string.c

/*
  NrrdIO: stand-alone code for basic nrrd functionality
  Copyright (C) 2013, 2012, 2011, 2010, 2009  University of Chicago
  Copyright (C) 2008, 2007, 2006, 2005  Gordon Kindlmann
  Copyright (C) 2004, 2003, 2002, 2001, 2000, 1999, 1998  University of Utah

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any
  damages arising from the use of this software.

  Permission is granted to anyone to use this software for any
  purpose, including commercial applications, and to alter it and
  redistribute it freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must
     not claim that you wrote the original software. If you use this
     software in a product, an acknowledgment in the product
     documentation would be appreciated but is not required.

  2. Altered source versions must be plainly marked as such, and must
     not be misrepresented as being the original software.

  3. This notice may not be removed or altered from any source distribution.
*/

#include "NrrdIO.h"

/* this has to default to false in order for airStrtok to be a
   functional substitute for strtok() */
int airStrtokQuoting = AIR_FALSE;

/*
******** airStrdup()
**
** because they didn't put strdup() in ANSI.
** This will return NULL if given NULL.
*/
char *
airStrdup(const char *s) {
  char *ret;

  if (!s) {
    ret = NULL;
  }
  else {
    ret = (char *)malloc(strlen(s)+1);
    if (ret) {
      strcpy(ret, s);
    }
  }
  return ret;
}

/*
******** airStrlen()
**
** just like strlen, but safe to call on NULL (for which return is 0)
*/
size_t
airStrlen(const char *s) {
  size_t ret;

  if (!s) {
    ret = 0;
  }
  else {
    ret = strlen(s);
  }
  return ret;
}

/*
******** airStrtok()
**
** thread-safe strtok() replacement.  Use just like strtok(), but on
** each call to parse a given string, pass as the last argument the
** address of a char*, to be used for saving state while the string is
** traversed.  Like strtok(), this will alter the "s" array passed to
** it on the first call, and like strtok(), this returns pointers into
** this string (rather than allocating new strings for each token).
*/
char *
airStrtok(char *s, const char *ct, char **last) {
  char *h, *e, *q;

  if (!(ct && last)) {
    /* can't do any work, bail */
    return NULL;
  }
  h = s ? s : *last;
  if (!airStrlen(h))
    return NULL;
  h += strspn(h, ct);
  if ('\"' == *h && airStrtokQuoting) {
    /* something is trying to be quoted, and, we'll respect that */
    /* have to find the next un-escaped '\"' */
    h++;
    q = h;
    while (*q && !('\"' == *q && '\\' != q[-1])) {
      q++;
    }
    if (*q) {
      /* we found an unescaped '\"' */
      e = q;
    } else {
      /* give up; pretend we never tried to do this quoting stuff */
      e = h + strcspn(h, ct);
    }
  } else {
    e = h + strcspn(h, ct);
  }
  if ('\0' == *e) {
    *last = e;
  }
  else {
    *e = '\0';
    *last = e + 1;
  }
  return h;
}

/*
******** airStrntok()
**
** returns the number of tokens parsable by airStrtok(), but does
** NOT alter the given string
*/
unsigned int
airStrntok(const char *_s, const char *ct) {
  char *s, *t, *l=NULL;
  unsigned int n = 0;

  if (_s && ct) {
    s = airStrdup(_s);
    t = airStrtok(s, ct, &l);
    while (t) {
      n++;
      t = airStrtok(NULL, ct, &l);
    }
    airFree(s);  /* no NULL assignment to s, else compile warnings */
  }
  return n;
}

char *
airStrtrans(char *s, char from, char to) {
  size_t i, l;

  if (s) {
    l = strlen(s);
    for (i=0; i<l; i++) {
      if (s[i] == from) {
        s[i] = to;
      }
    }
  }
  return s;
}

/*
******** airStrcpy
**
** Like strncpy but logic is different (and perhaps more useful), being:
** "dst is allocated for dstSize chars. Copy as much of src as can
** "fit in dst, and always 0-terminate the resulting dst.",
** instead of strncpy's "Copy at most n characters, blah blah blah,
** and you still have to 0-terminate the rest yourself".
**
** E.g. with declaration buff[AIR_STRLEN_SMALL], you call
** airStrcpy(buff, AIR_STRLEN_SMALL, src), and know that then
** strlen(buff) <= AIR_STRLEN_SMALL-1. (see note in air.h about
** the meaning of the STRLEN #defines).
**
** Returns NULL if there was a problem (NULL dst or dstSize zero),
** otherwise returns dst
*/
char *
airStrcpy(char *dst, size_t dstSize, const char *src) {
  size_t ii, copyLen, srcLen;

  if (!(dst && dstSize > 0)) {
    return NULL;
  }
  srcLen = airStrlen(src);
  if (1 == dstSize || !srcLen) {
    dst[0] = '\0';
    return dst;
  }
  /* else dstSize > 1  AND src is a non-empy string */
  copyLen = AIR_MIN(dstSize-1, srcLen);
  for (ii=0; ii<copyLen; ii++) {
    dst[ii] = src[ii];
  }
  dst[copyLen] = '\0';
  return dst;
}

/*
******** airEndsWith
**
** if "s" ends with "suff", then returns 1, 0 otherwise
*/
int
airEndsWith(const char *s, const char *suff) {

  if (!(s && suff))
    return 0;
  if (!(strlen(s) >= strlen(suff)))
    return 0;
  if (!strncmp(s + strlen(s) - strlen(suff), suff, strlen(suff)))
    return 1;
  else
    return 0;
}

/*
******** airUnescape()
**
** unescapes \\ and \n in place in a given string.
** Always returns the same pointer as given
*/
char *
airUnescape(char *s) {
  size_t i, j, len;
  int found=0;

  len = airStrlen(s);
  if (!len)
    return s;

  for (i=1, j=0; i<len; i++, j++) {
    if (s[i-1] == '\\' && s[i] == '\\') {
      s[j] = '\\'; i++; found = 1;
    } else if (s[i-1] == '\\' && s[i] == 'n') {
      s[j] = '\n'; i++; found = 1;
    } else {
      s[j] = s[i-1]; found = 0;
    }
  }
  if (i == len || !found) s[j++] = s[len-1];
  s[j] = 0;

  return s;
}

/*
******** airOneLinify()
**
** converts all contiguous white space (as determined by isspace()) to
** a single ' ', entirely removes non-printable (as determined by
** isprint()) characters, and entirely removes white space contiguous
** with the end of the string, even if that means shrinking the string
** to "".
**
** Useful for cleaning up lines of text to be saved as strings in
** fields of other structs.
**
** Whatever happens, this returns the pointer passed to it
*/
char *
airOneLinify(char *s) {
  size_t i, j, len;

  len = airStrlen(s);
  if (!len)
    return s;

  /* convert white space to space (' '), and delete unprintables */
  for (i=0; i<len && s[i]; i++) {
    if (isspace(AIR_CAST(int, s[i]))) {
      s[i] = ' ';
      continue;
    }
    if (!isprint(AIR_CAST(int, s[i]))) {
      for (j=i; j<len; j++) {
        /* this will copy the '\0' at the end */
        s[j] = s[j+1];
      }
      i--;
      continue;
    }
  }

  /* compress all contiguous spaces into one */
  for (i=0; i<len; i++) {
    while (' ' == s[i] && ' ' == s[i+1]) {
      for (j=i+1; j<len; j++) {
        s[j] = s[j+1];
      }
    }
  }

  /* lose trailing white space */
  i = airStrlen(s);
  if (' ' == s[i-1]) {
    s[i-1] = '\0';
  }

  return s;
}

/*
******** airToLower()
**
** calls tolower() on all characters in a string, and returns the same
** pointer that it was given
*/
char *
airToLower(char *str) {
  char *c;

  if (str) {
    c = str;
    while (*c) {
      *c = AIR_CAST(char, tolower(AIR_INT(*c)));
      c++;
    }
  }
  return str;
}

/*
******** airToUpper()
**
** calls toupper() on all characters in a string, and returns the same
** pointer that it was given
*/
char *
airToUpper(char *str) {
  char *c;

  if (str) {
    c = str;
    while (*c) {
      *c = AIR_CAST(char, toupper(AIR_INT(*c)));
      c++;
    }
  }
  return str;
}

/*
******** airOneLine()
**
** gets one line from "file", putting it into an array of given size.
** "size" must be the size of line buffer "line": the size which
** "line" was allocated for, not the number of non-null characters it
** was meant to hold.  "size" must be at least 3.  Always
** null-terminates the contents of the array (except if the arguments
** are invalid).  The idea is that the null-termination replaces the
** line termination.
**
** 0: if saw EOF before seeing a newline, or arguments are invalid
** 1: if line was a single newline
** n; n <= size: if line was n-1 characters followed by newline
** size+1: if didn't see a newline within size-1 characters
**
** So except for returns of -1 and size+1, the return is the number of
** characters comprising the line, including the newline character.
**
** For all you DOS\Windows\Cygwin users, this will quietly pretend that
** a "\r\n" pair is really just "\n", including the way that characters
** comprising the line are counted.  However, there is no pretension
** that on those platforms, "\n" by itself does not actually count as
** a newline.
**
** Finally, for those trafficking in legacy Mac text files (for which
** the line termination is only "\r", the same applies- these are also
** effectively treated the same as a newline.
*/
unsigned int
airOneLine(FILE *file, char *line, unsigned int size) {
  int cc=0;
  unsigned int ii;

  if (!(size >= 3  /* need room for a character and a Windows newline */
        && line && file)) {
    return 0;
  }
  /* c is always set at least once, but not so for any char in line[]  */
  for (ii=0;
       (ii <= size-2              /* room for line[ii] and \0 after that */
        && EOF != (cc=getc(file)) /* didn't hit EOF trying to read char */
        && cc != '\n'             /* char isn't newline */
        && cc != '\r');           /* char isn't carriage return */
       ++ii) {
    line[ii] = AIR_CAST(char, cc);
  }

  if (EOF == cc) {
    /* for-loop terminated because we hit EOF */
    line[0] = '\0';
    return 0;
  } else if ('\r' == cc || '\n' == cc) {
    /* for-loop terminated because we hit '\n' or '\r' */
    /* if it was '\r', see if next character is '\n' */
    if ('\r' == cc) {
      cc = getc(file);
      if (EOF != cc && '\n' != cc) {
        /* oops, we got something, and it was not a '\n'; put it back */
        ungetc(cc, file);
      }
    }
    line[ii] = '\0';
    return ii+1;
  } else {
    /* for-loop terminated because we got to end of buffer (ii == size-1) */
    cc = getc(file);
    /* but see if we were about to get '\r', "\r\n", or '\n' */
    if ('\r' == cc) {
      int dd;
      dd = getc(file);
      if (EOF != dd && '\n' != dd) {
        /* oops, put it back */
        ungetc(dd, file);
      }
      line[ii] = '\0';
      return ii+1;
    } else if ('\n' == cc) {
      line[ii] = '\0';
      return ii+1;
    } else {
      /* weren't about to get a line termination,
         we really did run out of buffer */
      if (EOF != cc) {
        ungetc(cc, file);  /* we're allowed one ungetc on ANY stream */
      }
      line[size-1] = '\0';
      return size+1;
    }
  }
}