Create Subversion repository

git-svn-id: http://svn.code.sf.net/p/netpbm/code/trunk@1 9d0c8265-081b-0410-96cb-a4ca84ce46f8

1 files changed, 169 insertions, 0 deletions

diff --git a/urt/rle_putcom.c b/urt/rle_putcom.c
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+++ b/urt/rle_putcom.c
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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 "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;
+}