From aaf881d67295af1276abfd6669cb99732e83d7fb Mon Sep 17 00:00:00 2001
From: CismonX <admin@cismon.net>
Date: Thu, 4 Mar 2021 18:30:43 +0800
Subject: [PATCH] Move match stack to automatic storage duration.

---
 src/ctlseqs.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/src/ctlseqs.c b/src/ctlseqs.c
index c97ce53..0fd4b10 100644
--- a/src/ctlseqs.c
+++ b/src/ctlseqs.c
@@ -143,7 +143,7 @@ struct ctlseqs_matcher {
     struct ctlseqs_trie_node *node_pools[CTLSEQS_TRIE_NODE_POOL_MAX_NUM];
     size_t                    pool_idx;
     size_t                    pool_size;
-    struct ctlseqs_match_ctx *match_stack;
+    size_t                    match_stack_size;
 };
 
 struct ctlseqs_reader {
@@ -295,7 +295,7 @@ CTLSEQS_HOT static ssize_t
 ctlseqs_match_pattern(struct ctlseqs_matcher const *matcher, struct ctlseqs_match_args const *args)
 {
     struct ctlseqs_trie_node const *old_node, empty_node = { 0 };
-    struct ctlseqs_match_ctx match_ctx = {
+    struct ctlseqs_match_ctx match_stack[matcher->match_stack_size], match_ctx = {
         .node   = matcher == NULL ? &empty_node : &matcher->root,
         .seq    = args->seq + 1,
         .result = args->result + (args->save_seq ? 2 : 0),
@@ -314,7 +314,7 @@ ctlseqs_match_pattern(struct ctlseqs_matcher const *matcher, struct ctlseqs_matc
             old_node = match_ctx.node;
             match_ctx.node = match_ctx.node->children[-match_ctx.value];
             struct ctlseqs_trie_node *next_node = match_ctx.node->next;
-            matcher->match_stack[++match_stack_top] = (struct ctlseqs_match_ctx) {
+            match_stack[++match_stack_top] = (struct ctlseqs_match_ctx) {
                 .value  = next_node == NULL ? 0 : -next_node->placeholder,
                 .node   = old_node,
                 .seq    = match_ctx.seq,
@@ -330,7 +330,7 @@ ctlseqs_match_pattern(struct ctlseqs_matcher const *matcher, struct ctlseqs_matc
         }
     }
     if (match_stack_top >= 0) {
-        match_ctx = matcher->match_stack[match_stack_top--];
+        match_ctx = match_stack[match_stack_top--];
         if (match_ctx.value == 0) {
             goto match_character;
         } else {
@@ -483,12 +483,7 @@ ctlseqs_matcher_config(struct ctlseqs_matcher *matcher, struct ctlseqs_matcher_o
             old_node->value = -ch;
         }
     }
-    size_t stack_size = sizeof(struct ctlseqs_match_ctx) * max_format_size;
-    struct ctlseqs_match_ctx *new_stack = realloc(matcher->match_stack, stack_size);
-    if (CTLSEQS_UNLIKELY(new_stack == NULL)) {
-        return CTLSEQS_NOMEM;
-    }
-    matcher->match_stack = new_stack;
+    matcher->match_stack_size = max_format_size;
     return CTLSEQS_OK;
 }
 
@@ -522,7 +517,6 @@ ctlseqs_matcher_free(struct ctlseqs_matcher *matcher)
         for (size_t idx = 0; idx <= matcher->pool_idx; ++idx) {
             free(matcher->node_pools[idx]);
         }
-        free(matcher->match_stack);
         free(matcher);
     }
 }