[PATCH 1/2] CLEANUP/MINOR: sample: factor out common code for setting buffer

[astrothayne]

From: Thayne McCombs <astrotha...@gmail.com>

A couple of functions in sample.c have almost identical code for
updating the samples string buffer. This adds a new helper function to
do this and uses it in both places.
---
 include/haproxy/buf.h | 22 ++++++++++++++++++++++
 src/sample.c          | 29 ++---------------------------
 2 files changed, 24 insertions(+), 27 deletions(-)

diff --git a/include/haproxy/buf.h b/include/haproxy/buf.h
index 4ea4b73f1..303635c39 100644
--- a/include/haproxy/buf.h
+++ b/include/haproxy/buf.h
@@ -940,6 +940,28 @@ static inline int b_peek_varint(struct buffer *b, size_t 
ofs, uint64_t *vptr)
        return size;
 }
 
+/*
+ * b_set_area_sub(): Replace the current buffer with a sub-slice of the
+ * current buffer. Sets <area> to <new_area>, <data> to <new_data>, and
+ * <size> to the new size accounting for the change to area. The range from
+ * <new_area> to <new_area + new_data> must be within the range of the current 
buffer.
+ */
+static inline void b_set_area_sub(struct buffer *b, char *new_area, size_t 
new_data)
+{
+       BUG_ON_HOT(new_area < b->area);
+       BUG_ON_HOT(new_area + new_data > b->area + b->data);
+
+       b->data = new_data;
+       /* If buffer is len 0, no need to
+           change pointers or to update size */
+       if (!new_data)
+               return;
+       /* Compute remaining size if needed */
+       if (b->size)
+               b->size -= new_area - b->area;
+       b-> area = new_area;
+}
+
 
 /*
  * Buffer ring management.
diff --git a/src/sample.c b/src/sample.c
index 50ae76b6e..237b88056 100644
--- a/src/sample.c
+++ b/src/sample.c
@@ -2490,19 +2490,7 @@ static int sample_conv_field(const struct arg *arg_p, 
struct sample *smp, void *
                return 0;
        }
 found:
-       smp->data.u.str.data = end - start;
-       /* If ret string is len 0, no need to
-           change pointers or to update size */
-       if (!smp->data.u.str.data)
-               return 1;
-
-       /* Compute remaining size if needed
-           Note: smp->data.u.str.size cannot be set to 0 */
-       if (smp->data.u.str.size)
-               smp->data.u.str.size -= start - smp->data.u.str.area;
-
-       smp->data.u.str.area = start;
-
+       b_set_area_sub(&(smp->data.u.str), start, end - start);
        return 1;
 }
 
@@ -2590,20 +2578,7 @@ static int sample_conv_word(const struct arg *arg_p, 
struct sample *smp, void *p
                return 1;
        }
 found:
-       smp->data.u.str.data = end - start;
-       /* If ret string is len 0, no need to
-           change pointers or to update size */
-       if (!smp->data.u.str.data)
-               return 1;
-
-
-       /* Compute remaining size if needed
-           Note: smp->data.u.str.size cannot be set to 0 */
-       if (smp->data.u.str.size)
-               smp->data.u.str.size -= start - smp->data.u.str.area;
-
-       smp->data.u.str.area = start;
-
+       b_set_area_sub(&(smp->data.u.str), start, end - start);
        return 1;
 }
 
-- 
2.36.1