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      1 /* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
      2  * Use of this source code is governed by a BSD-style license that can be
      3  * found in the LICENSE file.
      4  */
      5 
      6 #include <stdlib.h>
      7 #include <sys/param.h>
      8 
      9 #include "cras_types.h"
     10 #include "buffer_share.h"
     11 
     12 static inline struct id_offset *find_unused(const struct buffer_share *mix)
     13 {
     14 	unsigned int i;
     15 
     16 	for (i = 0; i < mix->id_sz; i++) {
     17 		if (!mix->wr_idx[i].used)
     18 			return &mix->wr_idx[i];
     19 	}
     20 
     21 	return NULL;
     22 }
     23 
     24 
     25 static inline struct id_offset *find_id(const struct buffer_share *mix,
     26 					unsigned int id)
     27 {
     28 	unsigned int i;
     29 
     30 	for (i = 0; i < mix->id_sz; i++) {
     31 		if (mix->wr_idx[i].used && id == mix->wr_idx[i].id)
     32 			return &mix->wr_idx[i];
     33 	}
     34 
     35 	return NULL;
     36 }
     37 
     38 static void alloc_more_ids(struct buffer_share *mix)
     39 {
     40 	unsigned int new_size = mix->id_sz * 2;
     41 	unsigned int i;
     42 
     43 	mix->wr_idx = realloc(mix->wr_idx, sizeof(mix->wr_idx[0]) * new_size);
     44 
     45 	for (i = mix->id_sz; i < new_size; i++)
     46 		mix->wr_idx[i].used = 0;
     47 
     48 	mix->id_sz = new_size;
     49 }
     50 
     51 struct buffer_share *buffer_share_create(unsigned int buf_sz)
     52 {
     53 	struct buffer_share *mix;
     54 
     55 	mix = calloc(1, sizeof(*mix));
     56 	mix->id_sz = INITIAL_ID_SIZE;
     57 	mix->wr_idx = calloc(mix->id_sz, sizeof(mix->wr_idx[0]));
     58 	mix->buf_sz = buf_sz;
     59 
     60 	return mix;
     61 }
     62 
     63 void buffer_share_destroy(struct buffer_share *mix)
     64 {
     65 	if (!mix)
     66 		return;
     67 	free(mix->wr_idx);
     68 	free(mix);
     69 }
     70 
     71 int buffer_share_add_id(struct buffer_share *mix, unsigned int id, void *data)
     72 {
     73 	struct id_offset *o;
     74 
     75 	o = find_id(mix, id);
     76 	if (o)
     77 		return -EEXIST;
     78 
     79 	o = find_unused(mix);
     80 	if (!o)
     81 		alloc_more_ids(mix);
     82 
     83 	o = find_unused(mix);
     84 	o->used = 1;
     85 	o->id = id;
     86 	o->offset = 0;
     87 	o->data = data;
     88 
     89 	return 0;
     90 }
     91 
     92 int buffer_share_rm_id(struct buffer_share *mix, unsigned int id)
     93 {
     94 	struct id_offset *o;
     95 
     96 	o = find_id(mix, id);
     97 	if (!o)
     98 		return -ENOENT;
     99 	o->used = 0;
    100 	o->data = NULL;
    101 
    102 	return 0;
    103 }
    104 
    105 int buffer_share_offset_update(struct buffer_share *mix, unsigned int id,
    106 			       unsigned int delta)
    107 {
    108 	unsigned int i;
    109 
    110 	for (i = 0; i < mix->id_sz; i++) {
    111 		if (id != mix->wr_idx[i].id)
    112 			continue;
    113 
    114 		mix->wr_idx[i].offset += delta;
    115 		break;
    116 	}
    117 
    118 	return 0;
    119 }
    120 
    121 unsigned int buffer_share_get_new_write_point(struct buffer_share *mix)
    122 {
    123 	unsigned int min_written = mix->buf_sz + 1;
    124 	unsigned int i;
    125 
    126 	for (i = 0; i < mix->id_sz; i++) {
    127 		struct id_offset *o = &mix->wr_idx[i];
    128 
    129 		if (!o->used)
    130 			continue;
    131 
    132 		min_written = MIN(min_written, o->offset);
    133 	}
    134 	for (i = 0; i < mix->id_sz; i++) {
    135 		struct id_offset *o = &mix->wr_idx[i];
    136 		o->offset -= min_written;
    137 	}
    138 
    139 	if (min_written > mix->buf_sz)
    140 		return 0;
    141 
    142 	return min_written;
    143 }
    144 
    145 static struct id_offset *get_id_offset(const struct buffer_share *mix,
    146 				       unsigned int id)
    147 {
    148 	unsigned int i;
    149 	struct id_offset *o;
    150 
    151 	for (i = 0; i < mix->id_sz; i++) {
    152 		o = &mix->wr_idx[i];
    153 		if (o->used && o->id == id)
    154 			return o;
    155 	}
    156 	return NULL;
    157 }
    158 
    159 unsigned int buffer_share_id_offset(const struct buffer_share *mix,
    160 				    unsigned int id)
    161 {
    162 	struct id_offset *o = get_id_offset(mix, id);
    163 	return o ? o->offset : 0;
    164 }
    165 
    166 void *buffer_share_get_data(const struct buffer_share *mix,
    167 			    unsigned int id)
    168 {
    169 	struct id_offset *o = get_id_offset(mix, id);
    170 	return o ? o->data : NULL;
    171 }
    172