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/*
* This software is copyrighted as noted below. It may be freely copied,
* modified, and redistributed, provided that the copyright notice is
* preserved on all copies.
*
* There is no warranty or other guarantee of fitness for this software,
* it is provided solely "as is". Bug reports or fixes may be sent
* to the author, who may or may not act on them as he desires.
*
* You may not include this software in a program or other software product
* without supplying the source, or without informing the end-user that the
* source is available for no extra charge.
*
* If you modify this software, you should include a notice giving the
* name of the person performing the modification, the date of modification,
* and the reason for such modification.
*/
/*
* rle_putcom.c - Add a picture comment to the header struct.
*
* Author: Spencer W. Thomas
* Computer Science Dept.
* University of Utah
* Date: Mon Feb 2 1987
* Copyright (c) 1987, University of Utah
*/
#include <stdio.h>
#include "netpbm/mallocvar.h"
#include "netpbm/pm.h"
#include "rle.h"
/*****************************************************************
* TAG( match )
*
* Match a name against a test string for "name=value" or "name".
* If it matches name=value, return pointer to value part, if just
* name, return pointer to NUL at end of string. If no match, return NULL.
*
* Inputs:
* n: Name to match. May also be "name=value" to make it easier
* to replace comments.
* v: Test string.
* Outputs:
* Returns pointer as above.
* Assumptions:
* [None]
* Algorithm:
* [None]
*/
static const char *
match(const char * const nArg,
const char * const vArg) {
const char * n;
const char * v;
for (n = nArg, v = vArg; *n != '\0' && *n != '=' && *n == *v; ++n, ++v)
;
if (*n == '\0' || *n == '=') {
if (*v == '\0')
return v;
else if (*v == '=')
return ++v;
}
return NULL;
}
/*****************************************************************
* TAG( rle_putcom )
*
* Put a comment into the header struct.
* Inputs:
* value: Value to add to comments.
* the_hdr: Header struct to add to.
* Outputs:
* the_hdr: Modified header struct.
* Returns previous value;
* Assumptions:
* value pointer can be used as is (data is NOT copied).
* Algorithm:
* Find match if any, else add at end (realloc to make bigger).
*/
const char *
rle_putcom(const char * const value,
rle_hdr * const the_hdr) {
if ( the_hdr->comments == NULL) {
MALLOCARRAY_NOFAIL(the_hdr->comments, 2);
the_hdr->comments[0] = value;
the_hdr->comments[1] = NULL;
} else {
const char ** cp;
const char * v;
const char ** old_comments;
int i;
for (i = 2, cp = the_hdr->comments; *cp != NULL; ++i, ++cp)
if (match(value, *cp) != NULL) {
v = *cp;
*cp = value;
return v;
}
/* Not found */
/* Can't realloc because somebody else might be pointing to this
* comments block. Of course, if this were true, then the
* assignment above would change the comments for two headers.
* But at least, that won't crash the program. Realloc will.
* This would work a lot better in C++, where hdr1 = hdr2
* could copy the pointers, too.
*/
old_comments = the_hdr->comments;
MALLOCARRAY(the_hdr->comments, i);
if (the_hdr->comments == NULL)
pm_error("Unable to allocate memory for comments");
the_hdr->comments[--i] = NULL;
the_hdr->comments[--i] = value;
for (--i; i >= 0; --i)
the_hdr->comments[i] = old_comments[i];
}
return NULL;
}
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