strings.c

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/*!
  \file lib/gis/strings.c
  
  \brief GIS Library - string/chring movement functions
  
  \todo merge interesting functions from ../datetime/scan.c here
  
  (C) 1999-2008, 2011 by the GRASS Development Team
  
  This program is free software under the GNU General Public License
  (>=v2). Read the file COPYING that comes with GRASS for details.
  
  \author Dave Gerdes (USACERL)
  \author Michael Shapiro (USACERL)
  \author Amit Parghi (USACERL)
  \author Bernhard Reiter (Intevation GmbH, Germany) and many others
*/

#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <sys/types.h>
#include <grass/gis.h>

#ifndef NULL
#define NULL            0
#endif

static void *G__memccpy(void *, const void *, int, size_t);
static int _strncasecmp(const char *, const char *, int);

/*!
  \brief String compare ignoring case (upper or lower)
  
  Returning a value that has the same sign as the difference between
  the first differing pair of characters.

  Note: strcasecmp() is affected by the locale (LC_CTYPE), while
  G_strcasecmp() isn't.
  
  \param x first string to compare
  \param y second string to compare
  
  \return 0 the two strings are equal
  \return -1, 1
*/
int G_strcasecmp(const char *x, const char *y)
{
    return _strncasecmp(x, y, -1);
}

/*!
  \brief String compare ignoring case (upper or lower) - limited
  number of characters
  
  Returning a value that has the same sign as the difference between
  the first differing pair of characters.

  Note: strcasecmp() is affected by the locale (LC_CTYPE), while
  G_strcasecmp() isn't.
  
  \param x first string to compare
  \param y second string to compare
  \param n number or characters to compare
  
  \return 0 the two strings are equal
  \return -1, 1
*/
int G_strncasecmp(const char *x, const char *y, int n)
{
    return _strncasecmp(x, y, n);
}

/*!
  \brief Copy string to allocated memory.
  
  This routine allocates enough memory to hold the string <b>s</b>,
  copies <em>s</em> to the allocated memory, and returns a pointer
  to the allocated memory.
  
  If <em>s</em> is NULL then empty string is returned.
  
  \param s string
 
  \return pointer to newly allocated string
*/
char *G_store(const char *s)
{
    char *buf;

    if (s == NULL) {
        buf = G_malloc(sizeof(char));
        buf[0] = '\0';
    }
    else {
        buf = G_malloc(strlen(s) + 1);
        strcpy(buf, s);
    }
    
    return buf;
}

/*!
  \brief Copy string to allocated memory and convert copied string
  to upper case
  
  This routine allocates enough memory to hold the string <b>s</b>,
  copies <em>s</em> to the allocated memory, and returns a pointer
  to the allocated memory.
  
  If <em>s</em> is NULL then empty string is returned.
  
  \param s string
 
  \return pointer to newly allocated upper case string
*/
char *G_store_upper(const char *s)
{
    char *u_s;

    u_s = G_store(s);
    G_str_to_upper(u_s);

    return u_s;
}

/*!
  \brief Copy string to allocated memory and convert copied string
  to lower case
  
  This routine allocates enough memory to hold the string <b>s</b>,
  copies <em>s</em> to the allocated memory, and returns a pointer
  to the allocated memory.
  
  If <em>s</em> is NULL then empty string is returned.
  
  \param s string
 
  \return pointer to newly allocated lower case string
*/
char *G_store_lower(const char *s)
{
    char *l_s;

    l_s = G_store(s);
    G_str_to_lower(l_s);

    return l_s;
}

/*!
  \brief Replace all occurrences of character in string bug with new
  
  \param[in,out] bug base string
  \param character character to replace
  \param new new character
  
  \return bug string
*/
char *G_strchg(char *bug, char character, char new)
{
    char *help = bug;

    while (*help) {
        if (*help == character)
            *help = new;
        help++;
    }
    return bug;
}

/*!
  \brief Replace all occurrences of old_str in buffer with new_str
  
  Code example:
  \code
  char *name;
  name = G_str_replace ( inbuf, ".exe", "" );
  ... 
  G_free (name);
  \endcode
  
  \param buffer input string buffer
  \param old_str string to be replaced
  \param new_str new string
  
  \return the newly allocated string, input buffer is unchanged 
*/
char *G_str_replace(const char *buffer, const char *old_str, const char *new_str)
{
    char *R;
    const char *N, *B;
    char *replace;
    int count, len;

    /* Make sure old_str and new_str are not NULL */
    if (old_str == NULL || new_str == NULL)
        return G_store(buffer);
    /* Make sure buffer is not NULL */
    if (buffer == NULL)
        return NULL;

    /* Make sure old_str occurs */
    B = strstr(buffer, old_str);
    if (B == NULL)
        /* return NULL; */
        return G_store(buffer);

    if (strlen(new_str) > strlen(old_str)) {
        /* Count occurrences of old_str */
        count = 0;
        len = strlen(old_str);
        B = buffer;
        while (B != NULL && *B != '\0') {
            B = strstr(B, old_str);
            if (B != NULL) {
                B += len;
                count++;
            }
        }

        len = count * (strlen(new_str) - strlen(old_str))
            + strlen(buffer);

    }
    else
        len = strlen(buffer);

    /* Allocate new replacement */
    replace = G_malloc(len + 1);
    if (replace == NULL)
        return NULL;

    /* Replace old_str with new_str */
    B = buffer;
    R = replace;
    len = strlen(old_str);
    while (*B != '\0') {
        if (*B == old_str[0] && strncmp(B, old_str, len) == 0) {
            N = new_str;
            while (*N != '\0')
                *R++ = *N++;
            B += len;
        }
        else {
            *R++ = *B++;
        }
    }
    *R = '\0';

    return replace;
}

/*!
   \brief String concatenation

   Concatenates the strings in src_strings, which consists of num_strings number
   of strings, with the separator sep. The size of the concatenated string is
   limited by maxsize.

   \param src_strings array of strings to concatenate
   \param num_strings count of strings in src_strings
   \param sep separator string
   \param maxsize maximum number of characters of returned string

   \return the concatenated string (allocated)
 */
char *G_str_concat(const char **src_strings, int num_strings,
                   const char *sep, int maxsize)
{
    char buffer[maxsize];
    int i;
    char *end = buffer + maxsize;
    char *p = NULL;

    if (maxsize < 1 || num_strings < 1)
        return NULL;

    memset(buffer, 0, sizeof(buffer));

    for (i = 0; i < num_strings; i++) {
        if (i == 0)
            p = (char *)G__memccpy(buffer, src_strings[i], '\0', maxsize);
        else {
            if (p)
                p = (char *)G__memccpy(p - 1, sep, '\0', end - p);
            if (p)
                p = (char *)G__memccpy(p - 1, src_strings[i], '\0', end - p);
        }
    }

    return G_store(buffer);
}

/*!
  \brief Removes all leading and trailing white space from string.
  
  \param[in,out] buf buffer to be worked on
*/
void G_strip(char *buf)
{
    char *a, *b;

    /* remove leading white space */
    for (a = b = buf; *a == ' ' || *a == '\t'; a++) ;
    if (a != b)
        while ((*b++ = *a++)) ;
    /* remove trailing white space */
    for (a = buf; *a; a++) ;
    if (a != buf) {
        for (a--; *a == ' ' || *a == '\t'; a--) ;
        a++;
        *a = 0;
    }
}

/*!
  \brief Chop leading and trailing white spaces.
  
  \verbatim space, \f, \n, \r, \t, \v \endverbatim
  
  Modified copy of G_squeeze() by RB in March 2000.
  
  \param line buffer to be worked on
  
  \return pointer to string
*/
char *G_chop(char *line)
{
    char *f = line, *t = line;

    while (isspace(*f))         /* go to first non white-space char */
        f++;

    if (!*f) {                  /* no more chars in string */
        *t = '\0';
        return (line);
    }

    for (t = f; *t; t++)        /* go from first non white-space char to end */
        ;
    while (isspace(*--t)) ;
    *++t = '\0';                /* remove trailing white-spaces */

    if (f != line) {
        t = line;
        while (*f)              /* leading white spaces, shift */
            *t++ = *f++;
        *t = '\0';
    }

    return (line);
}

/*!
  \brief Convert string to upper case
  
  \param[in,out] str pointer to string
*/
void G_str_to_upper(char *str)
{
    int i = 0;

    if (!str)
        return;

    while (str[i]) {
        str[i] = toupper(str[i]);
        i++;
    }
}

/*!
  \brief Convert string to lower case
  
  \param[in,out] str pointer to string
*/
void G_str_to_lower(char *str)
{
    int i = 0;

    if (!str)
        return;

    while (str[i]) {
        str[i] = tolower(str[i]);
        i++;
    }
}

/*!
  \brief Make string SQL compliant
  
  \param[in,out] str pointer to string
  
  \return number of changed characters
*/
int G_str_to_sql(char *str)
{
    int count;
    char *c;

    count = 0;

    if (!str || !*str)
        return 0;

    c = str;
    while (*c) {
        *c = toascii(*c);

        if (!(*c >= 'A' && *c <= 'Z') && !(*c >= 'a' && *c <= 'z') &&
            !(*c >= '0' && *c <= '9')) {
            *c = '_';
            count++;
        }
        c++;
    }

    c = str;
    if (!(*c >= 'A' && *c <= 'Z') && !(*c >= 'a' && *c <= 'z')) {
        *c = 'x';
        count++;
    }

    return count;
}

/*!
  \brief Remove superfluous white space.
  
  Leading and trailing white space is removed from the string 
  <b>line</b> and internal white space which is more than one character 
  is reduced to a single space character. White space here means 
  spaces, tabs, linefeeds, newlines, and formfeeds.
  
  \param[in,out] line

  \return Pointer to <b>line</b>
*/
void G_squeeze(char *line)
{
    char *f = line, *t = line;
    int l;

    /* skip over space at the beginning of the line. */
    while (isspace(*f))
        f++;

    while (*f)
        if (!isspace(*f))
            *t++ = *f++;
        else if (*++f)
            if (!isspace(*f))
                *t++ = ' ';
    *t = '\0';
    l = strlen(line) - 1;
    if (*(line + l) == '\n')
        *(line + l) = '\0';
}

/*!
  \brief Finds the first occurrence of the sub-string in the
  null-terminated string ignoring case (upper or lower)
  
  \param str string where to find sub-string
  \param substr sub-string
  
  \return a pointer to the first occurrence of sub-string
  \return NULL if no occurrences are found
*/
char *G_strcasestr(const char *str, const char *substr)
{
    const char *p;
    const char *q;
    int length;

    p = substr;
    q = str;
    length = strlen(substr);

    do {
        /* match 1st substr char */
        while (*q != '\0' && toupper(*q) != toupper(*p)) {
            q++;
        }
    } while (*q != '\0' && G_strncasecmp(p, q, length) != 0 && q++);
    
    if (*q == '\0') {   
        /* ran off end of str */
        return NULL;
    }
    
    return (char *) q;
}

/*!
   \brief Copy string until character found

   The bytes from string src are copied to string dst.  If the character c (as
   converted to an unsigned char) occurs in the string src, the copy stops and
   a pointer to the byte after the copy of c in the string dst is returned.
   Otherwise, n bytes are copied, and a NULL pointer is returned.

   The source and destination strings should not overlap, as the behavior
   is undefined.

   \param dst destination
   \param src source
   \param c stop character
   \param n max number of bytes to copy

   \return a pointer to the next character in dest after c
   \return NULL if c was not found in the first n  characters of src
 */
static void *G__memccpy(void *dst, const void *src, int c, size_t n)
{
    const char *s = src;
    char *ret;

    for (ret = dst; n; ++ret, ++s, --n) {
        *ret = *s;
        if ((unsigned char)*ret == (unsigned char)c)
            return ret + 1;
    }

    return NULL;
}

static int _strncasecmp(const char *x, const char *y, int n)
{
    int xx, yy, i;

    if (!x)
        return y ? -1 : 0;
    if (!y)
        return x ? 1 : 0;

    i = 1;
    while (*x && *y) {
        xx = *x++;
        yy = *y++;
        if (xx >= 'A' && xx <= 'Z')
            xx = xx + 'a' - 'A';
        if (yy >= 'A' && yy <= 'Z')
            yy = yy + 'a' - 'A';
        if (xx < yy)
            return -1;
        if (xx > yy)
            return 1;
        
        if (n > -1 && i >= n)
            return 0;
        
        i++;
    }
    
    if (*x)
        return 1;
    if (*y)
        return -1;
    return 0;
}