From 19fff8444e7074f546a0af1133fc32829bc2bc1d Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Mon, 6 Apr 2020 11:58:35 +0200
Subject: [PATCH] shared/strbuf: add nm_str_buf_erase() helper

---
 shared/nm-glib-aux/nm-str-buf.h               | 38 +++++++++++++++++++
 .../nm-glib-aux/tests/test-shared-general.c   | 35 +++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/shared/nm-glib-aux/nm-str-buf.h b/shared/nm-glib-aux/nm-str-buf.h
index 83cf27562..fdf7e3aaf 100644
--- a/shared/nm-glib-aux/nm-str-buf.h
+++ b/shared/nm-glib-aux/nm-str-buf.h
@@ -119,6 +119,44 @@ nm_str_buf_set_size (NMStrBuf *strbuf,
 
 /*****************************************************************************/
 
+static inline void
+nm_str_buf_erase (NMStrBuf *strbuf,
+                  gsize pos,
+                  gssize len,
+                  gboolean honor_do_bzero_mem)
+{
+	gsize new_len;
+
+	_nm_str_buf_assert (strbuf);
+
+	nm_assert (pos <= strbuf->len);
+
+	if (len == 0)
+		return;
+
+	if (len < 0) {
+		/* truncate the string before pos */
+		nm_assert (len == -1);
+		new_len = pos;
+	} else {
+		gsize l = len;
+
+		nm_assert (l <= strbuf->len - pos);
+
+		new_len = strbuf->len - l;
+		if (pos + l < strbuf->len) {
+			memmove (&strbuf->_str[pos],
+			         &strbuf->_str[pos + l],
+			         strbuf->len - (pos + l));
+		}
+	}
+
+	nm_assert (new_len <= strbuf->len);
+	nm_str_buf_set_size (strbuf, new_len, honor_do_bzero_mem, TRUE);
+}
+
+/*****************************************************************************/
+
 static inline void
 nm_str_buf_append_c (NMStrBuf *strbuf,
                      char ch)
diff --git a/shared/nm-glib-aux/tests/test-shared-general.c b/shared/nm-glib-aux/tests/test-shared-general.c
index 61c6c4a4c..5c8bdf18e 100644
--- a/shared/nm-glib-aux/tests/test-shared-general.c
+++ b/shared/nm-glib-aux/tests/test-shared-general.c
@@ -9,6 +9,7 @@
 
 #include "nm-std-aux/unaligned.h"
 #include "nm-glib-aux/nm-random-utils.h"
+#include "nm-glib-aux/nm-str-buf.h"
 #include "nm-glib-aux/nm-time-utils.h"
 #include "nm-glib-aux/nm-ref-string.h"
 
@@ -737,6 +738,39 @@ test_nm_utils_get_next_realloc_size (void)
 
 /*****************************************************************************/
 
+static void
+test_nm_str_buf (void)
+{
+	guint i_run;
+
+	for (i_run = 0; TRUE; i_run++) {
+		nm_auto_str_buf NMStrBuf strbuf = { };
+		nm_auto_free_gstring GString *gstr = NULL;
+		int i, j, k;
+		int c;
+
+		nm_str_buf_init (&strbuf,
+		                 nmtst_get_rand_uint32 () % 200u + 1u,
+		                 nmtst_get_rand_bool ());
+
+		if (i_run < 1000) {
+			c = nmtst_get_rand_word_length (NULL);
+			for (i = 0; i < c; i++)
+				nm_str_buf_append_c (&strbuf, '0' + (i % 10));
+			gstr = g_string_new (nm_str_buf_get_str (&strbuf));
+			j = nmtst_get_rand_uint32 () % (strbuf.len + 1);
+			k = nmtst_get_rand_uint32 () % (strbuf.len - j + 2) - 1;
+
+			nm_str_buf_erase (&strbuf, j, k, nmtst_get_rand_bool ());
+			g_string_erase (gstr, j, k);
+			g_assert_cmpstr (gstr->str, ==, nm_str_buf_get_str (&strbuf));
+		} else
+			return;
+	}
+}
+
+/*****************************************************************************/
+
 NMTST_DEFINE ();
 
 int main (int argc, char **argv)
@@ -757,6 +791,7 @@ int main (int argc, char **argv)
 	g_test_add_func ("/general/test_nm_ref_string", test_nm_ref_string);
 	g_test_add_func ("/general/test_string_table_lookup", test_string_table_lookup);
 	g_test_add_func ("/general/test_nm_utils_get_next_realloc_size", test_nm_utils_get_next_realloc_size);
+	g_test_add_func ("/general/test_nm_str_buf", test_nm_str_buf);
 
 	return g_test_run ();
 }