From ea89f59bebc6529e3270eebcc86825ee1eb7055e Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@meshlink.io>
Date: Sun, 18 Oct 2015 13:44:43 +0200
Subject: [PATCH] Allow putting data in a buffer at an arbitrary offset.
---
utcp.c | 38 +++++++++++++++++++++++++++++---------
1 file changed, 29 insertions(+), 9 deletions(-)
diff --git a/utcp.c b/utcp.c
index ce05690..e6f6cf9 100644
--- a/utcp.c
+++ b/utcp.c
@@ -130,16 +130,30 @@ static int32_t seqdiff(uint32_t a, uint32_t b) {
// TODO: convert to ringbuffers to avoid memmove() operations.
// Store data into the buffer
-static ssize_t buffer_put(struct buffer *buf, const void *data, size_t len) {
+static ssize_t buffer_put_at(struct buffer *buf, size_t offset, const void *data, size_t len) {
if(buf->maxsize <= buf->used)
return 0;
- if(len > buf->maxsize - buf->used)
- len = buf->maxsize - buf->used;
- if(len > buf->size - buf->used) {
+
+ debug("buffer_put_at %zu %zu %zu\n", buf->used, offset, len);
+
+ size_t required = offset + len;
+ if(required > buf->maxsize) {
+ if(offset >= buf->maxsize)
+ return 0;
+ abort();
+ len = buf->maxsize - offset;
+ required = buf->maxsize;
+ }
+
+ if(required > buf->size) {
size_t newsize = buf->size;
- do {
- newsize *= 2;
- } while(newsize < buf->used + len);
+ if(!newsize) {
+ newsize = required;
+ } else {
+ do {
+ newsize *= 2;
+ } while(newsize < buf->used + len);
+ }
if(newsize > buf->maxsize)
newsize = buf->maxsize;
char *newdata = realloc(buf->data, newsize);
@@ -148,11 +162,17 @@ static ssize_t buffer_put(struct buffer *buf, const void *data, size_t len) {
buf->data = newdata;
buf->size = newsize;
}
- memcpy(buf->data + buf->used, data, len);
- buf->used += len;
+
+ memcpy(buf->data + offset, data, len);
+ if(required > buf->used)
+ buf->used = required;
return len;
}
+static ssize_t buffer_put(struct buffer *buf, const void *data, size_t len) {
+ return buffer_put_at(buf, buf->used, data, len);
+}
+
// Get data from the buffer. data can be NULL.
static ssize_t buffer_get(struct buffer *buf, void *data, size_t len) {
if(len > buf->used)
--
2.39.5