ZBar是一种流行的二维码扫描和解码工具，它在嵌入式系统中拥有广泛的应用。在嵌入式系统中，我们面临着有限的资源和更严格的性能要求，因此，选择适当的库来完成特定的任务非常重要。
ZBar适用于各种嵌入式平台，包括ARM、x86和MIPS等处理器架构。它可以轻松地整合到各种嵌入式系统中，如智能家居设备、智能手机、平板电脑、远程控制设备、工业控制器等。
ZBar使用C/C++编写，具有高度优化的算法，能够快速准确地读取各种二维码和条形码，包括QR码、Data Matrix码、PDF417码、EAN-13码等等。同时，ZBar还支持自定义解码器，开发者可以根据自己的需求配置扫描器以实现更好的解码效果。
ZBar还具有非常灵活的API，可用于C/C++、Python、Java、Ruby等语言，开发人员可以根据自己的需求灵活选择相应的API。此外，ZBar还支持多种操作系统和平台，包括Linux、Windows、Mac OS X等。
总之，ZBar是一种非常有用的嵌入式二维码和条形码扫描库，它提供了高效的解码算法、可定制的解码器和灵活的API，能够轻松地满足嵌入式设备的扫描和解码需求。
这里感谢之前大佬移植zbar库到stm32，具体链接如下：https://www.cnblogs.com/greyorbit/p/8456814.html
移植步骤也很简单，按照博文把对应文件和头文件路径加入到工程中，然后使用图片数组转成灰度数据，在调用zbar既可以识别。
不过移植后会有一个问题，不能重复调用识别二维码，很容易内存就崩了。为了解决这个问题，让这个zbar库可以真正的用起来，不得不找到问题所在。
这里直观的看就是内存问题，奈何如果从源码直接去查找malloc和free的匹配所需时间太大，只能动态调试查找原因，所以第一步，我移植了rt-thread系统，使用rt的内存管理api。
移植rt-thread很方便，现在stm32代码生成工具cubemx可以直接添加rt-thread库，所以移植rt-thread系统很快。具体如下图：
移植完rt-thread后，就需要把zbar库中用到的malloc、calloc、free等操作函数换成 rt-malloc、rt-calloc、rt-free等，直接用全局搜索和替换。
替换后打开rt的内存调试功能宏定义：在rtdebug.h文件中
更改后既可以看到打印内存申请和释放日志，以下为日志打印内容
malloc size 156 allocate memory at 0x2001008c, size: 168 malloc size 296 allocate memory at 0x20010134, size: 308 malloc size 32 allocate memory at 0x20010268, size: 44 malloc size 48 allocate memory at 0x20010294, size: 60 malloc size 2856 allocate memory at 0x200102d0, size: 2868 malloc size 52 allocate memory at 0x20010e04, size: 64 allocate memory at 0x20010e04, size: 64 malloc size 16 allocate memory at 0x20010e44, size: 28 malloc size 20 allocate memory at 0x20011388, size: 32 malloc size 60 allocate memory at 0x200113a8, size: 72 release memory 0x20011388, size: 32 malloc size 140 allocate memory at 0x200113f0, size: 152 release memory 0x200113a8, size: 72 malloc size 300 allocate memory at 0x20011488, size: 312 release memory 0x200113f0, size: 152 malloc size 620 allocate memory at 0x200115c0, size: 632 release memory 0x20011488, size: 312 malloc size 1260 allocate memory at 0x20011838, size: 1272 release memory 0x200115c0, size: 632 malloc size 2540 allocate memory at 0x20011d30, size: 2552 release memory 0x20011838, size: 1272 malloc size 20 allocate memory at 0x20011388, size: 32 malloc size 60 allocate memory at 0x200113a8, size: 72 release memory 0x20011388, size: 32 malloc size 140 allocate memory at 0x200113f0, size: 152 release memory 0x200113a8, size: 72 malloc size 300 allocate memory at 0x20011488, size: 312 release memory 0x200113f0, size: 152 malloc size 620 allocate memory at 0x200115c0, size: 632 release memory 0x20011488, size: 312 malloc size 1260 allocate memory at 0x20011838, size: 1272 release memory 0x200115c0, size: 632 malloc size 2540 allocate memory at 0x20012728, size: 2552 release memory 0x20011838, size: 1272 malloc size 352 allocate memory at 0x20011388, size: 364 malloc size 352 allocate memory at 0x200114f4, size: 364 malloc size 88 allocate memory at 0x20011660, size: 100 release memory 0x20011660, size: 100 malloc size 440 allocate memory at 0x20011660, size: 452 malloc size 440 allocate memory at 0x20011824, size: 452 malloc size 110, but align to 112 allocate memory at 0x200119e8, size: 124 release memory 0x200119e8, size: 124 malloc size 5792 allocate memory at 0x20013120, size: 5804 malloc size 80 allocate memory at 0x200119e8, size: 92 malloc size 20 allocate memory at 0x20011a44, size: 32 malloc size 32 allocate memory at 0x20011a64, size: 44 malloc size 5, but align to 8 allocate memory at 0x20011a90, size: 24 malloc size 8 allocate memory at 0x20011aa8, size: 24 release memory 0x20011aa8, size: 24 release memory 0x20011a90, size: 24 release memory 0x20011a64, size: 44 release memory 0x20011a44, size: 32 release memory 0x20011824, size: 452 release memory 0x20011660, size: 452 release memory 0x200114f4, size: 364 release memory 0x20011388, size: 364 malloc size 57600 allocate memory at 0x200147cc, size: 57612 malloc size 960 allocate memory at 0x20011388, size: 972 release memory 0x20011388, size: 972 malloc size 3, but align to 4 allocate memory at 0x20011388, size: 24 malloc size 360 allocate memory at 0x200113a0, size: 372 release memory 0x200113a0, size: 372 malloc size 360 allocate memory at 0x200113a0, size: 372 release memory 0x200113a0, size: 372 malloc size 176 allocate memory at 0x200113a0, size: 188 release memory 0x200113a0, size: 188 malloc size 176 allocate memory at 0x200113a0, size: 188 release memory 0x200113a0, size: 188 malloc size 552 allocate memory at 0x200113a0, size: 564 malloc size 552 allocate memory at 0x200115d4, size: 564 release memory 0x200113a0, size: 564 release memory 0x200115d4, size: 564 malloc size 52 allocate memory at 0x200113a0, size: 64 allocate memory at 0x200113a0, size: 64 malloc size 116 allocate memory at 0x200113e0, size: 128 malloc size 32 allocate memory at 0x20011460, size: 44 malloc size 32 allocate memory at 0x2001148c, size: 44 release memory 0x20011460, size: 44 release memory 0x2001148c, size: 44 malloc size 116 allocate memory at 0x20011460, size: 128 malloc size 8 allocate memory at 0x200114e0, size: 24 malloc size 70, but align to 72 allocate memory at 0x200114f8, size: 84 release memory 0x200113e0, size: 128 release memory 0x200113a0, size: 64 release memory 0x200114e0, size: 24 release memory 0x20011460, size: 128 malloc size 12 allocate memory at 0x200113a0, size: 24 malloc size 15, but align to 16 allocate memory at 0x200113b8, size: 28 release memory 0x200114f8, size: 84 malloc size 48 allocate memory at 0x200113d4, size: 60 release memory 0x20011388, size: 24 malloc size 4 allocate memory at 0x20011388, size: 24 malloc size 1, but align to 4 allocate memory at 0x20011410, size: 24 malloc size 31, but align to 32 allocate memory at 0x20011428, size: 44 malloc size 52 allocate memory at 0x20011454, size: 64 allocate memory at 0x20011454, size: 64 malloc size 8 allocate memory at 0x20011494, size: 24 malloc size 16 allocate memory at 0x200114ac, size: 28 release memory 0x20011494, size: 24 malloc size 24 allocate memory at 0x200114c8, size: 36 release memory 0x200114ac, size: 28 malloc size 32 allocate memory at 0x20011494, size: 52 release memory 0x200114c8, size: 36 malloc size 16 allocate memory at 0x200114c8, size: 28 release memory 0x20011428, size: 44 release memory 0x20011410, size: 24 release memory 0x200113b8, size: 28 release memory 0x200113a0, size: 24 release memory 0x200113d4, size: 60 release memory 0x200147cc, size: 57612 release memory 0x200119e8, size: 92 release memory 0x20013120, size: 5804 n = 1 decoded QR-Code symbol "EEWorld STM32H5" len = 15 release memory 0x20010e04, size: 64 release memory 0x20011494, size: 52 release memory 0x200114c8, size: 28 release memory 0x20011454, size: 64 release memory 0x20010e44, size: 28 release memory 0x20010294, size: 60 release memory 0x20010268, size: 44 release memory 0x20010134, size: 308 release memory 0x20011d30, size: 2552 release memory 0x20012728, size: 2552 release memory 0x200102d0, size: 2868 release memory 0x2001008c, size: 168 45 45 57 6F 72 6C 64 20 53 54 4D 33 32 48 35 zbar ok zbar count;56
通过对申请和释放的对应关系，我们可以分析得出问题所在，zbar库在图片识别后释放了img->data指针，而这个指针是在zbar调用外部申请的空间，是不需要zbar内部释放的，具体代码如下：
int main(void)
{
/* USER CODE BEGIN 1 */
uint8_t test[]="start test\n";
uint16_t i,j;
int qr_img_width = 240;
uint16_t Color;
uint16_t cnt = 0;
unsigned char *pic_rgb = (unsigned char *)gImage_test;
unsigned char *pic_hd = NULL;
unsigned char *pic_data = NULL;
void * ptr_start;
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
//HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
//SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_ADC1_Init();
MX_ETH_Init();
MX_ICACHE_Init();
MX_LPUART1_UART_Init();
//MX_USART3_UART_Init();
MX_UCPD1_Init();
MX_USB_PCD_Init();
/* USER CODE BEGIN 2 */
pic_data = rt_malloc(qr_img_width*qr_img_width);
if(pic_data == NULL)
{
printf("malloc error\n");
return 0;
}
else
{
printf("pic_data:0x%x\n",pic_data);
}
//memset(pic_data,0,qr_img_width*qr_img_width);
pic_hd = pic_data;
for(i=0;i<qr_img_width;i++)
{
for(j=0;j<qr_img_width;j++) //将RGB565图片转成灰度
{
Color = (*pic_rgb) | (*(pic_rgb+1)<<8);
*pic_hd = (((Color&0xF800)>> 8)*77+((Color&0x7E0)>>3)*150+((Color&0x001F)<<3)*29)/256;
pic_hd++;
pic_rgb++;
pic_rgb++;
}
}
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
if( Zbar_Test((void* )pic_data,qr_img_width,qr_img_width) == 0 )
{
printf("zbar failed \n");
//rt_free(pic_data);
}
else
{
cnt ++;
printf("zbar ok \n");
//rt_free(pic_data);
}
printf("zbar count;%d\n",cnt);
//list_thread();
rt_thread_mdelay(5000);
}
rt_free(pic_data);
/* USER CODE END 3 */
}
即pic_data灰度图片数据是不需要zbar释放的，但是zbar库中做了释放操作，代码如下：
inline void zbar_image_rt_free_data (zbar_image_t *img)
{
if(!img)
return;
if(img->src) {
/* replace video image w/new copy */
assert(img->refcnt); /* FIXME needs lock */
zbar_image_t *newimg = zbar_image_create();
memcpy(newimg, img, sizeof(zbar_image_t));
/* recycle video image */
newimg->cleanup(newimg);
/* detach old image from src */
img->cleanup = NULL;
img->src = NULL;
img->srcidx = -1;
}
else if(img->cleanup && img->data) {
if(img->cleanup != zbar_image_rt_free_data) {
/* using function address to detect this case is a bad idea;
* windows link libraries add an extra layer of indirection...
* this works around that problem (bug #2796277)
*/
zbar_image_cleanup_handler_t *cleanup = img->cleanup;
img->cleanup = zbar_image_rt_free_data;
cleanup(img);
}
//传入图片为外部指针，zbar内部不用free此指针
// else
// rt_free((void*)img->data);
}
img->data = NULL;
}
这里把这一句屏蔽，则可以解决问题，经过我测试，现在已经连续运行上千次
decoded QR-Code symbol "EEWorld STM32H5" len = 15 45 45 57 6F 72 6C 64 20 53 54 4D 33 32 48 35 zbar ok zbar count;4290 n = 1 decoded QR-Code symbol "EEWorld STM32H5" len = 15 45 45 57 6F 72 6C 64 20 53 54 4D 33 32 48 35 zbar ok zbar count;4291 n = 1 decoded QR-Code symbol "EEWorld STM32H5" len = 15 45 45 57 6F 72 6C 64 20 53 54 4D 33 32 48 35 zbar ok zbar count;4292 n = 1 decoded QR-Code symbol "EEWorld STM32H5" len = 15 45 45 57 6F 72 6C 64 20 53 54 4D 33 32 48 35 zbar ok zbar count;4293 n = 1 decoded QR-Code symbol "EEWorld STM32H5" len = 15 45 45 57 6F 72 6C 64 20 53 54 4D 33 32 48 35 zbar ok zbar count;4294