filter.h

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/* Simple Plugin API
 *
 * Copyright © 2018 Wim Taymans
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */
 
#ifndef SPA_POD_FILTER_H
#define SPA_POD_FILTER_H
 
#ifdef __cplusplus
extern "C" {
#endif
 
#include <errno.h>
#include <stdint.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
 
#include <spa/param/props.h>
#include <spa/pod/iter.h>
#include <spa/pod/builder.h>
#include <spa/pod/compare.h>
 
static inline int spa_pod_choice_fix_default(struct spa_pod_choice *choice)
{
        void *val, *alt;
        int i, nvals;
        uint32_t type, size;
 
        nvals = SPA_POD_CHOICE_N_VALUES(choice);
        type = SPA_POD_CHOICE_VALUE_TYPE(choice);
        size = SPA_POD_CHOICE_VALUE_SIZE(choice);
        alt = val = SPA_POD_CHOICE_VALUES(choice);
 
        switch (choice->body.type) {
        case SPA_CHOICE_None:
                break;
        case SPA_CHOICE_Range:
        case SPA_CHOICE_Step:
                if (nvals > 1) {
                        alt = SPA_PTROFF(alt, size, void);
                        if (spa_pod_compare_value(type, val, alt, size) < 0)
                                memcpy(val, alt, size);
                }
                if (nvals > 2) {
                        alt = SPA_PTROFF(alt, size, void);
                        if (spa_pod_compare_value(type, val, alt, size) > 0)
                                memcpy(val, alt, size);
                }
                break;
        case SPA_CHOICE_Flags:
        case SPA_CHOICE_Enum:
        {
                void *best = NULL;
 
                for (i = 1; i < nvals; i++) {
                        alt = SPA_PTROFF(alt, size, void);
                        if (spa_pod_compare_value(type, val, alt, size) == 0) {
                                best = alt;
                                break;
                        }
                        if (best == NULL)
                                best = alt;
                }
                if (best)
                        memcpy(val, best, size);
 
                if (nvals <= 1)
                        choice->body.type = SPA_CHOICE_None;
                break;
        }
        }
        return 0;
}
 
static inline int spa_pod_filter_flags_value(struct spa_pod_builder *b,
                uint32_t type, const void *r1, const void *r2, uint32_t size)
{
        switch (type) {
        case SPA_TYPE_Int:
        {
                int32_t val = (*(int32_t *) r1) & (*(int32_t *) r2);
                if (val == 0)
                        return 0;
                spa_pod_builder_int(b, val);
                break;
        }
        case SPA_TYPE_Long:
        {
                int64_t val = (*(int64_t *) r1) & (*(int64_t *) r2);
                if (val == 0)
                        return 0;
                spa_pod_builder_long(b, val);
                break;
        }
        default:
                return -ENOTSUP;
        }
        return 1;
}
 
 
static inline int
spa_pod_filter_prop(struct spa_pod_builder *b,
            const struct spa_pod_prop *p1,
            const struct spa_pod_prop *p2)
{
        const struct spa_pod *v1, *v2;
        struct spa_pod_choice *nc;
        uint32_t j, k, nalt1, nalt2;
        void *alt1, *alt2, *a1, *a2;
        uint32_t type, size, p1c, p2c;
        struct spa_pod_frame f;
 
        v1 = spa_pod_get_values(&p1->value, &nalt1, &p1c);
        alt1 = SPA_POD_BODY(v1);
        v2 = spa_pod_get_values(&p2->value, &nalt2, &p2c);
        alt2 = SPA_POD_BODY(v2);
 
        type = v1->type;
        size = v1->size;
 
        /* incompatible property types */
        if (type != v2->type || size != v2->size || p1->key != p2->key)
                return -EINVAL;
 
        if (p1c == SPA_CHOICE_None || p1c == SPA_CHOICE_Flags) {
                nalt1 = 1;
        } else {
                alt1 = SPA_PTROFF(alt1, size, void);
                nalt1--;
        }
 
        if (p2c == SPA_CHOICE_None || p2c == SPA_CHOICE_Flags) {
                nalt2 = 1;
        } else {
                alt2 = SPA_PTROFF(alt2, size, void);
                nalt2--;
        }
 
        /* start with copying the property */
        spa_pod_builder_prop(b, p1->key, p1->flags & p2->flags);
        spa_pod_builder_push_choice(b, &f, 0, 0);
        nc = (struct spa_pod_choice*)spa_pod_builder_frame(b, &f);
 
        /* default value */
        spa_pod_builder_primitive(b, v1);
 
        if ((p1c == SPA_CHOICE_None && p2c == SPA_CHOICE_None) ||
            (p1c == SPA_CHOICE_None && p2c == SPA_CHOICE_Enum) ||
            (p1c == SPA_CHOICE_Enum && p2c == SPA_CHOICE_None) ||
            (p1c == SPA_CHOICE_Enum && p2c == SPA_CHOICE_Enum)) {
                int n_copied = 0;
                /* copy all equal values but don't copy the default value again */
                for (j = 0, a1 = alt1; j < nalt1; j++, a1 = SPA_PTROFF(a1, size, void)) {
                        for (k = 0, a2 = alt2; k < nalt2; k++, a2 = SPA_PTROFF(a2,size,void)) {
                                if (spa_pod_compare_value(type, a1, a2, size) == 0) {
                                        if (p1c == SPA_CHOICE_Enum || j > 0)
                                                spa_pod_builder_raw(b, a1, size);
                                        n_copied++;
                                }
                        }
                }
                if (n_copied == 0)
                        return -EINVAL;
                nc->body.type = SPA_CHOICE_Enum;
        }
 
        if ((p1c == SPA_CHOICE_None && p2c == SPA_CHOICE_Range) ||
            (p1c == SPA_CHOICE_Enum && p2c == SPA_CHOICE_Range)) {
                int n_copied = 0;
                /* copy all values inside the range */
                for (j = 0, a1 = alt1, a2 = alt2; j < nalt1; j++, a1 = SPA_PTROFF(a1,size,void)) {
                        if (spa_pod_compare_value(type, a1, a2, size) < 0)
                                continue;
                        if (spa_pod_compare_value(type, a1, SPA_PTROFF(a2,size,void), size) > 0)
                                continue;
                        spa_pod_builder_raw(b, a1, size);
                        n_copied++;
                }
                if (n_copied == 0)
                        return -EINVAL;
                nc->body.type = SPA_CHOICE_Enum;
        }
 
        if ((p1c == SPA_CHOICE_None && p2c == SPA_CHOICE_Step) ||
            (p1c == SPA_CHOICE_Enum && p2c == SPA_CHOICE_Step)) {
                return -ENOTSUP;
        }
 
        if ((p1c == SPA_CHOICE_Range && p2c == SPA_CHOICE_None) ||
            (p1c == SPA_CHOICE_Range && p2c == SPA_CHOICE_Enum)) {
                int n_copied = 0;
                /* copy all values inside the range */
                for (k = 0, a1 = alt1, a2 = alt2; k < nalt2; k++, a2 = SPA_PTROFF(a2,size,void)) {
                        if (spa_pod_compare_value(type, a2, a1, size) < 0)
                                continue;
                        if (spa_pod_compare_value(type, a2, SPA_PTROFF(a1,size,void), size) > 0)
                                continue;
                        spa_pod_builder_raw(b, a2, size);
                        n_copied++;
                }
                if (n_copied == 0)
                        return -EINVAL;
                nc->body.type = SPA_CHOICE_Enum;
        }
 
        if ((p1c == SPA_CHOICE_Range && p2c == SPA_CHOICE_Range) ||
            (p1c == SPA_CHOICE_Range && p2c == SPA_CHOICE_Step) ||
            (p1c == SPA_CHOICE_Step && p2c == SPA_CHOICE_Range) ||
            (p1c == SPA_CHOICE_Step && p2c == SPA_CHOICE_Step)) {
                if (spa_pod_compare_value(type, alt1, alt2, size) < 0)
                        spa_pod_builder_raw(b, alt2, size);
                else
                        spa_pod_builder_raw(b, alt1, size);
 
                alt1 = SPA_PTROFF(alt1,size,void);
                alt2 = SPA_PTROFF(alt2,size,void);
 
                if (spa_pod_compare_value(type, alt1, alt2, size) < 0)
                        spa_pod_builder_raw(b, alt1, size);
                else
                        spa_pod_builder_raw(b, alt2, size);
 
                nc->body.type = SPA_CHOICE_Range;
        }
 
        if ((p1c == SPA_CHOICE_None && p2c == SPA_CHOICE_Flags) ||
            (p1c == SPA_CHOICE_Flags && p2c == SPA_CHOICE_None) ||
            (p1c == SPA_CHOICE_Flags && p2c == SPA_CHOICE_Flags)) {
                if (spa_pod_filter_flags_value(b, type, alt1, alt2, size) != 1)
                        return -EINVAL;
                nc->body.type = SPA_CHOICE_Flags;
        }
 
        if (p1c == SPA_CHOICE_Range && p2c == SPA_CHOICE_Flags)
                return -ENOTSUP;
 
        if (p1c == SPA_CHOICE_Enum && p2c == SPA_CHOICE_Flags)
                return -ENOTSUP;
 
        if (p1c == SPA_CHOICE_Step && p2c == SPA_CHOICE_None)
                return -ENOTSUP;
        if (p1c == SPA_CHOICE_Step && p2c == SPA_CHOICE_Enum)
                return -ENOTSUP;
        if (p1c == SPA_CHOICE_Step && p2c == SPA_CHOICE_Flags)
                return -ENOTSUP;
 
        if (p1c == SPA_CHOICE_Flags && p2c == SPA_CHOICE_Range)
                return -ENOTSUP;
        if (p1c == SPA_CHOICE_Flags && p2c == SPA_CHOICE_Step)
                return -ENOTSUP;
        if (p1c == SPA_CHOICE_Flags && p2c == SPA_CHOICE_Enum)
                return -ENOTSUP;
 
        spa_pod_builder_pop(b, &f);
        spa_pod_choice_fix_default(nc);
 
        return 0;
}
 
static inline int spa_pod_filter_part(struct spa_pod_builder *b,
               const struct spa_pod *pod, uint32_t pod_size,
               const struct spa_pod *filter, uint32_t filter_size)
{
        const struct spa_pod *pp, *pf;
        int res = 0;
 
        pf = filter;
 
        SPA_POD_FOREACH(pod, pod_size, pp) {
                bool do_copy = false, do_advance = false;
                uint32_t filter_offset = 0;
                struct spa_pod_frame f;
 
                switch (SPA_POD_TYPE(pp)) {
                case SPA_TYPE_Object:
                        if (pf != NULL) {
                                struct spa_pod_object *op = (struct spa_pod_object *) pp;
                                struct spa_pod_object *of = (struct spa_pod_object *) pf;
                                const struct spa_pod_prop *p1, *p2;
 
                                if (SPA_POD_TYPE(pf) != SPA_POD_TYPE(pp))
                                        return -EINVAL;
 
                                spa_pod_builder_push_object(b, &f, op->body.type, op->body.id);
                                p2 = NULL;
                                SPA_POD_OBJECT_FOREACH(op, p1) {
                                        p2 = spa_pod_object_find_prop(of, p2, p1->key);
                                        if (p2 != NULL)
                                                res = spa_pod_filter_prop(b, p1, p2);
                                        else if ((p1->flags & SPA_POD_PROP_FLAG_MANDATORY) != 0)
                                                res = -EINVAL;
                                        else
                                                spa_pod_builder_raw_padded(b, p1, SPA_POD_PROP_SIZE(p1));
                                        if (res < 0)
                                                break;
                                }
                                if (res >= 0) {
                                        p1 = NULL;
                                        SPA_POD_OBJECT_FOREACH(of, p2) {
                                                p1 = spa_pod_object_find_prop(op, p1, p2->key);
                                                if (p1 != NULL)
                                                        continue;
                                                if ((p2->flags & SPA_POD_PROP_FLAG_MANDATORY) != 0)
                                                        res = -EINVAL;
                                                if (res < 0)
                                                        break;
                                                spa_pod_builder_raw_padded(b, p2, SPA_POD_PROP_SIZE(p2));
                                        }
                                }
                                spa_pod_builder_pop(b, &f);
                                do_advance = true;
                        }
                        else
                                do_copy = true;
                        break;
 
                case SPA_TYPE_Struct:
                        if (pf != NULL) {
                                if (SPA_POD_TYPE(pf) != SPA_POD_TYPE(pp))
                                        return -EINVAL;
 
                                filter_offset = sizeof(struct spa_pod_struct);
                                spa_pod_builder_push_struct(b, &f);
                                res = spa_pod_filter_part(b,
                                        SPA_PTROFF(pp,filter_offset,const struct spa_pod),
                                        SPA_POD_SIZE(pp) - filter_offset,
                                        SPA_PTROFF(pf,filter_offset,const struct spa_pod),
                                        SPA_POD_SIZE(pf) - filter_offset);
                                spa_pod_builder_pop(b, &f);
                                do_advance = true;
                        }
                        else
                                do_copy = true;
                        break;
 
                default:
                        if (pf != NULL) {
                                if (SPA_POD_SIZE(pp) != SPA_POD_SIZE(pf))
                                        return -EINVAL;
                                if (memcmp(pp, pf, SPA_POD_SIZE(pp)) != 0)
                                        return -EINVAL;
                                do_advance = true;
                        }
                        do_copy = true;
                        break;
                }
                if (do_copy)
                        spa_pod_builder_raw_padded(b, pp, SPA_POD_SIZE(pp));
                if (do_advance) {
                        pf = (const struct spa_pod*)spa_pod_next(pf);
                        if (!spa_pod_is_inside(filter, filter_size, pf))
                                pf = NULL;
                }
                if (res < 0)
                        break;
        }
        return res;
}
 
static inline int
spa_pod_filter(struct spa_pod_builder *b,
               struct spa_pod **result,
               const struct spa_pod *pod,
               const struct spa_pod *filter)
{
        int res;
        struct spa_pod_builder_state state;
 
        spa_return_val_if_fail(pod != NULL, -EINVAL);
        spa_return_val_if_fail(b != NULL, -EINVAL);
 
        spa_pod_builder_get_state(b, &state);
        if (filter == NULL)
                res = spa_pod_builder_raw_padded(b, pod, SPA_POD_SIZE(pod));
        else
                res = spa_pod_filter_part(b, pod, SPA_POD_SIZE(pod), filter, SPA_POD_SIZE(filter));
 
        if (res < 0) {
                spa_pod_builder_reset(b, &state);
        } else if (result) {
                *result = (struct spa_pod*)spa_pod_builder_deref(b, state.offset);
                if (*result == NULL)
                        res = -ENOSPC;
        }
        return res;
}
 
#ifdef __cplusplus
} /* extern "C" */
#endif
 
#endif /* SPA_POD_FILTER_H */