295 lines
7.2 KiB
C
295 lines
7.2 KiB
C
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/*
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* FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
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* Copyright (C) 2005-2014, Anthony Minessale II <anthm@freeswitch.org>
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*
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* Version: MPL 1.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
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*
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* The Initial Developer of the Original Code is
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* Anthony Minessale II <anthm@freeswitch.org>
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* Portions created by the Initial Developer are Copyright (C)
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Anthony Minessale II <anthm@freeswitch.org>
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*
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*
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* switch_bitpack.h -- BITPACKING code for RFC3551 and AAL2 packing
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*
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*/
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/*! \file switch_bitpack.h
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\brief BITPACKING code for RFC3551 and AAL2 packing
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*/
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#ifndef SWITCH_BITPACK_H
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#define SWITCH_BITPACK_H
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SWITCH_BEGIN_EXTERN_C
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#include <switch.h>
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#ifdef DEBUG_BITS
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static char bb[80] = "";
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static inline char *print_bits(switch_byte_t byte, char *x)
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{
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int i, j = 0;
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x[j++] = '[';
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for (i = 7; i >= 0; i--) {
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x[j++] = (byte & (1 << i)) ? '1' : '0';
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}
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x[j++] = ']';
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x[j++] = '\0';
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return x;
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}
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#endif
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/*!
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\defgroup bp1 Bitpacking
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\ingroup core1
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\{
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*/
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static const uint8_t SWITCH_BITPACKED_MASKS[] = { 0, 1, 3, 7, 15, 31, 63, 127, 255 };
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static const uint8_t SWITCH_REVERSE_BITPACKED_MASKS[] = { 255, 254, 252, 248, 240, 224, 192, 128 };
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/*!
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\brief Initialize a bitpack object
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\param pack the pack object
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\param bitlen the number of bits per packet
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\param buf the buffer to use for storage
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\param buflen the length of the storage buffer
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\param mode RFC3551 or AAL2 mode (curse you backwards folks)
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*/
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DoxyDefine(void switch_bitpack_init(switch_bitpack_t *pack, int32_t bitlen, switch_byte_t *buf, uint32_t buflen, switch_bitpack_mode_t mode))
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static inline int8_t switch_bitpack_init(switch_bitpack_t *pack, switch_byte_t bitlen, switch_byte_t *buf, uint32_t buflen,
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switch_bitpack_mode_t mode)
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{
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if (!pack || (bitlen > SWITCH_BITS_PER_BYTE) || !buf || !buflen) {
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return -1;
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}
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memset(pack, 0, sizeof(*pack));
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memset(buf, 0, buflen);
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pack->frame_bits = bitlen;
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pack->buf = buf;
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pack->buflen = buflen;
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pack->cur = pack->buf;
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pack->mode = mode;
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return 0;
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}
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static inline void pack_check_over(switch_bitpack_t *pack)
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{
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switch_byte_t this_byte = pack->this_byte;
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if (pack->over) {
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pack->bits_cur = pack->over;
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if (pack->mode == SWITCH_BITPACK_MODE_RFC3551) {
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switch_assert(pack->over <= 8);
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this_byte &= SWITCH_BITPACKED_MASKS[pack->over];
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this_byte <<= pack->under;
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*pack->cur |= this_byte;
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pack->cur++;
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} else {
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switch_byte_t mask = SWITCH_BITS_PER_BYTE - pack->over;
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switch_assert(mask < 8); /* if pack->over this will allways be true */
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this_byte &= SWITCH_REVERSE_BITPACKED_MASKS[mask];
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this_byte >>= mask;
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*pack->cur <<= pack->over;
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*pack->cur |= this_byte;
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pack->cur++;
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}
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pack->bytes++;
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pack->over = pack->under = 0;
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}
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}
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/*!
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\brief finalize a bitpack object
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\param pack the pack/unpack object
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*/
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DoxyDefine(int8_t switch_bitpack_done(switch_bitpack_t *pack))
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static inline int8_t switch_bitpack_done(switch_bitpack_t *pack)
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{
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if (pack->bits_cur && pack->bits_cur < SWITCH_BITS_PER_BYTE) {
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pack->bytes++;
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if (pack->mode == SWITCH_BITPACK_MODE_AAL2) {
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*pack->cur <<= SWITCH_BITS_PER_BYTE - pack->bits_cur;
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}
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}
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if (pack->over) {
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pack_check_over(pack);
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}
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return 0;
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}
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/*!
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\brief pull data out of a bitpack object into it's buffer
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\param unpack the pack/unpack object
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\param in a 1 byte int packed with bits
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\return -1 if the buffer is full otherwise 0
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*/
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DoxyDefine(int8_t switch_bitpack_out(switch_bitpack_t *unpack, switch_byte_t in))
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static inline int8_t switch_bitpack_out(switch_bitpack_t *unpack, switch_byte_t in)
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{
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switch_byte_t this_byte;
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if ((uint32_t) (unpack->cur - unpack->buf) > unpack->buflen) {
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return -1;
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}
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unpack->bits_cur = 0;
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unpack->this_byte = this_byte = in;
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pack_check_over(unpack);
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while (unpack->bits_cur <= SWITCH_BITS_PER_BYTE) {
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switch_byte_t next = unpack->bits_cur + unpack->frame_bits;
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switch_byte_t under_in;
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switch_byte_t mask;
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this_byte = unpack->this_byte;
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if (next > SWITCH_BITS_PER_BYTE) {
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unpack->over = next - SWITCH_BITS_PER_BYTE;
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unpack->under = unpack->frame_bits - unpack->over;
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if (unpack->mode == SWITCH_BITPACK_MODE_RFC3551) {
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mask = SWITCH_BITS_PER_BYTE - unpack->under;
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under_in = this_byte & SWITCH_REVERSE_BITPACKED_MASKS[mask];
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under_in >>= mask;
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*unpack->cur |= under_in;
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} else {
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mask = unpack->under;
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under_in = this_byte & SWITCH_BITPACKED_MASKS[mask];
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*unpack->cur <<= mask;
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*unpack->cur |= under_in;
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}
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break;
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}
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if (unpack->mode == SWITCH_BITPACK_MODE_RFC3551) {
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this_byte >>= unpack->bits_cur;
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this_byte &= SWITCH_BITPACKED_MASKS[unpack->frame_bits];
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*unpack->cur |= this_byte;
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unpack->cur++;
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} else {
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this_byte >>= (SWITCH_BITS_PER_BYTE - next);
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this_byte &= SWITCH_BITPACKED_MASKS[unpack->frame_bits];
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*unpack->cur |= this_byte;
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unpack->cur++;
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}
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unpack->bits_cur = next;
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unpack->bytes++;
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}
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return 0;
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}
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/*!
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\brief pack data into a bitpack object's buffer
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\param pack the pack/unpack object
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\param in a 1 byte int with 1 packet worth of bits
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\return -1 if the buffer is full otherwise 0
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*/
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DoxyDefine(int8_t switch_bitpack_in(switch_bitpack_t *pack, switch_byte_t in))
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static inline int8_t switch_bitpack_in(switch_bitpack_t *pack, switch_byte_t in)
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{
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int next = pack->bits_cur + pack->frame_bits;
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if ((uint32_t) (pack->cur - pack->buf) > pack->buflen) {
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return -1;
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}
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pack->bits_tot += pack->frame_bits;
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if (next > SWITCH_BITS_PER_BYTE) {
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switch_byte_t a = 0, b = 0, rem, nxt;
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rem = SWITCH_BITS_PER_BYTE - pack->bits_cur;
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nxt = pack->frame_bits - rem;
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if (pack->mode == SWITCH_BITPACK_MODE_RFC3551) {
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a = in & SWITCH_BITPACKED_MASKS[rem];
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b = in >> rem;
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a <<= pack->shiftby;
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*pack->cur |= a;
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pack->cur++;
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*pack->cur |= b;
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pack->bits_cur = pack->shiftby = nxt;
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} else {
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a = in >> nxt;
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b = in & SWITCH_BITPACKED_MASKS[nxt];
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*pack->cur <<= rem;
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*pack->cur |= a;
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pack->cur++;
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*pack->cur |= b;
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pack->bits_cur = nxt;
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}
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pack->bytes++;
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} else {
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if (pack->mode == SWITCH_BITPACK_MODE_RFC3551) {
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in <<= pack->shiftby;
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*pack->cur |= in;
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pack->shiftby = (switch_byte_t) (pack->shiftby + pack->frame_bits);
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} else {
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*pack->cur <<= pack->frame_bits;
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*pack->cur |= in;
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}
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if (next == SWITCH_BITS_PER_BYTE) {
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pack->cur++;
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pack->bytes++;
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pack->bits_cur = pack->shiftby = 0;
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} else {
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pack->bits_cur = (switch_byte_t) next;
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}
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}
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return 0;
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}
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///\}
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SWITCH_END_EXTERN_C
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#endif
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/* For Emacs:
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* Local Variables:
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* mode:c
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* indent-tabs-mode:t
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* tab-width:4
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* c-basic-offset:4
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* End:
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* For VIM:
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* vim:set softtabstop=4 shiftwidth=4 tabstop=4 noet:
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*/
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