22b586b3d8
This adds the glfwInitAllocator function for specifying a custom memory allocator to use instead of the C runtime library. The allocator is a struct of type GLFWallocator with fields corresponding to malloc, realloc and free, while the internal API corresponds to calloc, realloc and free. Heap allocation calls are filtered before reaching the user-provided functions, so deallocation of NULL and allocations of zero bytes are not passed on, reallocating NULL is transformed into an allocation and reallocating to size zero is transformed into deallocation. The clearing of a new block to zero is performed by the internal calloc-like function. Closes #544. Fixes #1628. Closes #1947.
142 lines
3.9 KiB
C
142 lines
3.9 KiB
C
//========================================================================
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// Custom heap allocator test
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// Copyright (c) Camilla Löwy <elmindreda@glfw.org>
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//
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// This software is provided 'as-is', without any express or implied
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// warranty. In no event will the authors be held liable for any damages
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// arising from the use of this software.
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//
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// Permission is granted to anyone to use this software for any purpose,
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// including commercial applications, and to alter it and redistribute it
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// freely, subject to the following restrictions:
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//
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// 1. The origin of this software must not be misrepresented; you must not
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// claim that you wrote the original software. If you use this software
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// in a product, an acknowledgment in the product documentation would
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// be appreciated but is not required.
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//
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// 2. Altered source versions must be plainly marked as such, and must not
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// be misrepresented as being the original software.
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//
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// 3. This notice may not be removed or altered from any source
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// distribution.
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//
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//========================================================================
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#include <glad/gl.h>
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#define GLFW_INCLUDE_NONE
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#include <GLFW/glfw3.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#define CALL(x) (function_name = #x, x)
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static const char* function_name = NULL;
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struct allocator_stats
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{
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size_t total;
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size_t current;
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size_t maximum;
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};
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static void error_callback(int error, const char* description)
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{
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fprintf(stderr, "Error: %s\n", description);
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}
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static void* allocate(size_t size, void* user)
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{
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struct allocator_stats* stats = user;
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assert(size > 0);
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stats->total += size;
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stats->current += size;
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if (stats->current > stats->maximum)
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stats->maximum = stats->current;
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printf("%s: allocate %zu bytes (current %zu maximum %zu total %zu)\n",
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function_name, size, stats->current, stats->maximum, stats->total);
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size_t* real_block = malloc(size + sizeof(size_t));
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assert(real_block != NULL);
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*real_block = size;
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return real_block + 1;
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}
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static void deallocate(void* block, void* user)
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{
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struct allocator_stats* stats = user;
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assert(block != NULL);
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size_t* real_block = (size_t*) block - 1;
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stats->current -= *real_block;
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printf("%s: deallocate %zu bytes (current %zu maximum %zu total %zu)\n",
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function_name, *real_block, stats->current, stats->maximum, stats->total);
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free(real_block);
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}
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static void* reallocate(void* block, size_t size, void* user)
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{
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struct allocator_stats* stats = user;
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assert(block != NULL);
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assert(size > 0);
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size_t* real_block = (size_t*) block - 1;
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stats->total += size;
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stats->current += size - *real_block;
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if (stats->current > stats->maximum)
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stats->maximum = stats->current;
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printf("%s: reallocate %zu bytes to %zu bytes (current %zu maximum %zu total %zu)\n",
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function_name, *real_block, size, stats->current, stats->maximum, stats->total);
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real_block = realloc(real_block, size + sizeof(size_t));
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assert(real_block != NULL);
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*real_block = size;
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return real_block + 1;
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}
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int main(void)
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{
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struct allocator_stats stats = {0};
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const GLFWallocator allocator =
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{
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.allocate = allocate,
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.deallocate = deallocate,
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.reallocate = reallocate,
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.user = &stats
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};
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glfwSetErrorCallback(error_callback);
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glfwInitAllocator(&allocator);
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if (!CALL(glfwInit)())
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exit(EXIT_FAILURE);
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GLFWwindow* window = CALL(glfwCreateWindow)(400, 400, "Custom allocator test", NULL, NULL);
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if (!window)
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{
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glfwTerminate();
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exit(EXIT_FAILURE);
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}
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CALL(glfwMakeContextCurrent)(window);
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gladLoadGL(glfwGetProcAddress);
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CALL(glfwSwapInterval)(1);
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while (!CALL(glfwWindowShouldClose)(window))
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{
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glClear(GL_COLOR_BUFFER_BIT);
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CALL(glfwSwapBuffers)(window);
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CALL(glfwWaitEvents)();
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}
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CALL(glfwTerminate)();
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exit(EXIT_SUCCESS);
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}
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