finished

trim.c

@@ -2,9 +2,108 @@
  *				HTBLA-Leonding
  * ---------------------------------------------------------
  * Title:			Trim String
- * Author:			*/<your name>;/*
+ * Author:			Marc Tismonar
  * ----------------------------------------------------------
  * Description:
  * Implementation of 'trim' functionality.
  * ----------------------------------------------------------
  */
+
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include "trim.h"
+
+// private functions
+bool is_whitespace(char c) {
+    return c == ' ' || c == '\t' || c == '\n' || c == '\r';
+}
+
+void shift(char* string, int start, int end) {
+    int i;
+    for (i = 0; i <= end - start; i++) {
+        string[i] = string[i + start];
+    }
+    string[i] = '\0';
+}
+
+void override_all(char* string) {
+    for (int i = 0; i < strlen(string); i++) {
+        string[i] = ' ';
+    }
+}
+
+/**
+* Provides the trimmed string WITHOUT making a copy 
+* of the source string.
+* Trimming means that leading and trailing whitespace 
+* characters are removed.
+*
+* Whitespace characters are:
+* - space (' '),
+* - tabulator ('\t')
+* - new line ('\n')
+* - line feed ('\r')
+* @param string The string to be trimmed.
+* @return The trimmed string.
+*/
+char* trim(char* string) {
+    if (string == 0) {
+        return 0;
+    }
+
+    int start = 0;
+    while (string[start] != '\0' && is_whitespace(string[start])) {
+        start++;
+    }
+    
+    // if empty or only whitespace
+    if (string[start] == '\0') {
+        string[0] = '\0';
+        return string;
+    }
+    
+    int end = strlen(string) - 1;
+    while (end > start && is_whitespace(string[end])) {
+        end--;
+    }
+    
+    // shift
+    if (start > 0) {
+        shift(string, start, end);
+    } else {
+        string[end + 1] = '\0';
+    }
+    
+    return string;
+}
+
+/**
+* Provides the trimmed string as COPY of the source string.
+* Trimming means that leading and trailing whitespace 
+* characters are removed.
+*
+* Whitespace characters are:
+* - space (' '),
+* - tabulator ('\t')
+* - new line ('\n')
+* - line feed ('\r')
+* @param string The string to be trimmed.
+* @param trimmed_string Container which takes the trimmed
+* version of source. This function expects a buffer that
+* is large enough for carrying the trimmed string.
+*/
+void trim_cpy(char* string, char* trimmed_string) {
+    if (string == 0 || trimmed_string == 0) {
+        return;
+    }
+
+    if (strlen(string) == 0) {
+        trimmed_string[0] = '\0';
+        return;
+    }
+
+    override_all(trimmed_string);
+    trimmed_string = strncpy(trimmed_string, string, strlen(string));
+    trimmed_string = trim(trimmed_string);
+}

trim_str.c

@@ -2,7 +2,7 @@
  *				HTBLA-Leonding
  * ---------------------------------------------------------
  * Title:			Trim String
- * Author:		*/<your name>;/*
+ * Author:		Marc Tismonar
  * ----------------------------------------------------------
  * Description:
  * Application entry point for 'trim'.