/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved. The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#include "e.h"
#include "e.def"

void
bshiftb(int p1, int dir, int p2)
{
        int shval, d1, h1, b1, h2, b2;
#ifndef NEQN
        int diffps, effps, effps2;
        char *sh1, *sh2;
#endif  /* NEQN */

        yyval = p1;
        h1 = eht[p1];
        b1 = ebase[p1];
        h2 = eht[p2];
        b2 = ebase[p2];
#ifndef NEQN
        effps = EFFPS(ps);
        effps2 = EFFPS(ps+deltaps);
        diffps = deltaps;
        sh1 = sh2 = "";
#endif  /* NEQN */
        if (dir == SUB) {       /* subscript */
#ifndef NEQN
                /* top 1/2m above bottom of main box */
                d1 = VERT(EM(0.5, effps2));
#else   /* NEQN */
                d1 = VERT(1);
#endif  /* NEQN */
                shval = - d1 + h2 - b2;
                if (d1+b1 > h2) /* move little sub down */
                        shval = b1-b2;
                ebase[yyval] = b1 + max(0, h2-b1-d1);
                eht[yyval] = h1 + max(0, h2-b1-d1);
#ifndef NEQN
                if (rfont[p1] == ITAL && lfont[p2] == ROM)
                        sh1 = "\\|";
                if (rfont[p2] == ITAL)
                        sh2 = "\\|";
#endif  /* NEQN */
        } else {        /* superscript */
#ifndef NEQN
                /* 4/10 up main box */
                d1 = VERT(EM(0.2, effps));
#else   /* NEQN */
                d1 = VERT(1);
#endif  /* NEQN */
                ebase[yyval] = b1;
#ifndef NEQN
                shval = -VERT((4 * (h1-b1)) / 10) - b2;
                if (VERT(4*(h1-b1)/10) + h2 < h1-b1)    /* raise little super */
#else   /* NEQN */
                shval = -VERT(1) - b2;
                if (VERT(1) + h2 < h1-b1)       /* raise little super */
#endif  /* NEQN */
                        shval = -(h1-b1) + h2-b2 - d1;
#ifndef NEQN
                eht[yyval] = h1 + max(0, h2-VERT((6*(h1-b1))/10));
                if (rfont[p1] == ITAL)
                        sh1 = "\\|";
                if (rfont[p2] == ITAL)
                        sh2 = "\\|";
#else   /* NEQN */
                eht[yyval] = h1 + max(0, h2 - VERT(1));
#endif  /* NEQN */
        }
        if (dbg)
                printf(".\tb:b shift b: S%d <- S%d vert %d S%d vert %d; "
                    "b=%d, h=%d\n", yyval, p1, shval, p2, -shval,
                    ebase[yyval], eht[yyval]);
#ifndef NEQN
        printf(".as %d \\v'%du'\\s-%d%s\\*(%d\\s+%d%s\\v'%du'\n",
            yyval, shval, diffps, sh1, p2, diffps, sh2, -shval);
        ps += deltaps;
        if (rfont[p2] == ITAL)
                rfont[p1] = 0;
        else
                rfont[p1] = rfont[p2];
#else   /* NEQN */
        printf(".as %d \\v'%du'\\*(%d\\v'%du'\n",
            yyval, shval, p2, -shval);
#endif  /* NEQN */
        ofree(p2);
}

void
shift(int p1)
{
        ps -= deltaps;
        yyval = p1;
        if (dbg) printf(".\tshift: %d;ps=%d\n", yyval, ps);
}

void
shift2(int p1, int p2, int p3)
{
        int effps, h1, h2, h3, b1, b2, b3, subsh, d1, d2, supsh, treg;
#ifndef NEQN
        int effps2;
#endif  /* NEQN */

        treg = oalloc();
        yyval = p1;
        if (dbg) printf(".\tshift2 s%d <- %d %d %d\n", yyval, p1, p2, p3);
        effps = EFFPS(ps+deltaps);
#ifndef NEQN
        eht[p3] = h3 = VERT((eht[p3] * effps) / EFFPS(ps));
        ps += deltaps;
        effps2 = EFFPS(ps+deltaps);
#endif  /* NEQN */
        h1 = eht[p1]; b1 = ebase[p1];
        h2 = eht[p2]; b2 = ebase[p2];
#ifndef NEQN
        b3 = ebase[p3];
        d1 = VERT(EM(0.5, effps2));
#else   /* NEQN */
        h3 = eht[p3]; b3 = ebase[p3];
        d1 = VERT(1);
#endif  /* NEQN */
        subsh = -d1+h2-b2;
        if (d1+b1 > h2) /* move little sub down */
                subsh = b1-b2;
#ifndef NEQN
        supsh = -VERT((4*(h1-b1))/10) - b3;
        d2 = VERT(EM(0.2, effps));
        if (VERT(4*(h1-b1)/10)+h3 < h1-b1)
#else   /* NEQN */
        supsh = - VERT(1) - b3;
        d2 = VERT(1);
        if (VERT(1)+h3 < h1-b1)
#endif  /* NEQN */
                supsh = -(h1-b1) + (h3-b3) - d2;
#ifndef NEQN
        eht[yyval] = h1 + max(0, h3-VERT((6*(h1-b1))/10)) + max(0, h2-b1-d1);
#else   /* NEQN */
        eht[yyval] = h1 + max(0, h3-VERT(1)) + max(0, h2-b1-d1);
#endif  /* NEQN */
        ebase[yyval] = b1+max(0, h2-b1-d1);
#ifndef NEQN
        if (rfont[p1] == ITAL && lfont[p2] == ROM)
                printf(".ds %d \\|\\*(%d\n", p2, p2);
        if (rfont[p2] == ITAL)
                printf(".as %d \\|\n", p2);
#endif  /* NEQN */
        nrwid(p2, effps, p2);
#ifndef NEQN
        if (rfont[p1] == ITAL && lfont[p3] == ROM)
                printf(".ds %d \\|\\|\\*(%d\n", p3, p3);
        else
                printf(".ds %d \\|\\*(%d\n", p3, p3);
#endif  /* NEQN */
        nrwid(p3, effps, p3);
        printf(".nr %d \\n(%d\n", treg, p3);
        printf(".if \\n(%d>\\n(%d .nr %d \\n(%d\n", p2, treg, treg, p2);
#ifndef NEQN
        printf(".as %d \\v'%du'\\s%d\\*(%d\\h'-\\n(%du'\\v'%du'\\\n",
            p1, subsh, effps, p2, p2, -subsh+supsh);
        printf("\\s%d\\*(%d\\h'-\\n(%du+\\n(%du'\\s%d\\v'%du'\n",
            effps, p3, p3, treg, effps2, -supsh);
#else   /* NEQN */
        printf(".as %d \\v'%du'\\*(%d\\h'-\\n(%du'\\v'%du'\\\n",
            p1, subsh, p2, p2, -subsh+supsh);
        printf("\\*(%d\\h'-\\n(%du+\\n(%du'\\v'%du'\n",
            p3, p3, treg, -supsh);
#endif  /* NEQN */
        ps += deltaps;
#ifndef NEQN
        if (rfont[p2] == ITAL)
                rfont[yyval] = 0;       /* lie */
#endif  /* NEQN */
        ofree(p2); ofree(p3); ofree(treg);
}