srs/trunk/src/kernel/srs_kernel_buffer.cpp

/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2013-2018 Winlin
 *
 * 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 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.
 */

#include <srs_kernel_buffer.hpp>

using namespace std;

#include <srs_kernel_log.hpp>
#include <srs_kernel_error.hpp>
#include <srs_kernel_utility.hpp>

ISrsCodec::ISrsCodec()
{
}

ISrsCodec::~ISrsCodec()
{
}

SrsBuffer::SrsBuffer()
{
    p = bytes = NULL;
    nb_bytes = 0;
    
    // TODO: support both little and big endian.
    srs_assert(srs_is_little_endian());
}

SrsBuffer::SrsBuffer(char* b, int nb_b)
{
    p = bytes = b;
    nb_bytes = nb_b;
    
    // TODO: support both little and big endian.
    srs_assert(srs_is_little_endian());
}

SrsBuffer::~SrsBuffer()
{
}

char* SrsBuffer::data()
{
    return bytes;
}

int SrsBuffer::size()
{
    return nb_bytes;
}

int SrsBuffer::pos()
{
    return (int)(p - bytes);
}

int SrsBuffer::left()
{
    return nb_bytes - (int)(p - bytes);
}

bool SrsBuffer::empty()
{
    return !bytes || (p >= bytes + nb_bytes);
}

bool SrsBuffer::require(int required_size)
{
    srs_assert(required_size >= 0);
    
    return required_size <= nb_bytes - (p - bytes);
}

void SrsBuffer::skip(int size)
{
    srs_assert(p);
    
    p += size;
}

int8_t SrsBuffer::read_1bytes()
{
    srs_assert(require(1));
    
    return (int8_t)*p++;
}

int16_t SrsBuffer::read_2bytes()
{
    srs_assert(require(2));
    
    int16_t value;
    char* pp = (char*)&value;
    pp[1] = *p++;
    pp[0] = *p++;
    
    return value;
}

int32_t SrsBuffer::read_3bytes()
{
    srs_assert(require(3));
    
    int32_t value = 0x00;
    char* pp = (char*)&value;
    pp[2] = *p++;
    pp[1] = *p++;
    pp[0] = *p++;
    
    return value;
}

int32_t SrsBuffer::read_4bytes()
{
    srs_assert(require(4));
    
    int32_t value;
    char* pp = (char*)&value;
    pp[3] = *p++;
    pp[2] = *p++;
    pp[1] = *p++;
    pp[0] = *p++;
    
    return value;
}

int64_t SrsBuffer::read_8bytes()
{
    srs_assert(require(8));
    
    int64_t value;
    char* pp = (char*)&value;
    pp[7] = *p++;
    pp[6] = *p++;
    pp[5] = *p++;
    pp[4] = *p++;
    pp[3] = *p++;
    pp[2] = *p++;
    pp[1] = *p++;
    pp[0] = *p++;
    
    return value;
}

string SrsBuffer::read_string(int len)
{
    srs_assert(require(len));
    
    std::string value;
    value.append(p, len);
    
    p += len;
    
    return value;
}

void SrsBuffer::read_bytes(char* data, int size)
{
    srs_assert(require(size));
    
    memcpy(data, p, size);
    
    p += size;
}

void SrsBuffer::write_1bytes(int8_t value)
{
    srs_assert(require(1));
    
    *p++ = value;
}

void SrsBuffer::write_2bytes(int16_t value)
{
    srs_assert(require(2));
    
    char* pp = (char*)&value;
    *p++ = pp[1];
    *p++ = pp[0];
}

void SrsBuffer::write_4bytes(int32_t value)
{
    srs_assert(require(4));
    
    char* pp = (char*)&value;
    *p++ = pp[3];
    *p++ = pp[2];
    *p++ = pp[1];
    *p++ = pp[0];
}

void SrsBuffer::write_3bytes(int32_t value)
{
    srs_assert(require(3));
    
    char* pp = (char*)&value;
    *p++ = pp[2];
    *p++ = pp[1];
    *p++ = pp[0];
}

void SrsBuffer::write_8bytes(int64_t value)
{
    srs_assert(require(8));
    
    char* pp = (char*)&value;
    *p++ = pp[7];
    *p++ = pp[6];
    *p++ = pp[5];
    *p++ = pp[4];
    *p++ = pp[3];
    *p++ = pp[2];
    *p++ = pp[1];
    *p++ = pp[0];
}

void SrsBuffer::write_string(string value)
{
    srs_assert(require((int)value.length()));
    
    memcpy(p, value.data(), value.length());
    p += value.length();
}

void SrsBuffer::write_bytes(char* data, int size)
{
    srs_assert(require(size));
    
    memcpy(p, data, size);
    p += size;
}

SrsBitBuffer::SrsBitBuffer()
{
    cb = 0;
    cb_left = 0;
    stream = NULL;
}

SrsBitBuffer::~SrsBitBuffer()
{
}

srs_error_t SrsBitBuffer::initialize(SrsBuffer* s) {
    stream = s;
    cb = 0;
    cb_left = 0;
    return srs_success;
}

bool SrsBitBuffer::empty() {
    if (cb_left) {
        return false;
    }
    return stream->empty();
}

int8_t SrsBitBuffer::read_bit() {
    if (!cb_left) {
        srs_assert(!stream->empty());
        cb = stream->read_1bytes();
        cb_left = 8;
    }
    
    int8_t v = (cb >> (cb_left - 1)) & 0x01;
    cb_left--;
    return v;
}