shithub: neatroff

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fmt: support stretchable no-break space (\~)

Suggested and tested by aksr <aksr@t-com.me>.

--- a/fmt.c

+++ b/fmt.c

@@ -271,14 +271,14 @@

 	word->wid = wb_wid(wb);

 	word->elsn = wb->els_neg;

 	word->elsp = wb->els_pos;

-	word->cost = cost ? wb_cost(wb) : 0;

 	word->hy = hy ? wb_hywid(wb) : 0;

 	word->str = str;

 	word->gap = gap;

+	word->cost = cost;

 }

-/* find explicit hyphenation positions: dashes, \: and \% */

-static int fmt_hyphmarks(char *word, int *hyidx, int *hyins)

+/* find explicit break positions: dashes, \:, \%, and \~ */

+static int fmt_hyphmarks(char *word, int *hyidx, int *hyins, int *hygap)

 {

 	char *s = word;

 	char *d = NULL;

@@ -296,6 +296,10 @@

 			hyins[n] = 0;

 			hyidx[n++] = s - word;

 		}

+		if (!c && !strcmp(c_nb, d)) {

+			hygap[n] = 1;

+			hyidx[n++] = s - word;

+		}

 	}

 	return n;

 }

@@ -312,8 +316,9 @@

 static void fmt_insertword(struct fmt *f, struct wb *wb, int gap)

 {

-	int hyidx[NHYPHSWORD];

-	int hyins[NHYPHSWORD] = {0};

+	int hyidx[NHYPHSWORD];		/* sub-word boundaries */

+	int hyins[NHYPHSWORD] = {0};	/* insert dash */

+	int hygap[NHYPHSWORD] = {0};	/* stretchable no-break space */

 	char *src = wb_buf(wb);

 	struct wb wbc;

 	char *beg;

@@ -320,9 +325,9 @@

 	char *end;

 	int n, i;

 	int cf, cs, cm;

-	n = fmt_hyphmarks(src, hyidx, hyins);

+	n = fmt_hyphmarks(src, hyidx, hyins, hygap);

 	if (n <= 0) {

-		fmt_wb2word(f, fmt_mkword(f), wb, 0, 1, gap, 1);

+		fmt_wb2word(f, fmt_mkword(f), wb, 0, 1, gap, wb_cost(wb));

 		return;

 	}

 	/* update f->fillreq considering the new sub-words */

@@ -329,16 +334,23 @@

 	if (f->fillreq == f->words_n + 1)

 		f->fillreq += n;

 	wb_init(&wbc);

+	/* add sub-words */

 	for (i = 0; i <= n; i++) {

+		int ihy = i < n && hyins[i];		/* dash width */

+		int istr = i == 0 || hygap[i - 1];	/* stretchable */

+		int igap;				/* gap width */

+		int icost;				/* hyphenation cost */

 		beg = src + (i > 0 ? hyidx[i - 1] : 0);

 		end = src + (i < n ? hyidx[i] : strlen(src));

+		if (i < n && hygap[i])			/* remove \~ */

+			end -= strlen(c_nb);

 		wb_catstr(&wbc, beg, end);

-		fmt_wb2word(f, fmt_mkword(f), &wbc,

-			i < n && hyins[i], i == 0, i == 0 ? gap : 0, i == n);

-		/* restoring wbc */

-		wb_fnszget(&wbc, &cs, &cf, &cm);

+		wb_fnszget(&wbc, &cf, &cs, &cm);

+		icost = i == n ? wb_cost(&wbc) : hygap[i] * 10000000;

+		igap = i == 0 ? gap : hygap[i - 1] * font_swid(dev_font(cf), cs, n_ss);

+		fmt_wb2word(f, fmt_mkword(f), &wbc, ihy, istr, igap, icost);

 		wb_reset(&wbc);

-		wb_fnszset(&wbc, cs, cf, cm);

+		wb_fnszset(&wbc, cf, cs, cm);		/* restoring wbc */

 	}

 	wb_done(&wbc);

 }

--- a/roff.h

+++ b/roff.h

@@ -73,6 +73,7 @@

 #define c_tc	env_tc()

 #define c_lc	env_lc()

 #define c_bp	"\\:"	/* zero-width word break point */

+#define c_nb	"\\~"	/* stretchable no-break space */

 /* number registers */

 #define num_get(id)	(*nreg(id))

--- a/wb.c

+++ b/wb.c

@@ -251,6 +251,12 @@

 		wb_hmov(wb, font_swid(dev_font(R_F(wb)), R_S(wb), n_ss));

 		return;

 	}

+	if (!strcmp(c_nb, c)) {

+		wb_flushsub(wb);

+		sbuf_append(&wb->sbuf, c);

+		wb->h += font_swid(dev_font(R_F(wb)), R_S(wb), n_ss);

+		return;

+	}

 	if (wb_pendingfont(wb) || wb->sub_n == LEN(wb->sub_c))

 		wb_flush(wb);

 	if (wb->sub_collect) {