diff options
Diffstat (limited to 'urt/rle_putcom.c')
| -rw-r--r-- | urt/rle_putcom.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/urt/rle_putcom.c b/urt/rle_putcom.c new file mode 100644 index 00000000..b1215661 --- /dev/null +++ b/urt/rle_putcom.c @@ -0,0 +1,169 @@ +/* + * 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 "mallocvar.h" +#include "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; +} + + + +/***************************************************************** + * TAG( rle_delcom ) + * + * Delete a comment from header struct. + * Inputs: + * name: Name of comment to delete. + * the_hdr: Header to delete comment from. + * Outputs: + * the_hdr: Modified header struct. + * Returns original comment value. + * Assumptions: + * [None] + * Algorithm: + * [None] + */ +const char * +rle_delcom(const char * const name, + rle_hdr * const the_hdr) { + + const char * v = NULL; + + if (the_hdr->comments == NULL) + v = NULL; + else { + const char ** cp; + + for (cp = the_hdr->comments; *cp != NULL; ++cp) + if (match(name, *cp) != NULL) { + v = *cp; + for ( ; *cp != NULL; ++cp) + *cp = cp[1]; + break; + } + /* Not found */ + if (*the_hdr->comments == NULL) + the_hdr->comments = NULL; + } + + return v; +} |