MicroPython - cstruct example

gistfile1.txt

#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>

#include "nlr.h"
#include "misc.h"
#include "mpconfig.h"
#include "mpqstr.h"
#include "obj.h"
#include "stream.h"

#define ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0]))
//int cstruct_find_field(const char *name, const char **arr, int size);

typedef int (*getter_fun_t)(void *p, int id);
typedef void (*setter_fun_t)(void *p, int id, int val);
void cstruct_load_attr(const char **fields, int num_fields, getter_fun_t get_field, mp_obj_t self_in, qstr attr, mp_obj_t *dest);
bool cstruct_store_attr(const char **fields, int num_fields, setter_fun_t set_field, mp_obj_t self_in, qstr attr, mp_obj_t value);
void cstruct_print(const char **fields, int num_fields, getter_fun_t get_field,
                   void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o_in, mp_print_kind_t kind);



typedef struct _mp_obj_sockaddr_in_t {
    mp_obj_base_t base;
    struct sockaddr_in cstruct;
} mp_obj_sockaddr_in_t;

enum {
    ID_sin_family,
    ID_sin_addr,
    ID_sin_port,
};

static const char *sockaddr_in_fields[] = { "sin_family", "sin_addr", "sin_port" };


static int sockaddr_in_get_field(void *_s, int id) {
    struct sockaddr_in *s = _s;
    switch (id) {
        case ID_sin_family:
            return s->sin_family; break;
        case ID_sin_addr:
            return *(uint32_t*)&s->sin_addr; break;
        case ID_sin_port:
            return s->sin_port; break;
    }
    return -1;
}


static void sockaddr_in_set_field(void *_s, int id, int val) {
    struct sockaddr_in *s = _s;
    switch (id) {
        case ID_sin_family:
            s->sin_family = val; break;
        case ID_sin_addr:
            *(uint32_t*)&s->sin_addr = val; break;
        case ID_sin_port:
            s->sin_port = val; break;
    }
}


static void sockaddr_in_load_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
    cstruct_load_attr(sockaddr_in_fields, ARRAY_SIZE(sockaddr_in_fields), sockaddr_in_get_field, self_in, attr, dest);
}

static bool sockaddr_in_store_attr(mp_obj_t self_in, qstr attr, mp_obj_t value) {
    return cstruct_store_attr(sockaddr_in_fields, ARRAY_SIZE(sockaddr_in_fields), sockaddr_in_set_field, self_in, attr, value);
}


extern const mp_obj_type_t sockaddr_in_type;
static mp_obj_t sockaddr_in_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args) {
    mp_obj_sockaddr_in_t *o = m_new(mp_obj_sockaddr_in_t, 1);
    o->base.type = &sockaddr_in_type;
    memset(&o->cstruct, 0, sizeof(o->cstruct));
    return (mp_obj_t)o;
}

static void sockaddr_in_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o_in, mp_print_kind_t kind) {
    cstruct_print(sockaddr_in_fields, ARRAY_SIZE(sockaddr_in_fields), sockaddr_in_get_field, print, env, o_in, kind);
}


static machine_int_t sockaddr_in_get_buffer(mp_obj_t o_in, buffer_info_t *bufinfo, int flags) {
    mp_obj_sockaddr_in_t *o = o_in;
    bufinfo->buf = &o->cstruct;
    bufinfo->len = sizeof(o->cstruct);
    return 0;
}


const mp_obj_type_t sockaddr_in_type = {
    { &mp_const_type },
    "sockaddr_in",
    .print = sockaddr_in_print,
    .make_new = sockaddr_in_make_new,
    .load_attr = sockaddr_in_load_attr,
    .store_attr = sockaddr_in_store_attr,
    .buffer_p = { .get_buffer = sockaddr_in_get_buffer },
};

//-------------------
#include <string.h>

#include "misc.h"
#include "mpconfig.h"
#include "mpqstr.h"
#include "obj.h"

typedef int (*getter_fun_t)(void *p, int id);
typedef void (*setter_fun_t)(void *p, int id, int val);

static int cstruct_find_field(const char *name, const char **arr, int size) {
    for (int i = 0; i < size; i++) {
        if (!strcmp(arr[i], name)) {
            return i;
        }
    }
    return -1;
}

void cstruct_load_attr(const char **fields, int num_fields, getter_fun_t get_field, mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
    struct _mp_obj_base_t *self = self_in;
    int id = cstruct_find_field(qstr_str(attr), fields, num_fields);
    if (id < 0) {
        return;
    }
    // Pass pointer to beyond _mp_obj_base_t, i.e. to cstruct
    machine_int_t v = get_field(self + 1, id);
    dest[1] = mp_obj_new_int(v);
}

bool cstruct_store_attr(const char **fields, int num_fields, setter_fun_t set_field, mp_obj_t self_in, qstr attr, mp_obj_t value) {
    struct _mp_obj_base_t *self = self_in;
    int id = cstruct_find_field(qstr_str(attr), fields, num_fields);
    if (id < 0) {
        return false;
    }
    machine_int_t v = mp_obj_get_int(value);
    // Pass pointer to beyond _mp_obj_base_t, i.e. to cstruct
    set_field(self + 1, id, v);
    return true;
}

void cstruct_print(const char **fields, int num_fields, getter_fun_t get_field,
                   void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o_in, mp_print_kind_t kind) {
    struct _mp_obj_base_t *o = o_in;
    print(env, o->type->name);
    print(env, "(");
    for (int i = 0; i < num_fields; i++) {
        if (i > 0) {
            print(env, ", ");
        }
        print(env, "%s=0x%x", fields[i], get_field(o + 1, i));
    }
    print(env, ")");
}