xref: /aosp_15_r20/external/libxaac/encoder/ixheaace_bitbuffer_hp.c (revision 15dc779a375ca8b5125643b829a8aa4b70d7f451)
1 /******************************************************************************
2  *                                                                            *
3  * Copyright (C) 2023 The Android Open Source Project
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at:
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  *
17  *****************************************************************************
18  * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
19  */
20 
21 #include "ixheaac_type_def.h"
22 #include "ixheaac_constants.h"
23 #include "ixheaace_aac_constants.h"
24 #include <stdlib.h>
25 #include "ixheaac_basic_ops32.h"
26 #include "ixheaac_basic_ops16.h"
27 #include "ixheaac_basic_ops40.h"
28 #include "ixheaac_basic_ops.h"
29 
30 #include "ixheaace_bitbuffer.h"
31 #include "ixheaace_common_utils.h"
32 
33 UWORD8
ixheaace_write_bits(ixheaace_bit_buf_handle pstr_bit_buf,UWORD32 write_value,UWORD8 num_bits_to_write)34 ixheaace_write_bits(ixheaace_bit_buf_handle pstr_bit_buf, UWORD32 write_value,
35                     UWORD8 num_bits_to_write) {
36   WORD8 bits_to_write;
37   WORD32 write_position;
38   UWORD8 *ptr_write_next;
39   UWORD8 *ptr_bit_buf_end;
40   UWORD8 *ptr_bit_buf_base;
41 
42   UWORD8 bits_written = num_bits_to_write;
43 
44   if (pstr_bit_buf == NULL) {
45     return num_bits_to_write;
46   }
47 
48   pstr_bit_buf->cnt_bits += num_bits_to_write;
49 
50   write_position = pstr_bit_buf->write_position;
51   ptr_write_next = pstr_bit_buf->ptr_write_next;
52   ptr_bit_buf_end = pstr_bit_buf->ptr_bit_buf_end;
53   ptr_bit_buf_base = pstr_bit_buf->ptr_bit_buf_base;
54 
55   while (num_bits_to_write) {
56     UWORD8 tmp, msk;
57     bits_to_write = (WORD8)MIN(write_position + 1, num_bits_to_write);
58 
59     tmp = (UWORD8)(write_value << (32 - num_bits_to_write) >>
60                    (32 - bits_to_write) << (write_position + 1 - bits_to_write));
61 
62     msk = ~(((1 << bits_to_write) - 1) << (write_position + 1 - bits_to_write));
63 
64     *ptr_write_next &= msk;
65     *ptr_write_next |= tmp;
66 
67     write_position -= bits_to_write;
68 
69     num_bits_to_write -= bits_to_write;
70 
71     if (write_position < 0) {
72       write_position += 8;
73       ptr_write_next++;
74 
75       if (ptr_write_next > ptr_bit_buf_end) {
76         ptr_write_next = ptr_bit_buf_base;
77       }
78     }
79   }
80 
81   pstr_bit_buf->write_position = write_position;
82   pstr_bit_buf->ptr_write_next = ptr_write_next;
83 
84   return bits_written;
85 }
86 
ixheaace_byte_align_buffer(ixheaace_bit_buf_handle pstr_it_bit_buff)87 UWORD32 ixheaace_byte_align_buffer(ixheaace_bit_buf_handle pstr_it_bit_buff) {
88   WORD alignment;
89   alignment = (WORD)((pstr_it_bit_buff->cnt_bits) & 0x07);
90 
91   if (alignment) {
92     ixheaace_write_bits(pstr_it_bit_buff, 0, (UWORD8)(8 - alignment));
93     return (8 - alignment);
94   }
95   return 0;
96 }