ref: 61f4c085c402af665b436f6d010d61107551d8a3
dir: /sys/src/cmd/troff/n8.c/
#include "tdef.h"
#include "fns.h"
#include "ext.h"
#include <assert.h>
#define HY_BIT 0200 /* stuff in here only works for 7-bit ascii */
/* this value is used (as a literal) in suftab.c */
/* to encode possible hyphenation points in suffixes. */
/* it could be changed, by widening the tables */
/* to be shorts instead of chars. */
/*
* troff8.c
*
* hyphenation
*/
int hexsize = 0; /* hyphenation exception list size */
char *hbufp = NULL; /* base of list */
char *nexth = NULL; /* first free slot in list */
Tchar *hyend;
#define THRESH 160 /* digram goodness threshold */
int thresh = THRESH;
int texhyphen(void);
static int alpha(Tchar);
void hyphen(Tchar *wp)
{
int j;
Tchar *i;
i = wp;
while (punct((*i++)))
;
if (!alpha(*--i))
return;
wdstart = i++;
while (alpha(*i++))
;
hyend = wdend = --i - 1;
while (punct((*i++)))
;
if (*--i)
return;
if (wdend - wdstart < 4) /* 4 chars is too short to hyphenate */
return;
hyp = hyptr;
*hyp = 0;
hyoff = 2;
/* for now, try exceptions first, then tex (if hyphalg is non-zero),
then suffix and digram if tex didn't hyphenate it at all.
*/
if (!exword() && !texhyphen() && !suffix())
digram();
/* this appears to sort hyphenation points into increasing order */
*hyp++ = 0;
if (*hyptr)
for (j = 1; j; ) {
j = 0;
for (hyp = hyptr + 1; *hyp != 0; hyp++) {
if (*(hyp - 1) > *hyp) {
j++;
i = *hyp;
*hyp = *(hyp - 1);
*(hyp - 1) = i;
}
}
}
}
static alpha(Tchar i) /* non-zero if really alphabetic */
{
if (ismot(i))
return 0;
else if (cbits(i) >= ALPHABET) /* this isn't very elegant, but there's */
return 0; /* no good way to make sure i is in range for */
else /* the call of isalpha */
return isalpha(cbits(i));
}
punct(Tchar i)
{
if (!i || alpha(i))
return(0);
else
return(1);
}
void caseha(void) /* set hyphenation algorithm */
{
hyphalg = HYPHALG;
if (skip())
return;
noscale++;
hyphalg = atoi0();
noscale = 0;
}
void caseht(void) /* set hyphenation threshold; not in manual! */
{
thresh = THRESH;
if (skip())
return;
noscale++;
thresh = atoi0();
noscale = 0;
}
char *growh(char *where)
{
char *new;
hexsize += NHEX;
if ((new = grow(hbufp, hexsize, sizeof(char))) == NULL)
return NULL;
if (new == hbufp) {
return where;
} else {
int diff;
diff = where - hbufp;
hbufp = new;
return new + diff;
}
}
void casehw(void)
{
int i, k;
char *j;
Tchar t;
if (nexth == NULL) {
if ((nexth = hbufp = grow(hbufp, NHEX, sizeof(char))) == NULL) {
ERROR "No space for exception word list." WARN;
return;
}
hexsize = NHEX;
}
k = 0;
while (!skip()) {
if ((j = nexth) >= hbufp + hexsize - 2)
if ((j = nexth = growh(j)) == NULL)
goto full;
for (;;) {
if (ismot(t = getch()))
continue;
i = cbits(t);
if (i == ' ' || i == '\n') {
*j++ = 0;
nexth = j;
*j = 0;
if (i == ' ')
break;
else
return;
}
if (i == '-') {
k = HY_BIT;
continue;
}
*j++ = maplow(i) | k;
k = 0;
if (j >= hbufp + hexsize - 2)
if ((j = growh(j)) == NULL)
goto full;
}
}
return;
full:
ERROR "Cannot grow exception word list." WARN;
*nexth = 0;
}
int exword(void)
{
Tchar *w;
char *e, *save;
e = hbufp;
while (1) {
save = e;
if (e == NULL || *e == 0)
return(0);
w = wdstart;
while (*e && w <= hyend && (*e & 0177) == maplow(cbits(*w))) {
e++;
w++;
}
if (!*e) {
if (w-1 == hyend || (w == wdend && maplow(cbits(*w)) == 's')) {
w = wdstart;
for (e = save; *e; e++) {
if (*e & HY_BIT)
*hyp++ = w;
if (hyp > hyptr + NHYP - 1)
hyp = hyptr + NHYP - 1;
w++;
}
return(1);
} else {
e++;
continue;
}
} else
while (*e++)
;
}
}
suffix(void)
{
Tchar *w;
char *s, *s0;
Tchar i;
extern char *suftab[];
again:
i = cbits(*hyend);
if (!alpha(i))
return(0);
if (i < 'a')
i -= 'A' - 'a';
if ((s0 = suftab[i-'a']) == 0)
return(0);
for (;;) {
if ((i = *s0 & 017) == 0)
return(0);
s = s0 + i - 1;
w = hyend - 1;
while (s > s0 && w >= wdstart && (*s & 0177) == maplow(cbits(*w))) {
s--;
w--;
}
if (s == s0)
break;
s0 += i;
}
s = s0 + i - 1;
w = hyend;
if (*s0 & HY_BIT)
goto mark;
while (s > s0) {
w--;
if (*s-- & HY_BIT) {
mark:
hyend = w - 1;
if (*s0 & 0100) /* 0100 used in suftab to encode something too */
continue;
if (!chkvow(w))
return(0);
*hyp++ = w;
}
}
if (*s0 & 040)
return(0);
if (exword())
return(1);
goto again;
}
maplow(int i)
{
if (isupper(i))
i = tolower(i);
return(i);
}
vowel(int i)
{
switch (i) {
case 'a': case 'A':
case 'e': case 'E':
case 'i': case 'I':
case 'o': case 'O':
case 'u': case 'U':
case 'y': case 'Y':
return(1);
default:
return(0);
}
}
Tchar *chkvow(Tchar *w)
{
while (--w >= wdstart)
if (vowel(cbits(*w)))
return(w);
return(0);
}
void digram(void)
{
Tchar *w;
int val;
Tchar *nhyend, *maxw;
int maxval;
extern char bxh[26][13], bxxh[26][13], xxh[26][13], xhx[26][13], hxx[26][13];
again:
if (!(w = chkvow(hyend + 1)))
return;
hyend = w;
if (!(w = chkvow(hyend)))
return;
nhyend = w;
maxval = 0;
w--;
while (++w < hyend && w < wdend - 1) {
val = 1;
if (w == wdstart)
val *= dilook('a', cbits(*w), bxh);
else if (w == wdstart + 1)
val *= dilook(cbits(*(w-1)), cbits(*w), bxxh);
else
val *= dilook(cbits(*(w-1)), cbits(*w), xxh);
val *= dilook(cbits(*w), cbits(*(w+1)), xhx);
val *= dilook(cbits(*(w+1)), cbits(*(w+2)), hxx);
if (val > maxval) {
maxval = val;
maxw = w + 1;
}
}
hyend = nhyend;
if (maxval > thresh)
*hyp++ = maxw;
goto again;
}
dilook(int a, int b, char t[26][13])
{
int i, j;
i = t[maplow(a)-'a'][(j = maplow(b)-'a')/2];
if (!(j & 01))
i >>= 4;
return(i & 017);
}
/* here beginneth the tex hyphenation code, as interpreted freely */
/* the main difference is that there is no attempt to squeeze space */
/* as tightly at tex does. */
static int texit(Tchar *, Tchar *);
static int readpats(void);
static void install(char *);
static void fixup(void);
static int trieindex(int, int);
static char pats[50000]; /* size ought to be computed dynamically */
static char *nextpat = pats;
static char *trie[27*27]; /* english-specific sizes */
int texhyphen(void)
{
static int loaded = 0; /* -1: couldn't find tex file */
if (hyphalg == 0 || loaded == -1) /* non-zero => tex for now */
return 0;
if (loaded == 0) {
if (readpats())
loaded = 1;
else
loaded = -1;
}
return texit(wdstart, wdend);
}
static int texit(Tchar *start, Tchar *end) /* hyphenate as in tex, return # found */
{
int nw, i, k, equal, cnt[500];
char w[500+1], *np, *pp, *wp, *xpp, *xwp;
w[0] = '.';
for (nw = 1; start <= end && nw < 500-1; nw++, start++)
w[nw] = maplow(tolower(cbits(*start)));
start -= (nw - 1);
w[nw++] = '.';
w[nw] = 0;
/*
* printf("try %s\n", w);
*/
for (i = 0; i <= nw; i++)
cnt[i] = '0';
for (wp = w; wp+1 < w+nw; wp++) {
for (pp = trie[trieindex(*wp, *(wp+1))]; pp < nextpat; ) {
if (pp == 0 /* no trie entry */
|| *pp != *wp /* no match on 1st letter */
|| *(pp+1) != *(wp+1)) /* no match on 2nd letter */
break; /* so move to next letter of word */
equal = 1;
for (xpp = pp+2, xwp = wp+2; *xpp; )
if (*xpp++ != *xwp++) {
equal = 0;
break;
}
if (equal) {
np = xpp+1; /* numpat */
for (k = wp-w; *np; k++, np++)
if (*np > cnt[k])
cnt[k] = *np;
/*
* printf("match: %s %s\n", pp, xpp+1);
*/
}
pp += *(pp-1); /* skip over pattern and numbers to next */
}
}
/*
* for (i = 0; i < nw; i++) printf("%c", w[i]);
* printf(" ");
* for (i = 0; i <= nw; i++) printf("%c", cnt[i]);
* printf("\n");
*/
/*
* for (i = 1; i < nw - 1; i++) {
* if (i > 2 && i < nw - 3 && cnt[i] % 2)
* printf("-");
* if (cbits(start[i-1]) != '.')
* printf("%c", cbits(start[i-1]));
* }
* printf("\n");
*/
for (i = 1; i < nw -1; i++)
if (i > 2 && i < nw - 3 && cnt[i] % 2)
*hyp++ = start + i - 1;
return hyp - hyptr; /* non-zero if a hyphen was found */
}
/*
This code assumes that hyphen.tex looks like
% some comments
\patterns{ % more comments
pat5ter4ns, 1 per line, SORTED, nothing else
}
more goo
\hyphenation{ % more comments
ex-cep-tions, one per line; i ignore this part for now
}
this code is NOT robust against variations. unfortunately,
it looks like every local language version of this file has
a different format. i have also made no provision for weird
characters. sigh.
*/
static int readpats(void)
{
FILE *fp;
char buf[200], buf1[200];
if ((fp = fopen(TEXHYPHENS, "r")) == NULL
&& (fp = fopen(DWBalthyphens, "r")) == NULL) {
ERROR "warning: can't find hyphen.tex" WARN;
return 0;
}
while (fgets(buf, sizeof buf, fp) != NULL) {
sscanf(buf, "%s", buf1);
if (strcmp(buf1, "\\patterns{") == 0)
break;
}
while (fgets(buf, sizeof buf, fp) != NULL) {
if (buf[0] == '}')
break;
install(buf);
}
fclose(fp);
fixup();
return 1;
}
static void install(char *s) /* map ab4c5de to: 12 abcde \0 00405 \0 */
{
int npat, lastpat;
char num[500], *onextpat = nextpat;
num[0] = '0';
*nextpat++ = ' '; /* fill in with count later */
for (npat = lastpat = 0; *s != '\n' && *s != '\0'; s++) {
if (isdigit(*s)) {
num[npat] = *s;
lastpat = npat;
} else {
*nextpat++ = *s;
npat++;
num[npat] = '0';
}
}
*nextpat++ = 0;
if (nextpat > pats + sizeof(pats)-20) {
ERROR "tex hyphenation table overflow, tail end ignored" WARN;
nextpat = onextpat;
}
num[lastpat+1] = 0;
strcat(nextpat, num);
nextpat += strlen(nextpat) + 1;
}
static void fixup(void) /* build indexes of where . a b c ... start */
{
char *p, *lastc;
int n;
for (lastc = pats, p = pats+1; p < nextpat; p++)
if (*p == ' ') {
*lastc = p - lastc;
lastc = p;
}
*lastc = p - lastc;
for (p = pats+1; p < nextpat; ) {
n = trieindex(p[0], p[1]);
if (trie[n] == 0)
trie[n] = p;
p += p[-1];
}
/* printf("pats = %d\n", nextpat - pats); */
}
static int trieindex(int d1, int d2)
{
int i;
i = 27*(d1 == '.'? 0: d1 - 'a' + 1) + (d2 == '.'? 0: d2 - 'a' + 1);
assert(0 <= i && i < 27*27);
return i;
}