| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| |
| * l1oip_codec.c generic codec using lookup table |
| * -> conversion from a-Law to u-Law |
| * -> conversion from u-Law to a-Law |
| * -> compression by reducing the number of sample resolution to 4 |
| * |
| * NOTE: It is not compatible with any standard codec like ADPCM. |
| * |
| * Author Andreas Eversberg (jolly@eversberg.eu) |
| * |
| |
| */ |
| |
| /* |
| |
| How the codec works: |
| -------------------- |
| |
| The volume is increased to increase the dynamic range of the audio signal. |
| Each sample is converted to a-LAW with only 16 steps of level resolution. |
| A pair of two samples are stored in one byte. |
| |
| The first byte is stored in the upper bits, the second byte is stored in the |
| lower bits. |
| |
| To speed up compression and decompression, two lookup tables are formed: |
| |
| - 16 bits index for two samples (law encoded) with 8 bit compressed result. |
| - 8 bits index for one compressed data with 16 bits decompressed result. |
| |
| NOTE: The bytes are handled as they are law-encoded. |
| |
| */ |
| |
| #include <linux/vmalloc.h> |
| #include <linux/mISDNif.h> |
| #include <linux/in.h> |
| #include "core.h" |
| #include "l1oip.h" |
| |
| /* definitions of codec. don't use calculations, code may run slower. */ |
| |
| static u8 *table_com; |
| static u16 *table_dec; |
| |
| |
| /* alaw -> ulaw */ |
| static u8 alaw_to_ulaw[256] = |
| { |
| 0xab, 0x2b, 0xe3, 0x63, 0x8b, 0x0b, 0xc9, 0x49, |
| 0xba, 0x3a, 0xf6, 0x76, 0x9b, 0x1b, 0xd7, 0x57, |
| 0xa3, 0x23, 0xdd, 0x5d, 0x83, 0x03, 0xc1, 0x41, |
| 0xb2, 0x32, 0xeb, 0x6b, 0x93, 0x13, 0xcf, 0x4f, |
| 0xaf, 0x2f, 0xe7, 0x67, 0x8f, 0x0f, 0xcd, 0x4d, |
| 0xbe, 0x3e, 0xfe, 0x7e, 0x9f, 0x1f, 0xdb, 0x5b, |
| 0xa7, 0x27, 0xdf, 0x5f, 0x87, 0x07, 0xc5, 0x45, |
| 0xb6, 0x36, 0xef, 0x6f, 0x97, 0x17, 0xd3, 0x53, |
| 0xa9, 0x29, 0xe1, 0x61, 0x89, 0x09, 0xc7, 0x47, |
| 0xb8, 0x38, 0xf2, 0x72, 0x99, 0x19, 0xd5, 0x55, |
| 0xa1, 0x21, 0xdc, 0x5c, 0x81, 0x01, 0xbf, 0x3f, |
| 0xb0, 0x30, 0xe9, 0x69, 0x91, 0x11, 0xce, 0x4e, |
| 0xad, 0x2d, 0xe5, 0x65, 0x8d, 0x0d, 0xcb, 0x4b, |
| 0xbc, 0x3c, 0xfa, 0x7a, 0x9d, 0x1d, 0xd9, 0x59, |
| 0xa5, 0x25, 0xde, 0x5e, 0x85, 0x05, 0xc3, 0x43, |
| 0xb4, 0x34, 0xed, 0x6d, 0x95, 0x15, 0xd1, 0x51, |
| 0xac, 0x2c, 0xe4, 0x64, 0x8c, 0x0c, 0xca, 0x4a, |
| 0xbb, 0x3b, 0xf8, 0x78, 0x9c, 0x1c, 0xd8, 0x58, |
| 0xa4, 0x24, 0xde, 0x5e, 0x84, 0x04, 0xc2, 0x42, |
| 0xb3, 0x33, 0xec, 0x6c, 0x94, 0x14, 0xd0, 0x50, |
| 0xb0, 0x30, 0xe8, 0x68, 0x90, 0x10, 0xce, 0x4e, |
| 0xbf, 0x3f, 0xfe, 0x7e, 0xa0, 0x20, 0xdc, 0x5c, |
| 0xa8, 0x28, 0xe0, 0x60, 0x88, 0x08, 0xc6, 0x46, |
| 0xb7, 0x37, 0xf0, 0x70, 0x98, 0x18, 0xd4, 0x54, |
| 0xaa, 0x2a, 0xe2, 0x62, 0x8a, 0x0a, 0xc8, 0x48, |
| 0xb9, 0x39, 0xf4, 0x74, 0x9a, 0x1a, 0xd6, 0x56, |
| 0xa2, 0x22, 0xdd, 0x5d, 0x82, 0x02, 0xc0, 0x40, |
| 0xb1, 0x31, 0xea, 0x6a, 0x92, 0x12, 0xcf, 0x4f, |
| 0xae, 0x2e, 0xe6, 0x66, 0x8e, 0x0e, 0xcc, 0x4c, |
| 0xbd, 0x3d, 0xfc, 0x7c, 0x9e, 0x1e, 0xda, 0x5a, |
| 0xa6, 0x26, 0xdf, 0x5f, 0x86, 0x06, 0xc4, 0x44, |
| 0xb5, 0x35, 0xee, 0x6e, 0x96, 0x16, 0xd2, 0x52 |
| }; |
| |
| /* ulaw -> alaw */ |
| static u8 ulaw_to_alaw[256] = |
| { |
| 0xab, 0x55, 0xd5, 0x15, 0x95, 0x75, 0xf5, 0x35, |
| 0xb5, 0x45, 0xc5, 0x05, 0x85, 0x65, 0xe5, 0x25, |
| 0xa5, 0x5d, 0xdd, 0x1d, 0x9d, 0x7d, 0xfd, 0x3d, |
| 0xbd, 0x4d, 0xcd, 0x0d, 0x8d, 0x6d, 0xed, 0x2d, |
| 0xad, 0x51, 0xd1, 0x11, 0x91, 0x71, 0xf1, 0x31, |
| 0xb1, 0x41, 0xc1, 0x01, 0x81, 0x61, 0xe1, 0x21, |
| 0x59, 0xd9, 0x19, 0x99, 0x79, 0xf9, 0x39, 0xb9, |
| 0x49, 0xc9, 0x09, 0x89, 0x69, 0xe9, 0x29, 0xa9, |
| 0xd7, 0x17, 0x97, 0x77, 0xf7, 0x37, 0xb7, 0x47, |
| 0xc7, 0x07, 0x87, 0x67, 0xe7, 0x27, 0xa7, 0xdf, |
| 0x9f, 0x7f, 0xff, 0x3f, 0xbf, 0x4f, 0xcf, 0x0f, |
| 0x8f, 0x6f, 0xef, 0x2f, 0x53, 0x13, 0x73, 0x33, |
| 0xb3, 0x43, 0xc3, 0x03, 0x83, 0x63, 0xe3, 0x23, |
| 0xa3, 0x5b, 0xdb, 0x1b, 0x9b, 0x7b, 0xfb, 0x3b, |
| 0xbb, 0xbb, 0x4b, 0x4b, 0xcb, 0xcb, 0x0b, 0x0b, |
| 0x8b, 0x8b, 0x6b, 0x6b, 0xeb, 0xeb, 0x2b, 0x2b, |
| 0xab, 0x54, 0xd4, 0x14, 0x94, 0x74, 0xf4, 0x34, |
| 0xb4, 0x44, 0xc4, 0x04, 0x84, 0x64, 0xe4, 0x24, |
| 0xa4, 0x5c, 0xdc, 0x1c, 0x9c, 0x7c, 0xfc, 0x3c, |
| 0xbc, 0x4c, 0xcc, 0x0c, 0x8c, 0x6c, 0xec, 0x2c, |
| 0xac, 0x50, 0xd0, 0x10, 0x90, 0x70, 0xf0, 0x30, |
| 0xb0, 0x40, 0xc0, 0x00, 0x80, 0x60, 0xe0, 0x20, |
| 0x58, 0xd8, 0x18, 0x98, 0x78, 0xf8, 0x38, 0xb8, |
| 0x48, 0xc8, 0x08, 0x88, 0x68, 0xe8, 0x28, 0xa8, |
| 0xd6, 0x16, 0x96, 0x76, 0xf6, 0x36, 0xb6, 0x46, |
| 0xc6, 0x06, 0x86, 0x66, 0xe6, 0x26, 0xa6, 0xde, |
| 0x9e, 0x7e, 0xfe, 0x3e, 0xbe, 0x4e, 0xce, 0x0e, |
| 0x8e, 0x6e, 0xee, 0x2e, 0x52, 0x12, 0x72, 0x32, |
| 0xb2, 0x42, 0xc2, 0x02, 0x82, 0x62, 0xe2, 0x22, |
| 0xa2, 0x5a, 0xda, 0x1a, 0x9a, 0x7a, 0xfa, 0x3a, |
| 0xba, 0xba, 0x4a, 0x4a, 0xca, 0xca, 0x0a, 0x0a, |
| 0x8a, 0x8a, 0x6a, 0x6a, 0xea, 0xea, 0x2a, 0x2a |
| }; |
| |
| /* alaw -> 4bit compression */ |
| static u8 alaw_to_4bit[256] = { |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0d, 0x02, |
| 0x0e, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x01, 0x0a, 0x05, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x09, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
| 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
| 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
| }; |
| |
| /* 4bit -> alaw decompression */ |
| static u8 _4bit_to_alaw[16] = { |
| 0x5d, 0x51, 0xd9, 0xd7, 0x5f, 0x53, 0xa3, 0x4b, |
| 0x2a, 0x3a, 0x22, 0x2e, 0x26, 0x56, 0x20, 0x2c, |
| }; |
| |
| /* ulaw -> 4bit compression */ |
| static u8 ulaw_to_4bit[256] = { |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, |
| 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, |
| 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, |
| 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, |
| 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, |
| 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, |
| 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, |
| 0x04, 0x04, 0x04, 0x04, 0x05, 0x05, 0x05, 0x05, |
| 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, |
| 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, |
| 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, |
| 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x08, |
| 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, |
| 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, |
| 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, |
| 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, |
| 0x0f, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, |
| 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, |
| 0x0e, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, |
| 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, |
| 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, |
| 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0b, 0x0b, |
| 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, |
| 0x0b, 0x0b, 0x0b, 0x0b, 0x0a, 0x0a, 0x0a, 0x0a, |
| 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, |
| 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, |
| 0x09, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, |
| 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, |
| }; |
| |
| /* 4bit -> ulaw decompression */ |
| static u8 _4bit_to_ulaw[16] = { |
| 0x11, 0x21, 0x31, 0x40, 0x4e, 0x5c, 0x68, 0x71, |
| 0xfe, 0xef, 0xe7, 0xdb, 0xcd, 0xbf, 0xaf, 0x9f, |
| }; |
| |
| |
| /* |
| * Compresses data to the result buffer |
| * The result size must be at least half of the input buffer. |
| * The number of samples also must be even! |
| */ |
| int |
| l1oip_law_to_4bit(u8 *data, int len, u8 *result, u32 *state) |
| { |
| int ii, i = 0, o = 0; |
| |
| if (!len) |
| return 0; |
| |
| /* send saved byte and first input byte */ |
| if (*state) { |
| *result++ = table_com[(((*state) << 8) & 0xff00) | (*data++)]; |
| len--; |
| o++; |
| } |
| |
| ii = len >> 1; |
| |
| while (i < ii) { |
| *result++ = table_com[(data[0]<<8) | (data[1])]; |
| data += 2; |
| i++; |
| o++; |
| } |
| |
| /* if len has an odd number, we save byte for next call */ |
| if (len & 1) |
| *state = 0x100 + *data; |
| else |
| *state = 0; |
| |
| return o; |
| } |
| |
| /* Decompress data to the result buffer |
| * The result size must be the number of sample in packet. (2 * input data) |
| * The number of samples in the result are even! |
| */ |
| int |
| l1oip_4bit_to_law(u8 *data, int len, u8 *result) |
| { |
| int i = 0; |
| u16 r; |
| |
| while (i < len) { |
| r = table_dec[*data++]; |
| *result++ = r >> 8; |
| *result++ = r; |
| i++; |
| } |
| |
| return len << 1; |
| } |
| |
| |
| /* |
| * law conversion |
| */ |
| int |
| l1oip_alaw_to_ulaw(u8 *data, int len, u8 *result) |
| { |
| int i = 0; |
| |
| while (i < len) { |
| *result++ = alaw_to_ulaw[*data++]; |
| i++; |
| } |
| |
| return len; |
| } |
| |
| int |
| l1oip_ulaw_to_alaw(u8 *data, int len, u8 *result) |
| { |
| int i = 0; |
| |
| while (i < len) { |
| *result++ = ulaw_to_alaw[*data++]; |
| i++; |
| } |
| |
| return len; |
| } |
| |
| |
| /* |
| * generate/free compression and decompression table |
| */ |
| void |
| l1oip_4bit_free(void) |
| { |
| vfree(table_dec); |
| vfree(table_com); |
| table_com = NULL; |
| table_dec = NULL; |
| } |
| |
| int |
| l1oip_4bit_alloc(int ulaw) |
| { |
| int i1, i2, c, sample; |
| |
| /* in case, it is called again */ |
| if (table_dec) |
| return 0; |
| |
| /* alloc conversion tables */ |
| table_com = vzalloc(65536); |
| table_dec = vzalloc(512); |
| if (!table_com || !table_dec) { |
| l1oip_4bit_free(); |
| return -ENOMEM; |
| } |
| /* generate compression table */ |
| i1 = 0; |
| while (i1 < 256) { |
| if (ulaw) |
| c = ulaw_to_4bit[i1]; |
| else |
| c = alaw_to_4bit[i1]; |
| i2 = 0; |
| while (i2 < 256) { |
| table_com[(i1 << 8) | i2] |= (c << 4); |
| table_com[(i2 << 8) | i1] |= c; |
| i2++; |
| } |
| i1++; |
| } |
| |
| /* generate decompression table */ |
| i1 = 0; |
| while (i1 < 16) { |
| if (ulaw) |
| sample = _4bit_to_ulaw[i1]; |
| else |
| sample = _4bit_to_alaw[i1]; |
| i2 = 0; |
| while (i2 < 16) { |
| table_dec[(i1 << 4) | i2] |= (sample << 8); |
| table_dec[(i2 << 4) | i1] |= sample; |
| i2++; |
| } |
| i1++; |
| } |
| |
| return 0; |
| } |
