = realloc_line(html_context, document,
Y(y), X(x) + charslen);
if (orig_length < 0) /* error */
return 0;
if (utf8) {
unsigned char *const end = chars + charslen;
unicode_val_T data;
if (document->buf_length) {
/* previous char was broken in the middle */
int length = utf8charlen(document->buf);
unsigned char i;
unsigned char *buf_ptr = document->buf;
for (i = document->buf_length; i < length && chars < end;) {
document->buf[i++] = *chars++;
}
document->buf_length = i;
document->buf[i] = '\0';
data = utf8_to_unicode(&buf_ptr, buf_ptr + i);
if (data != UCS_NO_CHAR) {
/* FIXME: If there was invalid
* UTF-8 in the buffer,
* @utf8_to_unicode may have left
* some bytes unused. Those
* bytes should be pulled back
* into @chars, rather than
* discarded. This is not
* trivial to implement because
* each byte may have arrived in
* a separate call. */
document->buf_length = 0;
goto good_char;
} else {
/* Still not full char */
assert_comb_x_y_ok(document);
LINE(y).length = orig_length;
assert_comb_x_y_ok(document);
if_assert_failed discard_comb_x_y(document);
return 0;
}
}
while (chars < end) {
/* ELinks does not use NBSP_CHAR in UTF-8. */
data = utf8_to_unicode(&chars, end);
if (data == UCS_NO_CHAR) {
part->spaces[x] = 0;
if (charslen == 1) {
/* HR */
unsigned char attr = schar->attr;
schar->data = *chars++;
schar->attr = SCREEN_ATTR_FRAME;
copy_screen_chars(&POS(x, y), schar, 1);
schar->attr = attr;
part->char_width[x++] = 0;
continue;
} else {
unsigned char i;
for (i = 0; chars < end;i++) {
document->buf[i] = *chars++;
}
document->buf_length = i;
break;
}
/* not reached */
}
good_char:
if (data == UCS_SOFT_HYPHEN)
continue;
if (data == UCS_NO_BREAK_SPACE
&& html_context->options->wrap_nbsp)
data = UCS_SPACE;
#ifdef CONFIG_COMBINE
if (wcwidth((wchar_t)data)) {
put_combined(part, x);
document->combi[0] = data;
} else {
if (part->cx == x) {
if (X(x)) {
/* Isolated combining
* character not on the
* first column: combine
* it with whatever is
* printed at its left. */
document->combi[0] = POS(x - 1, y).data;
set_comb_x_y(part, x - 1, y);
} else {
/* Isolated combining
* character on the
* first column: use
* UCS_NO_BREAK_SPACE as
* the base character.
* */
document->combi[0] = UCS_NO_BREAK_SPACE;
set_comb_x_y(part, x, y);
schar->data = UCS_SPACE;
copy_screen_chars(&POS(x++, y), schar, 1);
}
}
if (document->combi_length < (UCS_MAX_LENGTH_COMBINED - 1))
document->combi[++document->combi_length] = data;
continue;
}
#endif /* CONFIG_COMBINE */
part->spaces[x] = (data == UCS_SPACE);
if (unicode_to_cell(data) == 0)
continue;
else if (unicode_to_cell(data) == 2) {
schar->data = (unicode_val_T)data;
part->char_width[x] = 2;
copy_screen_chars(&POS(x++, y), schar, 1);
schar->data = UCS_NO_CHAR;
part->spaces[x] = 0;
part->char_width[x] = 0;
} else {
part->char_width[x] = unicode_to_cell(data);
schar->data = (unicode_val_T)data;
}
set_comb_x_y(part, x, y);
copy_screen_chars(&POS(x++, y), schar, 1);
} /* while chars < end */
/* Display any trailing combining characters. */
put_combined(part, x);
} else { /* not UTF-8 */
for (; charslen > 0; charslen--, x++, chars++) {
part->char_width[x] = 1;
if (*chars == NBSP_CHAR) {
schar->data = ' ';
part->spaces[x] = html_context->options->wrap_nbsp;
} else {
part->spaces[x] = (*chars == ' ');
schar->data = *chars;
}
copy_screen_chars(&POS(x, y), schar, 1);
}
} /* end of UTF-8 check */
/* Assert that we haven't written past the end of the
* LINE(y).chars array. @x here is one greater than
* the last one used in POS(x, y). Instead of this,
* we could assert(X(x) < LINE(y).length) immediately
* before each @copy_screen_chars call above, but
* those are in an inner loop that should be fast. */
assert(X(x) <= LINE(y).length);
/* Some part of the code is apparently using LINE(y).length
* for line-wrapping decisions. It may currently be too
* large because it was allocated above based on @charslen
* which is the number of bytes, not the number of cells.
* Change the length to the correct size, but don't let it
* get smaller than it was on entry to this function. */
assert_comb_x_y_ok(document);
LINE(y).length = int_max(orig_length, X(x));
assert_comb_x_y_ok(document);
if_assert_failed discard_comb_x_y(document);
len = x - x2;
} else { /* part->document == NULL */
if (utf8) {
unsigned char *const end = chars + charslen;
while (chars < end) {
unicode_val_T data;
data = utf8_to_unicode(&chars, end);
#ifdef CONFIG_COMBINE
if (data == UCS_SOFT_HYPHEN
|| (data != UCS_NO_CHAR && wcwidth((wchar_t)data) == 0))
#else
if (data == UCS_SOFT_HYPHEN)
#endif
continue;
if (data == UCS_NO_BREAK_SPACE
&& html_context->options->wrap_nbsp)
data = UCS_SPACE;
part->spaces[x] = (data == UCS_SPACE);
part->char_width[x] = unicode_to_cell(data);
if (part->char_width[x] == 2) {
x++;
part->spaces[x] = 0;
part->char_width[x] = 0;
}
if (data == UCS_NO_CHAR) {
/* this is at the end only */
return x - x2;
}
x++;
} /* while chars < end */
len = x - x2;
} else { /* not UTF-8 */
for (; charslen > 0; charslen--, x++, chars++) {
part->char_width[x] = 1;
if (*chars == NBSP_CHAR) {
part->spaces[x] = html_context->options->wrap_nbsp;
} else {
part->spaces[x] = (*chars == ' ');
}
}
}
} /* end of part->document check */
return len;
}
#else
/* First possibly do the format change and then find out what coordinates
* to use since sub- or superscript might change them */
static inline void
set_hline(struct html_context *html_context, unsigned char *chars, int charslen,
enum link_state link_state)
{
struct part *part = html_context->part;
struct screen_char *schar = get_format_screen_char(html_context,
link_state);
int x = part->cx;
int y = part->cy;
assert(part);
if_assert_failed return;
if (realloc_spaces(part, x + charslen))
return;
if (part->document) {
if (realloc_line(html_context, part->document,
Y(y), X(x) + charslen - 1) < 0)
return;
for (; charslen > 0; charslen--, x++, chars++) {
if (*chars == NBSP_CHAR) {
schar->data = ' ';
part->spaces[x] = html_context->options->wrap_nbsp;
} else {
part->spaces[x] = (*chars == ' ');
schar->data = *chars;
}
copy_screen_chars(&POS(x, y), schar, 1);
}
} else {
for (; charslen > 0; charslen--, x++, chars++) {
if (*chars == NBSP_CHAR) {
part->spaces[x] = html_context->options->wrap_nbsp;
} else {
part->spaces[x] = (*chars == ' ');
}
}
}
}
#endif /* CONFIG_UTF8 */
static void
move_links(struct html_context *html_context, int xf, int yf, int xt, int yt)
{
struct part *part;
struct tag *tag;
int nlink = renderer_context.last_link_to_move;
int matched = 0;
assert(html_context);
if_assert_failed return;
part = html_context->part;
assert(part && part->document);
if_assert_failed return;
if (!realloc_lines(part->document, Y(yt)))
return;
for (; nlink < part->document->nlinks; nlink++) {
struct link *link = &part->document->links[nlink];
int i;
for (i = 0; i < link->npoints; i++) {
/* Fix for bug 479 (part one) */
/* The scenario that triggered it:
*
* Imagine a centered element containing a really long
* word (over half of the screen width long) followed
* by a few links with no spaces between them where all
* the link text combined with the really long word
* will force the line to be wrapped. When rendering
* the line first words (including link text words) are
* put on one line. Then wrapping is performed moving
* all links from current line to the one below. Then
* the current line (now only containing the really
* long word) is centered. This will trigger a call to
* move_links() which will increment.
*
* Without the fix below the centering of the current
* line will increment last_link_to_move to that of the
* last link which means centering of the next line
* with all the links will only move the last link
* leaving all the other links' points dangling and
* causing buggy link highlighting.
*
* Even links like textareas will be correctly handled
* because @last_link_to_move is a way to optimize how
* many links move_links() will have to iterate and
* this little fix will only decrease the effect of the
* optimization by always ensuring it is never
* incremented too far. */
if (!matched && link->points[i].y > Y(yf)) {
matched = 1;
continue;
}
if (link->points[i].y != Y(yf))
continue;
matched = 1;
if (link->points[i].x < X(xf))
continue;
if (yt >= 0) {
link->points[i].y = Y(yt);
link->points[i].x += -xf + xt;
} else {
int to_move = link->npoints - (i + 1);
assert(to_move >= 0);
if (to_move > 0) {
memmove(&link->points[i],
&link->points[i + 1],
to_move *
sizeof(*link->points));
i--;
}
link->npoints--;
}
}
if (!matched) {
renderer_context.last_link_to_move = nlink;
}
}
/* Don't move tags when removing links. */
if (yt < 0) return;
matched = 0;
tag = renderer_context.last_tag_to_move;
while (list_has_next(part->document->tags, tag)) {
tag = tag->next;
if (tag->y == Y(yf)) {
matched = 1;
if (tag->x >= X(xf)) {
tag->y = Y(yt);
tag->x += -xf + xt;
}
} else if (!matched && tag->y > Y(yf)) {
/* Fix for bug 479 (part two) */
matched = 1;
}
if (!matched) renderer_context.last_tag_to_move = tag;
}
}
/* This function does not update document.comb_x and document.comb_y.
* That is the caller's responsibility. */
static inline void
copy_chars(struct html_context *html_context, int x, int y, int width, struct screen_char *d)
{
struct part *part;
assert(html_context);
if_assert_failed return;
part = html_context->part;
assert(width > 0 && part && part->document && part->document->data);
if_assert_failed return;
if (realloc_line(html_context, part->document, Y(y), X(x) + width - 1) < 0)
return;
copy_screen_chars(&POS(x, y), d, width);
}
static inline void
move_chars(struct html_context *html_context, int x, int y, int nx, int ny)
{
struct part *part;
assert(html_context);
if_assert_failed return;
part = html_context->part;
assert(part && part->document && part->document->data);
if_assert_failed return;
if (LEN(y) - x <= 0) return;
copy_chars(html_context, nx, ny, LEN(y) - x, &POS(x, y));
assert_comb_x_y_ok(part->document);
move_comb_x_y(part, x, y, nx, ny);
LINE(y).length = X(x);
assert_comb_x_y_ok(part->document);
if_assert_failed discard_comb_x_y(part->document);
move_links(html_context, x, y, nx, ny);
}
/** Shift the line @a y to the right by @a shift character cells,
* and update document.comb_x and document.comb_y. */
static inline void
shift_chars(struct html_context *html_context, int y, int shift)
{
struct part *part;
struct screen_char *a;
int len;
assert(html_context);
if_assert_failed return;
part = html_context->part;
assert(part && part->document && part->document->data);
if_assert_failed return;
len = LEN(y);
a = fmem_alloc(len * sizeof(*a));
if (!a) return;
copy_screen_chars(a, &POS(0, y), len);
assert_comb_x_y_ok(part->document);
if_assert_failed discard_comb_x_y(part->document);
clear_hchars(html_context, 0, y, shift, a);
copy_chars(html_context, shift, y, len, a);
fmem_free(a);
move_links(html_context, 0, y, shift, y);
move_comb_x_y(part, 0, y, shift, y);
assert_comb_x_y_ok(part->document);
if_assert_failed discard_comb_x_y(part->document);
}
static inline void
del_chars(struct html_context *html_context, int x, int y)
{
struct part *part;
assert(html_context);
if_assert_failed return;
part = html_context->part;
assert(part && part->document && part->document->data);
if_assert_failed return;
assert_comb_x_y_ok(part->document);
if_assert_failed discard_comb_x_y(part->document);
LINE(y).length = X(x);
move_comb_x_y(part, x, y, -1, -1);
move_links(html_context, x, y, -1, -1);
assert_comb_x_y_ok(part->document);
if_assert_failed discard_comb_x_y(part->document);
}
#if TABLE_LINE_PADDING < 0
# define overlap_width(x) (x).width
#else
# define overlap_width(x) int_min((x).width, \
html_context->options->document_width - TABLE_LINE_PADDING)
#endif
#define overlap(x) int_max(overlap_width(x) - (x).rightmargin, 0)
static int inline
split_line_at(struct html_context *html_context, int width)
{
struct part *part;
int tmp;
int new_width = width + par_format.rightmargin;
assert(html_context);
if_assert_failed return 0;
part = html_context->part;
assert(part);
if_assert_failed return 0;
/* Make sure that we count the right margin to the total
* actual box width. */
int_lower_bound(&part->box.width, new_width);
if (part->document) {
assert(part->document->data);
if_assert_failed return 0;
#ifdef CONFIG_UTF8
if (html_context->options->utf8
&& width < part->spaces_len && part->char_width[width] == 2) {
move_chars(html_context, width, part->cy, par_format.leftmargin, part->cy + 1);
del_chars(html_context, width, part->cy);
} else
#endif
{
assertm(POS(width, part->cy).data == ' ',
"bad split: %c", POS(width, part->cy).data);
move_chars(html_context, width + 1, part->cy, par_format.leftmargin, part->cy + 1);
del_chars(html_context, width, part->cy);
}
}
#ifdef CONFIG_UTF8
if (!(html_context->options->utf8
&& width < part->spaces_len
&& part->char_width[width] == 2))
#endif
width++; /* Since we were using (x + 1) only later... */
tmp = part->spaces_len - width;
if (tmp > 0) {
/* 0 is possible and I'm paranoid ... --Zas */
memmove(part->spaces, part->spaces + width, tmp);
#ifdef CONFIG_UTF8
memmove(part->char_width, part->char_width + width, tmp);
#endif
}
assert(tmp >= 0);
if_assert_failed tmp = 0;
memset(part->spaces + tmp, 0, width);
#ifdef CONFIG_UTF8
memset(part->char_width + tmp, 0, width);
#endif
if (par_format.leftmargin > 0) {
tmp = part->spaces_len - par_format.leftmargin;
assertm(tmp > 0, "part->spaces_len - par_format.leftmargin == %d", tmp);
/* So tmp is zero, memmove() should survive that. Don't recover. */
memmove(part->spaces + par_format.leftmargin, part->spaces, tmp);
#ifdef CONFIG_UTF8
memmove(part->char_width + par_format.leftmargin, part->char_width, tmp);
#endif
}
part->cy++;
if (part->cx == width) {
part->cx = -1;
int_lower_bound(&part->box.height, part->cy);
return 2;
} else {
part->cx -= width - par_format.leftmargin;
int_lower_bound(&part->box.height, part->cy + 1);
return 1;
}
}
/* Here, we scan the line for a possible place where we could split it into two
* (breaking it, because it is too long), if it is overlapping from the maximal
* box width. */
/* Returns 0 if there was found no spot suitable for breaking the line.
* 1 if the line was split into two.
* 2 if the (second) splitted line is blank (that is useful to determine
* ie. if the next line_break() should really break the line; we don't
* want to see any blank lines to pop up, do we?). */
static int
split_line(struct html_context *html_context)
{
struct part *part;
int x;
assert(html_context);
if_assert_failed return 0;
part = html_context->part;
assert(part);
if_assert_failed return 0;
#ifdef CONFIG_UTF8
if (html_context->options->utf8) {
for (x = overlap(par_format); x >= par_format.leftmargin; x--) {
if (x < part->spaces_len && (part->spaces[x]
|| (part->char_width[x] == 2
/* Ugly hack. If we haven't place for
* double-width characters we print two
* double-width characters. */
&& x != par_format.leftmargin)))
return split_line_at(html_context, x);
}
for (x = par_format.leftmargin; x < part->cx ; x++) {
if (x < part->spaces_len && (part->spaces[x]
|| (part->char_width[x] == 2
/* We want to break line after _second_
* double-width character. */
&& x > par_format.leftmargin)))
return split_line_at(html_context, x);
}
} else
#endif
{
for (x = overlap(par_format); x >= par_format.leftmargin; x--)
if (x < part->spaces_len && part->spaces[x])
return split_line_at(html_context, x);
for (x = par_format.leftmargin; x < part->cx ; x++)
if (x < part->spaces_len && part->spaces[x])
return split_line_at(html_context, x);
}
/* Make sure that we count the right margin to the total
* actual box width. */
int_lower_bound(&part->box.width, part->cx + par_format.rightmargin);
return 0;
}
/* Insert @new_spaces spaces before the coordinates @x and @y,
* adding those spaces to whatever link is at those coordinates. */
/* TODO: Integrate with move_links. */
static void
insert_spaces_in_link(struct part *part, int x, int y, int new_spaces)
{
int i = part->document->nlinks;
x = X(x);
y = Y(y);
while (i--) {
struct link *link = &part->document->links[i];
int j = link->npoints;
while (j-- > 1) {
struct point *point = &link->points[j];
if (point->x != x || point->y != y)
continue;
if (!realloc_points(link, link->npoints + new_spaces))
return;
link->npoints += new_spaces;
point = &link->points[link->npoints - 1];
while (new_spaces--) {
point->x = --x;
point->y = y;
point--;
}
return;
}
}
}
/* This function is very rare exemplary of clean and beautyful code here.
* Please handle with care. --pasky */
static void
justify_line(struct html_context *html_context, int y)
{
struct part *part;
struct screen_char *line; /* we save original line here */
int len;
int pos;
int *space_list;
int spaces;
int diff;
assert(html_context);
if_assert_failed return;
part = html_context->part;
assert(part && part->document && part->document->data);
if_assert_failed return;
len = LEN(y);
assert(len > 0);
if_assert_failed return;
line = fmem_alloc(len * sizeof(*line));
if (!line) return;
/* It may sometimes happen that the line is only one char long and that
* char is space - then we're going to write to both [0] and [1], but
* we allocated only one field. Thus, we've to do (len + 1). --pasky */
space_list = fmem_alloc((len + 1) * sizeof(*space_list));
if (!space_list) {
fmem_free(line);
return;
}
copy_screen_chars(line, &POS(0, y), len);
/* Skip leading spaces */
spaces = 0;
pos = 0;
while (line[pos].data == ' ')
pos++;
/* Yes, this can be negative, we know. But we add one to it always
* anyway, so it's ok. */
space_list[spaces++] = pos - 1;
/* Count spaces */
for (; pos < len; pos++)
if (line[pos].data == ' ')
space_list[spaces++] = pos;
space_list[spaces] = len;
/* Realign line */
/* Diff is the difference between the width of the paragraph
* and the current length of the line. */
diff = overlap(par_format) - len;
/* We check diff > 0 because diff can be negative (i.e., we have
* an unbroken line of length > overlap(par_format))
* even when spaces > 1 if the line has only non-breaking spaces. */
if (spaces > 1 && diff > 0) {
int prev_end = 0;
int word;
/* Allocate enough memory for the justified line.
* If the memory is not available, then leave the
* line unchanged, rather than halfway there. The
* following loop assumes the allocation succeeded. */
if (!realloc_line(html_context, html_context->part->document,
Y(y), X(overlap(par_format))))
goto out_of_memory;
for (word = 0; word < spaces; word++) {
/* We have to increase line length by 'diff' num. of
* characters, so we move 'word'th word 'word_shift'
* characters right. */
int word_start = space_list[word] + 1;
int word_len = space_list[word + 1] - word_start;
int word_shift;
int new_start;
int new_spaces;
assert(word_len >= 0);
if_assert_failed continue;
word_shift = (word * diff) / (spaces - 1);
new_start = word_start + word_shift;
/* Assert that the realloc_line() above
* allocated enough memory for the word
* and the preceding spaces. */
assert(LEN(y) >= new_start + word_len);
if_assert_failed continue;
/* Copy the original word, without any spaces.
* word_len may be 0 here. */
copy_screen_chars(&POS(new_start, y),
&line[word_start], word_len);
/* Copy the space that preceded the word,
* duplicating it as many times as necessary.
* This preserves its attributes, such as
* background color and underlining. If this
* is the first word, then skip the copy
* because there might not be a space there
* and anyway it need not be duplicated. */
if (word) {
int spacex;
for (spacex = prev_end; spacex < new_start;
++spacex) {
copy_screen_chars(&POS(spacex, y),
&line[word_start - 1],
1);
}
}
/* Remember that any links at the right side
* of the added spaces have moved, and the
* spaces themselves may also belong to a
* link. */
new_spaces = new_start - prev_end - 1;
if (word && new_spaces) {
move_comb_x_y(part, prev_end + 1, y, new_start, y);
move_links(html_context, prev_end + 1, y, new_start, y);
insert_spaces_in_link(part,
new_start, y, new_spaces);
}
prev_end = new_start + word_len;
}
}
out_of_memory:
fmem_free(space_list);
fmem_free(line);
}
static void
align_line(struct html_context *html_context, int y, int last)
{
struct part *part;
int shift;
int len;
assert(html_context);
if_assert_failed return;
part = html_context->part;
assert(part && part->document && part->document->data);
if_assert_failed return;
len = LEN(y);
if (!len || par_format.align == ALIGN_LEFT)
return;
if (par_format.align == ALIGN_JUSTIFY) {
if (!last)
justify_line(html_context, y);
return;
}
shift = overlap(par_format) - len;
if (par_format.align == ALIGN_CENTER)
shift /= 2;
if (shift > 0)
shift_chars(html_context, y, shift);
}
static inline void
init_link_event_hooks(struct html_context *html_context, struct link *link)
{
link->event_hooks = mem_calloc(1, sizeof(*link->event_hooks));
if (!link->event_hooks) return;
#define add_evhook(list_, type_, src_) \
do { \
struct script_event_hook *evhook; \
\
if (!src_) break; \
\
evhook = mem_calloc(1, sizeof(*evhook)); \
if (!evhook) break; \
\
evhook->type = type_; \
evhook->src = stracpy(src_); \
add_to_list(*(list_), evhook); \
} while (0)
init_list(*link->event_hooks);
add_evhook(link->event_hooks, SEVHOOK_ONCLICK, format.onclick);
add_evhook(link->event_hooks, SEVHOOK_ONDBLCLICK, format.ondblclick);
add_evhook(link->event_hooks, SEVHOOK_ONMOUSEOVER, format.onmouseover);
add_evhook(link->event_hooks, SEVHOOK_ONHOVER, format.onhover);
add_evhook(link->event_hooks, SEVHOOK_ONFOCUS, format.onfocus);
add_evhook(link->event_hooks, SEVHOOK_ONMOUSEOUT, format.onmouseout);
add_evhook(link->event_hooks, SEVHOOK_ONBLUR, format.onblur);
#undef add_evhook
}
static struct link *
new_link(struct html_context *html_context, unsigned char *name, int namelen)
{
struct document *document;
struct part *part;
int link_number;
struct link *link;
assert(html_context);
if_assert_failed return NULL;
part = html_context->part;
assert(part);
if_assert_failed return NULL;
document = part->document;
assert(document);
if_assert_failed return NULL;
link_number = part->link_num;
if (!ALIGN_LINK(&document->links, document->nlinks, document->nlinks + 1))
return NULL;
link = &document->links[document->nlinks++];
link->number = link_number - 1;
if (document->options.use_tabindex) link->number += format.tabindex;
link->accesskey = format.accesskey;
link->title = null_or_stracpy(format.title);
link->where_img = null_or_stracpy(format.image);
if (!format.form) {
link->target = null_or_stracpy(format.target);
link->data.name = memacpy(name, namelen);
/* if (strlen(url) > 4 && !c_strncasecmp(url, "MAP@", 4)) { */
if (format.link
&& ((format.link[0]|32) == 'm')
&& ((format.link[1]|32) == 'a')
&& ((format.link[2]|32) == 'p')
&& (format.link[3] == '@')
&& format.link[4]) {
link->type = LINK_MAP;
link->where = stracpy(format.link + 4);
} else {
link->type = LINK_HYPERTEXT;
link->where = null_or_stracpy(format.link);
}
} else {
struct form_control *fc = format.form;
struct form *form;
switch (fc->type) {
case FC_TEXT:
case FC_PASSWORD:
case FC_FILE:
link->type = LINK_FIELD;
break;
case FC_TEXTAREA:
link->type = LINK_AREA;
break;
case FC_CHECKBOX:
case FC_RADIO:
link->type = LINK_CHECKBOX;
break;
case FC_SELECT:
link->type = LINK_SELECT;
break;
case FC_SUBMIT:
case FC_IMAGE:
case FC_RESET:
case FC_BUTTON:
case FC_HIDDEN:
link->type = LINK_BUTTON;
}
link->data.form_control = fc;
/* At this point, format.form might already be set but
* the form_control not registered through SP_CONTROL
* yet, therefore without fc->form set. It is always
* after the "good" last form was already processed,
* though, so we can safely just take that. */
form = fc->form;
if (!form && !list_empty(document->forms))
form = document->forms.next;
link->target = null_or_stracpy(form ? form->target : NULL);
}
link->color.background = format.style.color.background;
link->color.foreground = link_is_textinput(link)
? format.style.color.foreground
: format.color.clink;
init_link_event_hooks(html_context, link);
document->links_sorted = 0;
return link;
}
static void
html_special_tag(struct document *document, unsigned char *t, int x, int y)
{
struct tag *tag;
int tag_len;
assert(document);
if_assert_failed return;
tag_len = strlen(t);
/* One byte is reserved for name in struct tag. */
tag = mem_alloc(sizeof(*tag) + tag_len);
if (!tag) return;
tag->x = x;
tag->y = y;
memcpy(tag->name, t, tag_len + 1);
add_to_list(document->tags, tag);
if (renderer_context.last_tag_for_newline == (struct tag *) &document->tags)
renderer_context.last_tag_for_newline = tag;
}
static void
put_chars_conv(struct html_context *html_context,
unsigned char *chars, int charslen)
{
struct part *part;
assert(html_context);
if_assert_failed return;
part = html_context->part;
assert(part && chars && charslen);
if_assert_failed return;
if (format.style.attr & AT_GRAPHICS) {
put_chars(html_context, chars, charslen);
return;
}
convert_string(renderer_context.convert_table, chars, charslen,
html_context->options->cp,
(format.style.attr & AT_NO_ENTITIES) ? CSM_NONE : CSM_DEFAULT,
NULL, (void (*)(void *, unsigned char *, int)) put_chars, html_context);
}
/*
* Converts a number in base 10 to a string in another base whose symbols are
* represented by key. I the trivial case, key="0123456789". A more homerow
* friendly key="gfdsahjkl;trewqyuiopvcxznm". Returns the length of link_sym.
*/
int
dec2qwerty(int num, unsigned char *link_sym, const unsigned char *key, int base)
{
int newlen, i, pow;
if (base < 2) return 0;
for (newlen = 1, pow = base; pow <= num; ++newlen, pow *= base);
link_sym[newlen] = '\0';
for (i = 1; i <= newlen; ++i) {
int key_index = num % base;
link_sym[newlen - i] = key[key_index];
num /= base;
}
return newlen;
}
/*
* Returns the value of link_sym in decimal according to key.
*/
int
qwerty2dec(const unsigned char *link_sym, const unsigned char *key, int base)
{
int z = 0;
int symlen = strlen(link_sym);
int i;
int pow;
for (i = 0, pow = 1; i < symlen; ++i, pow *= base) {
int j = 0;
while (key[j] != link_sym[symlen - 1 - i]) ++j;
z += j * pow;
}
return z;
}
static inline void
put_link_number(struct html_context *html_context)
{
char *symkey = get_opt_str("document.browse.links.label_key", NULL);
struct part *part = html_context->part;
unsigned char s[64];
unsigned char *fl = format.link;
unsigned char *ft = format.target;
unsigned char *fi = format.image;
struct text_style old_style = format.style;
struct form_control *ff = format.form;
int slen = 0;
int base = strlen(symkey);
format.link = format.target = format.image = NULL;
format.form = NULL;
if (html_context->options->use_link_number_color) {
format.style.attr &= ~AT_BOLD;
format.style.color.foreground = format.color.link_number;
}
s[slen++] = '[';
slen += dec2qwerty(part->link_num, s + 1, symkey, base);
s[slen++] = ']';
s[slen] = '\0';
renderer_context.nosearchable = 1;
put_chars(html_context, s, slen);
renderer_context.nosearchable = 0;
if (ff && ff->type == FC_TEXTAREA) line_break(html_context);
/* We might have ended up on a new line after the line breaking
* or putting the link number chars. */
if (part->cx == -1) part->cx = par_format.leftmargin;
format.link = fl;
format.target = ft;
format.image = fi;
format.form = ff;
format.style = old_style;
}
#define assert_link_variable(old, new) \
assertm(!(old), "Old link value [%s]. New value [%s]", old, new);
static inline void
init_link_state_info(unsigned char *link, unsigned char *target,
unsigned char *image, struct form_control *form)
{
assert_link_variable(renderer_context.link_state_info.image, image);
assert_link_variable(renderer_context.link_state_info.target, target);
assert_link_variable(renderer_context.link_state_info.link, link);
renderer_context.link_state_info.link = null_or_stracpy(link);
renderer_context.link_state_info.target = null_or_stracpy(target);
renderer_context.link_state_info.image = null_or_stracpy(image);
renderer_context.link_state_info.form = form;
}
static inline void
done_link_state_info(void)
{
mem_free_if(renderer_context.link_state_info.link);
mem_free_if(renderer_context.link_state_info.target);
mem_free_if(renderer_context.link_state_info.image);
memset(&renderer_context.link_state_info, 0,
sizeof(renderer_context.link_state_info));
}
#ifdef CONFIG_UTF8
static inline void
process_link(struct html_context *html_context, enum link_state link_state,
unsigned char *chars, int charslen, int cells)
#else
static inline void
process_link(struct html_context *html_context, enum link_state link_state,
unsigned char *chars, int charslen)
#endif /* CONFIG_UTF8 */
{
struct part *part = html_context->part;
struct link *link;
int x_offset = 0;
switch (link_state) {
case LINK_STATE_SAME: {
unsigned char *name;
if (!part->document) return;
assertm(part->document->nlinks > 0, "no link");
if_assert_failed return;
link = &part->document->links[part->document->nlinks - 1];
name = get_link_name(link);
if (name) {
unsigned char *new_name;
new_name = straconcat(name, chars,
(unsigned char *) NULL);
if (new_name) {
mem_free(name);
link->data.name = new_name;
}
}
/* FIXME: Concatenating two adjectent elements to a single
* link is broken since we lose the event handlers for the
* second one. OTOH simply appending them here won't fly since
* we may get here multiple times for even a single link. We
* will probably need some SP_ for creating a new link or so.
* --pasky */
break;
}
case LINK_STATE_NEW:
part->link_num++;
init_link_state_info(format.link, format.target,
format.image, format.form);
if (!part->document) return;
/* Trim leading space from the link text */
while (x_offset < charslen && chars[x_offset] <= ' ')
x_offset++;
if (x_offset) {
charslen -= x_offset;
chars += x_offset;
#ifdef CONFIG_UTF8
cells -= x_offset;
#endif /* CONFIG_UTF8 */
}
link = new_link(html_context, chars, charslen);
if (!link) return;
break;
case LINK_STATE_NONE:
default:
INTERNAL("bad link_state %i", (int) link_state);
return;
}
/* Add new canvas positions to the link. */
#ifdef CONFIG_UTF8
if (realloc_points(link, link->npoints + cells))
#else
if (realloc_points(link, link->npoints + charslen))
#endif /* CONFIG_UTF8 */
{
struct point *point = &link->points[link->npoints];
int x = X(part->cx) + x_offset;
int y = Y(part->cy);
#ifdef CONFIG_UTF8
link->npoints += cells;
for (; cells > 0; cells--, point++, x++)
#else
link->npoints += charslen;
for (; charslen > 0; charslen--, point++, x++)
#endif /* CONFIG_UTF8 */
{
point->x = x;
point->y = y;
}
}
}
static inline enum link_state
get_link_state(struct html_context *html_context)
{
enum link_state state;
if (!(format.link || format.image || format.form)) {
state = LINK_STATE_NONE;
} else if ((renderer_context.link_state_info.link
|| renderer_context.link_state_info.image
|| renderer_context.link_state_info.form)
&& !xstrcmp(format.link, renderer_context.link_state_info.link)
&& !xstrcmp(format.target, renderer_context.link_state_info.target)
&& !xstrcmp(format.image, renderer_context.link_state_info.image)
&& format.form == renderer_context.link_state_info.form) {
return LINK_STATE_SAME;
} else {
state = LINK_STATE_NEW;
}
done_link_state_info();
return state;
}
static inline int
html_has_non_space_chars(unsigned char *chars, int charslen)
{
int pos = 0;
while (pos < charslen)
if (!isspace(chars[pos++]))
return 1;
return 0;
}
static void
put_chars(struct html_context *html_context, unsigned char *chars, int charslen)
{
enum link_state link_state;
struct part *part;
#ifdef CONFIG_UTF8
int cells;
#endif /* CONFIG_UTF8 */
assert(html_context);
if_assert_failed return;
part = html_context->part;
assert(part);
if_assert_failed return;
assert(chars && charslen);
if_assert_failed return;
/* If we are not handling verbatim aligning and we are at the begining
* of a line trim whitespace. */
if (part->cx == -1) {
/* If we are not handling verbatim aligning trim leading
* whitespaces. */
if (!html_is_preformatted()) {
while (charslen && *chars == ' ') {
chars++;
charslen--;
}
if (charslen < 1) return;
}
part->cx = par_format.leftmargin;
}
/* For preformatted html always update 'the last tag' so we never end
* up moving tags to the wrong line (Fixes bug 324). For all other html
* it is moved only when the line being rendered carry some real
* non-whitespace content. */
if (html_is_preformatted()
|| html_has_non_space_chars(chars, charslen)) {
renderer_context.last_tag_for_newline = (struct tag *) &part->document->tags;
}
int_lower_bound(&part->box.height, part->cy + 1);
link_state = get_link_state(html_context);
if (link_state == LINK_STATE_NEW) {
int x_offset = 0;
/* Don't add inaccessible links. It seems to be caused
* by the parser putting a space char after stuff like
* -tags or comments wrapped in -tags. See bug
* 30 for test case. */
while (x_offset < charslen && chars[x_offset] <= ' ')
x_offset++;
/* For pure spaces reset the link state */
if (x_offset == charslen)
link_state = LINK_STATE_NONE;
else if (html_context->options->links_numbering)
put_link_number(html_context);
}
#ifdef CONFIG_UTF8
cells =
#endif /* CONFIG_UTF8 */
set_hline(html_context, chars, charslen, link_state);
if (link_state != LINK_STATE_NONE) {
#ifdef CONFIG_UTF8
process_link(html_context, link_state, chars, charslen,
cells);
#else
process_link(html_context, link_state, chars, charslen);
#endif /* CONFIG_UTF8 */
}
#ifdef CONFIG_UTF8
if (renderer_context.nowrap
&& part->cx + cells > overlap(par_format))
return;
part->cx += cells;
#else
if (renderer_context.nowrap
&& part->cx + charslen > overlap(par_format))
return;
part->cx += charslen;
#endif /* CONFIG_UTF8 */
renderer_context.nobreak = 0;
if (!(html_context->options->wrap || html_is_preformatted())) {
while (part->cx > overlap(par_format)
&& part->cx > par_format.leftmargin) {
int x = split_line(html_context);
if (!x) break;
if (part->document)
align_line(html_context, part->cy - 1, 0);
renderer_context.nobreak = !!(x - 1);
}
}
assert(charslen > 0);
#ifdef CONFIG_UTF8
part->xa += cells;
#else
part->xa += charslen;
#endif /* CONFIG_UTF8 */
int_lower_bound(&part->max_width, part->xa
+ par_format.leftmargin + par_format.rightmargin
- (chars[charslen - 1] == ' '
&& !html_is_preformatted()));
return;
}
#undef overlap
static void
line_break(struct html_context *html_context)
{
struct part *part;
struct tag *tag;
assert(html_context);
if_assert_failed return;
part = html_context->part;
assert(part);
if_assert_failed return;
int_lower_bound(&part->box.width, part->cx + par_format.rightmargin);
if (renderer_context.nobreak) {
renderer_context.nobreak = 0;
part->cx = -1;
part->xa = 0;
return;
}
if (!part->document || !part->document->data) goto end;
if (!realloc_lines(part->document, part->box.height + part->cy + 1))
return;
if (part->cx > par_format.leftmargin && LEN(part->cy) > part->cx - 1
&& POS(part->cx - 1, part->cy).data == ' ') {
del_chars(html_context, part->cx - 1, part->cy);
part->cx--;
}
if (part->cx > 0) align_line(html_context, part->cy, 1);
for (tag = renderer_context.last_tag_for_newline;
tag && tag != (struct tag *) &part->document->tags;
tag = tag->prev) {
tag->x = X(0);
tag->y = Y(part->cy + 1);
}
end:
part->cy++;
part->cx = -1;
part->xa = 0;
memset(part->spaces, 0, part->spaces_len);
#ifdef CONFIG_UTF8
memset(part->char_width, 0, part->spaces_len);
#endif
}
static void
html_special_form(struct part *part, struct form *form)
{
struct form *nform;
assert(part && form);
assert(form->form_num > 0);
assert(form->form_end == INT_MAX);
if_assert_failed return;
if (!part->document) {
done_form(form);
return;
}
/* Make a fake form with form_num == 0 so that there is
* something to use if form controls appear above the first
* actual FORM element. There can never be a real form with
* form_num == 0 because the form_num is the position after the
* "