alloc.h

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/* Simple Plugin API */
/* SPDX-FileCopyrightText: Copyright © 2018 Wim Taymans */
/* SPDX-License-Identifier: MIT */

#ifndef SPA_BUFFER_ALLOC_H
#define SPA_BUFFER_ALLOC_H

#ifdef __cplusplus
extern "C" {
#endif

#include <spa/buffer/buffer.h>

#ifndef SPA_API_BUFFER_ALLOC
 #ifdef SPA_API_IMPL
  #define SPA_API_BUFFER_ALLOC SPA_API_IMPL
 #else
  #define SPA_API_BUFFER_ALLOC static inline
 #endif
#endif

struct spa_buffer_alloc_info {
#define SPA_BUFFER_ALLOC_FLAG_INLINE_META       (1<<0)  
#define SPA_BUFFER_ALLOC_FLAG_INLINE_CHUNK      (1<<1)  
#define SPA_BUFFER_ALLOC_FLAG_INLINE_DATA       (1<<2)  
#define SPA_BUFFER_ALLOC_FLAG_INLINE_ALL        0b111
#define SPA_BUFFER_ALLOC_FLAG_NO_DATA           (1<<3)  
        uint32_t flags;
        uint32_t max_align;     
        uint32_t n_metas;
        uint32_t n_datas;
        struct spa_meta *metas;
        struct spa_data *datas;
        uint32_t *data_aligns;
        size_t skel_size;       
        size_t meta_size;       
        size_t chunk_size;      
        size_t data_size;       
        size_t mem_size;        
};

SPA_API_BUFFER_ALLOC int spa_buffer_alloc_fill_info(struct spa_buffer_alloc_info *info,
                                             uint32_t n_metas, struct spa_meta metas[],
                                             uint32_t n_datas, struct spa_data datas[],
                                             uint32_t data_aligns[])
{
        size_t size, *target;
        uint32_t i;

        info->n_metas = n_metas;
        info->metas = metas;
        info->n_datas = n_datas;
        info->datas = datas;
        info->data_aligns = data_aligns;
        info->max_align = 16;
        info->mem_size = 0;
        /*
         * The buffer skeleton is placed in memory like below and can
         * be accessed as a regular structure.
         *
         *      +==============================+
         *      | struct spa_buffer            |
         *      |   uint32_t n_metas           | number of metas
         *      |   uint32_t n_datas           | number of datas
         *    +-|   struct spa_meta *metas     | pointer to array of metas
         *   +|-|   struct spa_data *datas     | pointer to array of datas
         *   || +------------------------------+
         *   |+>| struct spa_meta              |
         *   |  |   uint32_t type              | metadata
         *   |  |   uint32_t size              | size of metadata
         *  +|--|   void *data                 | pointer to metadata
         *  ||  | ... <n_metas>                | more spa_meta follow
         *  ||  +------------------------------+
         *  |+->| struct spa_data              |
         *  |   |   uint32_t type              | memory type
         *  |   |   uint32_t flags             |
         *  |   |   int fd                     | fd of shared memory block
         *  |   |   uint32_t mapoffset         | offset in shared memory of data
         *  |   |   uint32_t maxsize           | size of data block
         *  | +-|   void *data                 | pointer to data
         *  |+|-|   struct spa_chunk *chunk    | pointer to chunk
         *  ||| | ... <n_datas>                | more spa_data follow
         *  ||| +==============================+
         *  VVV
         *
         * metadata, chunk and memory can either be placed right
         * after the skeleton (inlined) or in a separate piece of memory.
         *
         *  vvv
         *  ||| +==============================+
         *  +-->| meta data memory             | metadata memory, 8 byte aligned
         *   || | ... <n_metas>                |
         *   || +------------------------------+
         *   +->| struct spa_chunk             | memory for n_datas chunks
         *    | |   uint32_t offset            |
         *    | |   uint32_t size              |
         *    | |   int32_t stride             |
         *    | |   int32_t dummy              |
         *    | | ... <n_datas> chunks         |
         *    | +------------------------------+
         *    +>| data                         | memory for n_datas data, aligned
         *      | ... <n_datas> blocks         | according to alignments
         *      +==============================+
         */
        info->skel_size = sizeof(struct spa_buffer);
        info->skel_size += n_metas * sizeof(struct spa_meta);
        info->skel_size += n_datas * sizeof(struct spa_data);

        for (i = 0, size = 0; i < n_metas; i++)
                size += SPA_ROUND_UP_N(metas[i].size, 8);
        info->meta_size = size;

        if (SPA_FLAG_IS_SET(info->flags, SPA_BUFFER_ALLOC_FLAG_INLINE_META))
                target = &info->skel_size;
        else
                target = &info->mem_size;
        *target += info->meta_size;

        info->chunk_size = n_datas * sizeof(struct spa_chunk);
        if (SPA_FLAG_IS_SET(info->flags, SPA_BUFFER_ALLOC_FLAG_INLINE_CHUNK))
                target = &info->skel_size;
        else
                target = &info->mem_size;
        *target += info->chunk_size;

        for (i = 0, size = 0; i < n_datas; i++) {
                int64_t align = data_aligns[i];
                info->max_align = SPA_MAX(info->max_align, data_aligns[i]);
                size = SPA_ROUND_UP_N(size, align);
                size += datas[i].maxsize;
        }
        info->data_size = size;

        if (!SPA_FLAG_IS_SET(info->flags, SPA_BUFFER_ALLOC_FLAG_NO_DATA) &&
            SPA_FLAG_IS_SET(info->flags, SPA_BUFFER_ALLOC_FLAG_INLINE_DATA))
                target = &info->skel_size;
        else
                target = &info->mem_size;

        *target = SPA_ROUND_UP_N(*target, n_datas ? data_aligns[0] : 1);
        *target += info->data_size;
        *target = SPA_ROUND_UP_N(*target, info->max_align);

        return 0;
}

SPA_API_BUFFER_ALLOC struct spa_buffer *
spa_buffer_alloc_layout(struct spa_buffer_alloc_info *info,
                        void *skel_mem, void *data_mem)
{
        struct spa_buffer *b = (struct spa_buffer*)skel_mem;
        size_t size;
        uint32_t i;
        void **dp, *skel, *data;
        struct spa_chunk *cp;

        b->n_metas = info->n_metas;
        b->metas = SPA_PTROFF(b, sizeof(struct spa_buffer), struct spa_meta);
        b->n_datas = info->n_datas;
        b->datas = SPA_PTROFF(b->metas, info->n_metas * sizeof(struct spa_meta), struct spa_data);

        skel = SPA_PTROFF(b->datas, info->n_datas * sizeof(struct spa_data), void);
        data = data_mem;

        if (SPA_FLAG_IS_SET(info->flags, SPA_BUFFER_ALLOC_FLAG_INLINE_META))
                dp = &skel;
        else
                dp = &data;

        for (i = 0; i < info->n_metas; i++) {
                struct spa_meta *m = &b->metas[i];
                *m = info->metas[i];
                m->data = *dp;
                *dp = SPA_PTROFF(*dp, SPA_ROUND_UP_N(m->size, 8), void);
        }

        size = info->n_datas * sizeof(struct spa_chunk);
        if (SPA_FLAG_IS_SET(info->flags, SPA_BUFFER_ALLOC_FLAG_INLINE_CHUNK)) {
                cp = (struct spa_chunk*)skel;
                skel = SPA_PTROFF(skel, size, void);
        }
        else {
                cp = (struct spa_chunk*)data;
                data = SPA_PTROFF(data, size, void);
        }

        if (SPA_FLAG_IS_SET(info->flags, SPA_BUFFER_ALLOC_FLAG_INLINE_DATA))
                dp = &skel;
        else
                dp = &data;

        for (i = 0; i < info->n_datas; i++) {
                struct spa_data *d = &b->datas[i];

                *d = info->datas[i];
                d->chunk = &cp[i];
                if (!SPA_FLAG_IS_SET(info->flags, SPA_BUFFER_ALLOC_FLAG_NO_DATA)) {
                        *dp = SPA_PTR_ALIGN(*dp, info->data_aligns[i], void);
                        d->data = *dp;
                        *dp = SPA_PTROFF(*dp, d->maxsize, void);
                }
        }
        return b;
}

SPA_API_BUFFER_ALLOC int
spa_buffer_alloc_layout_array(struct spa_buffer_alloc_info *info,
                              uint32_t n_buffers, struct spa_buffer *buffers[],
                              void *skel_mem, void *data_mem)
{
        uint32_t i;
        for (i = 0; i < n_buffers; i++) {
                buffers[i] = spa_buffer_alloc_layout(info, skel_mem, data_mem);
                skel_mem = SPA_PTROFF(skel_mem, info->skel_size, void);
                data_mem = SPA_PTROFF(data_mem, info->mem_size, void);
        }
        return 0;
}

SPA_API_BUFFER_ALLOC struct spa_buffer **
spa_buffer_alloc_array(uint32_t n_buffers, uint32_t flags,
                       uint32_t n_metas, struct spa_meta metas[],
                       uint32_t n_datas, struct spa_data datas[],
                       uint32_t data_aligns[])
{

        struct spa_buffer **buffers;
        struct spa_buffer_alloc_info info = { flags | SPA_BUFFER_ALLOC_FLAG_INLINE_ALL,
                                        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
        void *skel;

        spa_buffer_alloc_fill_info(&info, n_metas, metas, n_datas, datas, data_aligns);

        buffers = (struct spa_buffer **)calloc(1, info.max_align +
                        n_buffers * (sizeof(struct spa_buffer *) + info.skel_size));
        if (buffers == NULL)
                return NULL;

        skel = SPA_PTROFF(buffers, sizeof(struct spa_buffer *) * n_buffers, void);
        skel = SPA_PTR_ALIGN(skel, info.max_align, void);

        spa_buffer_alloc_layout_array(&info, n_buffers, buffers, skel, NULL);

        return buffers;
}

#ifdef __cplusplus
}  /* extern "C" */
#endif

#endif /* SPA_BUFFER_ALLOC_H */