Add support for having no malloc function.

Fixes #99.

.github/workflows/cmake.yml

@@ -64,3 +64,8 @@ jobs:
       working-directory: ${{github.workspace}}/build
       shell: bash
       run: if [ "${{ matrix.os }}" == "windows-latest" ]; then cd ${{ matrix.type }}; fi; ./utf8_test
+
+    - name: Test No Malloc
+      working-directory: ${{github.workspace}}/build
+      shell: bash
+      run: if [ "${{ matrix.os }}" == "windows-latest" ]; then cd ${{ matrix.type }}; fi; ./utf8_no_malloc_test

test/CMakeLists.txt

@@ -32,6 +32,10 @@ add_executable(utf8_test
   main.c
 )
 
+add_executable(utf8_no_malloc_test
+  no_malloc.c
+)
+
 add_executable(utf8_test_c90 test.c)
 if("${CMAKE_C_COMPILER_ID}" STREQUAL "GNU")
   target_compile_options(utf8_test_c90 PUBLIC "-std=c90")

test/main.c

@@ -798,7 +798,7 @@ UTEST(utf8ndup, ascii_larger) {
   free(dup);
 }
 
-utf8_int8_t *allocate_from_buffer(utf8_int8_t *user_data, size_t n) {
+static utf8_int8_t *allocate_from_buffer(utf8_int8_t *user_data, size_t n) {
   return user_data;
 }
 
@@ -1638,18 +1638,18 @@ UTEST(utf8makevalid, invalid_replacement) {
 }
 
 UTEST(utf8nvalid, exactly_2_bytes) {
-    const char terminated[] = "\xc2\xa3";
-    ASSERT_EQ(utf8nvalid(terminated, 2), NULL);
+  const char terminated[] = "\xc2\xa3";
+  ASSERT_EQ(utf8nvalid(terminated, 2), NULL);
 }
 
 UTEST(utf8nvalid, exactly_3_bytes) {
-    const char terminated[] = "\xe1\xbd\xb6";
-    ASSERT_EQ(utf8nvalid(terminated, 3), NULL);
+  const char terminated[] = "\xe1\xbd\xb6";
+  ASSERT_EQ(utf8nvalid(terminated, 3), NULL);
 }
 
 UTEST(utf8nvalid, exactly_4_bytes) {
-    const char terminated[] = "\xf0\x90\x8d\x88";
-    ASSERT_EQ(utf8nvalid(terminated, 4), NULL);
+  const char terminated[] = "\xf0\x90\x8d\x88";
+  ASSERT_EQ(utf8nvalid(terminated, 4), NULL);
 }
 
 UTEST_MAIN();

test/no_malloc.c

@@ -0,0 +1,64 @@
+// This is free and unencumbered software released into the public domain.
+//
+// Anyone is free to copy, modify, publish, use, compile, sell, or
+// distribute this software, either in source code form or as a compiled
+// binary, for any purpose, commercial or non-commercial, and by any
+// means.
+//
+// In jurisdictions that recognize copyright laws, the author or authors
+// of this software dedicate any and all copyright interest in the
+// software to the public domain. We make this dedication for the benefit
+// of the public at large and to the detriment of our heirs and
+// successors. We intend this dedication to be an overt act of
+// relinquishment in perpetuity of all present and future rights to this
+// software under copyright law.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+// IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+// OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+// OTHER DEALINGS IN THE SOFTWARE.
+//
+// For more information, please refer to <http://unlicense.org/>
+
+// include the unit testing framework
+#include "utest.h"
+
+// include the header we are testing
+#define UTF8_NO_STD_MALLOC
+#include "utf8.h"
+
+UTEST(no_malloc_utf8dup, ascii) {
+  void *const dup = utf8dup("1234567890");
+  ASSERT_FALSE(dup);
+}
+
+UTEST(no_malloc_utf8ndup, ascii) {
+  void *const dup = utf8ndup("1234567890", 4);
+  ASSERT_FALSE(dup);
+}
+
+static utf8_int8_t *allocate_from_buffer(utf8_int8_t *user_data, size_t n) {
+  return user_data;
+}
+
+UTEST(no_malloc_utf8dup_ex, ascii) {
+  char user_data[1024];
+  void *const dup = utf8dup_ex("1234567890", allocate_from_buffer, user_data);
+  ASSERT_TRUE(dup);
+  ASSERT_EQ(dup, user_data);
+  ASSERT_EQ(10, utf8len(dup));
+}
+
+UTEST(no_malloc_utf8ndup_ex, ascii) {
+  char user_data[1024];
+  void *const dup =
+      utf8ndup_ex("1234567890", 4, allocate_from_buffer, user_data);
+  ASSERT_TRUE(dup);
+  ASSERT_EQ(dup, user_data);
+  ASSERT_EQ(4, utf8len(dup));
+}
+
+UTEST_MAIN();

utf8.h

@@ -484,7 +484,11 @@ utf8_int8_t *utf8dup_ex(const utf8_int8_t *src,
   if (alloc_func_ptr) {
     n = alloc_func_ptr(user_data, bytes);
   } else {
+#if !defined(UTF8_NO_STD_MALLOC)
     n = (utf8_int8_t *)malloc(bytes);
+#else
+    return utf8_null;
+#endif
   }
 
   if (utf8_null == n) {
@@ -711,7 +715,11 @@ utf8_int8_t *utf8ndup_ex(const utf8_int8_t *src, size_t n,
   if (alloc_func_ptr) {
     c = alloc_func_ptr(user_data, bytes + 1);
   } else {
+#if !defined(UTF8_NO_STD_MALLOC)
     c = (utf8_int8_t *)malloc(bytes + 1);
+#else
+    c = utf8_null;
+#endif
   }
 
   if (utf8_null == c) {