BLOB二进制对象(blob.c/h)

来源：互联网发布：数据库关闭启动命令编辑：程序博客网时间：2024/06/05 01:44

转载：https://segmentfault.com/a/1190000002391970

BLOB二进制对象(blob.c/h)

数据结构

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struct blob_attr {    uint32_t id_len;    /** 高1位为extend标志，高7位存储id，                         *  低24位存储data的内存大小 */    char data[];} __packed;struct blob_attr_info {    unsigned int type;    unsigned int minlen;    unsigned int maxlen;    bool (*validate)(const struct blob_attr_info *, struct blob_attr *);};struct blob_buf {    struct blob_attr *head;    bool (*grow)(struct blob_buf *buf, int minlen);    int buflen;    void *buf;};

存储结构

接口说明

获取BLOB属性信息

/** * 返回指向BLOB属性数据区指针 */static inline void * blob_data(const struct blob_attr *attr)/** * 返回BLOB属性ID */static inline unsigned int blob_id(const struct blob_attr *attr)/** * 判断BLOB属性扩展标志是否为真 */static inline bool blob_is_extended(const struct blob_attr *attr)/** * 返回BLOB属性有效存储空间大小 */static inline unsigned int blob_len(const struct blob_attr *attr)/* * 返回BLOB属性完全存储空间大小(包括头部) */static inline unsigned int blob_raw_len(const struct blob_attr *attr)/* * 返回BLOB属性填补后存储空间大小(包括头部) */static inline unsigned int blob_pad_len(const struct blob_attr *attr)

获取BLOB数据信息

static inline uint8_t blob_get_u8(const struct blob_attr *attr)static inline uint16_t blob_get_u16(const struct blob_attr *attr)static inline uint32_t blob_get_u32(const struct blob_attr *attr)static inline uint64_t blob_get_u64(const struct blob_attr *attr)static inline int8_t blob_get_int8(const struct blob_attr *attr)static inline int16_t blob_get_int16(const struct blob_attr *attr)static inline int32_t blob_get_int32(const struct blob_attr *attr)static inline int64_t blob_get_int64(const struct blob_attr *attr)static inline const char * blob_get_string(const struct blob_attr *attr)

设置BLOB数据信息

static inline struct blob_attr *blob_put_string(struct blob_buf *buf, int id, const char *str)static inline struct blob_attr *blob_put_u8(struct blob_buf *buf, int id, uint8_t val)static inline struct blob_attr *blob_put_u16(struct blob_buf *buf, int id, uint16_t val)static inline struct blob_attr *blob_put_u32(struct blob_buf *buf, int id, uint32_t val)static inline struct blob_attr *blob_put_u64(struct blob_buf *buf, int id, uint64_t val)#define blob_put_int8   blob_put_u8#define blob_put_int16  blob_put_u16#define blob_put_int32  blob_put_u32#define blob_put_int64  blob_put_u64struct blob_attr *blob_put(struct blob_buf *buf, int id, const void *ptr, unsigned int len)/** * ptr - 指向struct blob_attr */struct blob_attr *blob_put_raw(struct blob_buf *buf, const void *ptr, unsigned int len)

遍历

#define __blob_for_each_attr(pos, attr, rem)#define blob_for_each_attr(pos, attr, rem)

复制

struct blob_attr * blob_memdup(struct blob_attr *attr)

数据类型判断

enum {    BLOB_ATTR_UNSPEC,    BLOB_ATTR_NESTED,  /** 嵌套 */    BLOB_ATTR_BINARY,    BLOB_ATTR_STRING,    BLOB_ATTR_INT8,    BLOB_ATTR_INT16,    BLOB_ATTR_INT32,    BLOB_ATTR_INT64,    BLOB_ATTR_LAST};bool blob_check_type(const void *ptr, unsigned int len, int type)

嵌套操作

void * blob_nest_start(struct blob_buf *buf, int id)Void blob_nest_end(struct blob_buf *buf, void *cookie)

判断

bool blob_attr_equal(const struct blob_attr *a1, const struct blob_attr *a2)

初始/销毁

/** * 初始化BLOB buffer */int blob_buf_init(struct blob_buf *buf, int id)/** * 销毁BLOB buffer */void blob_buf_free(struct blob_buf *buf)

解析BLOB

/** * 从attr串中根据info策略过滤，得到的结果存储在data属性数组中 * * @param  attr 输入BLOB属性串 * @param  data 输出BLOB属性数组 * @param  info 属性过滤策略 * @param  max data数组大小 */int blob_parse(struct blob_attr *attr, struct blob_attr **data,                const struct blob_attr_info *info, int max)

BLOB消息对象(blobmsg.c/h)

数据结构

struct blobmsg_hdr {    uint16_t namelen;    uint8_t name[];} __packed;struct blobmsg_policy {    const char *name;    enum blobmsg_type type;};

存储结构

消息类型

enum blobmsg_type {    BLOBMSG_TYPE_UNSPEC,    BLOBMSG_TYPE_ARRAY,    BLOBMSG_TYPE_TABLE,    BLOBMSG_TYPE_STRING,    BLOBMSG_TYPE_INT64,    BLOBMSG_TYPE_INT32,    BLOBMSG_TYPE_INT16,    BLOBMSG_TYPE_INT8,    __BLOBMSG_TYPE_LAST,    BLOBMSG_TYPE_LAST = __BLOBMSG_TYPE_LAST - 1,    BLOBMSG_TYPE_BOOL = BLOBMSG_TYPE_INT8,};

接口说明

基本操作

/** * 根据BLOB消息名字长度计算出blobmsg头部大小 */static inline int blobmsg_hdrlen(unsigned int namelen)/** * 获取BLOB消息名字 */static inline const char *blobmsg_name(const struct blob_attr *attr)/** * 获取BLOB消息类型 */static inline int blobmsg_type(const struct blob_attr *attr)/** * 获取BLOB消息数据内容 */static inline void *blobmsg_data(const struct blob_attr *attr)/** * 获取BLOB消息数据内容大小 */static inline int blobmsg_data_len(const struct blob_attr *attr)static inline int blobmsg_len(const struct blob_attr *attr)

数据类型判断

/** * 判断BLOBMSG属性类型是否合法 */bool blobmsg_check_attr(const struct blob_attr *attr, bool name)

设置

int blobmsg_add_field(struct blob_buf *buf, int type, const char *name,                      const void *data, unsigned int len)static inline intblobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)static inline intblobmsg_add_u16(struct blob_buf *buf, const char *name, uint16_t val)static inline intblobmsg_add_u32(struct blob_buf *buf, const char *name, uint32_t val)static inline intblobmsg_add_u64(struct blob_buf *buf, const char *name, uint64_t val)static inline intblobmsg_add_string(struct blob_buf *buf, const char *name, const char *string)static inline intblobmsg_add_blob(struct blob_buf *buf, struct blob_attr *attr)/** * 格式化设备BLOGMSG */void blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)

获取

static inline uint8_t blobmsg_get_u8(struct blob_attr *attr)static inline bool blobmsg_get_bool(struct blob_attr *attr)static inline uint16_t blobmsg_get_u16(struct blob_attr *attr)static inline uint32_t blobmsg_get_u32(struct blob_attr *attr)static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)static inline char *blobmsg_get_string(struct blob_attr *attr)

创建

/** * 创建BLOBMSG，返回数据区开始地址 */void *blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen)/** * 扩大BLOGMSG，返回数据区开始地址 */void *blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen)void blobmsg_add_string_buffer(struct blob_buf *buf)

遍历

#define blobmsg_for_each_attr(pos, attr, rem)

嵌套

static inline void * blobmsg_open_array(struct blob_buf *buf, const char *name)static inline void blobmsg_close_array(struct blob_buf *buf, void *cookie)static inline void *blobmsg_open_table(struct blob_buf *buf, const char *name)static inline void blobmsg_close_table(struct blob_buf *buf, void *cookie)

解析BLOGMSG

/** * 从data BLOGMSG串中根据policy策略过滤，得到的结果存储在tb BLOGATTR数组中 * * @param  policy 过滤策略 * @param  policy_len 策略个数 * @param  tb 返回属性数据 * @param  len data属性个数 */int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,                  struct blob_attr **tb, void *data, unsigned int len)

例子

把UCI转化为BLOB

UCI配置文件:
/etc/config/test

config policy test    option name 'test'    option enable '1'    option dns '1.1.1.1 2.2.2.2'

定义参数列表:

enum {    POLICY_ATTR_NAME,       /** name */    POLICY_ATTR_ENABLE,     /** enable */    POLICY_ATTR_DNS,        /** dns */    __POLICY_ATTR_MAX};static const struct blobmsg_policy policy_attrs[__POLICY_ATTR_MAX] = {    [POLICY_ATTR_NAME] = { .name = "name", .type = BLOBMSG_TYPE_STRING },    [POLICY_ATTR_ENABLE] = { .name = "enable", .type = BLOBMSG_TYPE_BOOL },    [POLICY_ATTR_DNS] = { .name = "dns", .type = BLOBMSG_TYPE_ARRAY },};/** 定义BLOBMSG_TYPE_ARRAY类型参数的实际数据类型 */static const struct uci_blob_param_info policy_attr_info[__POLICY_ATTR_MAX] = {    [POLICY_ATTR_DNS] = { .type = BLOBMSG_TYPE_STRING },};static const struct uci_blob_param_list policy_attr_list = {    .n_params = __POLICY_ATTR_MAX,    .params = policy_attrs,    .info = policy_attr_info,};

转化为BLOB:

static struct uci_context *g_uci_ctx;static struct blob_buf *b;voidtransform(const char *config){    struct uci_context *ctx = g_uci_ctx;    struct uci_package *p = NULL;    if (!ctx) {        ctx = uci_alloc_context();        g_uci_ctx = ctx;        uci_set_confdir(ctx, NULL);    } else {        p = uci_lookup_package(ctx, config);        if (p)            uci_unload(ctx, p);    }    if (uci_load(ctx, config, &p))        return;        struct uci_element *e;    struct blob_attr *config = NULL;    uci_foreach_element(&p->sectons, e) {        struct uci_section *s = uci_to_section(e);        blob_buf_init(&b, 0);        uci_to_blob(&b, s, &policy_attr_list);        config = blob_memdup(b.head);        /**         * do something with `config`          * free(config), when not use it         */    }}

使用转化后的blob_attr

voidfoo(blob_attr *confg){    struct blob_attr *tb[__POLICY_ATTR_MAX];    blobmsg_parse(policy_attrs, __POLICY_ATTR_MAX, tb,            blob_data(config), blob_len(config));    /**     * do something with *tb[]      */}

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