QString: Introduce qstring_from_substr()

Note that we can now write qstring_from_str() as a wrapper.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

2 files changed, 16 insertions, 5 deletions

diff --git a/qstring.c b/qstring.c
index ad17769..740a106 100644
--- a/qstring.c
+++ b/qstring.c
@@ -31,21 +31,21 @@ QString *qstring_new(void)
 }
 
 /**
- * qstring_from_str(): Create a new QString from a regular C string
+ * qstring_from_substr(): Create a new QString from a C string substring
  *
- * Return strong reference.
+ * Return string reference
  */
-QString *qstring_from_str(const char *str)
+QString *qstring_from_substr(const char *str, int start, int end)
 {
     QString *qstring;
 
     qstring = qemu_malloc(sizeof(*qstring));
 
-    qstring->length = strlen(str);
+    qstring->length = end - start + 1;
     qstring->capacity = qstring->length;
 
     qstring->string = qemu_malloc(qstring->capacity + 1);
-    memcpy(qstring->string, str, qstring->length);
+    memcpy(qstring->string, str + start, qstring->length);
     qstring->string[qstring->length] = 0;
 
     QOBJECT_INIT(qstring, &qstring_type);
@@ -53,6 +53,16 @@ QString *qstring_from_str(const char *str)
     return qstring;
 }
 
+/**
+ * qstring_from_str(): Create a new QString from a regular C string
+ *
+ * Return strong reference.
+ */
+QString *qstring_from_str(const char *str)
+{
+    return qstring_from_substr(str, 0, strlen(str) - 1);
+}
+
 static void capacity_increase(QString *qstring, size_t len)
 {
     if (qstring->capacity < (qstring->length + len)) {
diff --git a/qstring.h b/qstring.h
index c065331..6aaa7d5 100644
--- a/qstring.h
+++ b/qstring.h
@@ -13,6 +13,7 @@ typedef struct QString {
 
 QString *qstring_new(void);
 QString *qstring_from_str(const char *str);
+QString *qstring_from_substr(const char *str, int start, int end);
 const char *qstring_get_str(const QString *qstring);
 void qstring_append_int(QString *qstring, int64_t value);
 void qstring_append(QString *qstring, const char *str);