The R Project SVN R

/*
 *  R : A Computer Language for Statistical Data Analysis
 *  Copyright (C) 1995, 1996  Robert Gentleman and Ross Ihaka
 *  Copyright (C) 1997--1999  Robert Gentleman, Ross Ihaka and the
 *                            R Development Core Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Pulic 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, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

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

#include "Defn.h"

/* Functions to perform analogues of the standard C string library. */
/* Most are vectorized */

SEXP do_nchar(SEXP call, SEXP op, SEXP args, SEXP env)
{
    SEXP d, s, x;
    int i, len;

    checkArity(op, args);
    PROTECT(x = coerceVector(CAR(args), STRSXP));
    if (!isString(x))
    errorcall(call, "nchar() requires a character vector");
    len = LENGTH(x);
    PROTECT(s = allocVector(INTSXP, len));
    for (i = 0; i < len; i++)
    INTEGER(s)[i] = strlen(CHAR(STRING(x)[i]));
    if ((d = getAttrib(x, R_DimSymbol)) != R_NilValue)
    setAttrib(s, R_DimSymbol, d);
    if ((d = getAttrib(x, R_DimNamesSymbol)) != R_NilValue)
    setAttrib(s, R_DimNamesSymbol, d);
    UNPROTECT(2);
    return s;
}

static char *buff=NULL;     /* Buffer for character strings */

static void AllocBuffer(int len)
{
    static int bufsize = 0;

    if(len >= 0 ) {
    if(len*sizeof(char) < bufsize) return;
    len = (len+1)*sizeof(char);
    if(len < MAXELTSIZE) len = MAXELTSIZE;
    buff = (char *) realloc(buff, len);
    bufsize = len;
    if(!buff) {
        bufsize = 0;
        error("Could not allocate memory for substr / strsplit");
    }
    } else {
    if(bufsize == MAXELTSIZE) return;
    free(buff);
    buff = (char *) malloc(MAXELTSIZE);
    bufsize = MAXELTSIZE;
    }
}


static void substr(char *buf, char *str, int sa, int so)
{
/* Store the substring  str [sa:so]  into buf[] */
    int i;
    str += (sa - 1);
    for (i = 0; i <= (so - sa); i++)
    *buf++ = *str++;
    *buf = '\0';
}

SEXP do_substr(SEXP call, SEXP op, SEXP args, SEXP env)
{
    SEXP s, x, sa, so;
    int i, len, start, stop, slen, k, l;
/*    char buff[MAXELTSIZE];*/

    checkArity(op, args);
    x = CAR(args);
    sa = CADR(args);
    so = CAR(CDDR(args));
    k = LENGTH(sa);
    l = LENGTH(so);

    if (!isString(x) || !isInteger(sa) || !isInteger(so) || k==0 || l==0)
    errorcall(call,"invalid argument in substr()");

    len = LENGTH(x);
    PROTECT(s = allocVector(STRSXP, len));
    for (i = 0; i < len; i++) {
    start = INTEGER(sa)[i % k];
    stop = INTEGER(so)[i % l];
    slen = strlen(CHAR(STRING(x)[i]));
    if (start < 1)
        start = 1;
    if (start > stop || start > slen) {
        AllocBuffer(1);
        buff[0]='\0';
    }
    else {
        AllocBuffer(slen);
        if (stop > slen)
        stop = slen;
        /* if (stop > MAXELTSIZE) {
        stop = MAXELTSIZE;
        warningcall(call, "a string was truncated in substr()");
        }*/
        substr(buff, CHAR(STRING(x)[i]), start, stop);
    }
    STRING(s)[i] = mkChar(buff);
    }
    UNPROTECT(1);
    AllocBuffer(-1);
    return s;
}


/* strsplit is going to split the strings in the first argument into */
/* tokens depending on the second argument. The characters of the second */
/* argument are used to split the first argument.  A list of vectors is */
/* returned of length equal to the input vector x, each element of the */
/* list is the collection of splits for the corresponding element of x. */

SEXP do_strsplit(SEXP call, SEXP op, SEXP args, SEXP env)
{
    SEXP s, t, tok, x;
    int i, j, len, tlen, ntok;
    char *pt, *split = "";

    checkArity(op, args);
    x = CAR(args);
    tok = CADR(args);
    if (!isString(x) || !isString(tok))
    errorcall(call,"non-character argument in strsplit()");
    len = LENGTH(x);
    tlen = LENGTH(tok);
    PROTECT(s = allocVector(VECSXP, len));
    for (i = 0; i < len; i++) {
    /* find out how many splits there will be */
    AllocBuffer(strlen(CHAR(STRING(x)[i])));
    strcpy(buff, CHAR(STRING(x)[i]));
    if (tlen > 0) {
        split = CHAR(STRING(tok)[i % tlen]);
        ntok = 0;
        if (strtok(buff, split) != NULL) {
        do {
            ntok++;
        }
        while (strtok(NULL, split) != NULL);
        }
    }
    else ntok = strlen(buff);
    PROTECT(t = allocVector(STRSXP, ntok));
    if (tlen > 0) {
        strcpy(buff, CHAR(STRING(x)[i]));
        pt = strtok(buff, split);
        for (j = 0; j < ntok; j++) {
        STRING(t)[j] = mkChar(pt);
        pt = strtok(NULL, split);
        }
    }
    else {
        char bf[2];
        bf[1]='\0';
        for (j = 0; j < ntok; j++) {
        bf[0]=buff[j];
        STRING(t)[j] = mkChar(bf);
        }
    }
    UNPROTECT(1);
    VECTOR(s)[i] = t;
    }
    UNPROTECT(1);
    AllocBuffer(-1);
    return s;
}


/* Abbreviate
   long names in the S-designated fashion:
   1) spaces
   2) lower case vowels
   3) lower case consonants
   4) upper case letters
   5) special characters.

   Letters are dropped from the end of words
   and at least one letter is retained from each word.

   If unique abbreviations are not produced letters are added until the
   results are unique (duplicated names are removed prior to entry).
   names, minlength, use.classes, dot
*/


#define FIRSTCHAR(i) (isspace(buff1[i-1]))
#define LASTCHAR(i) (!isspace(buff1[i-1]) && (!buff1[i+1] || isspace(buff1[i+1])))
#define LOWVOW(i) (buff1[i] == 'a' || buff1[i] == 'e' || buff1[i] == 'i' || \
           buff1[i] == 'o' || buff1[i] == 'u')

static SEXP stripchars(SEXP inchar, int minlen)
{
/* abbreviate(inchar, minlen) */

    int i, j, nspace = 0, upper;
    char buff1[MAXELTSIZE];

    strcpy(buff1, CHAR(inchar));
    upper = strlen(buff1)-1;

    /* remove leading blanks */
    j = 0;
    for (i = 0 ; i < upper ; i++)
    if (isspace(buff1[i]))
        j++;
    else
        break;

    strcpy(buff1, &buff1[j]);
    upper = strlen(buff1) - 1;

    if (strlen(buff1) < minlen)
    goto donesc;

    for (i = upper, j = 1; i > 0; i--) {
    if (isspace(buff1[i])) {
        if (j)
        buff1[i] = '\0' ;
        else
        nspace++;
    }
    else
        j = 0;
    /*strcpy(buff1[i],buff1[i+1]);*/
    if (strlen(buff1) - nspace <= minlen)
        goto donesc;
    }

    upper = strlen(buff1) -1;
    for (i = upper; i > 0; i--) {
    if(LOWVOW(i) && LASTCHAR(i))
        strcpy(&buff1[i], &buff1[i + 1]);
    if (strlen(buff1) - nspace <= minlen)
        goto donesc;
    }

    upper = strlen(buff1) -1;
    for (i = upper; i > 0; i--) {
    if (LOWVOW(i) && !FIRSTCHAR(i))
        strcpy(&buff1[i], &buff1[i + 1]);
    if (strlen(buff1) - nspace <= minlen)
        goto donesc;
    }

    upper = strlen(buff1) - 1;
    for (i = upper; i > 0; i--) {
    if (islower(buff1[i]) && LASTCHAR(i))
        strcpy(&buff1[i], &buff1[i + 1]);
    if (strlen(buff1) - nspace <= minlen)
        goto donesc;
    }

    upper = strlen(buff1) -1;
    for (i = upper; i > 0; i--) {
    if (islower(buff1[i]) && !FIRSTCHAR(i))
        strcpy(&buff1[i], &buff1[i + 1]);
    if (strlen(buff1) - nspace <= minlen)
        goto donesc;
    }

    /* all else has failed so we use brute force */

    upper = strlen(buff1) - 1;
    for (i = upper; i > 0; i--) {
    if (!FIRSTCHAR(i) && !isspace(buff1[i]))
        strcpy(&buff1[i], &buff1[i + 1]);
    if (strlen(buff1) - nspace <= minlen)
        goto donesc;
    }

donesc:

    upper = strlen(buff1);
    if (upper > minlen)
    for (i = upper - 1; i > 0; i--)
        if (isspace(buff1[i]))
        strcpy(&buff1[i], &buff1[i + 1]);

    return(mkChar(buff1));
}


SEXP do_abbrev(SEXP call, SEXP op, SEXP args, SEXP env)
{
    SEXP ans;
    int i, len, minlen, uclass;

    checkArity(op,args);

    if (!isString(CAR(args)))
    errorcall(call, "the first argument must be a string");
    len = length(CAR(args));

    PROTECT(ans = allocVector(STRSXP, len));
    minlen = asInteger(CADR(args));
    uclass = asLogical(CAR(CDDR(args)));
    for (i = 0 ; i < len ; i++)
    STRING(ans)[i] = stripchars(STRING(CAR(args))[i], minlen);

    UNPROTECT(1);
    return(ans);
}


SEXP do_makenames(SEXP call, SEXP op, SEXP args, SEXP env)
{
    SEXP arg, ans;
    int i, l, n;
    char *p;

    checkArity(op ,args);
    arg = CAR(args);
    if (!isString(arg))
    errorcall(call, "non-character names");
    n = length(arg);
    PROTECT(ans = allocVector(STRSXP, n));
    for (i = 0 ; i < n ; i++) {
    l = strlen(CHAR(STRING(arg)[i]));
    if (isalpha(CHAR(STRING(arg)[i])[0])) {
        STRING(ans)[i] = allocString(l);
        strcpy(CHAR(STRING(ans)[i]), CHAR(STRING(arg)[i]));
    }
    else {
        STRING(ans)[i] = allocString(l + 1);
        strcpy(CHAR(STRING(ans)[i]), "X");
        strcat(CHAR(STRING(ans)[i]), CHAR(STRING(arg)[i]));
    }
    p = CHAR(STRING(ans)[i]);
    while (*p) {
        if (!isalnum(*p) && *p != '.')
        *p = '.';
        p++;
    }
    }
    UNPROTECT(1);
    return ans;
}

#ifdef HAVE_REGCOMP
#ifndef Macintosh
#include <sys/types.h>
#endif
#include "regex.h"
#else
#define NO_REGEX_ERROR() \
    errorcall(call, "POSIX regular expressions not available.\nSee " \
        "R../src/regex/README, install it; then ./configure and make R.");\
    return R_NilValue;
#endif

SEXP do_grep(SEXP call, SEXP op, SEXP args, SEXP env)
{
#ifdef HAVE_REGCOMP
    SEXP pat, vec, ind, ans;
    regex_t reg;
    int i, j, n, nmatches;
    int igcase_opt, extended_opt, value_opt, eflags;

    checkArity(op, args);
    pat = CAR(args); args = CDR(args);
    vec = CAR(args); args = CDR(args);
    igcase_opt = asLogical(CAR(args)); args = CDR(args);
    extended_opt = asLogical(CAR(args)); args = CDR(args);
    value_opt = asLogical(CAR(args)); args = CDR(args);
    if (igcase_opt == NA_INTEGER) igcase_opt = 0;
    if (extended_opt == NA_INTEGER) extended_opt = 1;
    if (value_opt == NA_INTEGER) value_opt = 0;

    if (!isString(pat) || length(pat) < 1 || !isString(vec))
    errorcall(call, "invalid argument");

    eflags = 0;

    if (extended_opt) eflags = eflags | REG_EXTENDED;
    if (igcase_opt) eflags = eflags | REG_ICASE;

    if (regcomp(&reg, CHAR(STRING(pat)[0]), eflags))
    errorcall(call, "invalid regular expression");

    n = length(vec);
    ind = allocVector(LGLSXP, n);
    nmatches = 0;
    for (i = 0 ; i < n ; i++) {
    if (regexec(&reg, CHAR(STRING(vec)[i]), 0, NULL, 0) == 0) {
        INTEGER(ind)[i] = 1;
        nmatches++;
    }
    else INTEGER(ind)[i] = 0;
    }
    regfree(&reg);
    PROTECT(ind);
    if (value_opt) {
    ans = allocVector(STRSXP, nmatches);
    j = 0;
    for (i = 0 ; i < n ; i++)
        if (INTEGER(ind)[i]) {
        STRING(ans)[j++] = STRING(vec)[i];
        /* FIXME: Want to inherit 'names(vec)': [the following is wrong]
           TAG   (ans)[j]   = TAG(vec)[i]; */
        }
    }
    else {
    ans = allocVector(INTSXP, nmatches);
    j = 0;
    for (i = 0 ; i < n ; i++)
        if (INTEGER(ind)[i]) INTEGER(ans)[j++] = i + 1;
    }
    UNPROTECT(1);
    return ans;
#else
    NO_REGEX_ERROR();
#endif
}

#ifdef HAVE_REGCOMP

/* The following R functions do substitution for regular expressions,
 * either once or globally.
 * The functions are loosely patterned on the "sub" and "gsub" in "nawk". */

static int length_adj(char *repl, regmatch_t *regmatch, int nsubexpr)
{
    int k, n;
    char *p = repl;
    n = strlen(repl) - (regmatch[0].rm_eo - regmatch[0].rm_so);
    while (*p) {
    if (*p == '\\') {
        if ('1' <= p[1] && p[1] <= '9') {
        k = p[1] - '0';
        if (k > nsubexpr)
            error("invalid backreference in regular expression");
        n += (regmatch[k].rm_eo - regmatch[k].rm_so) - 2;
        p++;
        }
        else if (p[1] == 0) {
                /* can't escape the final '\0' */
        n -= 1;
        }
        else {
        n -= 1;
        p++;
        }
    }
    p++;
    }
    return n;
}

static char *string_adj(char *target, char *orig, char *repl,
            regmatch_t *regmatch, int nsubexpr)
{
    int i, k;
    char *p = repl, *t = target;
    while (*p) {
    if (*p == '\\') {
        if ('1' <= p[1] && p[1] <= '9') {
        k = p[1] - '0';
        for (i = regmatch[k].rm_so ; i < regmatch[k].rm_eo ; i++)
            *t++ = orig[i];
        p += 2;
        }
        else if (p[1] == 0) {
        p += 1;
        }
        else {
        p += 1;
        *t++ = *p++;
        }
    }
    else *t++ = *p++;
    }
    return t;
}

#endif

SEXP do_gsub(SEXP call, SEXP op, SEXP args, SEXP env)
{
#ifdef HAVE_REGCOMP
    SEXP pat, rep, vec, ans;
    regex_t reg;
    regmatch_t regmatch[10];
    int i, j, n, ns, nmatch, offset;
    int global, igcase_opt, extended_opt, eflags;
    char *s, *t, *u;

    checkArity(op, args);

    global = PRIMVAL(op);

    pat = CAR(args); args = CDR(args);
    rep = CAR(args); args = CDR(args);
    vec = CAR(args); args = CDR(args);
    igcase_opt = asLogical(CAR(args)); args = CDR(args);
    extended_opt = asLogical(CAR(args)); args = CDR(args);
    if (igcase_opt == NA_INTEGER) igcase_opt = 0;
    if (extended_opt == NA_INTEGER) extended_opt = 1;

    if (!isString(pat) || length(pat) < 1 ||
    !isString(rep) || length(rep) < 1 ||
    !isString(vec))
    errorcall(call, "invalid argument");

    eflags = 0;
    if (extended_opt) eflags = eflags | REG_EXTENDED;
    if (igcase_opt) eflags = eflags | REG_ICASE;

    if (regcomp(&reg, CHAR(STRING(pat)[0]), eflags))
    errorcall(call, "invalid regular expression");

    n = length(vec);
    PROTECT(ans = allocVector(STRSXP, n));

    for (i = 0 ; i < n ; i++) {
    offset = 0;
    nmatch = 0;
    s = CHAR(STRING(vec)[i]);
    t = CHAR(STRING(rep)[0]);
    ns = strlen(s);
    while (regexec(&reg, &s[offset], 10, regmatch, 0) == 0) {
        nmatch += 1;
        if (regmatch[0].rm_eo == 0)
        offset++;
        else {
        ns += length_adj(t, regmatch, reg.re_nsub);
        offset += regmatch[0].rm_eo;
        }
        if (s[offset] == '\0' || !global)
        break;
    }
    if (nmatch == 0)
        STRING(ans)[i] = STRING(vec)[i];
    else {
        STRING(ans)[i] = allocString(ns);
        offset = 0;
        nmatch = 0;
        s = CHAR(STRING(vec)[i]);
        t = CHAR(STRING(rep)[0]);
        u = CHAR(STRING(ans)[i]);
        ns = strlen(s);
        while (regexec(&reg, &s[offset], 10, regmatch, 0) == 0) {
        for (j = 0; j < regmatch[0].rm_so ; j++)
            *u++ = s[offset+j];
        if (regmatch[0].rm_eo == 0) {
            *u++ = s[offset];
            offset++;
        }
        else {
            u = string_adj(u, &s[offset], t, regmatch,
                   reg.re_nsub);
            offset += regmatch[0].rm_eo;
        }
        if (s[offset] == '\0' || !global)
            break;
        }
        for (j = offset ; s[j] ; j++)
        *u++ = s[j];
        *u = '\0';
    }
    }
    regfree(&reg);
    UNPROTECT(1);
    return ans;
#else
    NO_REGEX_ERROR();
#endif
}