From: Stephan Bosch <stephan.bosch@dovecot.fi>
Date: Sun, 31 Mar 2019 11:18:04 +0000 (+0200)
Subject: lib: buffer - Add buffer_get_avail_size().
X-Git-Tag: 2.3.8~135
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=62f938265fd941e4f5556fcb7a0133ac57763ab0;p=thirdparty%2Fdovecot%2Fcore.git

lib: buffer - Add buffer_get_avail_size().

This determines how much data can be added to buffer.
---

diff --git a/src/lib/buffer.c b/src/lib/buffer.c
index 18ef955176..2f84f72cdc 100644
--- a/src/lib/buffer.c
+++ b/src/lib/buffer.c
@@ -345,6 +345,14 @@ size_t buffer_get_writable_size(const buffer_t *_buf)
 	return buf->alloc-1;
 }
 
+size_t buffer_get_avail_size(const buffer_t *_buf)
+{
+	const struct real_buffer *buf = (const struct real_buffer *)_buf;
+
+	i_assert(buf->alloc >= buf->used);
+	return ((buf->dynamic ? SIZE_MAX : buf->alloc) - buf->used);
+}
+
 bool buffer_cmp(const buffer_t *buf1, const buffer_t *buf2)
 {
 	if (buf1->used != buf2->used)
diff --git a/src/lib/buffer.h b/src/lib/buffer.h
index 7480f3128b..c8a0ea8f62 100644
--- a/src/lib/buffer.h
+++ b/src/lib/buffer.h
@@ -99,6 +99,9 @@ size_t buffer_get_size(const buffer_t *buf) ATTR_PURE;
    With dynamic buffers this is buffer_get_size()-1, because the extra 1 byte
    is reserved for str_c()'s NUL. */
 size_t buffer_get_writable_size(const buffer_t *buf) ATTR_PURE;
+/* Returns the maximum number of bytes we can append to the buffer. If the
+   buffer is dynamic, this is always near SIZE_MAX. */
+size_t buffer_get_avail_size(const buffer_t *buf) ATTR_PURE;
 
 /* Returns TRUE if buffer contents are identical. */
 bool buffer_cmp(const buffer_t *buf1, const buffer_t *buf2);