Implemented string append function.

strings/strapp.c

@@ -0,0 +1,48 @@
+/**
+* C_lib Copyright (C) 2021 Wael Karram.
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, version 3 of the License.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/* This file contains the function implementation for string append. */
+/* Include guards + includes. */
+#ifndef STRAPP_C
+#define STRAPP_C
+/* Include statements. */
+#include "strapp.h"
+#endif /* STRAPP_C */
+
+/**
+* This function takes two strings and appends source to destination, resizing destination if needed.
+* Returns the destination address on success and NULL on failure.
+* Assumes the size of each buffer to be (length + 1L) * sizeof(char).
+* User should free the source strings.
+*/
+static inline char *strapp(char *restrict dest, const char *restrict src, const size_t dest_len, const size_t src_len) {
+	/* Sanity check. */
+	assert(src && src_len && ((!dest && !dest_len) || (dest && dest_len)));
+
+	/* Start by allocating the new array. */
+	char *result = calloc(dest_len + src_len + 1L, sizeof(char));
+	/* Check if the allocation failed. */
+	if (!result)
+		return NULL;
+
+	/* Copy the first string. */
+	strncpy(result, dest, dest_len);
+	/* Append the second string. */
+	strncat(result, src, src_len);
+
+	/* Return the buffer. */
+	return result;
+}

strings/strapp.h

@@ -0,0 +1,41 @@
+/**
+* C_lib Copyright (C) 2021 Wael Karram.
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, version 3 of the License.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/* This header file defines a strapp function, for general string appending. */
+/* Include guards + includes. */
+#ifndef STRAPP_H
+#define STRAPP_H
+/* Include string.h */
+#include <string.h>
+/* Include assert.h to allow code generation, but only run with debug flag. */
+#ifdef DEBUG
+#ifndef NDEBUG
+#define NDEBUG
+#endif	/* NDEBUG. */
+#endif	/* DEBUG. */
+#include <assert.h>
+
+/* Constants. */
+#define NULL_CHAR	'\0'
+
+
+/**
+* This function takes two strings and appends source to destination, resizing destination if needed.
+* Returns the destination address on success and NULL on failure.
+*/
+static inline char *strapp(char *restrict dest, const char *restrict src, const size_t dest_len, const size_t src_len);
+
+#endif /* STRAPP_H */