On Sat, 17 Oct 2009 08:36:01 -0500
Anthony Liguori <aligu...@us.ibm.com> wrote:
> This allows qstring to be used for dynamic string construction.
>
> Signed-off-by: Anthony Liguori <aligu...@us.ibm.com>
> ---
> qstring.c | 37 ++++++++++++++++++++++++++++++++++++-
> qstring.h | 4 ++++
> 2 files changed, 40 insertions(+), 1 deletions(-)
>
> diff --git a/qstring.c b/qstring.c
> index 6d411da..441a9e6 100644
> --- a/qstring.c
> +++ b/qstring.c
> @@ -21,6 +21,16 @@ static const QType qstring_type = {
> };
>
> /**
> + * qstring_new(): Create a new empty QString
> + *
> + * Return strong reference.
> + */
> +QString *qstring_new(void)
> +{
> + return qstring_from_str("");
> +}
> +
> +/**
> * qstring_from_str(): Create a new QString from a regular C string
> *
> * Return strong reference.
> @@ -30,12 +40,37 @@ QString *qstring_from_str(const char *str)
> QString *qstring;
>
> qstring = qemu_malloc(sizeof(*qstring));
> - qstring->string = qemu_strdup(str);
> +
> + qstring->length = strlen(str);
> + qstring->capacity = qstring->length;
> +
> + qstring->string = qemu_malloc(qstring->capacity + 1);
> + memcpy(qstring->string, str, qstring->length);
> + qstring->string[qstring->length] = 0;
Couldn't this be:
qstring->string = qemu_strdup(str);
qstring->length = qstring->capacity = strlen(str);
> +
> QOBJECT_INIT(qstring, &qstring_type);
>
> return qstring;
> }
>
> +/* qstring_append(): Append a C string to a QString
> + */
Forgot the 'little roof' in the comment style. :-)
> +void qstring_append(QString *qstring, const char *str)
> +{
> + size_t len = strlen(str);
> +
> + if (qstring->capacity < (qstring->length + len)) {
> + qstring->capacity += len;
> + qstring->capacity *= 2; /* use exponential growth */
> +
> + qstring->string = qemu_realloc(qstring->string, qstring->capacity +
> 1);
> + }
Why do we need to double it? Wouldn't be enough to only keep track
of the current string length and add 'len' to it? We could drop
'capacity' then.
> +
> + memcpy(qstring->string + qstring->length, str, len);
> + qstring->length += len;
> + qstring->string[qstring->length] = 0;
I would use strcat().
> +}
> +
> /**
> * qobject_to_qstring(): Convert a QObject to a QString
> */
> diff --git a/qstring.h b/qstring.h
> index e012cb7..65905d4 100644
> --- a/qstring.h
> +++ b/qstring.h
> @@ -6,10 +6,14 @@
> typedef struct QString {
> QObject_HEAD;
> char *string;
> + size_t length;
> + size_t capacity;
> } QString;
>
> +QString *qstring_new(void);
> QString *qstring_from_str(const char *str);
> const char *qstring_get_str(const QString *qstring);
> +void qstring_append(QString *qstring, const char *str);
> QString *qobject_to_qstring(const QObject *obj);
>
> #endif /* QSTRING_H */
