The R Project SVN R

/*
 *  R : A Computer Language for Statistical Data Analysis
 *  Copyright (C) 1995-1998  Robert Gentleman and Ross Ihaka
 *  Copyright (C) 1998-2012  The R Core Team.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, a copy is available at
 *  http://www.r-project.org/Licenses/
 */

/* The x:y  primitive calls do_colon(); do_colon() calls cross_colon() if
   both arguments are factors and seq_colon() otherwise.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <Defn.h>
#include <float.h>  /* for DBL_EPSILON */
#include <Rmath.h>

#include "RBufferUtils.h"
static R_StringBuffer cbuff = {NULL, 0, MAXELTSIZE};

#define _S4_rep_keepClass
/* ==>  rep(<S4>, .) keeps class e.g., for list-like */

static SEXP cross_colon(SEXP call, SEXP s, SEXP t)
{
    SEXP a, la, ls, lt, rs, rt;
    int i, j, k, n, nls, nlt;
    char *cbuf;

    if (length(s) != length(t))
    errorcall(call, _("unequal factor lengths"));
    n = length(s);
    ls = getAttrib(s, R_LevelsSymbol);
    lt = getAttrib(t, R_LevelsSymbol);
    nls = LENGTH(ls);
    nlt = LENGTH(lt);
    PROTECT(a = allocVector(INTSXP, n));
    PROTECT(rs = coerceVector(s, INTSXP));
    PROTECT(rt = coerceVector(t, INTSXP));
    for (i = 0; i < n; i++) {
    int vs = INTEGER(rs)[i];
    int vt = INTEGER(rt)[i];
    if ((vs == NA_INTEGER) || (vt == NA_INTEGER))
        INTEGER(a)[i] = NA_INTEGER;
    else
        INTEGER(a)[i] = vt + (vs - 1) * nlt;
    }
    UNPROTECT(2);
    if (!isNull(ls) && !isNull(lt)) {
    PROTECT(la = allocVector(STRSXP, nls * nlt));
    k = 0;
    /* FIXME: possibly UTF-8 version */
    for (i = 0; i < nls; i++) {
        const char *vi = translateChar(STRING_ELT(ls, i));
        size_t vs = strlen(vi);
        for (j = 0; j < nlt; j++) {
        const char *vj = translateChar(STRING_ELT(lt, j));
        size_t vt = strlen(vj);
        cbuf = R_AllocStringBuffer(vs + vt + 1, &cbuff);
        sprintf(cbuf, "%s:%s", vi, vj);
        SET_STRING_ELT(la, k, mkChar(cbuf));
        k++;
        }
    }
    setAttrib(a, R_LevelsSymbol, la);
    UNPROTECT(1);
    }
    PROTECT(la = mkString("factor"));
    setAttrib(a, R_ClassSymbol, la);
    UNPROTECT(2);
    R_FreeStringBufferL(&cbuff);
    return(a);
}

static SEXP seq_colon(double n1, double n2, SEXP call)
{
    int in1;
    R_xlen_t n;
    double r;
    SEXP ans;
    Rboolean useInt;

    r = fabs(n2 - n1);
    if(r >= R_XLEN_T_MAX) 
    errorcall(call, _("result would be too long a vector"));

    n = (R_xlen_t)(r + 1 + FLT_EPSILON);

    in1 = (int)(n1);
    useInt = (n1 == in1);
    if(useInt) {
    if(n1 <= INT_MIN || n1 > INT_MAX)
        useInt = FALSE;
    else {
        /* r := " the effective 'to' "  of  from:to */
        double dn = (double) n;
        r = n1 + ((n1 <= n2) ? dn-1 : -(dn-1));
        if(r <= INT_MIN || r > INT_MAX) useInt = FALSE;
    }
    }
    if (useInt) {
    ans = allocVector(INTSXP, n);
    if (n1 <= n2)
        for (int i = 0; i < n; i++) INTEGER(ans)[i] = in1 + i;
    else
        for (int i = 0; i < n; i++) INTEGER(ans)[i] = in1 - i;
    } else {
    ans = allocVector(REALSXP, n);
    if (n1 <= n2)
        for (R_xlen_t i = 0; i < n; i++) REAL(ans)[i] = n1 + (double)i;
    else
        for (R_xlen_t i = 0; i < n; i++) REAL(ans)[i] = n1 - (double)i;
    }
    return ans;
}

SEXP attribute_hidden do_colon(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP s1, s2;
    double n1, n2;

    checkArity(op, args);
    if (inherits(CAR(args), "factor") && inherits(CADR(args), "factor"))
    return(cross_colon(call, CAR(args), CADR(args)));

    s1 = CAR(args);
    s2 = CADR(args);
    n1 = length(s1);
    n2 = length(s2);
    if (n1 > 1)
    warningcall(call, _("numerical expression has %d elements: only the first used"), (int) n1);
    else if (n1 == 0 || n2 == 0)
    errorcall(call, _("argument of length 0"));
    if (n2 > 1)
    warningcall(call, _("numerical expression has %d elements: only the first used"), (int) n2);
    n1 = asReal(s1);
    n2 = asReal(s2);
    if (ISNAN(n1) || ISNAN(n2))
    errorcall(call, _("NA/NaN argument"));
    return seq_colon(n1, n2, call);
}

static SEXP rep2(SEXP s, SEXP ncopy)
{
    R_xlen_t i, na, nc, n;
    int j;
    SEXP a, t, u;

    PROTECT(t = coerceVector(ncopy, INTSXP));

    nc = xlength(ncopy);
    na = 0;
    for (i = 0; i < nc; i++) {
    if (INTEGER(t)[i] == NA_INTEGER || INTEGER(t)[i]<0)
        error(_("invalid '%s' value"), "times");
    na += INTEGER(t)[i];
    }

    if (isVector(s))
    a = allocVector(TYPEOF(s), na);
    else {
    if (na > INT_MAX) error("too long for a pairlist");
    a = allocList((int) na);
    }
    PROTECT(a);
    n = 0;
    switch (TYPEOF(s)) {
    case LGLSXP:
    for (i = 0; i < nc; i++)
        for (j = 0; j < (INTEGER(t)[i]); j++)
        LOGICAL(a)[n++] = LOGICAL(s)[i];
    break;
    case INTSXP:
    for (i = 0; i < nc; i++)
        for (j = 0; j < (INTEGER(t)[i]); j++)
        INTEGER(a)[n++] = INTEGER(s)[i];
    break;
    case REALSXP:
    for (i = 0; i < nc; i++)
        for (j = 0; j < (INTEGER(t)[i]); j++)
        REAL(a)[n++] = REAL(s)[i];
    break;
    case CPLXSXP:
    for (i = 0; i < nc; i++)
        for (j = 0; j < (INTEGER(t)[i]); j++)
        COMPLEX(a)[n++] = COMPLEX(s)[i];
    break;
    case STRSXP:
    for (i = 0; i < nc; i++)
        for (j = 0; j < (INTEGER(t)[i]); j++)
        SET_STRING_ELT(a, n++, STRING_ELT(s, i));
    break;
    case VECSXP:
    case EXPRSXP:
    for (i = 0; i < nc; i++)
        for (j = 0; j < (INTEGER(t)[i]); j++)
        SET_VECTOR_ELT(a, n++, VECTOR_ELT(s, i));
    break;
    case LISTSXP:
    u = a;
    for (int ii = 0; ii < (int)nc; ii++)
        for (j = 0; j < (INTEGER(t)[ii]); j++) {
        SETCAR(u, duplicate(CAR(nthcdr(s, ii))));
        u = CDR(u);
        }
    break;
    case RAWSXP:
    for (i = 0; i < nc; i++)
        for (j = 0; j < (INTEGER(t)[i]); j++)
        RAW(a)[n++] = RAW(s)[i];
    break;
    default:
    UNIMPLEMENTED_TYPE("rep2", s);
    }
#ifdef _S4_rep_keepClass
    if(IS_S4_OBJECT(s)) { /* e.g. contains = "list" */
    setAttrib(a, R_ClassSymbol, getAttrib(s, R_ClassSymbol));
    SET_S4_OBJECT(a);
    }
#endif
    if (inherits(s, "factor")) {
    SEXP tmp;
    if(inherits(s, "ordered")) {
        PROTECT(tmp = allocVector(STRSXP, 2));
        SET_STRING_ELT(tmp, 0, mkChar("ordered"));
        SET_STRING_ELT(tmp, 1, mkChar("factor"));
    }
    else {
        PROTECT(tmp = mkString("factor"));
    }
    setAttrib(a, R_ClassSymbol, tmp);
    UNPROTECT(1);
    setAttrib(a, R_LevelsSymbol, getAttrib(s, R_LevelsSymbol));
    }
    UNPROTECT(2);
    return a;
}

/* called in do_rep_int() only */
static SEXP rep1(SEXP s, SEXP ncopy)
{
    R_xlen_t i, ns, na, nc;
    SEXP a, t;

    if (!isVector(ncopy))
    error(_("incorrect type for second argument"));

    if (!isVector(s) && (!isList(s)))
    error(_("attempt to replicate non-vector"));

    nc = xlength(ncopy);
    /* FIXME: only want to do this for nc > 1 */
    if (nc == xlength(s)) return rep2(s, ncopy);
    if (nc != 1) error(_("invalid '%s' value"), "times");

#ifdef LONG_VECTOR_SUPPORT
    double snc = asReal(ncopy);
    if (!R_FINITE(snc) || snc < 0)
    error(_("invalid '%s' value"), "times");
    nc = (R_xlen_t) snc;
#else
    if ((nc = asInteger(ncopy)) == NA_INTEGER || nc < 0)/* nc = 0 ok */
    error(_("invalid '%s' value"), "times");
#endif

    ns = xlength(s);
    na = nc * ns;
    if (isVector(s))
    a = allocVector(TYPEOF(s), na);
    else {
    if (na > INT_MAX) error("too long for a pairlist");
    a = allocList((int) na);
    }
    PROTECT(a);

#ifdef _S4_rep_keepClass
    if(IS_S4_OBJECT(s)) { /* e.g. contains = "list" */
    setAttrib(a, R_ClassSymbol, getAttrib(s, R_ClassSymbol));
    SET_S4_OBJECT(a);
    }
#endif

    switch (TYPEOF(s)) {
    case LGLSXP:
    for (i = 0; i < na; i++)
        LOGICAL(a)[i] = LOGICAL(s)[i % ns];
    break;
    case INTSXP:
    for (i = 0; i < na; i++)
        INTEGER(a)[i] = INTEGER(s)[i % ns];
    break;
    case REALSXP:
    for (i = 0; i < na; i++)
        REAL(a)[i] = REAL(s)[i % ns];
    break;
    case CPLXSXP:
    for (i = 0; i < na; i++)
        COMPLEX(a)[i] = COMPLEX(s)[i % ns];
    break;
    case STRSXP:
    for (i = 0; i < na; i++)
        SET_STRING_ELT(a, i, STRING_ELT(s, i% ns));
    break;
    case LISTSXP:
    {
    int i = 0, nss = (int) ns;
    for (t = a; t != R_NilValue; t = CDR(t), i++)
        SETCAR(t, duplicate(CAR(nthcdr(s, (i % nss)))));
    }
    break;
    case VECSXP:
    i = 0;
    for (i = 0; i < na; i++)
        SET_VECTOR_ELT(a, i, duplicate(VECTOR_ELT(s, i % ns)));
    break;
    case RAWSXP:
    for (i = 0; i < na; i++)
        RAW(a)[i] = RAW(s)[i % ns];
    break;
    default:
    UNIMPLEMENTED_TYPE("rep", s);
    }
    if (inherits(s, "factor")) {
    SEXP tmp;
    if(inherits(s, "ordered")) {
        PROTECT(tmp = allocVector(STRSXP, 2));
        SET_STRING_ELT(tmp, 0, mkChar("ordered"));
        SET_STRING_ELT(tmp, 1, mkChar("factor"));
    }
    else {
        PROTECT(tmp = mkString("factor"));
    }
    setAttrib(a, R_ClassSymbol, tmp);
    UNPROTECT(1);
    setAttrib(a, R_LevelsSymbol, getAttrib(s, R_LevelsSymbol));
    }
    UNPROTECT(1);
    return a;
}

SEXP attribute_hidden do_rep_int(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    checkArity(op, args);
    return rep1(CAR(args), CADR(args));
}

/* We are careful to use evalListKeepMissing here (inside
   DispatchOrEval) to avoid dropping missing arguments so e.g.
   rep(1:3,,8) matches length.out */

/* This is a primitive SPECIALSXP with internal argument matching */
SEXP attribute_hidden do_rep(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ans, x, ap, times = R_NilValue /* -Wall */, ind;
    int each = 1, nprotect = 4;
    R_xlen_t i, lx, len = NA_INTEGER, nt;

    if (DispatchOrEval(call, op, "rep", args, rho, &ans, 0, 0))
    return(ans);

    /* This has evaluated all the non-missing arguments into ans */
    PROTECT(args = ans);

    /* This is a primitive, and we have not dispatched to a method
       so we manage the argument matching ourselves.  We pretend this is
       rep(x, times, length.out, each, ...)
    */
    PROTECT(ap = CONS(R_NilValue,
              list4(R_NilValue, R_NilValue, R_NilValue, R_NilValue)));
    SET_TAG(ap,  install("x"));
    SET_TAG(CDR(ap), install("times"));
    SET_TAG(CDDR(ap), install("length.out"));
    SET_TAG(CDR(CDDR(ap)), install("each"));
    SET_TAG(CDDR(CDDR(ap)), R_DotsSymbol);
    PROTECT(args = matchArgs(ap, args, call));

    x = CAR(args);
    lx = xlength(x);

    double slen = asReal(CADDR(args));
    if (R_FINITE(slen)) {
    if(slen < 0)
        errorcall(call, _("invalid '%s' argument"), "length.out");
    len = (R_xlen_t) slen;
    } else {
    len = asInteger(CADDR(args));
    if(len != NA_INTEGER && len < 0)
        errorcall(call, _("invalid '%s' argument"), "length.out");
    }
    if(length(CADDR(args)) != 1)
    warningcall(call, _("first element used of '%s' argument"), 
            "length.out");

    each = asInteger(CADDDR(args));
    if(each != NA_INTEGER && each < 0)
    errorcall(call, _("invalid '%s' argument"), "each");
    if(length(CADDDR(args)) != 1)
    warningcall(call, _("first element used of '%s' argument"), "each");
    if(each == NA_INTEGER) each = 1;

    if(lx == 0) {
    UNPROTECT(3);
    if(len == NA_INTEGER) return x;
    else return xlengthgets(duplicate(x), len);
    }

    if(len != NA_INTEGER) { /* takes precedence over times */
    nt = 1;
    } else {
    R_xlen_t sum = 0;
    if(CADR(args) == R_MissingArg) PROTECT(times = ScalarInteger(1));
    else PROTECT(times = coerceVector(CADR(args), INTSXP));
    nprotect++;
    nt = XLENGTH(times);
    if(nt != 1 && nt != lx * each)
        errorcall(call, _("invalid '%s' argument"), "times");
    if(nt == 1) {
        int it = INTEGER(times)[0];
        if (it == NA_INTEGER || it < 0)
        errorcall(call, _("invalid '%s' argument"), "times");
        len = lx * it * each;
    } else {
        for(i = 0; i < nt; i++) {
        int it = INTEGER(times)[i];
        if (it == NA_INTEGER || it < 0)
            errorcall(call, _("invalid '%s' argument"), "times");
        sum += it;
        }
            len = sum;
    }
    }
    if(len > 0 && each == 0)
    errorcall(call, _("invalid '%s' argument"), "each");
 #ifdef LONG_VECTOR_SUPPORT
    if (len > INT_MAX) {
    PROTECT(ind = allocVector(REALSXP, len));
    if(nt == 1)
        for(i = 0; i < len; i++)
        REAL(ind)[i] = (double)( 1 + ((i/each) % lx));
    else {
        R_xlen_t j, k, k2, k3;
        for(i = 0, k = 0, k2 = 0; i < lx; i++) {
        R_xlen_t sum = 0;
        for(j = 0; j < each; j++) sum += INTEGER(times)[k++];
        for(k3 = 0; k3 < sum; k3++) {
            REAL(ind)[k2++] = (double)(i+1);
            if(k2 == len) goto done;
        }
        }
    }
    } else
#endif
    {
    PROTECT(ind = allocVector(INTSXP, len));
    if(nt == 1)
        for(i = 0; i < len; i++)
        INTEGER(ind)[i] = (int)( 1 + ((i/each) % lx));
    else {
        R_xlen_t j, k, k2, k3;
        for(i = 0, k = 0, k2 = 0; i < lx; i++) {
        R_xlen_t sum = 0;
        for(j = 0; j < each; j++) sum += INTEGER(times)[k++];
        for(k3 = 0; k3 < sum; k3++) {
            INTEGER(ind)[k2++] = (int)(i+1);
            if(k2 == len) goto done;
        }
        }
    }
    }

done:
    ans = do_subset_dflt(R_NilValue, R_NilValue, list2(x, ind), rho);
#ifdef _S4_rep_keepClass
    if(IS_S4_OBJECT(x)) { /* e.g. contains = "list" */
    setAttrib(ans, R_ClassSymbol, getAttrib(x, R_ClassSymbol));
    SET_S4_OBJECT(ans);
    }
#endif
    /* 1D arrays get dimensions preserved */
    setAttrib(ans, R_DimSymbol, R_NilValue);
    UNPROTECT(nprotect);
    return ans;
}


/*
  This is a primitive SPECIALSXP with internal argument matching,
  implementing seq.int.

   'along' has to be used on an unevaluated argument, and evalList
   tries to evaluate language objects.
 */

#define FEPS 1e-10
#define myabs(x) (x < 0 ? x : -x)
/* to match seq.default */
SEXP attribute_hidden do_seq(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ans = R_NilValue /* -Wall */, ap, tmp, from, to, by, len, along;
    int nargs = length(args), lf;
    Rboolean One = nargs == 1;
    R_xlen_t i, lout = NA_INTEGER;

    if (DispatchOrEval(call, op, "seq", args, rho, &ans, 0, 1))
    return(ans);

    /* This is a primitive and we manage argument matching ourselves.
       We pretend this is
       seq(from, to, by, length.out, along.with, ...)
    */
    PROTECT(ap = CONS(R_NilValue,
              CONS(R_NilValue,
               list4(R_NilValue, R_NilValue, R_NilValue,
                 R_NilValue))));
    tmp = ap;
    SET_TAG(tmp, install("from")); tmp = CDR(tmp);
    SET_TAG(tmp, install("to")); tmp = CDR(tmp);
    SET_TAG(tmp, install("by")); tmp = CDR(tmp);
    SET_TAG(tmp, install("length.out")); tmp = CDR(tmp);
    SET_TAG(tmp, install("along.with")); tmp = CDR(tmp);
    SET_TAG(tmp, R_DotsSymbol);
    PROTECT(args = matchArgs(ap, args, call));

    from = CAR(args); args = CDR(args);
    to = CAR(args); args = CDR(args);
    by = CAR(args); args = CDR(args);
    len = CAR(args); args = CDR(args);
    along = CAR(args);

    if(One && from != R_MissingArg) {
    lf = length(from);
    if(lf == 1 && (TYPEOF(from) == INTSXP || TYPEOF(from) == REALSXP))
        ans = seq_colon(1.0, asReal(from), call);
    else if (lf)
        ans = seq_colon(1.0, (double)lf, call);
    else
        ans = allocVector(INTSXP, 0);
    goto done;
    }
    if(along != R_MissingArg) {
    lout = XLENGTH(along);
    if(One) {
        ans = lout ? seq_colon(1.0, (double)lout, call) : allocVector(INTSXP, 0);
        goto done;
    }
    } else if(len != R_MissingArg && len != R_NilValue) {
    double rout = asReal(len);
    if(ISNAN(rout) || rout <= -0.5)
        errorcall(call, _("'length.out' must be a non-negative number"));
    if(length(len) != 1)
        warningcall(call, _("first element used of '%s' argument"), 
            "length.out");
    lout = (R_xlen_t) ceil(rout);
    }

    if(lout == NA_INTEGER) {
    double rfrom = asReal(from), rto = asReal(to), rby = asReal(by), *ra;
    if(from == R_MissingArg) rfrom = 1.0;
    else if(length(from) != 1) error("'from' must be of length 1");
    if(to == R_MissingArg) rto = 1.0;
    else if(length(to) != 1) error("'to' must be of length 1");
    if(by == R_MissingArg)
        ans = seq_colon(rfrom, rto, call);
    else {
        if(length(by) != 1) error("'by' must be of length 1");
        double del = rto - rfrom, n, dd;
        R_xlen_t nn;
        if(!R_FINITE(rfrom))
        errorcall(call, _("'from' must be finite"));
        if(!R_FINITE(rto))
        errorcall(call, _("'to' must be finite"));
        if(del == 0.0 && rto == 0.0) {
        ans = to;
        goto done;
        }
        /* printf("from = %f, to = %f, by = %f\n", rfrom, rto, rby); */
        n = del/rby;
        if(!R_FINITE(n)) {
        if(del == 0.0 && rby == 0.0) {
            ans = from;
            goto done;
        } else
            errorcall(call, _("invalid '(to - from)/by' in 'seq'"));
        }
        dd = fabs(del)/fmax2(fabs(rto), fabs(rfrom));
        if(dd < 100 * DBL_EPSILON) {
        ans = from;
        goto done;
        }
#ifdef LONG_VECTOR_SUPPORT
        if(n > 100 * (double) INT_MAX)
#else
        if(n > (double) INT_MAX)
#endif
        errorcall(call, _("'by' argument is much too small"));
        if(n < - FEPS)
        errorcall(call, _("wrong sign in 'by' argument"));
        if(TYPEOF(from) == INTSXP &&
           TYPEOF(to) == INTSXP &&
           TYPEOF(by) == INTSXP) {
        int *ia, ifrom = asInteger(from), iby = asInteger(by);
        /* With the current limits on integers and FEPS
           reduced below 1/INT_MAX this is the same as the
           next, so this is future-proofing against longer integers.
        */
        /* seq.default gives integer result from
           from + (0:n)*by
        */
        nn = (R_xlen_t) n;
        ans = allocVector(INTSXP, nn+1);
        ia = INTEGER(ans);
        for(i = 0; i <= nn; i++)
            ia[i] = (int)(ifrom + i * iby);
        } else {
        nn = (int)(n + FEPS);
        ans = allocVector(REALSXP, nn+1);
        ra = REAL(ans);
        for(i = 0; i <= nn; i++)
            ra[i] = rfrom + (double)i * rby;
        /* Added in 2.9.0 */
        if (nn > 0)
            if((rby > 0 && ra[nn] > rto) || (rby < 0 && ra[nn] < rto))
            ra[nn] = rto;
        }
    }
    } else if (lout == 0) {
    ans = allocVector(INTSXP, 0);
    } else if (One) {
    ans = seq_colon(1.0, (double)lout, call);
    } else if (by == R_MissingArg) {
    double rfrom = asReal(from), rto = asReal(to), rby;
    if(to == R_MissingArg) rto = rfrom + (double)lout - 1;
    if(from == R_MissingArg) rfrom = rto - (double)lout + 1;
    if(!R_FINITE(rfrom))
        errorcall(call, _("'from' must be finite"));
    if(!R_FINITE(rto))
        errorcall(call, _("'to' must be finite"));
    ans = allocVector(REALSXP, lout);
    if(lout > 0) REAL(ans)[0] = rfrom;
    if(lout > 1) REAL(ans)[lout - 1] = rto;
    if(lout > 2) {
        rby = (rto - rfrom)/(double)(lout - 1);
        for(i = 1; i < lout-1; i++) REAL(ans)[i] = rfrom + (double)i*rby;
    }
    } else if (to == R_MissingArg) {
    double rfrom = asReal(from), rby = asReal(by), rto;
    if(from == R_MissingArg) rfrom = 1.0;
    if(!R_FINITE(rfrom))
        errorcall(call, _("'from' must be finite"));
    if(!R_FINITE(rby))
        errorcall(call, _("'by' must be finite"));
    rto = rfrom + (double)(lout-1)*rby;
    if(rby == (int)rby && rfrom <= INT_MAX && rfrom >= INT_MIN
       && rto <= INT_MAX && rto >= INT_MIN) {
        ans = allocVector(INTSXP, lout);
        for(i = 0; i < lout; i++)
        INTEGER(ans)[i] = (int)(rfrom + (double)i*rby);
    } else {
        ans = allocVector(REALSXP, lout);
        for(i = 0; i < lout; i++)
        REAL(ans)[i] = rfrom + (double)i*rby;
    }
    } else if (from == R_MissingArg) {
    double rto = asReal(to), rby = asReal(by),
        rfrom = rto - (double)(lout-1)*rby;
    if(!R_FINITE(rto))
        errorcall(call, _("'to' must be finite"));
    if(!R_FINITE(rby))
        errorcall(call, _("'by' must be finite"));
    if(rby == (int)rby && rfrom <= INT_MAX && rfrom >= INT_MIN
       && rto <= INT_MAX && rto >= INT_MIN) {
        ans = allocVector(INTSXP, lout);
        for(i = 0; i < lout; i++)
        INTEGER(ans)[i] = (int)(rto - (double)(lout - 1 - i)*rby);
    } else {
        ans = allocVector(REALSXP, lout);
        for(i = 0; i < lout; i++)
        REAL(ans)[i] = rto - (double)(lout - 1 - i)*rby;
    }
    } else
    errorcall(call, _("too many arguments"));

done:
    UNPROTECT(2);
    return ans;
}

SEXP attribute_hidden do_seq_along(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ans;
    R_xlen_t len;
    static SEXP length_op = NULL;

    /* Store the .Primitive for 'length' for DispatchOrEval to use. */
    if (length_op == NULL) {
    SEXP R_lengthSymbol = install("length");
    length_op = eval(R_lengthSymbol, R_BaseEnv);
    if (TYPEOF(length_op) != BUILTINSXP) {
        length_op = NULL;
        error("'length' is not a BUILTIN");
    }
    R_PreserveObject(length_op);
    }

    checkArity(op, args);
    check1arg(args, call, "along.with");

    /* Try to dispatch to S3 or S4 methods for 'length'.  For cases
       where no methods are defined this is more efficient than an
       unconditional callback to R */
    if (isObject(CAR(args)) &&
    DispatchOrEval(call, length_op, "length", args, rho, &ans, 0, 1)) {
    len = asInteger(ans);
    }
    else
    len = xlength(CAR(args));

#ifdef LONG_VECTOR_SUPPORT
    if (len > INT_MAX) {
    ans = allocVector(REALSXP, len);
    double *p = REAL(ans);
    for(R_xlen_t i = 0; i < len; i++) p[i] = (double) (i+1);
    } else
#endif
    {
    ans = allocVector(INTSXP, len);
    int *p = INTEGER(ans);
    for(int i = 0; i < len; i++) p[i] = i+1;
    }
    return ans;
}

SEXP attribute_hidden do_seq_len(SEXP call, SEXP op, SEXP args, SEXP rho)
{
    SEXP ans;

    checkArity(op, args);
    check1arg(args, call, "length.out");
    double dlen = asReal(CAR(args));
    if(!R_FINITE(dlen) || dlen < 0)
    errorcall(call, _("argument must be coercible to non-negative integer"));
    if(length(CAR(args)) != 1)
    warningcall(call, _("first element used of '%s' argument"),
            "length.out");
    R_xlen_t len = (R_xlen_t) dlen;

 #ifdef LONG_VECTOR_SUPPORT
    if (len > INT_MAX) {
    ans = allocVector(REALSXP, len);
    double *p = REAL(ans);
    for(R_xlen_t i = 0; i < len; i++) p[i] = (double) (i+1);
    } else
#endif
    {
    ans = allocVector(INTSXP, len);
    int *p = INTEGER(ans);
    for(int i = 0; i < len; i++) p[i] = i+1;
    }
    return ans;
}