From 07dbb6538ca55e69a33ada6761e749f4ee06affe Mon Sep 17 00:00:00 2001
From: Martin Kagamino Lehoux <martin@lehoux.net>
Date: Fri, 22 Aug 2025 21:15:31 +0200
Subject: json: Improved parsing performance

---
 README.md      | 10 ++++++----
 include/json.h |  2 +-
 include/str.h  |  7 +++++++
 src/json.c     |  8 ++++----
 src/memory.c   |  7 +++++--
 src/str.c      | 11 +++++++++++
 6 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/README.md b/README.md
index 6c8eda3..5c28f84 100644
--- a/README.md
+++ b/README.md
@@ -12,10 +12,12 @@
 
 ## Benchmarks
 
-| version | result |
-|---|---|
-|json.loads|652 ms ± 6.65 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)|
-|v1|336 ms ± 163 ms per loop (mean ± std. dev. of 10 runs, 1 loop each)|
+| version | result | throughput | ram|
+|---|---|---|---|
+|json.loads|652 ms ± 6.65 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)|||
+|v1|336 ms ± 163 ms per loop (mean ± std. dev. of 10 runs, 1 loop each)|||
+|no 0 mem alloc|299 ms ±   8 ms per loop (mean ± std. dev. of 10 runs, 1 loop each)|||
+|Str_view|272 ms ±   6 ms per loop (mean ± std. dev. of 10 runs, 1 loop each)|330.46 MB/s|1255 MB|
 
 ## Resources
 
diff --git a/include/json.h b/include/json.h
index 749a3e0..9bd668e 100644
--- a/include/json.h
+++ b/include/json.h
@@ -24,7 +24,7 @@ typedef struct {
         i32 integer;
         f32 floating;
         Vec array; // Vec<JSON>
-        Str string;
+        StrView string;
         JSONObject object;
     } as;
 } JSON;
diff --git a/include/str.h b/include/str.h
index 300d5ea..3ccd072 100644
--- a/include/str.h
+++ b/include/str.h
@@ -12,7 +12,14 @@ typedef struct {
     byte *data;
     size len;
 } Str;
+typedef struct {
+    byte *data;
+    size len;
+} StrView;
 i32 Str_equals(Str a, Str b);
 u64 Str_hash64(Str s);
 Str Str_copy(Arena *a, byte *data, size len);
 i32 Str_fprint(FILE *w, Str s);
+
+StrView Str_view(byte *data, size len);
+i32 StrView_fprint(FILE *w, StrView s);
diff --git a/src/json.c b/src/json.c
index 6f00da8..af93d06 100644
--- a/src/json.c
+++ b/src/json.c
@@ -38,7 +38,7 @@ JSON JSON_array(Vec items) {
     return json;
 }
 
-JSON JSON_string(Str value) {
+JSON JSON_string(StrView value) {
     JSON json = {0};
     json.type = JSON_STRING;
     json.as.string = value;
@@ -72,7 +72,7 @@ i32 JSON_fprint(FILE *w, JSON json) {
     switch (json.type) {
     case JSON_STRING:
         fprintf(w, "\"");
-        Str_fprint(w, json.as.string);
+        StrView_fprint(w, json.as.string);
         return fprintf(w, "\"");
     case JSON_INTEGER:
         return fprintf(w, "%d", json.as.integer);
@@ -182,8 +182,8 @@ parse_result parse_string(Arena *a, byte *src, uptr start_pos) {
         result.pos++;
     }
     assert(src[result.pos] == '"');
-    result.value = JSON_string(
-        Str_copy(a, &src[start_pos + 1], result.pos - start_pos - 1));
+    result.value =
+        JSON_string(Str_view(&src[start_pos + 1], result.pos - start_pos - 1));
     result.pos++;
 
     return result;
diff --git a/src/memory.c b/src/memory.c
index 63acb39..62f47e7 100644
--- a/src/memory.c
+++ b/src/memory.c
@@ -22,9 +22,12 @@ void *alloc(Arena *a, size count, size tsize, size align) {
     size alloc_size = count * tsize;
     assert(beg + alloc_size < a->end);
     a->beg = beg + alloc_size;
-    return memset(beg, 0, count * tsize);
+    return beg;
 }
 
-void Arena_reset(Arena *a) { a->beg = a->end - a->cap; }
+void Arena_reset(Arena *a) {
+    a->beg = a->end - a->cap;
+    memset(a->beg, 0, a->end - a->beg);
+}
 
 size Arena_get_used(Arena a) { return a.cap - (a.end - a.beg); }
diff --git a/src/str.c b/src/str.c
index eccacd8..2899ca9 100644
--- a/src/str.c
+++ b/src/str.c
@@ -30,3 +30,14 @@ Str Str_copy(Arena *a, byte *data, size len) {
 i32 Str_fprint(FILE *w, Str s) {
     return fprintf(w, "%.*s", (i32)s.len, s.data);
 }
+
+StrView Str_view(byte *data, size len) {
+    StrView str = {0};
+    str.len = len;
+    str.data = data;
+    return str;
+}
+
+i32 StrView_fprint(FILE *w, StrView s) {
+    return fprintf(w, "%.*s", (i32)s.len, s.data);
+}
-- 
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