109 lines
No EOL
2.7 KiB
C
109 lines
No EOL
2.7 KiB
C
/*----------------------------------------------------------
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* HTBLA-Leonding
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* ---------------------------------------------------------
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* Title: Trim String
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* Author: Marc Tismonar
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* ----------------------------------------------------------
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* Description:
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* Implementation of 'trim' functionality.
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* ----------------------------------------------------------
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*/
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#include <stdio.h>
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#include <stdbool.h>
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#include <string.h>
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#include "trim.h"
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// private functions
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bool is_whitespace(char c) {
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return c == ' ' || c == '\t' || c == '\n' || c == '\r';
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}
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void shift(char* string, int start, int end) {
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int i;
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for (i = 0; i <= end - start; i++) {
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string[i] = string[i + start];
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}
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string[i] = '\0';
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}
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void override_all(char* string) {
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for (int i = 0; i < strlen(string); i++) {
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string[i] = ' ';
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}
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}
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/**
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* Provides the trimmed string WITHOUT making a copy
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* of the source string.
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* Trimming means that leading and trailing whitespace
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* characters are removed.
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*
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* Whitespace characters are:
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* - space (' '),
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* - tabulator ('\t')
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* - new line ('\n')
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* - line feed ('\r')
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* @param string The string to be trimmed.
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* @return The trimmed string.
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*/
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char* trim(char* string) {
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if (string == 0) {
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return 0;
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}
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int start = 0;
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while (string[start] != '\0' && is_whitespace(string[start])) {
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start++;
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}
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// if empty or only whitespace
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if (string[start] == '\0') {
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string[0] = '\0';
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return string;
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}
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int end = strlen(string) - 1;
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while (end > start && is_whitespace(string[end])) {
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end--;
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}
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// shift
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if (start > 0) {
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shift(string, start, end);
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} else {
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string[end + 1] = '\0';
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}
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return string;
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}
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/**
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* Provides the trimmed string as COPY of the source string.
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* Trimming means that leading and trailing whitespace
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* characters are removed.
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*
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* Whitespace characters are:
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* - space (' '),
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* - tabulator ('\t')
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* - new line ('\n')
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* - line feed ('\r')
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* @param string The string to be trimmed.
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* @param trimmed_string Container which takes the trimmed
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* version of source. This function expects a buffer that
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* is large enough for carrying the trimmed string.
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*/
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void trim_cpy(char* string, char* trimmed_string) {
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if (string == 0 || trimmed_string == 0) {
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return;
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}
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if (strlen(string) == 0) {
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trimmed_string[0] = '\0';
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return;
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}
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override_all(trimmed_string);
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trimmed_string = strncpy(trimmed_string, string, strlen(string));
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trimmed_string = trim(trimmed_string);
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} |