output_buffer: only realloc once, and memset just what we need

[fio.git] / lib / output_buffer.c

diff --git a/lib/output_buffer.c b/lib/output_buffer.c
index 7a8d792f26294c1afc956ba57dfa7acca2a4769a..c1fdfc95f610aca10ece35ebdc2dac437c01af66 100644 (file)
--- a/lib/output_buffer.c
+++ b/lib/output_buffer.c
@@ -4,15 +4,15 @@
 
 #include "output_buffer.h"
 #include "../log.h"
+#include "../minmax.h"
 
 #define BUF_INC        1024
 
-void buf_output_init(struct buf_output *out, int index)
+void buf_output_init(struct buf_output *out)
 {
-       out->max_buflen = BUF_INC;
-       out->buf = malloc(out->max_buflen);
-       memset(out->buf, 0, out->max_buflen);
+       out->max_buflen = 0;
        out->buflen = 0;
+       out->buf = NULL;
 }
 
 void buf_output_free(struct buf_output *out)
@@ -20,25 +20,36 @@ void buf_output_free(struct buf_output *out)
        free(out->buf);
 }
 
-void buf_output_add(struct buf_output *out, const char *buf, size_t len)
+size_t buf_output_add(struct buf_output *out, const char *buf, size_t len)
 {
-       while (out->max_buflen - out->buflen < len) {
-               size_t newlen = out->max_buflen + BUF_INC - out->buflen;
-
-               out->buf = realloc(out->buf, out->max_buflen + BUF_INC);
-               out->max_buflen += BUF_INC;
-               memset(&out->buf[out->buflen], 0, newlen);
+       if (out->max_buflen - out->buflen < len) {
+               size_t need = len - (out->max_buflen - out->buflen);
+               size_t old_max = out->max_buflen;
+
+               need = max((size_t) BUF_INC, need);
+               out->max_buflen += need;
+               out->buf = realloc(out->buf, out->max_buflen);
+
+               old_max = max(old_max, out->buflen + len);
+               if (old_max + need > out->max_buflen)
+                       need = out->max_buflen - old_max;
+               memset(&out->buf[old_max], 0, need);
        }
 
        memcpy(&out->buf[out->buflen], buf, len);
        out->buflen += len;
+       return len;
 }
 
-void buf_output_flush(struct buf_output *out)
+size_t buf_output_flush(struct buf_output *out)
 {
+       size_t ret = 0;
+
        if (out->buflen) {
-               log_local_buf(out->buf, out->buflen);
+               ret = log_info_buf(out->buf, out->buflen);
                memset(out->buf, 0, out->max_buflen);
                out->buflen = 0;
        }
+
+       return ret;
 }