It can be used to fill caller-specified buffer with data already in
ustream read buffer. Useful in the following use pattern.
int available = ustream_pending_data(s, false);
if (available >= sizeof(struct msghdr)) {
struct msghdr h;
ustream_read(s, &h, sizeof(h));
}
Signed-off-by: Yousong Zhou <[email protected]>
---
ustream.c | 20 ++++++++++++++++++++
ustream.h | 5 +++++
2 files changed, 25 insertions(+)
diff --git a/ustream.c b/ustream.c
index 828a025..fc93bc2 100644
--- a/ustream.c
+++ b/ustream.c
@@ -333,6 +333,26 @@ char *ustream_get_read_buf(struct ustream *s, int *buflen)
return data;
}
+int ustream_read(struct ustream *s, char *buf, int buflen)
+{
+ char *chunk;
+ int chunk_len;
+ int len = 0;
+
+ do {
+ chunk = ustream_get_read_buf(s, &chunk_len);
+ if (!chunk)
+ break;
+ if (chunk_len > buflen - len)
+ chunk_len = buflen - len;
+ memcpy(buf + len, chunk, chunk_len);
+ ustream_consume(s, chunk_len);
+ len += chunk_len;
+ } while (len < buflen);
+
+ return len;
+}
+
static void ustream_write_error(struct ustream *s)
{
if (!s->write_error)
diff --git a/ustream.h b/ustream.h
index 6431744..53e0828 100644
--- a/ustream.h
+++ b/ustream.h
@@ -143,6 +143,11 @@ void ustream_free(struct ustream *s);
/* ustream_consume: remove data from the head of the read buffer */
void ustream_consume(struct ustream *s, int len);
+/*
+ * ustream_read: read and consume data in read buffer into caller-specified
+ * area. Return length of data read.
+ */
+int ustream_read(struct ustream *s, char *buf, int buflen);
/* ustream_write: add data to the write buffer */
int ustream_write(struct ustream *s, const char *buf, int len, bool more);
int ustream_printf(struct ustream *s, const char *format, ...);
--
2.2.1
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