#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <glib.h>

#if 0
/* old */
static void
replace_all(GString *haystack,
            const gchar *needle,
            const gchar *replacement)
{
  gchar *ptr;
  gsize needle_len = strlen(needle);

  /* For each occurrence of needle in haystack */
  while ((ptr = strstr(haystack->str, needle)) != NULL) {
    goffset offset = ptr - haystack->str;
    g_string_erase(haystack, offset, needle_len);
    g_string_insert(haystack, offset, replacement);
  }
}
#else
/* new */
static void
replace_all(GString *haystack,
            const gchar *needle,
            const gchar *replacement)
{
  gchar *ptr;
  gsize needle_len = strlen(needle);
  gsize replacement_len = strlen(replacement);
  goffset offset = 0;

  /* For each occurrence of needle in haystack */
  while ((ptr = strstr(haystack->str + offset, needle)) != NULL) {
    offset = ptr - haystack->str;
    g_string_erase(haystack, offset, needle_len);
    g_string_insert(haystack, offset, replacement);
    offset += replacement_len;
  }
}
#endif

int main(void)
{
#define TEST_REPLACE_ALL(hs, s, r, ex)        \
  G_STMT_START {                              \
    GString *haystack_ = g_string_new(hs);    \
    replace_all(haystack_, s, r);             \
    g_assert_cmpstr(haystack_->str, ==, ex);  \
    g_string_free(haystack_, TRUE);           \
  } G_STMT_END

  TEST_REPLACE_ALL("hello", "a", "b", "hello");
  TEST_REPLACE_ALL("hallo", "a", "b", "hbllo");
  TEST_REPLACE_ALL("foobarbaz", "ba", "BA", "fooBArBAz");
  TEST_REPLACE_ALL("ababab", "ba", "BA", "aBABAb");
  TEST_REPLACE_ALL("ababab", "ab", "AB", "ABABAB");
  TEST_REPLACE_ALL("foobarbaz", "o", "oo", "foooobarbaz");

#undef TEST_REPLACE_ALL

  return 0;
}