From ee5421470a92d66ff79098f68e2ceb99c4cbfd3c Mon Sep 17 00:00:00 2001
From: TazyFoundSoup <gardendistrict0x0@outlook.com>
Date: Thu, 11 Jun 2026 19:07:19 +1000
Subject: fix(thread): Add mutex to ff_ctx and make ff_dprintf thread-safe

---
 include/tinyff/common.h |  9 +++++++++
 src/common.c            | 16 ++++++++++++++++
 src/dbg.c               | 18 ++++++++++++++++++
 3 files changed, 43 insertions(+)

diff --git a/include/tinyff/common.h b/include/tinyff/common.h
index 2b17911..6d93a70 100644
--- a/include/tinyff/common.h
+++ b/include/tinyff/common.h
@@ -8,6 +8,10 @@
 #include <stddef.h>
 #include <tinyff/stream.h>
 
+#ifdef USE_THREAD
+#include <pthread.h>
+#endif
+
 #ifdef USE_BENCH
 
 #include <tinyff/bench/bench.h>
@@ -128,6 +132,11 @@ typedef struct ff_ctx {
     #ifdef USE_BENCH
     ff_bench bench;
     #endif
+
+    #ifdef USE_THREAD
+    /* mutex to protect ctx internal mutable state when threads are enabled */
+    pthread_mutex_t ff_lock;
+    #endif
 } ff_ctx;
 
 ff_ctx* ff_init(ff_allocator* allocator);
diff --git a/src/common.c b/src/common.c
index bde1bac..f9e46d5 100644
--- a/src/common.c
+++ b/src/common.c
@@ -6,6 +6,9 @@
 #include <stdlib.h>
 #endif
 
+#ifdef USE_THREAD
+#include <pthread.h>
+#endif
 
 // Initializes a new tinyff context.
 ff_ctx* ff_init(ff_allocator* allocator)
@@ -27,12 +30,25 @@ ff_ctx* ff_init(ff_allocator* allocator)
 
     ctx->allocator = *allocator;
 
+#ifdef USE_THREAD
+    /* initialize mutex used to protect ctx state */
+    if (pthread_mutex_init(&ctx->ff_lock, NULL) != 0) {
+        ctx->allocator.ff_free(ctx);
+        return NULL;
+    }
+#endif
+
     return ctx;
 }
 
 void ff_cleanup(ff_ctx *ctx) {
     if (!ctx) return;
     ff_dprintf(ctx, "goodbye from tinyff ;]\n");
+
+#ifdef USE_THREAD
+    pthread_mutex_destroy(&ctx->ff_lock);
+#endif
+
     ctx->allocator.ff_free(ctx);    
     
 }
diff --git a/src/dbg.c b/src/dbg.c
index a12545d..13c3f18 100644
--- a/src/dbg.c
+++ b/src/dbg.c
@@ -3,6 +3,10 @@
 #include <stdarg.h>
 #include <stdint.h>
 
+#ifdef USE_THREAD
+#include <pthread.h>
+#endif
+
 static size_t ff_internal_itoa(int value, char* buf)
 {
     char temp[12];
@@ -52,6 +56,9 @@ static inline void ff_debug_flush(ff_ctx* ctx, char* buffer, size_t* idx)
 {
     if (*idx == 0) return;
 
+#ifdef USE_THREAD
+    pthread_mutex_lock(&ctx->ff_lock);
+#endif
     ctx->ff_debug_stream.write(
         buffer,
         *idx,
@@ -59,6 +66,9 @@ static inline void ff_debug_flush(ff_ctx* ctx, char* buffer, size_t* idx)
     );
 
     *idx = 0;
+#ifdef USE_THREAD
+    pthread_mutex_unlock(&ctx->ff_lock);
+#endif
 }
 
 ff_result ff_dprintf(ff_ctx* ctx, const char *format, ...)
@@ -74,6 +84,10 @@ ff_result ff_dprintf(ff_ctx* ctx, const char *format, ...)
     size_t buf_idx = 0;
     const char* p = format;
 
+#ifdef USE_THREAD
+    pthread_mutex_lock(&ctx->ff_lock);
+#endif
+
     while (*p) {
 
         if (buf_idx >= sizeof(buffer) - 64) {
@@ -152,6 +166,10 @@ ff_result ff_dprintf(ff_ctx* ctx, const char *format, ...)
 
     ff_debug_flush(ctx, buffer, &buf_idx);
 
+#ifdef USE_THREAD
+    pthread_mutex_unlock(&ctx->ff_lock);
+#endif
+
     va_end(args);
     return FF_RESULT_OK;
 }
\ No newline at end of file
-- 
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