[v2,01/12] malloc: Add specialized dynarray for C strings

diff --git a/malloc/Makefile b/malloc/Makefile
index 17873e6..1b0b5c5 100644
--- a/malloc/Makefile
+++ b/malloc/Makefile
@@ -50,6 +50,7 @@  tests-internal += \
 	 tst-dynarray \
 	 tst-dynarray-fail \
 	 tst-dynarray-at-fail \
+	 tst-char_array
 
 ifneq (no,$(have-tunables))
 tests += tst-malloc-usable-tunables
@@ -62,7 +63,7 @@  test-srcs = tst-mtrace
 routines = malloc morecore mcheck mtrace obstack reallocarray \
   scratch_buffer_grow scratch_buffer_grow_preserve \
   scratch_buffer_set_array_size \
-  dynarray_at_failure \
+  dynarray_at_failure dynarray_overflow_failure \
   dynarray_emplace_enlarge \
   dynarray_finalize \
   dynarray_resize \
@@ -72,6 +73,7 @@  routines = malloc morecore mcheck mtrace obstack reallocarray \
   alloc_buffer_copy_bytes  \
   alloc_buffer_copy_string \
   alloc_buffer_create_failure \
+  char_array-impl
 
 install-lib := libmcheck.a
 non-lib.a := libmcheck.a
diff --git a/malloc/Versions b/malloc/Versions
index 2357cff..b21fe59 100644
--- a/malloc/Versions
+++ b/malloc/Versions
@@ -81,6 +81,7 @@  libc {
 
     # dynarray support
     __libc_dynarray_at_failure;
+    __libc_dynarray_overflow_failure;
     __libc_dynarray_emplace_enlarge;
     __libc_dynarray_finalize;
     __libc_dynarray_resize;
@@ -92,5 +93,11 @@  libc {
     __libc_alloc_buffer_copy_bytes;
     __libc_alloc_buffer_copy_string;
     __libc_alloc_buffer_create_failure;
+
+    # char_array support
+    __char_array_set_str_size;
+    __char_array_erase;
+    __char_array_prepend_str_size;
+    __char_array_replace_str_pos;
   }
 }
diff --git a/malloc/char_array-impl.c b/malloc/char_array-impl.c
new file mode 100644
index 0000000..3aef1f7
--- /dev/null
+++ b/malloc/char_array-impl.c
@@ -0,0 +1,57 @@ 
+/* Specialized dynarray for C strings.  Implementation file.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <malloc/char_array.h>
+
+void
+__char_array_set_str_size (struct dynarray_header *header, const char *str,
+			   size_t size)
+{
+  *((char *) mempcpy (header->array, str, size)) = '\0';
+  header->used = size + 1;
+}
+libc_hidden_def (__char_array_set_str_size)
+
+void
+__char_array_erase (struct dynarray_header *header, size_t pos)
+{
+  char *ppos = header->array + pos;
+  char *lpos = header->array + header->used;
+  ptrdiff_t size = lpos - ppos;
+  memmove (ppos, ppos + 1, size);
+  header->used--;
+}
+libc_hidden_def (__char_array_erase)
+
+void
+__char_array_prepend_str_size (struct dynarray_header *header,
+			       const char *str, size_t size, size_t used)
+{
+  memmove (header->array + size, header->array, used);
+  memcpy (header->array, str, size);
+}
+libc_hidden_def (__char_array_prepend_str_size)
+
+void
+__char_array_replace_str_pos (struct dynarray_header *header, size_t pos,
+			      const char *str, size_t len)
+{
+  char *start = header->array + pos;
+  *(char *) mempcpy (start, str, len) = '\0';
+}
+libc_hidden_def (__char_array_replace_str_pos)
diff --git a/malloc/char_array-skeleton.c b/malloc/char_array-skeleton.c
new file mode 100644
index 0000000..4d9e4c0
--- /dev/null
+++ b/malloc/char_array-skeleton.c
@@ -0,0 +1,288 @@ 
+/* Specialized dynarray for C strings.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* This file provides a dynamic C string with an initial stack allocated
+   buffer.  Since it is based on dynarray, it provides dynamic size
+   expansion and heap usage for large strings.
+
+   The following parameters are optional:
+
+   CHAR_ARRAY_INITIAL_SIZE
+      The size of the statically allocated array (default is 256).  It will
+      be used to define DYNARRAY_INITIAL_SIZE.
+
+   The following functions are provided:
+
+   bool char_array_init_empty (struct char_array *);
+   bool char_array_init_str (struct char_array *, const char *);
+   bool char_array_init_str_size (struct char_array *, const char *, size_t);
+   bool char_array_is_empty (struct char_array *);
+   const char *char_array_str (struct char_array *);
+   char char_array_pos (struct char_array *, size_t);
+   size_t char_array_length (struct char_array *);
+   bool char_array_set_str (struct char_array *, const char *);
+   bool char_array_set_str_size (struct char_array *, const char *, size_t);
+   void char_array_erase (struct char_array *, size_t);
+   bool char_array_crop (struct char_array *, size_t);
+   bool char_array_prepend_str (struct char_array *, const char *);
+   bool char_array_append_str (struct char_array *, const char *);
+   bool char_array_append_char (struct char_array *array, char c);
+   bool char_array_replace_str_pos (struct char_array *, size_t, const char *,
+				    size_t);
+
+   For instance:
+
+   struct char_array str;
+
+   // str == "testing"
+   char_array_init_str (&str, "testing");
+
+   // c == 's'
+   char c = char_array_pos (&str, 2);
+
+   // str = "testing2"
+   char_array_set_str (&str, "testing2");
+
+   // str = "testig2"
+   char_array_erase (&str, 5);
+
+   // str = "123testig2";
+   char_array_prepend_str (&str, "123");
+
+   // len = 10;
+   size_t len = char_array_length (&str);
+
+   // str = "123testig2456";
+   char_array_append_str (&str, "456");
+
+   // str = "123test789";
+   char_array_replace_str_pos (&str, 7, "789", 3);
+ */
+
+#define DYNARRAY_STRUCT            char_array
+#define DYNARRAY_ELEMENT           char
+#define DYNARRAY_PREFIX            char_array_
+#ifndef CHAR_ARRAY_INITIAL_SIZE
+# define CHAR_ARRAY_INITIAL_SIZE 256
+#endif
+#define DYNARRAY_INITIAL_SIZE  CHAR_ARRAY_INITIAL_SIZE
+#include <malloc/dynarray-skeleton.c>
+
+#include <malloc/malloc-internal.h>
+#include <malloc/char_array.h>
+
+/* Return a const char for the internal C string handled by 'array'.  */
+__attribute__ ((unused, nonnull (1)))
+static const char *
+char_array_str (const struct char_array *array)
+{
+  return array->dynarray_header.array;
+}
+
+/* Return the character at position 'pos' from the char_array 'array'.  */
+__attribute__ ((unused, nonnull (1)))
+static char
+char_array_pos (struct char_array *array, size_t pos)
+{
+  return *char_array_at (array, pos);
+}
+
+/* Calculate the length of the string, excluding the terminating null.  */
+__attribute__ ((unused, nonnull (1)))
+static size_t
+char_array_length (const struct char_array *array)
+{
+  /* Exclude the final '\0'.  */
+  return array->dynarray_header.used - 1;
+}
+
+/* Copy up 'size' bytes from string 'str' to char_array 'array'.  A final
+   '\0' is appended in the char_array.  */
+__attribute__ ((unused, nonnull (1, 2)))
+static bool
+char_array_set_str_size (struct char_array *array, const char *str,
+			 size_t size)
+{
+  size_t newsize;
+  if (check_add_overflow_size_t (size, 1, &newsize))
+    __libc_dynarray_overflow_failure (size, 1);
+
+  if (!char_array_resize (array, newsize))
+    return false;
+
+  __char_array_set_str_size (&array->dynarray_abstract, str, size);
+  return true;
+}
+
+/* Copy the contents of string 'str' to char_array 'array', including the
+   final '\0'.  */
+__attribute__ ((unused, nonnull (1, 2)))
+static bool
+char_array_set_str (struct char_array *array, const char *str)
+{
+  return char_array_set_str_size (array, str, strlen (str));
+}
+
+__attribute__ ((unused, nonnull (1, 2)))
+static bool
+char_array_set_array (struct char_array *array, const struct char_array *orig)
+{
+  return char_array_set_str_size (array, char_array_str (orig),
+				  char_array_length (orig));
+}
+
+/* Initialize the char_array 'array' and sets it to an empty string ("").  */
+__attribute__ ((unused, nonnull (1)))
+static bool
+char_array_init_empty (struct char_array *array)
+{
+  char_array_init (array);
+  return char_array_set_str (array, "");
+}
+
+/* Initialize the char_array 'array' and copy the content of string 'str'.  */
+__attribute__ ((unused, nonnull (1, 2)))
+static bool
+char_array_init_str (struct char_array *array, const char *str)
+{
+  char_array_init (array);
+  return char_array_set_str (array, str);
+}
+
+/* Initialize the char_array 'array' and copy the content of string 'str'
+   up to 'size' characteres.  */
+__attribute__ ((unused, nonnull (1, 2)))
+static bool
+char_array_init_str_size (struct char_array *array, const char *str,
+			  size_t size)
+{
+  char_array_init (array);
+  return char_array_set_str_size (array, str, size);
+}
+
+/* Return if the char_array contain any characteres.  */
+__attribute__ ((unused, nonnull (1)))
+static bool
+char_array_is_empty (struct char_array *array)
+{
+  return *char_array_begin (array) == '\0';
+}
+
+/* Remove the byte at position 'pos' from char_array 'array'.  The contents
+   are moved internally if the position is not at the end of the internal
+   buffer.  */
+__attribute__ ((unused, nonnull (1)))
+static bool
+char_array_erase (struct char_array *array, size_t pos)
+{
+  if (pos >= array->dynarray_header.used - 1)
+    return false;
+
+  __char_array_erase (&array->dynarray_abstract, pos);
+  return true;
+}
+
+/* Resize the char_array 'array' to size 'count' maintaining the ending
+   '\0' byte.  */
+__attribute__ ((unused, nonnull (1)))
+static bool
+char_array_crop (struct char_array *array, size_t size)
+{
+  if (size >= (array->dynarray_header.used - 1)
+      || !char_array_resize (array, size + 1))
+    return false;
+
+  array->dynarray_header.array[size] = '\0';
+  return true;
+}
+
+/* Prepend the contents of string 'str' to char_array 'array', including the
+   final '\0' byte.  */
+__attribute__ ((unused, nonnull (1, 2)))
+static bool
+char_array_prepend_str (struct char_array *array, const char *str)
+{
+  size_t size = strlen (str);
+  /* Resizing the array might change its used elements and we need below
+     to correct copy the elements.  */
+  size_t used = array->dynarray_header.used;
+
+  size_t newsize;
+  if (check_add_overflow_size_t (used, size, &newsize))
+    __libc_dynarray_overflow_failure (used, size);
+
+  /* Make room for the string and copy it.  */
+  if (!char_array_resize (array, newsize))
+    return false;
+  __char_array_prepend_str_size (&array->dynarray_abstract, str, size, used);
+  return true;
+}
+
+/* Append the contents of string 'str' to char_array 'array, including the
+   final '\0' byte.  */
+__attribute__ ((unused, nonnull (1, 2)))
+static bool
+char_array_append_str (struct char_array *array, const char *str)
+{
+  size_t size = strlen (str);
+  /* Resizing the array might change its used elements and it used it below
+     to correct copy the elements.  */
+  size_t used = array->dynarray_header.used - 1;
+
+  /* 'used' does account for final '\0', so there is no need to add
+     an extra element to calculate the final required size.  */
+  size_t newsize;
+  if (check_add_overflow_size_t (used + 1, size, &newsize))
+    __libc_dynarray_overflow_failure (used + 1, size);
+
+  if (!char_array_resize (array, newsize))
+    return false;
+
+  /* Start to append at '\0' up to string length and add a final '\0'.  */
+  *(char*) mempcpy (array->dynarray_header.array + used, str, size) = '\0';
+  return true;
+}
+
+/* Append the character 'c' on char_array 'array'.  */
+__attribute__ ((unused, nonnull (1)))
+static bool
+char_array_append_char (struct char_array *array, char c)
+{
+  return char_array_append_str (array, (const char[]) { c, '\0' });
+}
+
+/* Replace the contents starting of position 'pos' of char_array 'array'
+   with the contents of string 'str' up to 'len' bytes.  A final '\0'
+   is appended in the string.  */
+__attribute__ ((unused, nonnull (1, 3)))
+static bool
+char_array_replace_str_pos (struct char_array *array, size_t pos,
+                            const char *str, size_t len)
+{
+  if (pos > array->dynarray_header.used)
+    __libc_dynarray_at_failure (array->dynarray_header.used, pos);
+
+  size_t newsize;
+  if (check_add_overflow_size_t (pos, len, &newsize)
+      || check_add_overflow_size_t (newsize, 1, &newsize)
+      || !char_array_resize (array, newsize))
+    return false;
+
+  __char_array_replace_str_pos (&array->dynarray_abstract, pos, str, len);
+  return true;
+}
diff --git a/malloc/char_array.h b/malloc/char_array.h
new file mode 100644
index 0000000..93df0d9
--- /dev/null
+++ b/malloc/char_array.h
@@ -0,0 +1,53 @@ 
+/* Specialized dynarray for C strings.  Shared definitions.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _CHAR_ARRAY_H
+#define _CHAR_ARRAY_H
+
+#include <malloc/dynarray.h>
+
+/* Internal funciton.  Set the dynarray to the content of the string STR up
+   to SIZE bytes.  The dynarray must be resized previously.  */
+void __char_array_set_str_size (struct dynarray_header *, const char *str,
+				size_t size);
+
+/* Internal function.  Remove the character at position POS from dynarray.
+   The position must be a valid one.  */
+void __char_array_erase (struct dynarray_header *, size_t pos);
+
+/* Internal function.  Prepend the content of string STR up to SIZE bytes to
+   dynarray by moving USED bytes forward.  The dynarray must be resized
+   previously.  */
+void __char_array_prepend_str_size (struct dynarray_header *,
+				    const char *str, size_t size,
+				    size_t used);
+
+/* Internal function.  Replace the content of dynarray starting at position
+   POS with the content of string STR up to LEN bytes.  The dynarray must
+   be resize previously and STR must contain at least LEN bytes.  */
+void __char_array_replace_str_pos (struct dynarray_header *, size_t pos,
+				   const char *str, size_t len);
+
+#ifndef _ISOMAC
+libc_hidden_proto (__char_array_set_str_size)
+libc_hidden_proto (__char_array_erase)
+libc_hidden_proto (__char_array_prepend_str_size)
+libc_hidden_proto (__char_array_replace_str_pos)
+#endif
+
+#endif
diff --git a/malloc/dynarray.h b/malloc/dynarray.h
index 0b171da..fd8d218 100644
--- a/malloc/dynarray.h
+++ b/malloc/dynarray.h
@@ -168,12 +168,21 @@  bool __libc_dynarray_finalize (struct dynarray_header *list, void *scratch,
 void __libc_dynarray_at_failure (size_t size, size_t index)
   __attribute__ ((noreturn));
 
+/* Internal function.  Terminate the process after an overflow in
+   new size allocation.  SIZE is the current number of elements in
+   dynamic array and INCR is the new elements to add on current
+   size.  */
+void __libc_dynarray_overflow_failure (size_t size, size_t incr)
+  __attribute__ ((noreturn));
+
 #ifndef _ISOMAC
 libc_hidden_proto (__libc_dynarray_emplace_enlarge)
 libc_hidden_proto (__libc_dynarray_resize)
 libc_hidden_proto (__libc_dynarray_resize_clear)
 libc_hidden_proto (__libc_dynarray_finalize)
 libc_hidden_proto (__libc_dynarray_at_failure)
+libc_hidden_proto (__libc_dynarray_overflow_failure)
+
 #endif
 
 #endif /* _DYNARRAY_H */
diff --git a/malloc/dynarray_overflow_failure.c b/malloc/dynarray_overflow_failure.c
new file mode 100644
index 0000000..2bcef25
--- /dev/null
+++ b/malloc/dynarray_overflow_failure.c
@@ -0,0 +1,31 @@ 
+/* Report an dynamic array size overflow condition.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <dynarray.h>
+#include <stdio.h>
+
+void
+__libc_dynarray_overflow_failure (size_t size, size_t incr)
+{
+  char buf[200];
+  __snprintf (buf, sizeof (buf), "Fatal glibc error: "
+              "new size overflows (old %zu and increment %zu)\n",
+              size, incr);
+ __libc_fatal (buf);
+}
+libc_hidden_def (__libc_dynarray_overflow_failure)
diff --git a/malloc/malloc-internal.h b/malloc/malloc-internal.h
index ad05450..352db0bf 100644
--- a/malloc/malloc-internal.h
+++ b/malloc/malloc-internal.h
@@ -91,4 +91,18 @@  check_mul_overflow_size_t (size_t left, size_t right, size_t *result)
 #endif
 }
 
+/* Set *R = A + B.  Return true if the answer is mathematically incorrect due
+   to overflow; in this case, *R is the low order bits of the correct
+   answer.  */
+static inline bool
+check_add_overflow_size_t (size_t a, size_t b, size_t *r)
+{
+#if __GNUC__ >= 5
+  return __builtin_add_overflow (a, b, r);
+#else
+  *r = a + b;
+  return *r < a;
+#endif
+}
+
 #endif /* _MALLOC_INTERNAL_H */
diff --git a/malloc/tst-char_array.c b/malloc/tst-char_array.c
new file mode 100644
index 0000000..745ecf4
--- /dev/null
+++ b/malloc/tst-char_array.c
@@ -0,0 +1,112 @@ 
+/* Test for char_array.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <string.h>
+
+#include <malloc/char_array-skeleton.c>
+
+#include <malloc.h>
+#include <mcheck.h>
+#include <stdint.h>
+#include <support/check.h>
+#include <support/support.h>
+
+static int
+do_test (void)
+{
+  mtrace ();
+
+  {
+    struct char_array str;
+    TEST_VERIFY_EXIT (char_array_init_empty (&str) == true);
+    TEST_VERIFY_EXIT (char_array_length (&str) == 0);
+    TEST_VERIFY_EXIT (char_array_is_empty (&str) == true);
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "") == 0);
+    char_array_free (&str);
+  }
+
+  {
+    struct char_array str;
+    TEST_VERIFY_EXIT (char_array_init_str (&str, "testing"));
+    TEST_VERIFY_EXIT (char_array_length (&str) == strlen ("testing"));
+    TEST_VERIFY_EXIT (char_array_pos (&str, 2) == 's');
+    TEST_VERIFY_EXIT (char_array_is_empty (&str) == false);
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "testing") == 0);
+    char_array_free (&str);
+  }
+
+  {
+    struct char_array str;
+    TEST_VERIFY_EXIT (char_array_init_str_size (&str, "testing", 4));
+    TEST_VERIFY_EXIT (char_array_length (&str) == 4);
+    TEST_VERIFY_EXIT (char_array_pos (&str, 2) == 's');
+    TEST_VERIFY_EXIT (char_array_is_empty (&str) == false);
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "test") == 0);
+    char_array_free (&str);
+  }
+
+  {
+    struct char_array str;
+    TEST_VERIFY_EXIT (char_array_init_str (&str, "testing"));
+    TEST_VERIFY_EXIT (char_array_set_str (&str, "abcdef"));
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "abcdef") == 0);
+    TEST_VERIFY_EXIT (char_array_set_str_size (&str, "abcdef", 4));
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "abcd") == 0);
+    char_array_free (&str);
+  }
+
+  {
+    struct char_array str;
+    TEST_VERIFY_EXIT (char_array_init_str (&str, "testing"));
+    TEST_VERIFY_EXIT (char_array_erase (&str, 4) == true);
+    TEST_VERIFY_EXIT (char_array_length (&str) == strlen ("testing") - 1);
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "testng") == 0);
+    TEST_VERIFY_EXIT (char_array_erase (&str, char_array_length (&str))
+		      == false);
+    TEST_VERIFY_EXIT (char_array_length (&str) == strlen ("testing") - 1);
+    TEST_VERIFY_EXIT (char_array_erase (&str, char_array_length (&str) - 1)
+		      == true);
+    TEST_VERIFY_EXIT (char_array_length (&str) == strlen ("testing") - 2);
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "testn") == 0);
+    char_array_free (&str);
+  }
+
+  {
+    struct char_array str;
+    TEST_VERIFY_EXIT (char_array_init_str (&str, "test"));
+    TEST_VERIFY_EXIT (char_array_prepend_str (&str, "123"));
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "123test") == 0);
+    TEST_VERIFY_EXIT (char_array_length (&str) == strlen ("123test"));
+    TEST_VERIFY_EXIT (char_array_append_str (&str, "456"));
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "123test456") == 0);
+    TEST_VERIFY_EXIT (char_array_length (&str) == strlen ("123test456"));
+    TEST_VERIFY_EXIT (char_array_replace_str_pos (&str, 7, "789", 3));
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "123test789") == 0);
+    TEST_VERIFY_EXIT (char_array_length (&str) == strlen ("123test789"));
+    TEST_VERIFY_EXIT (char_array_crop (&str, 7));
+    TEST_VERIFY_EXIT (char_array_length (&str) == 7);
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "123test") == 0);
+    TEST_VERIFY_EXIT (char_array_append_char (&str, '4'));
+    TEST_VERIFY_EXIT (strcmp (char_array_str (&str), "123test4") == 0);
+    char_array_free (&str);
+  }
+
+  return 0;
+}
+
+#include <support/test-driver.c>