util.c

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/**********************************************************************

  util.c -

  $Author: matz $
  $Date: 2004/09/21 09:35:28 $
  created at: Fri Mar 10 17:22:34 JST 1995

  Copyright (C) 1993-2003 Yukihiro Matsumoto

**********************************************************************/

#include "ruby.h"

#include <ctype.h>
#include <stdio.h>
#include <errno.h>

#ifdef _WIN32
#include "missing/file.h"
#endif

#include "util.h"
#ifndef HAVE_STRING_H
char *strchr (char*,char);
#endif

unsigned long
scan_oct(start, len, retlen)
    const char *start;
    int len;
    int *retlen;
{
    register const char *s = start;
    register unsigned long retval = 0;

    while (len-- && *s >= '0' && *s <= '7') {
        retval <<= 3;
        retval |= *s++ - '0';
    }
    *retlen = s - start;
    return retval;
}

unsigned long
scan_hex(start, len, retlen)
    const char *start;
    int len;
    int *retlen;
{
    static char hexdigit[] = "0123456789abcdef0123456789ABCDEF";
    register const char *s = start;
    register unsigned long retval = 0;
    char *tmp;

    while (len-- && *s && (tmp = strchr(hexdigit, *s))) {
        retval <<= 4;
        retval |= (tmp - hexdigit) & 15;
        s++;
    }
    *retlen = s - start;
    return retval;
}

#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#if defined(HAVE_FCNTL_H)
#include <fcntl.h>
#endif

#ifndef S_ISDIR
#   define S_ISDIR(m) ((m & S_IFMT) == S_IFDIR)
#endif

#if defined(MSDOS) || defined(__CYGWIN32__) || defined(_WIN32)
/*
 *  Copyright (c) 1993, Intergraph Corporation
 *
 *  You may distribute under the terms of either the GNU General Public
 *  License or the Artistic License, as specified in the perl README file.
 *
 *  Various Unix compatibility functions and NT specific functions.
 *
 *  Some of this code was derived from the MSDOS port(s) and the OS/2 port.
 *
 */


/*
 * Suffix appending for in-place editing under MS-DOS and OS/2 (and now NT!).
 *
 * Here are the rules:
 *
 * Style 0:  Append the suffix exactly as standard perl would do it.
 *           If the filesystem groks it, use it.  (HPFS will always
 *           grok it.  So will NTFS. FAT will rarely accept it.)
 *
 * Style 1:  The suffix begins with a '.'.  The extension is replaced.
 *           If the name matches the original name, use the fallback method.
 *
 * Style 2:  The suffix is a single character, not a '.'.  Try to add the 
 *           suffix to the following places, using the first one that works.
 *               [1] Append to extension.  
 *               [2] Append to filename, 
 *               [3] Replace end of extension, 
 *               [4] Replace end of filename.
 *           If the name matches the original name, use the fallback method.
 *
 * Style 3:  Any other case:  Ignore the suffix completely and use the
 *           fallback method.
 *
 * Fallback method:  Change the extension to ".$$$".  If that matches the
 *           original name, then change the extension to ".~~~".
 *
 * If filename is more than 1000 characters long, we die a horrible
 * death.  Sorry.
 *
 * The filename restriction is a cheat so that we can use buf[] to store
 * assorted temporary goo.
 *
 * Examples, assuming style 0 failed.
 *
 * suffix = ".bak" (style 1)
 *                foo.bar => foo.bak
 *                foo.bak => foo.$$$    (fallback)
 *                foo.$$$ => foo.~~~    (fallback)
 *                makefile => makefile.bak
 *
 * suffix = "~" (style 2)
 *                foo.c => foo.c~
 *                foo.c~ => foo.c~~
 *                foo.c~~ => foo~.c~~
 *                foo~.c~~ => foo~~.c~~
 *                foo~~~~~.c~~ => foo~~~~~.$$$ (fallback)
 *
 *                foo.pas => foo~.pas
 *                makefile => makefile.~
 *                longname.fil => longname.fi~
 *                longname.fi~ => longnam~.fi~
 *                longnam~.fi~ => longnam~.$$$
 *                
 */


static int valid_filename(char *s);

static char suffix1[] = ".$$$";
static char suffix2[] = ".~~~";

#define ext (&buf[1000])

#define strEQ(s1,s2) (strcmp(s1,s2) == 0)

void
ruby_add_suffix(str, suffix)
    VALUE str;
    char *suffix;
{
    int baselen;
    int extlen = strlen(suffix);
    char *s, *t, *p;
    long slen;
    char buf[1024];

    if (RSTRING(str)->len > 1000)
        rb_fatal("Cannot do inplace edit on long filename (%ld characters)",
                 RSTRING(str)->len);

#if defined(DJGPP) || defined(__CYGWIN32__) || defined(_WIN32)
    /* Style 0 */
    slen = RSTRING(str)->len;
    rb_str_cat(str, suffix, extlen);
#if defined(DJGPP)
    if (_USE_LFN) return;
#else
    if (valid_filename(RSTRING(str)->ptr)) return;
#endif

    /* Fooey, style 0 failed.  Fix str before continuing. */
    RSTRING(str)->ptr[RSTRING(str)->len = slen] = '\0';
#endif

    slen = extlen;
    t = buf; baselen = 0; s = RSTRING(str)->ptr;
    while ((*t = *s) && *s != '.') {
        baselen++;
        if (*s == '\\' || *s == '/') baselen = 0;
        s++; t++;
    }
    p = t;

    t = ext; extlen = 0;
    while (*t++ = *s++) extlen++;
    if (extlen == 0) { ext[0] = '.'; ext[1] = 0; extlen++; }

    if (*suffix == '.') {        /* Style 1 */
        if (strEQ(ext, suffix)) goto fallback;
        strcpy(p, suffix);
    }
    else if (suffix[1] == '\0') {  /* Style 2 */
        if (extlen < 4) { 
            ext[extlen] = *suffix;
            ext[++extlen] = '\0';
        }
        else if (baselen < 8) {
            *p++ = *suffix;
        }
        else if (ext[3] != *suffix) {
            ext[3] = *suffix;
        }
        else if (buf[7] != *suffix) {
            buf[7] = *suffix;
        }
        else goto fallback;
        strcpy(p, ext);
    }
    else { /* Style 3:  Panic */
fallback:
        (void)memcpy(p, strEQ(ext, suffix1) ? suffix2 : suffix1, 5);
    }
    rb_str_resize(str, strlen(buf));
    memcpy(RSTRING(str)->ptr, buf, RSTRING(str)->len);
}

#if defined(__CYGWIN32__) || defined(_WIN32)
static int 
valid_filename(char *s)
{
    int fd;

    /*
    // if the file exists, then it's a valid filename!
    */

    if (_access(s, 0) == 0) {
        return 1;
    }

    /*
    // It doesn't exist, so see if we can open it.
    */

    if ((fd = _open(s, O_CREAT, 0666)) >= 0) {
        _close(fd);
        _unlink(s);     /* don't leave it laying around */
        return 1;
    }
    return 0;
}
#endif
#endif

#if defined __DJGPP__

#include <dpmi.h>

static char dbcs_table[256];

int
make_dbcs_table()
{
    __dpmi_regs r;
    struct {
        unsigned char start;
        unsigned char end;
    } vec;
    int offset;

    memset(&r, 0, sizeof(r));
    r.x.ax = 0x6300;
    __dpmi_int(0x21, &r);
    offset = r.x.ds * 16 + r.x.si;

    for (;;) {
        int i;
        dosmemget(offset, sizeof vec, &vec);
        if (!vec.start && !vec.end)
            break;
        for (i = vec.start; i <= vec.end; i++)
            dbcs_table[i] = 1;
        offset += 2;
    }
}

int
mblen(const char *s, size_t n)
{
    static int need_init = 1;
    if (need_init) {
        make_dbcs_table();
        need_init = 0;
    }
    if (s) {
        if (n == 0 || *s == 0)
            return 0;
        else if (!s[1])
            return 1;
        return dbcs_table[(unsigned char)*s] + 1;
    }
    else
        return 1;
}

struct PathList {
    struct PathList *next;
    char *path;
};

struct PathInfo {
    struct PathList *head;
    int count;
};

static void
push_element(const char *path, VALUE vinfo)
{
    struct PathList *p;
    struct PathInfo *info = (struct PathInfo *)vinfo;

    p = ALLOC(struct PathList);
    MEMZERO(p, struct PathList, 1);
    p->path = ruby_strdup(path);
    p->next = info->head;
    info->head = p;
    info->count++;
}

#include <dirent.h>
int __opendir_flags = __OPENDIR_PRESERVE_CASE;

char **
__crt0_glob_function(char *path)
{
    int len = strlen(path);
    int i;
    char **rv;
    char path_buffer[PATH_MAX];
    char *buf = path_buffer;
    char *p;
    struct PathInfo info;
    struct PathList *plist;

    if (PATH_MAX <= len)
        buf = ruby_xmalloc(len + 1);

    strncpy(buf, path, len);
    buf[len] = '\0';

    for (p = buf; *p; p += mblen(p, MB_CUR_MAX))
        if (*p == '\\')
            *p = '/';

    info.count = 0;
    info.head = 0;

    rb_globi(buf, push_element, (VALUE)&info);

    if (buf != path_buffer)
        ruby_xfree(buf);

    if (info.count == 0)
        return 0;

    rv = ruby_xmalloc((info.count + 1) * sizeof (char *));

    plist = info.head;
    i = 0;
    while (plist) {
        struct PathList *cur;
        rv[i] = plist->path;
        cur = plist;
        plist = plist->next;
        ruby_xfree(cur);
        i++;
    }
    rv[i] = 0;
    return rv;
}

#endif

/* mm.c */

#define A ((int*)a)
#define B ((int*)b)
#define C ((int*)c)
#define D ((int*)d)

#define mmprepare(base, size) do {\
 if (((long)base & (0x3)) == 0)\
   if (size >= 16) mmkind = 1;\
   else            mmkind = 0;\
 else              mmkind = -1;\
 high = (size & (~0xf));\
 low  = (size &  0x0c);\
} while (0)\

#define mmarg mmkind, size, high, low

static void mmswap_(a, b, mmarg)
    register char *a, *b;
    int mmarg;
{
 register int s;
 if (a == b) return;
 if (mmkind >= 0) {
   if (mmkind > 0) {
     register char *t = a + high;
     do {
       s = A[0]; A[0] = B[0]; B[0] = s;
       s = A[1]; A[1] = B[1]; B[1] = s;
       s = A[2]; A[2] = B[2]; B[2] = s;
       s = A[3]; A[3] = B[3]; B[3] = s;  a += 16; b += 16;
     } while (a < t);
   }
   if (low != 0) { s = A[0]; A[0] = B[0]; B[0] = s;
     if (low >= 8) { s = A[1]; A[1] = B[1]; B[1] = s;
       if (low == 12) {s = A[2]; A[2] = B[2]; B[2] = s;}}}
 }
 else {
   register char *t = a + size;
   do {s = *a; *a++ = *b; *b++ = s;} while (a < t);
 }
}
#define mmswap(a,b) mmswap_((a),(b),mmarg)

static void mmrot3_(a, b, c, mmarg)
    register char *a, *b, *c;
    int mmarg;
{
 register int s;
 if (mmkind >= 0) {
   if (mmkind > 0) {
     register char *t = a + high;
     do {
       s = A[0]; A[0] = B[0]; B[0] = C[0]; C[0] = s;
       s = A[1]; A[1] = B[1]; B[1] = C[1]; C[1] = s;
       s = A[2]; A[2] = B[2]; B[2] = C[2]; C[2] = s;
       s = A[3]; A[3] = B[3]; B[3] = C[3]; C[3] = s; a += 16; b += 16; c += 16;
     } while (a < t);
   }
   if (low != 0) { s = A[0]; A[0] = B[0]; B[0] = C[0]; C[0] = s;
     if (low >= 8) { s = A[1]; A[1] = B[1]; B[1] = C[1]; C[1] = s;
       if (low == 12) {s = A[2]; A[2] = B[2]; B[2] = C[2]; C[2] = s;}}}
 }
 else {
   register char *t = a + size;
   do {s = *a; *a++ = *b; *b++ = *c; *c++ = s;} while (a < t);
 }
}
#define mmrot3(a,b,c) mmrot3_((a),(b),(c),mmarg)

/* qs6.c */
/*****************************************************/
/*                                                   */
/*          qs6   (Quick sort function)              */
/*                                                   */
/* by  Tomoyuki Kawamura              1995.4.21      */
/* kawamura@tokuyama.ac.jp                           */
/*****************************************************/

typedef struct { char *LL, *RR; } stack_node; /* Stack structure for L,l,R,r */
#define PUSH(ll,rr) do { top->LL = (ll); top->RR = (rr); ++top; } while (0)  /* Push L,l,R,r */
#define POP(ll,rr)  do { --top; ll = top->LL; rr = top->RR; } while (0)      /* Pop L,l,R,r */

#define med3(a,b,c) ((*cmp)(a,b,d)<0 ?                                   \
                       ((*cmp)(b,c,d)<0 ? b : ((*cmp)(a,c,d)<0 ? c : a)) : \
                       ((*cmp)(b,c,d)>0 ? b : ((*cmp)(a,c,d)<0 ? a : c)))

void ruby_qsort (base, nel, size, cmp, d)
     void* base;
     const int nel;
     const int size;
     int (*cmp)();
     void *d;
{
  register char *l, *r, *m;             /* l,r:left,right group   m:median point */
  register int  t, eq_l, eq_r;          /* eq_l: all items in left group are equal to S */
  char *L = base;                       /* left end of curren region */
  char *R = (char*)base + size*(nel-1); /* right end of current region */
  int  chklim = 63;                     /* threshold of ordering element check */
  stack_node stack[32], *top = stack;   /* 32 is enough for 32bit CPU */
  int mmkind, high, low;

  if (nel <= 1) return;        /* need not to sort */
  mmprepare(base, size);
  goto start;

  nxt:
  if (stack == top) return;    /* return if stack is empty */
  POP(L,R);

  for (;;) {
    start:
    if (L + size == R) {       /* 2 elements */
      if ((*cmp)(L,R,d) > 0) mmswap(L,R); goto nxt;
    }

    l = L; r = R;
    t = (r - l + size) / size;  /* number of elements */
    m = l + size * (t >> 1);    /* calculate median value */

    if (t >= 60) {
      register char *m1;
      register char *m3;
      if (t >= 200) {
        t = size*(t>>3); /* number of bytes in splitting 8 */
        {
          register char *p1 = l  + t;
          register char *p2 = p1 + t;
          register char *p3 = p2 + t;
          m1 = med3(p1, p2, p3);
          p1 = m  + t;
          p2 = p1 + t;
          p3 = p2 + t;
          m3 = med3(p1, p2, p3);
        }
      }
      else {
        t = size*(t>>2); /* number of bytes in splitting 4 */
        m1 = l + t;
        m3 = m + t;
      }
      m = med3(m1, m, m3);
    }

    if ((t = (*cmp)(l,m,d)) < 0) {                           /*3-5-?*/
      if ((t = (*cmp)(m,r,d)) < 0) {                         /*3-5-7*/
        if (chklim && nel >= chklim) {   /* check if already ascending order */
          char *p;
          chklim = 0;
          for (p=l; p<r; p+=size) if ((*cmp)(p,p+size,d) > 0) goto fail;
          goto nxt;
        }
        fail: goto loopA;                                    /*3-5-7*/
      }
      if (t > 0) {
        if ((*cmp)(l,r,d) <= 0) {mmswap(m,r); goto loopA;}     /*3-5-4*/
        mmrot3(r,m,l); goto loopA;                           /*3-5-2*/
      }
      goto loopB;                                            /*3-5-5*/
    }

    if (t > 0) {                                             /*7-5-?*/
      if ((t = (*cmp)(m,r,d)) > 0) {                         /*7-5-3*/
        if (chklim && nel >= chklim) {   /* check if already ascending order */
          char *p;
          chklim = 0;
          for (p=l; p<r; p+=size) if ((*cmp)(p,p+size,d) < 0) goto fail2;
          while (l<r) {mmswap(l,r); l+=size; r-=size;}  /* reverse region */
          goto nxt;
        }
        fail2: mmswap(l,r); goto loopA;                      /*7-5-3*/
      }
      if (t < 0) {
        if ((*cmp)(l,r,d) <= 0) {mmswap(l,m); goto loopB;}   /*7-5-8*/
        mmrot3(l,m,r); goto loopA;                           /*7-5-6*/
      }
      mmswap(l,r); goto loopA;                               /*7-5-5*/
    }

    if ((t = (*cmp)(m,r,d)) < 0)  {goto loopA;}              /*5-5-7*/
    if (t > 0) {mmswap(l,r); goto loopB;}                    /*5-5-3*/

    /* determining splitting type in case 5-5-5 */           /*5-5-5*/
    for (;;) {
      if ((l += size) == r)      goto nxt;                   /*5-5-5*/
      if (l == m) continue;
      if ((t = (*cmp)(l,m,d)) > 0) {mmswap(l,r); l = L; goto loopA;}/*575-5*/
      if (t < 0)                 {mmswap(L,l); l = L; goto loopB;}  /*535-5*/
    }

    loopA: eq_l = 1; eq_r = 1;  /* splitting type A */ /* left <= median < right */
    for (;;) {
      for (;;) {
        if ((l += size) == r)
          {l -= size; if (l != m) mmswap(m,l); l -= size; goto fin;}
        if (l == m) continue;
        if ((t = (*cmp)(l,m,d)) > 0) {eq_r = 0; break;}
        if (t < 0) eq_l = 0;
      }
      for (;;) {
        if (l == (r -= size))
          {l -= size; if (l != m) mmswap(m,l); l -= size; goto fin;}
        if (r == m) {m = l; break;}
        if ((t = (*cmp)(r,m,d)) < 0) {eq_l = 0; break;}
        if (t == 0) break;
      }
      mmswap(l,r);    /* swap left and right */
    }

    loopB: eq_l = 1; eq_r = 1;  /* splitting type B */ /* left < median <= right */
    for (;;) {
      for (;;) {
        if (l == (r -= size))
          {r += size; if (r != m) mmswap(r,m); r += size; goto fin;}
        if (r == m) continue;
        if ((t = (*cmp)(r,m,d)) < 0) {eq_l = 0; break;}
        if (t > 0) eq_r = 0;
      }
      for (;;) {
        if ((l += size) == r)
          {r += size; if (r != m) mmswap(r,m); r += size; goto fin;}
        if (l == m) {m = r; break;}
        if ((t = (*cmp)(l,m,d)) > 0) {eq_r = 0; break;}
        if (t == 0) break;
      }
      mmswap(l,r);    /* swap left and right */
    }

    fin:
    if (eq_l == 0)                         /* need to sort left side */
      if (eq_r == 0)                       /* need to sort right side */
        if (l-L < R-r) {PUSH(r,R); R = l;} /* sort left side first */
        else           {PUSH(L,l); L = r;} /* sort right side first */
      else R = l;                          /* need to sort left side only */
    else if (eq_r == 0) L = r;             /* need to sort right side only */
    else goto nxt;                         /* need not to sort both sides */
  }
}

char *
ruby_strdup(str)
    const char *str;
{
    char *tmp;
    int len = strlen(str) + 1;

    tmp = xmalloc(len);
    memcpy(tmp, str, len);

    return tmp;
}

char *
ruby_getcwd()
{
#ifdef HAVE_GETCWD
    int size = 200;
    char *buf = xmalloc(size);

    while (!getcwd(buf, size)) {
        if (errno != ERANGE) {
            free(buf);
            rb_sys_fail("getcwd");
        }
        size *= 2;
        buf = xrealloc(buf, size);
    }
#else
# ifndef PATH_MAX
#  define PATH_MAX 8192
# endif
    char *buf = xmalloc(PATH_MAX+1);

    if (!getwd(buf)) {
        free(buf);
        rb_sys_fail("getwd");
    }
#endif
    return buf;
}

/* copyright notice for strtod implementation --
 *
 * Copyright (c) 1988-1993 The Regents of the University of California.
 * Copyright (c) 1994 Sun Microsystems, Inc.
 *
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appear in all copies.  The University of California
 * makes no representations about the suitability of this
 * software for any purpose.  It is provided "as is" without
 * express or implied warranty.
 *
 */

#define TRUE 1
#define FALSE 0

static  int     MDMINEXPT       = -323;
static  int     MDMAXEXPT       =  309;
static double powersOf10[] = {  /* Table giving binary powers of 10.  Entry */
    10.0,                       /* is 10^2^i.  Used to convert decimal */
    100.0,                      /* exponents into floating-point numbers. */
    1.0e4,
    1.0e8,
    1.0e16,
    1.0e32,
    1.0e64,
    1.0e128,
    1.0e256
};

/*
 *----------------------------------------------------------------------
 *
 * strtod --
 *
 *      This procedure converts a floating-point number from an ASCII
 *      decimal representation to internal double-precision format.
 *
 * Results:
 *      The return value is the double-precision floating-point
 *      representation of the characters in string.  If endPtr isn't
 *      NULL, then *endPtr is filled in with the address of the
 *      next character after the last one that was part of the
 *      floating-point number.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

double
ruby_strtod(string, endPtr)
    const char *string;         /* A decimal ASCII floating-point number,
                                 * optionally preceded by white space.
                                 * Must have form "-I.FE-X", where I is the
                                 * integer part of the mantissa, F is the
                                 * fractional part of the mantissa, and X
                                 * is the exponent.  Either of the signs
                                 * may be "+", "-", or omitted.  Either I
                                 * or F may be omitted, but both cannot be
                                 * ommitted at once. The decimal
                                 * point isn't necessary unless F is present.
                                 * The "E" may actually be an "e".  E and X
                                 * may both be omitted (but not just one).
                                 */
    char **endPtr;              /* If non-NULL, store terminating character's
                                 * address here. */
{
    int sign, expSign = FALSE;
    double fraction, dblExp, *d;
    register const char *p;
    register int c;
    int exp = 0;                /* Exponent read from "EX" field. */
    int fracExp = 0;            /* Exponent that derives from the fractional
                                 * part.  Under normal circumstatnces, it is
                                 * the negative of the number of digits in F.
                                 * However, if I is very long, the last digits
                                 * of I get dropped (otherwise a long I with a
                                 * large negative exponent could cause an
                                 * unnecessary overflow on I alone).  In this
                                 * case, fracExp is incremented one for each
                                 * dropped digit. */
    int mantSize = 0;           /* Number of digits in mantissa. */
    int hasPoint = FALSE;       /* Decimal point exists. */
    int hasDigit = FALSE;       /* I or F exists. */
    const char *pMant;          /* Temporarily holds location of mantissa
                                 * in string. */
    const char *pExp;           /* Temporarily holds location of exponent
                                 * in string. */

    /*
     * Strip off leading blanks and check for a sign.
     */

    errno = 0;
    p = string;
    while (ISSPACE(*p)) {
        p += 1;
    }
    if (*p == '-') {
        sign = TRUE;
        p += 1;
    }
    else {
        if (*p == '+') {
            p += 1;
        }
        sign = FALSE;
    }

    /*
     * Count the number of digits in the mantissa
     * and also locate the decimal point.
     */

    for ( ; c = *p; p += 1) {
        if (!ISDIGIT(c)) {
            if (c != '.' || hasPoint) {
                break;
            }
            hasPoint = TRUE;
        }
        else {
            if (hasPoint) { /* already in fractional part */
                fracExp -= 1;
            }
            if (mantSize) { /* already in mantissa */
                mantSize += 1;
            }
            else if (c != '0') { /* have entered mantissa */
                mantSize += 1;
                pMant = p;
            }
            hasDigit = TRUE;
        }
    }

    /*
     * Now suck up the digits in the mantissa.  Use two integers to
     * collect 9 digits each (this is faster than using floating-point).
     * If the mantissa has more than 18 digits, ignore the extras, since
     * they can't affect the value anyway.
     */
    
    pExp  = p;
    if (mantSize) {
        p = pMant;
    }
    if (mantSize > 18) {
        fracExp += (mantSize - 18);
        mantSize = 18;
    }
    if (!hasDigit) {
        fraction = 0.0;
        p = string;
    }
    else {
        int frac1, frac2;
        frac1 = 0;
        for ( ; mantSize > 9; mantSize -= 1) {
            c = *p;
            p += 1;
            if (c == '.') {
                c = *p;
                p += 1;
            }
            frac1 = 10*frac1 + (c - '0');
        }
        frac2 = 0;
        for (; mantSize > 0; mantSize -= 1) {
            c = *p;
            p += 1;
            if (c == '.') {
                c = *p;
                p += 1;
            }
            frac2 = 10*frac2 + (c - '0');
        }

        /*
         * Skim off the exponent.
         */

        p = pExp;
        if ((*p == 'E') || (*p == 'e')) {
            p += 1;
            if (*p == '-') {
                expSign = TRUE;
                p += 1;
            }
            else {
                if (*p == '+') {
                    p += 1;
                }
                expSign = FALSE;
            }
            while (ISDIGIT(*p)) {
                exp = exp * 10 + (*p - '0');
                p += 1;
            }
        }
        if (expSign) {
            exp = fracExp - exp;
        }
        else {
            exp = fracExp + exp;
        }

        /*
         * Generate a floating-point number that represents the exponent.
         * Do this by processing the exponent one bit at a time to combine
         * many powers of 2 of 10. Then combine the exponent with the
         * fraction.
         */
    
        if (exp >= MDMAXEXPT - 18) {
            exp = MDMAXEXPT;
            errno = ERANGE;
        }
        else if (exp < MDMINEXPT + 18) {
            exp = MDMINEXPT;
            errno = ERANGE;
        }
        fracExp = exp;
        exp += 9;
        if (exp < 0) {
            expSign = TRUE;
            exp = -exp;
        }
        else {
            expSign = FALSE;
        }
        dblExp = 1.0;
        for (d = powersOf10; exp != 0; exp >>= 1, d += 1) {
            if (exp & 01) {
                dblExp *= *d;
            }
        }
        if (expSign) {
            fraction = frac1 / dblExp;
        }
        else {
            fraction = frac1 * dblExp;
        }
        exp = fracExp;
        if (exp < 0) {
            expSign = TRUE;
            exp = -exp;
        }
        else {
            expSign = FALSE;
        }
        dblExp = 1.0;
        for (d = powersOf10; exp != 0; exp >>= 1, d += 1) {
            if (exp & 01) {
                dblExp *= *d;
            }
        }
        if (expSign) {
            fraction += frac2 / dblExp;
        }
        else {
            fraction += frac2 * dblExp;
        }
    }

    if (endPtr != NULL) {
        *endPtr = (char *) p;
    }

    if (sign) {
        return -fraction;
    }
    return fraction;
}

---