From de0324e1a79e46a765ec77d2475aa63d51a82509 Mon Sep 17 00:00:00 2001
From: daanx <daan@effp.org>
Date: Sat, 4 Jan 2025 22:01:28 -0800
Subject: [PATCH] return length from _mi_snprintf

---
 include/mimalloc/internal.h |  4 ++--
 src/libc.c                  | 24 +++++++++++++-----------
 src/page.c                  |  3 +--
 3 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/include/mimalloc/internal.h b/include/mimalloc/internal.h
index 4a798d0a..8d26de47 100644
--- a/include/mimalloc/internal.h
+++ b/include/mimalloc/internal.h
@@ -64,8 +64,8 @@ terms of the MIT license. A copy of the license can be found in the file
 
 // "libc.c"
 #include    <stdarg.h>
-void        _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args);
-void        _mi_snprintf(char* buf, size_t buflen, const char* fmt, ...);
+int         _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args);
+int         _mi_snprintf(char* buf, size_t buflen, const char* fmt, ...);
 char        _mi_toupper(char c);
 int         _mi_strnicmp(const char* s, const char* t, size_t n);
 void        _mi_strlcpy(char* dest, const char* src, size_t dest_size);
diff --git a/src/libc.c b/src/libc.c
index ce541f1b..1bd97aa3 100644
--- a/src/libc.c
+++ b/src/libc.c
@@ -7,7 +7,7 @@ terms of the MIT license. A copy of the license can be found in the file
 
 // --------------------------------------------------------
 // This module defines various std libc functions to reduce
-// the dependency on libc, and also prevent errors caused 
+// the dependency on libc, and also prevent errors caused
 // by some libc implementations when called before `main`
 // executes (due to malloc redirection)
 // --------------------------------------------------------
@@ -83,7 +83,7 @@ bool _mi_getenv(const char* name, char* result, size_t result_size) {
 // Define our own limited `_mi_vsnprintf` and `_mi_snprintf`
 // This is mostly to avoid calling these when libc is not yet
 // initialized (and to reduce dependencies)
-// 
+//
 // format:      d i, p x u, s
 // prec:        z l ll L
 // width:       10
@@ -130,7 +130,7 @@ static void mi_out_alignright(char fill, char* start, size_t len, size_t extra,
 }
 
 
-static void mi_out_num(uintmax_t x, size_t base, char prefix, char** out, char* end) 
+static void mi_out_num(uintmax_t x, size_t base, char prefix, char** out, char* end)
 {
   if (x == 0 || base == 0 || base > 16) {
     if (prefix != 0) { mi_outc(prefix, out, end); }
@@ -144,8 +144,8 @@ static void mi_out_num(uintmax_t x, size_t base, char prefix, char** out, char*
       mi_outc((digit <= 9 ? '0' + digit : 'A' + digit - 10),out,end);
       x = x / base;
     }
-    if (prefix != 0) { 
-      mi_outc(prefix, out, end); 
+    if (prefix != 0) {
+      mi_outc(prefix, out, end);
     }
     size_t len = *out - start;
     // and reverse in-place
@@ -160,8 +160,8 @@ static void mi_out_num(uintmax_t x, size_t base, char prefix, char** out, char*
 
 #define MI_NEXTC()  c = *in; if (c==0) break; in++;
 
-void _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args) {
-  if (buf == NULL || bufsize == 0 || fmt == NULL) return;
+int _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args) {
+  if (buf == NULL || bufsize == 0 || fmt == NULL) return 0;
   buf[bufsize - 1] = 0;
   char* const end = buf + (bufsize - 1);
   const char* in = fmt;
@@ -181,7 +181,7 @@ void _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args) {
       size_t width = 0;
       char   numtype = 'd';
       char   numplus = 0;
-      bool   alignright = true; 
+      bool   alignright = true;
       if (c == '+' || c == ' ') { numplus = c; MI_NEXTC(); }
       if (c == '-') { alignright = false; MI_NEXTC(); }
       if (c == '0') { fill = '0'; MI_NEXTC(); }
@@ -191,7 +191,7 @@ void _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args) {
           width = (10 * width) + (c - '0'); MI_NEXTC();
         }
         if (c == 0) break;  // extra check due to while
-      }      
+      }
       if (c == 'z' || c == 't' || c == 'L') { numtype = c; MI_NEXTC(); }
       else if (c == 'l') {
         numtype = c; MI_NEXTC();
@@ -265,11 +265,13 @@ void _mi_vsnprintf(char* buf, size_t bufsize, const char* fmt, va_list args) {
   }
   mi_assert_internal(out <= end);
   *out = 0;
+  return (int)(out - buf);
 }
 
-void _mi_snprintf(char* buf, size_t buflen, const char* fmt, ...) {
+int _mi_snprintf(char* buf, size_t buflen, const char* fmt, ...) {
   va_list args;
   va_start(args, fmt);
-  _mi_vsnprintf(buf, buflen, fmt, args);
+  const int written = _mi_vsnprintf(buf, buflen, fmt, args);
   va_end(args);
+  return written;
 }
diff --git a/src/page.c b/src/page.c
index 4388dd36..6d0d6db7 100644
--- a/src/page.c
+++ b/src/page.c
@@ -411,7 +411,7 @@ void _mi_page_force_abandon(mi_page_t* page) {
 
   // ensure this page is no longer in the heap delayed free list
   _mi_heap_delayed_free_all(heap);
-  // We can still access the page meta-info even if it is freed as we ensure 
+  // We can still access the page meta-info even if it is freed as we ensure
   // in `mi_segment_force_abandon` that the segment is not freed (yet)
   if (page->capacity == 0) return; // it may have been freed now
 
@@ -1003,7 +1003,6 @@ void* _mi_malloc_generic(mi_heap_t* heap, size_t size, bool zero, size_t huge_al
   }
   // move singleton pages to the full queue
   if (page->reserved == page->used) {
-    mi_assert_internal(page->reserved == 1);
     mi_page_to_full(page, mi_page_queue_of(page));
   }
   return p;