builder.h

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/* Simple Plugin API */
/* SPDX-FileCopyrightText: Copyright © 2018 Wim Taymans */
/* SPDX-License-Identifier: MIT */
 
#ifndef SPA_POD_BUILDER_H
#define SPA_POD_BUILDER_H
 
#ifdef __cplusplus
extern "C" {
#endif
 
#include <stdarg.h>
 
#include <spa/utils/hook.h>
#include <spa/pod/iter.h>
#include <spa/pod/vararg.h>
 
struct spa_pod_builder_state {
        uint32_t offset;
#define SPA_POD_BUILDER_FLAG_BODY       (1<<0)
#define SPA_POD_BUILDER_FLAG_FIRST      (1<<1)
        uint32_t flags;
        struct spa_pod_frame *frame;
};
 
struct spa_pod_builder;
 
struct spa_pod_builder_callbacks {
#define SPA_VERSION_POD_BUILDER_CALLBACKS 0
        uint32_t version;
 
        int (*overflow) (void *data, uint32_t size);
};
 
struct spa_pod_builder {
        void *data;
        uint32_t size;
        uint32_t _padding;
        struct spa_pod_builder_state state;
        struct spa_callbacks callbacks;
};
 
#define SPA_POD_BUILDER_INIT(buffer,size)  ((struct spa_pod_builder){ (buffer), (size), 0, {}, {} })
 
static inline void
spa_pod_builder_get_state(struct spa_pod_builder *builder, struct spa_pod_builder_state *state)
{
        *state = builder->state;
}
 
static inline void
spa_pod_builder_set_callbacks(struct spa_pod_builder *builder,
                const struct spa_pod_builder_callbacks *callbacks, void *data)
{
        builder->callbacks = SPA_CALLBACKS_INIT(callbacks, data);
}
 
static inline void
spa_pod_builder_reset(struct spa_pod_builder *builder, struct spa_pod_builder_state *state)
{
        struct spa_pod_frame *f;
        uint32_t size = builder->state.offset - state->offset;
        builder->state = *state;
        for (f = builder->state.frame; f ; f = f->parent)
                f->pod.size -= size;
}
 
static inline void spa_pod_builder_init(struct spa_pod_builder *builder, void *data, uint32_t size)
{
        *builder = SPA_POD_BUILDER_INIT(data, size);
}
 
static inline struct spa_pod *
spa_pod_builder_deref(struct spa_pod_builder *builder, uint32_t offset)
{
        uint32_t size = builder->size;
        if (offset + 8 <= size) {
                struct spa_pod *pod = SPA_PTROFF(builder->data, offset, struct spa_pod);
                if (offset + SPA_POD_SIZE(pod) <= size)
                        return pod;
        }
        return NULL;
}
 
static inline struct spa_pod *
spa_pod_builder_frame(struct spa_pod_builder *builder, struct spa_pod_frame *frame)
{
        if (frame->offset + SPA_POD_SIZE(&frame->pod) <= builder->size)
                return SPA_PTROFF(builder->data, frame->offset, struct spa_pod);
        return NULL;
}
 
static inline void
spa_pod_builder_push(struct spa_pod_builder *builder,
                     struct spa_pod_frame *frame,
                     const struct spa_pod *pod,
                     uint32_t offset)
{
        frame->pod = *pod;
        frame->offset = offset;
        frame->parent = builder->state.frame;
        frame->flags = builder->state.flags;
        builder->state.frame = frame;
 
        if (frame->pod.type == SPA_TYPE_Array || frame->pod.type == SPA_TYPE_Choice)
                builder->state.flags = SPA_POD_BUILDER_FLAG_FIRST | SPA_POD_BUILDER_FLAG_BODY;
}
 
static inline int spa_pod_builder_raw(struct spa_pod_builder *builder, const void *data, uint32_t size)
{
        int res = 0;
        struct spa_pod_frame *f;
        uint32_t offset = builder->state.offset;
 
        if (offset + size > builder->size) {
                res = -ENOSPC;
                if (offset <= builder->size)
                        spa_callbacks_call_res(&builder->callbacks,
                                        struct spa_pod_builder_callbacks, res,
                                        overflow, 0, offset + size);
        }
        if (res == 0 && data)
                memcpy(SPA_PTROFF(builder->data, offset, void), data, size);
 
        builder->state.offset += size;
 
        for (f = builder->state.frame; f ; f = f->parent)
                f->pod.size += size;
 
        return res;
}
 
static inline int spa_pod_builder_pad(struct spa_pod_builder *builder, uint32_t size)
{
        uint64_t zeroes = 0;
        size = SPA_ROUND_UP_N(size, 8) - size;
        return size ? spa_pod_builder_raw(builder, &zeroes, size) : 0;
}
 
static inline int
spa_pod_builder_raw_padded(struct spa_pod_builder *builder, const void *data, uint32_t size)
{
        int r, res = spa_pod_builder_raw(builder, data, size);
        if ((r = spa_pod_builder_pad(builder, size)) < 0)
                res = r;
        return res;
}
 
static inline void *spa_pod_builder_pop(struct spa_pod_builder *builder, struct spa_pod_frame *frame)
{
        struct spa_pod *pod;
 
        if (SPA_FLAG_IS_SET(builder->state.flags, SPA_POD_BUILDER_FLAG_FIRST)) {
                const struct spa_pod p = { 0, SPA_TYPE_None };
                spa_pod_builder_raw(builder, &p, sizeof(p));
        }
        if ((pod = (struct spa_pod*)spa_pod_builder_frame(builder, frame)) != NULL)
                *pod = frame->pod;
 
        builder->state.frame = frame->parent;
        builder->state.flags = frame->flags;
        spa_pod_builder_pad(builder, builder->state.offset);
        return pod;
}
 
static inline int
spa_pod_builder_primitive(struct spa_pod_builder *builder, const struct spa_pod *p)
{
        const void *data;
        uint32_t size;
        int r, res;
 
        if (builder->state.flags == SPA_POD_BUILDER_FLAG_BODY) {
                data = SPA_POD_BODY_CONST(p);
                size = SPA_POD_BODY_SIZE(p);
        } else {
                data = p;
                size = SPA_POD_SIZE(p);
                SPA_FLAG_CLEAR(builder->state.flags, SPA_POD_BUILDER_FLAG_FIRST);
        }
        res = spa_pod_builder_raw(builder, data, size);
        if (builder->state.flags != SPA_POD_BUILDER_FLAG_BODY)
                if ((r = spa_pod_builder_pad(builder, size)) < 0)
                        res = r;
        return res;
}
 
#define SPA_POD_INIT(size,type) ((struct spa_pod) { (size), (type) })
 
#define SPA_POD_INIT_None() SPA_POD_INIT(0, SPA_TYPE_None)
 
static inline int spa_pod_builder_none(struct spa_pod_builder *builder)
{
        const struct spa_pod p = SPA_POD_INIT_None();
        return spa_pod_builder_primitive(builder, &p);
}
 
static inline int spa_pod_builder_child(struct spa_pod_builder *builder, uint32_t size, uint32_t type)
{
        const struct spa_pod p = SPA_POD_INIT(size,type);
        SPA_FLAG_CLEAR(builder->state.flags, SPA_POD_BUILDER_FLAG_FIRST);
        return spa_pod_builder_raw(builder, &p, sizeof(p));
}
 
#define SPA_POD_INIT_Bool(val) ((struct spa_pod_bool){ { sizeof(uint32_t), SPA_TYPE_Bool }, (val) ? 1 : 0, 0 })
 
static inline int spa_pod_builder_bool(struct spa_pod_builder *builder, bool val)
{
        const struct spa_pod_bool p = SPA_POD_INIT_Bool(val);
        return spa_pod_builder_primitive(builder, &p.pod);
}
 
#define SPA_POD_INIT_Id(val) ((struct spa_pod_id){ { sizeof(uint32_t), SPA_TYPE_Id }, (val), 0 })
 
static inline int spa_pod_builder_id(struct spa_pod_builder *builder, uint32_t val)
{
        const struct spa_pod_id p = SPA_POD_INIT_Id(val);
        return spa_pod_builder_primitive(builder, &p.pod);
}
 
#define SPA_POD_INIT_Int(val) ((struct spa_pod_int){ { sizeof(int32_t), SPA_TYPE_Int }, (val), 0 })
 
static inline int spa_pod_builder_int(struct spa_pod_builder *builder, int32_t val)
{
        const struct spa_pod_int p = SPA_POD_INIT_Int(val);
        return spa_pod_builder_primitive(builder, &p.pod);
}
 
#define SPA_POD_INIT_Long(val) ((struct spa_pod_long){ { sizeof(int64_t), SPA_TYPE_Long }, (val) })
 
static inline int spa_pod_builder_long(struct spa_pod_builder *builder, int64_t val)
{
        const struct spa_pod_long p = SPA_POD_INIT_Long(val);
        return spa_pod_builder_primitive(builder, &p.pod);
}
 
#define SPA_POD_INIT_Float(val) ((struct spa_pod_float){ { sizeof(float), SPA_TYPE_Float }, (val), 0 })
 
static inline int spa_pod_builder_float(struct spa_pod_builder *builder, float val)
{
        const struct spa_pod_float p = SPA_POD_INIT_Float(val);
        return spa_pod_builder_primitive(builder, &p.pod);
}
 
#define SPA_POD_INIT_Double(val) ((struct spa_pod_double){ { sizeof(double), SPA_TYPE_Double }, (val) })
 
static inline int spa_pod_builder_double(struct spa_pod_builder *builder, double val)
{
        const struct spa_pod_double p = SPA_POD_INIT_Double(val);
        return spa_pod_builder_primitive(builder, &p.pod);
}
 
#define SPA_POD_INIT_String(len) ((struct spa_pod_string){ { (len), SPA_TYPE_String } })
 
static inline int
spa_pod_builder_write_string(struct spa_pod_builder *builder, const char *str, uint32_t len)
{
        int r, res;
        res = spa_pod_builder_raw(builder, str, len);
        if ((r = spa_pod_builder_raw(builder, "", 1)) < 0)
                res = r;
        if ((r = spa_pod_builder_pad(builder, builder->state.offset)) < 0)
                res = r;
        return res;
}
 
static inline int
spa_pod_builder_string_len(struct spa_pod_builder *builder, const char *str, uint32_t len)
{
        const struct spa_pod_string p = SPA_POD_INIT_String(len+1);
        int r, res = spa_pod_builder_raw(builder, &p, sizeof(p));
        if ((r = spa_pod_builder_write_string(builder, str, len)) < 0)
                res = r;
        return res;
}
 
static inline int spa_pod_builder_string(struct spa_pod_builder *builder, const char *str)
{
        uint32_t len = str ? strlen(str) : 0;
        return spa_pod_builder_string_len(builder, str ? str : "", len);
}
 
#define SPA_POD_INIT_Bytes(len) ((struct spa_pod_bytes){ { (len), SPA_TYPE_Bytes } })
 
static inline int
spa_pod_builder_bytes(struct spa_pod_builder *builder, const void *bytes, uint32_t len)
{
        const struct spa_pod_bytes p = SPA_POD_INIT_Bytes(len);
        int r, res = spa_pod_builder_raw(builder, &p, sizeof(p));
        if ((r = spa_pod_builder_raw_padded(builder, bytes, len)) < 0)
                res = r;
        return res;
}
static inline void *
spa_pod_builder_reserve_bytes(struct spa_pod_builder *builder, uint32_t len)
{
        uint32_t offset = builder->state.offset;
        if (spa_pod_builder_bytes(builder, NULL, len) < 0)
                return NULL;
        return SPA_POD_BODY(spa_pod_builder_deref(builder, offset));
}
 
#define SPA_POD_INIT_Pointer(type,value) ((struct spa_pod_pointer){ { sizeof(struct spa_pod_pointer_body), SPA_TYPE_Pointer }, { (type), 0, (value) } })
 
static inline int
spa_pod_builder_pointer(struct spa_pod_builder *builder, uint32_t type, const void *val)
{
        const struct spa_pod_pointer p = SPA_POD_INIT_Pointer(type, val);
        return spa_pod_builder_primitive(builder, &p.pod);
}
 
#define SPA_POD_INIT_Fd(fd) ((struct spa_pod_fd){ { sizeof(int64_t), SPA_TYPE_Fd }, (fd) })
 
static inline int spa_pod_builder_fd(struct spa_pod_builder *builder, int64_t fd)
{
        const struct spa_pod_fd p = SPA_POD_INIT_Fd(fd);
        return spa_pod_builder_primitive(builder, &p.pod);
}
 
#define SPA_POD_INIT_Rectangle(val) ((struct spa_pod_rectangle){ { sizeof(struct spa_rectangle), SPA_TYPE_Rectangle }, (val) })
 
static inline int
spa_pod_builder_rectangle(struct spa_pod_builder *builder, uint32_t width, uint32_t height)
{
        const struct spa_pod_rectangle p = SPA_POD_INIT_Rectangle(SPA_RECTANGLE(width, height));
        return spa_pod_builder_primitive(builder, &p.pod);
}
 
#define SPA_POD_INIT_Fraction(val) ((struct spa_pod_fraction){ { sizeof(struct spa_fraction), SPA_TYPE_Fraction }, (val) })
 
static inline int
spa_pod_builder_fraction(struct spa_pod_builder *builder, uint32_t num, uint32_t denom)
{
        const struct spa_pod_fraction p = SPA_POD_INIT_Fraction(SPA_FRACTION(num, denom));
        return spa_pod_builder_primitive(builder, &p.pod);
}
 
static inline int
spa_pod_builder_push_array(struct spa_pod_builder *builder, struct spa_pod_frame *frame)
{
        const struct spa_pod_array p =
            { {sizeof(struct spa_pod_array_body) - sizeof(struct spa_pod), SPA_TYPE_Array},
            {{0, 0}} };
        uint32_t offset = builder->state.offset;
        int res = spa_pod_builder_raw(builder, &p, sizeof(p) - sizeof(struct spa_pod));
        spa_pod_builder_push(builder, frame, &p.pod, offset);
        return res;
}
 
static inline int
spa_pod_builder_array(struct spa_pod_builder *builder,
                      uint32_t child_size, uint32_t child_type, uint32_t n_elems, const void *elems)
{
        const struct spa_pod_array p = {
                {(uint32_t)(sizeof(struct spa_pod_array_body) + n_elems * child_size), SPA_TYPE_Array},
                {{child_size, child_type}}
        };
        int r, res = spa_pod_builder_raw(builder, &p, sizeof(p));
        if ((r = spa_pod_builder_raw_padded(builder, elems, child_size * n_elems)) < 0)
                res = r;
        return res;
}
 
#define SPA_POD_INIT_CHOICE_BODY(type, flags, child_size, child_type)                           \
        ((struct spa_pod_choice_body) { (type), (flags), { (child_size), (child_type) }})
 
#define SPA_POD_INIT_Choice(type, ctype, child_type, n_vals, ...)                               \
        ((struct { struct spa_pod_choice choice; ctype vals[(n_vals)];})                        \
        { { { (n_vals) * sizeof(ctype) + sizeof(struct spa_pod_choice_body), SPA_TYPE_Choice }, \
                { (type), 0, { sizeof(ctype), (child_type) } } }, { __VA_ARGS__ } })
 
static inline int
spa_pod_builder_push_choice(struct spa_pod_builder *builder, struct spa_pod_frame *frame,
                uint32_t type, uint32_t flags)
{
        const struct spa_pod_choice p =
            { {sizeof(struct spa_pod_choice_body) - sizeof(struct spa_pod), SPA_TYPE_Choice},
            { type, flags, {0, 0}} };
        uint32_t offset = builder->state.offset;
        int res = spa_pod_builder_raw(builder, &p, sizeof(p) - sizeof(struct spa_pod));
        spa_pod_builder_push(builder, frame, &p.pod, offset);
        return res;
}
 
#define SPA_POD_INIT_Struct(size) ((struct spa_pod_struct){ { (size), SPA_TYPE_Struct } })
 
static inline int
spa_pod_builder_push_struct(struct spa_pod_builder *builder, struct spa_pod_frame *frame)
{
        const struct spa_pod_struct p = SPA_POD_INIT_Struct(0);
        uint32_t offset = builder->state.offset;
        int res = spa_pod_builder_raw(builder, &p, sizeof(p));
        spa_pod_builder_push(builder, frame, &p.pod, offset);
        return res;
}
 
#define SPA_POD_INIT_Object(size,type,id,...)   ((struct spa_pod_object){ { (size), SPA_TYPE_Object }, { (type), (id) }, ##__VA_ARGS__ })
 
static inline int
spa_pod_builder_push_object(struct spa_pod_builder *builder, struct spa_pod_frame *frame,
                uint32_t type, uint32_t id)
{
        const struct spa_pod_object p =
            SPA_POD_INIT_Object(sizeof(struct spa_pod_object_body), type, id);
        uint32_t offset = builder->state.offset;
        int res = spa_pod_builder_raw(builder, &p, sizeof(p));
        spa_pod_builder_push(builder, frame, &p.pod, offset);
        return res;
}
 
#define SPA_POD_INIT_Prop(key,flags,size,type)  \
        ((struct spa_pod_prop){ (key), (flags), { (size), (type) } })
 
static inline int
spa_pod_builder_prop(struct spa_pod_builder *builder, uint32_t key, uint32_t flags)
{
        const struct { uint32_t key; uint32_t flags; } p = { key, flags };
        return spa_pod_builder_raw(builder, &p, sizeof(p));
}
 
#define SPA_POD_INIT_Sequence(size,unit)        \
        ((struct spa_pod_sequence){ { (size), SPA_TYPE_Sequence}, {(unit), 0 } })
 
static inline int
spa_pod_builder_push_sequence(struct spa_pod_builder *builder, struct spa_pod_frame *frame, uint32_t unit)
{
        const struct spa_pod_sequence p =
            SPA_POD_INIT_Sequence(sizeof(struct spa_pod_sequence_body), unit);
        uint32_t offset = builder->state.offset;
        int res = spa_pod_builder_raw(builder, &p, sizeof(p));
        spa_pod_builder_push(builder, frame, &p.pod, offset);
        return res;
}
 
static inline int
spa_pod_builder_control(struct spa_pod_builder *builder, uint32_t offset, uint32_t type)
{
        const struct { uint32_t offset; uint32_t type; } p = { offset, type };
        return spa_pod_builder_raw(builder, &p, sizeof(p));
}
 
static inline uint32_t spa_choice_from_id(char id)
{
        switch (id) {
        case 'r':
                return SPA_CHOICE_Range;
        case 's':
                return SPA_CHOICE_Step;
        case 'e':
                return SPA_CHOICE_Enum;
        case 'f':
                return SPA_CHOICE_Flags;
        case 'n':
        default:
                return SPA_CHOICE_None;
        }
}
 
#define SPA_POD_BUILDER_COLLECT(builder,type,args)                              \
do {                                                                            \
        switch (type) {                                                         \
        case 'b':                                                               \
                spa_pod_builder_bool(builder, !!va_arg(args, int));             \
                break;                                                          \
        case 'I':                                                               \
                spa_pod_builder_id(builder, va_arg(args, uint32_t));            \
                break;                                                          \
        case 'i':                                                               \
                spa_pod_builder_int(builder, va_arg(args, int));                \
                break;                                                          \
        case 'l':                                                               \
                spa_pod_builder_long(builder, va_arg(args, int64_t));           \
                break;                                                          \
        case 'f':                                                               \
                spa_pod_builder_float(builder, va_arg(args, double));           \
                break;                                                          \
        case 'd':                                                               \
                spa_pod_builder_double(builder, va_arg(args, double));          \
                break;                                                          \
        case 's':                                                               \
        {                                                                       \
                char *strval = va_arg(args, char *);                            \
                if (strval != NULL) {                                           \
                        size_t len = strlen(strval);                            \
                        spa_pod_builder_string_len(builder, strval, len);       \
                }                                                               \
                else                                                            \
                        spa_pod_builder_none(builder);                          \
                break;                                                          \
        }                                                                       \
        case 'S':                                                               \
        {                                                                       \
                char *strval = va_arg(args, char *);                            \
                size_t len = va_arg(args, int);                                 \
                spa_pod_builder_string_len(builder, strval, len);               \
                break;                                                          \
        }                                                                       \
        case 'y':                                                               \
        {                                                                       \
                void *ptr  = va_arg(args, void *);                              \
                int len = va_arg(args, int);                                    \
                spa_pod_builder_bytes(builder, ptr, len);                       \
                break;                                                          \
        }                                                                       \
        case 'R':                                                               \
        {                                                                       \
                struct spa_rectangle *rectval =                                 \
                        va_arg(args, struct spa_rectangle *);                   \
                spa_pod_builder_rectangle(builder,                              \
                                rectval->width, rectval->height);               \
                break;                                                          \
        }                                                                       \
        case 'F':                                                               \
        {                                                                       \
                struct spa_fraction *fracval =                                  \
                        va_arg(args, struct spa_fraction *);                    \
                spa_pod_builder_fraction(builder, fracval->num, fracval->denom);\
                break;                                                          \
        }                                                                       \
        case 'a':                                                               \
        {                                                                       \
                int child_size = va_arg(args, int);                             \
                int child_type = va_arg(args, int);                             \
                int n_elems = va_arg(args, int);                                \
                void *elems = va_arg(args, void *);                             \
                spa_pod_builder_array(builder, child_size,                      \
                                child_type, n_elems, elems);                    \
                break;                                                          \
        }                                                                       \
        case 'p':                                                               \
        {                                                                       \
                int t = va_arg(args, uint32_t);                                 \
                spa_pod_builder_pointer(builder, t, va_arg(args, void *));      \
                break;                                                          \
        }                                                                       \
        case 'h':                                                               \
                spa_pod_builder_fd(builder, va_arg(args, int));                 \
                break;                                                          \
        case 'P':                                                               \
        case 'O':                                                               \
        case 'T':                                                               \
        case 'V':                                                               \
        {                                                                       \
                struct spa_pod *pod = va_arg(args, struct spa_pod *);           \
                if (pod == NULL)                                                \
                        spa_pod_builder_none(builder);                          \
                else                                                            \
                        spa_pod_builder_primitive(builder, pod);                \
                break;                                                          \
        }                                                                       \
        }                                                                       \
} while(false)
 
static inline int
spa_pod_builder_addv(struct spa_pod_builder *builder, va_list args)
{
        int res = 0;
        struct spa_pod_frame *frame = builder->state.frame;
        uint32_t ftype = frame ? frame->pod.type : (uint32_t)SPA_TYPE_None;
 
        do {
                const char *format;
                int n_values = 1;
                struct spa_pod_frame f;
                bool choice;
 
                switch (ftype) {
                case SPA_TYPE_Object:
                {
                        uint32_t key = va_arg(args, uint32_t);
                        if (key == 0)
                                goto exit;
                        spa_pod_builder_prop(builder, key, 0);
                        break;
                }
                case SPA_TYPE_Sequence:
                {
                        uint32_t offset = va_arg(args, uint32_t);
                        uint32_t type = va_arg(args, uint32_t);
                        if (type == 0)
                                goto exit;
                        spa_pod_builder_control(builder, offset, type);
                        SPA_FALLTHROUGH
                }
                default:
                        break;
                }
                if ((format = va_arg(args, const char *)) == NULL)
                        break;
 
                choice = *format == '?';
                if (choice) {
                        uint32_t type = spa_choice_from_id(*++format);
                        if (*format != '\0')
                                format++;
 
                        spa_pod_builder_push_choice(builder, &f, type, 0);
 
                        n_values = va_arg(args, int);
                }
                while (n_values-- > 0)
                        SPA_POD_BUILDER_COLLECT(builder, *format, args);
 
                if (choice)
                        spa_pod_builder_pop(builder, &f);
        } while (true);
 
      exit:
        return res;
}
 
static inline int spa_pod_builder_add(struct spa_pod_builder *builder, ...)
{
        int res;
        va_list args;
 
        va_start(args, builder);
        res = spa_pod_builder_addv(builder, args);
        va_end(args);
 
        return res;
}
 
#define spa_pod_builder_add_object(b,type,id,...)                               \
({                                                                              \
        struct spa_pod_builder *_b = (b);                                       \
        struct spa_pod_frame _f;                                                \
        spa_pod_builder_push_object(_b, &_f, type, id);                         \
        spa_pod_builder_add(_b, ##__VA_ARGS__, 0);                              \
        spa_pod_builder_pop(_b, &_f);                                           \
})
 
#define spa_pod_builder_add_struct(b,...)                                       \
({                                                                              \
        struct spa_pod_builder *_b = (b);                                       \
        struct spa_pod_frame _f;                                                \
        spa_pod_builder_push_struct(_b, &_f);                                   \
        spa_pod_builder_add(_b, ##__VA_ARGS__, NULL);                           \
        spa_pod_builder_pop(_b, &_f);                                           \
})
 
#define spa_pod_builder_add_sequence(b,unit,...)                                \
({                                                                              \
        struct spa_pod_builder *_b = (b);                                       \
        struct spa_pod_frame _f;                                                \
        spa_pod_builder_push_sequence(_b, &_f, unit);                           \
        spa_pod_builder_add(_b, ##__VA_ARGS__, 0, 0);                           \
        spa_pod_builder_pop(_b, &_f);                                           \
})
 
static inline struct spa_pod *
spa_pod_copy(const struct spa_pod *pod)
{
        size_t size;
        struct spa_pod *c;
 
        size = SPA_POD_SIZE(pod);
        if ((c = (struct spa_pod *) malloc(size)) == NULL)
                return NULL;
        return (struct spa_pod *) memcpy(c, pod, size);
}
 
#ifdef __cplusplus
}  /* extern "C" */
#endif
 
#endif /* SPA_POD_BUILDER_H */