use ngx_min() and ngx_max()

src/core/ngx_output_chain.c

diff --git a/src/core/ngx_output_chain.c b/src/core/ngx_output_chain.c
index 3ff25ff..f51d690 100644
--- a/src/core/ngx_output_chain.c
+++ b/src/core/ngx_output_chain.c
@@ -465,10 +465,7 @@
     dst = ctx->buf;
 
     size = ngx_buf_size(src);
-
-    if (size > dst->end - dst->pos) {
-        size = dst->end - dst->pos;
-    }
+    size = ngx_min(size, dst->end - dst->pos);
 
     sendfile = ctx->sendfile & !ctx->directio;
 

src/core/ngx_string.c

diff --git a/src/core/ngx_string.c b/src/core/ngx_string.c
index f513753..95ac9cb 100644
--- a/src/core/ngx_string.c
+++ b/src/core/ngx_string.c
@@ -229,9 +229,7 @@
             case 'V':
                 v = va_arg(args, ngx_str_t *);
 
-                len = v->len;
-                len = (buf + len < last) ? len : (size_t) (last - buf);
-
+                len = ngx_min(((size_t) (last - buf)), v->len);
                 buf = ngx_cpymem(buf, v->data, len);
                 fmt++;
 
@@ -240,9 +238,7 @@
             case 'v':
                 vv = va_arg(args, ngx_variable_value_t *);
 
-                len = vv->len;
-                len = (buf + len < last) ? len : (size_t) (last - buf);
-
+                len = ngx_min(((size_t) (last - buf)), vv->len);
                 buf = ngx_cpymem(buf, vv->data, len);
                 fmt++;
 
@@ -257,8 +253,7 @@
                     }
 
                 } else {
-                    len = (buf + slen < last) ? slen : (size_t) (last - buf);
-
+                    len = ngx_min(((size_t) (last - buf)), slen);
                     buf = ngx_cpymem(buf, p, len);
                 }
 

src/http/modules/ngx_http_log_module.c

diff --git a/src/http/modules/ngx_http_log_module.c b/src/http/modules/ngx_http_log_module.c
index 0752d03..1796ee2 100644
--- a/src/http/modules/ngx_http_log_module.c
+++ b/src/http/modules/ngx_http_log_module.c
@@ -533,7 +533,7 @@
 
     ms = (ngx_msec_int_t)
              ((tp->sec - r->start_sec) * 1000 + (tp->msec - r->start_msec));
-    ms = (ms >= 0) ? ms : 0;
+    ms = ngx_max(ms, 0);
 
     return ngx_sprintf(buf, "%T.%03M", ms / 1000, ms % 1000);
 }

src/http/ngx_http_upstream.c

diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index 273d357..522a605 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -3710,7 +3710,7 @@
         if (state[i].status) {
             ms = (ngx_msec_int_t)
                      (state[i].response_sec * 1000 + state[i].response_msec);
-            ms = (ms >= 0) ? ms : 0;
+            ms = ngx_max(ms, 0);
             p = ngx_sprintf(p, "%d.%03d", ms / 1000, ms % 1000);
 
         } else {