hist.c

/*
	hist.c of shell -- history substitutions etc	 3/27/86

	copyright (c) 1987 pm@Case
*/

#include "ue.h"

#define	SZH	20							/* default size of hist[]   */
static uchar HF[] = "histfile";
static int szh;							/* # cmds to be remembered  */
static uchar **histp;					/* ptr to the remembered history */
static int nh;							/* # actual commands in h[]; == # \n's in h[] */
static int hcount = 0;					/* # of cmds processed; >= 0    */
static uchar NSH[] = "no such history";
static int nprevcmd;

/* called from remember(), or after changing szh */
void histinit(void)
{
	uchar **p;
	int x;
	int i;
	int j;
	int n;

	szh = n = varnum("history");
	if (n <= 0)
		szh = n = SZH;
	p = histp;
	histp = (uchar **) gmalloc(n * ((uint) sizeof(uchar *)));
	if (histp == NULL)
	{
		histp = p;
		return;
	}									/* histp could still be NULL */

	if (p)								/* copy old history into new area   */
	{
		if (n >= nh)
		{
			i = nh;
			j = 0;
		} else
		{
			i = n;
			j = nh - n;
		}
		for (x = i; x < n;)
			histp[x++] = NULL;
		for (x = nh; x > j;)
			histp[--i] = p[--x];
		for (x = j; x > 0;)
			gfree(p[--x]);
		gfree(p);
		if (n < nh)
			nh = n;
	} else
		nh = 0;
	nprevcmd = 0;
}

/* Find the most recent cmd that matches    */
/* the str starting at q            */
static uchar *strhist(uchar *p, uchar *q)
{
	uchar *b;
	int n;
	int i;

	i = (int)strlen(q);
	for (n = nh - 1; n >= 0; n--)
	{
		b = histp[n];
		if (strncmp(q, b, ((size_t) i)) == 0)
			goto subst;
	}
	emsg = NSH;
	b = ES;
  subst:
	return str3cat(p, b, ES);
}


/* Find the n-th command            */
static uchar *wnumhist(int n, uchar *p, uchar *r)
{
	uchar *b;
	int i;

	i = n + nh - hcount - 1;
	if ((0 <= i) && (i < nh))
		b = histp[i];
	else
	{
		emsg = NSH;
		b = ES;
	}
	return str3cat(p, b, r);
}


/* Find the n-th command, where n is given in   */
/* ascii digits starting at q           */
static uchar *numhist(uchar *p, uchar *q)
{
	uchar *r;
	int c;
	int n;
	int minus;

	if (*q == '-')
	{
		minus = 1;
		q++;
	} else
		minus = 0;
	for (r = q, n = 0;;)
	{
		c = (int) *r++;
		if (('0' <= c) && (c <= '9'))
			n = 10 * n + c - '0';
		else
			break;
	}
	r--;
	if (minus)
		n = hcount - n;
	return wnumhist(n, p, r);
}

/* Get a previous command from history.  The prev cmd is one older than what
 was obtained through this routine last time, since the last call to
 remember().
*/
uchar *prevhist(void)
{
	int n;

	n = nprevcmd++;
	if (n == nh)
		nprevcmd = 0;
	return wnumhist(hcount - n, ES, ES);
}

/*************
 Substitute every substring of the form !xx with matched hist string.
 Unless substitutions do occur, return s as is.
 Otherwise, free s which does point to malloc'd area.
 `!!', `!number', `!string' => history
*/
uchar *substhist(uchar *s)
{
	char *p;
	char *q;
	WS *ws;
	int icq;
	int nsubst;

	if (histp == NULL)
		return s;
	/* BTRNQD is " \t\r\n'\"" - ie whitespace or quotes */
	lex(s, BTRNQD, EMPTY2);
	ws = initws();
	nsubst = 0;
	while ((p = lexgetword()) != NULL && *p && (p = gstrdup(p)) != NULL)
	{
		if (*p != '\'' && *p != '"')
			while (p && (q = strchr(p, '!')) != NULL && q[1] != '\0')  /* lonely '!' doesn't count */
			{
				nsubst++;
				*q = '\0';
				icq = (int) *++q;
				if (icq == '!')
					q = wnumhist(hcount, p, ++q);
				else if (('0' <= icq && icq <= '9') || (icq == '-'))
					q = numhist(p, q);
				else
					q = strhist(p, q);
				gfree(p);
				p = q;
			}
		strwcat(ws, p, 1);
		gfree(p);
	}
	if (nsubst == 0)
		freews(ws);
	else
	{
		gfree(s);
		s = catall(ws, 0);
		gfree(ws);
	}									/* not freews(ws) */
	return s;
}

/*  Insert a fresh copy of p into hist[]    */
void remember(char *p, int n)
{
	int i;
	uchar **hp;

	UNUSED(n);
	if (histp == NULL)
		histinit();
	hp = histp;
	if (hp == NULL)
		return;
	if (nh < szh)
		nh++;
	else
	{
		gfree(*hp);
		for (i = 0; i < nh - 1; i++)
			hp[i] = hp[i + 1];
	}
	hp[nh - 1] = gstrdup(p);
	hcount++;
	nprevcmd = 0;
	insertvar(Ncmd, itoal((long) (1 + hcount)));
}

/* List history into strg; if flag != 0, include line numbers	*/
static void histstr(int flag)
{
	int i;
	int n;
	uchar **hp;
	uchar *p;
	uchar *q;

	hp = histp;
	if (hp == NULL)
		return;
	for (i = 0, n = 0; n < nh; n++)
		i += (int)strlen(hp[n]);
	p = strg = gmalloc(i + nh * (8) + 1);	/* 8 == #\r\n + 5digits + 1space */
	if (p == NULL)
		return;

	i = hcount - nh;
	for (n = 0; n < nh; n++)
	{
		if (flag)
		{
			q = itoal((long) (++i));
			strcpy(p, "     ");
			p += 5;
			strcpy(p - strlen(q), q);
			*p++ = ' ';
		}
		strcpy(p, hp[n]);
		p += strlen(hp[n]);
		strcpy(p, CRLF);
		p += 2;
	}
}


void history(uchar *arg)
{
	uchar *p;

	UNUSED(arg);
	histstr(((p = lexgetword()) != NULL && (p[0] == '-') && (p[1] == 'h') ? 0 : 1));
}

#define	FIOSUC	0						/* see ue:  "..\\ue\\ed.h"  */

/* Read the history saved from a previous session into the history
data structure */

void readhistory(void)
{
	uchar *p;
	int fd;

	p = varstr(HF);
	if (*p == '\0' || (fd = (int)gfopen(p, 0)) < 0)
		return;
	eachline(fd, remember);				/* remember does not need a 2nd arg */
}

void savehistory(void)
{
	uchar *p;

	p = varstr(HF);
	if (*p == '\0' || ffwopen(p) != FIOSUC)
		return;
	histstr(0);
	ffputline(strg, ((int) strlen(strg)));
	gfree(strg);
	strg = NULL;
	ffclose();
}