1 files changed, 41 insertions, 0 deletions
diff --git a/src/lib/istream-sized.h b/src/lib/istream-sized.h
new file mode 100644
index 0000000..7cbb6c6
--- /dev/null
+++ b/src/lib/istream-sized.h
@@ -0,0 +1,41 @@
+#ifndef ISTREAM_SIZED_H
+#define ISTREAM_SIZED_H
+
+struct istream_sized_error_data {
+	/* Stream's current v_offset */
+	uoff_t v_offset;
+	/* How many more bytes are being added within this read() */
+	size_t new_bytes;
+	/* What's the original wanted size. */
+	uoff_t wanted_size;
+	/* TRUE if we're at EOF now */
+	bool eof;
+};
+
+typedef const char *
+istream_sized_callback_t(const struct istream_sized_error_data *data,
+			 void *context);
+
+/* Assume that input stream is exactly the given size. If the stream is too
+   small, fail with stream_errno=EPIPE. If stream is too large, fail with
+   stream_errno=EINVAL. */
+struct istream *i_stream_create_sized(struct istream *input, uoff_t size);
+struct istream *i_stream_create_sized_range(struct istream *input,
+					    uoff_t offset, uoff_t size);
+/* Like i_stream_create_sized*(), but allow input stream's size to be larger. */
+struct istream *i_stream_create_min_sized(struct istream *input, uoff_t min_size);
+struct istream *i_stream_create_min_sized_range(struct istream *input,
+						uoff_t offset, uoff_t min_size);
+/* Same as i_stream_create_sized(), but set the error message via the
+   callback. */
+struct istream *
+i_stream_create_sized_with_callback(struct istream *input, uoff_t size,
+				    istream_sized_callback_t *error_callback,
+				    void *context);
+#define i_stream_create_sized_with_callback(input, size, error_callback, context) \
+	i_stream_create_sized_with_callback(input, size - \
+		CALLBACK_TYPECHECK(error_callback, \
+			const char *(*)(const struct istream_sized_error_data *, typeof(context))), \
+		(istream_sized_callback_t *)error_callback, context)
+
+#endif