155 lines
3.6 KiB
C++
155 lines
3.6 KiB
C++
#pragma once
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namespace bitreader_helper {
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inline static size_t extract_bit(const uint8_t * p_stream,size_t p_offset) {
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return (p_stream[p_offset>>3] >> (7-(p_offset&7)))&1;
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}
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inline static size_t extract_int(const uint8_t * p_stream,size_t p_base,size_t p_width) {
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size_t ret = 0;
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size_t offset = p_base;
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for(size_t bit=0;bit<p_width;bit++) {
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ret <<= 1;
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ret |= extract_bit(p_stream,offset++);
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}
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return ret;
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}
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inline static void write_bit( uint8_t * p_stream, size_t p_offset, size_t bit ) {
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size_t bshift = 7 - (p_offset&7);
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size_t mask = 1 << bshift;
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uint8_t & b = p_stream[p_offset>>3];
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b = (b & ~mask) | ((bit&1) << bshift);
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}
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inline static void write_int( uint8_t * p_stream, size_t p_base, size_t p_width, size_t p_value) {
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size_t offset = p_base;
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size_t val = p_value;
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for( size_t bit = 0; bit < p_width; ++ bit ) {
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write_bit( p_stream, offset++, val >> (p_width - bit - 1));
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}
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}
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class bitreader
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{
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public:
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inline bitreader(const t_uint8 * p_ptr,t_size p_base)
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: m_ptr(p_ptr), m_bitptr(p_base)
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{
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}
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inline void skip(t_size p_bits)
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{
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m_bitptr += p_bits;
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}
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template<typename t_ret>
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t_ret peek_t(t_size p_bits) const {
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size_t ptr = m_bitptr;
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t_ret ret = 0;
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for(t_size bit=0;bit<p_bits;bit++)
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{
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ret <<= 1;
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ret |= (m_ptr[ptr >>3] >> (7-(ptr &7)))&1;
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ptr++;
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}
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return ret;
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}
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template<typename t_ret>
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t_ret read_t(t_size p_bits) {
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t_ret ret = peek_t<t_ret>(p_bits);
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skip(p_bits);
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return ret;
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}
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size_t peek(size_t bits) const {
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return peek_t<size_t>(bits);
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}
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t_size read(t_size p_bits) {return read_t<t_size>(p_bits);}
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inline t_size get_bitptr() const {return m_bitptr;}
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inline bool read_bit() {
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bool state = ( (m_ptr[m_bitptr>>3] >> (7-(m_bitptr&7)))&1 ) != 0;
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m_bitptr++;
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return state;
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}
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private:
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const t_uint8 * m_ptr;
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t_size m_bitptr;
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};
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class bitreader_fromfile
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{
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public:
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inline bitreader_fromfile(service_ptr_t<file> const& p_file) : m_file(p_file), m_buffer_ptr(0) {}
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t_size read(t_size p_bits,abort_callback & p_abort) {
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t_size ret = 0;
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for(t_size bit=0;bit<p_bits;bit++) {
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if (m_buffer_ptr == 0)
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m_file->read_object(&m_buffer,1,p_abort);
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ret <<= 1;
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ret |= (m_buffer >> (7-m_buffer_ptr))&1;
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m_buffer_ptr = (m_buffer_ptr+1) & 7;
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}
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return ret;
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}
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void skip(t_size p_bits,abort_callback & p_abort) {
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for(t_size bit=0;bit<p_bits;bit++) {
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if (m_buffer_ptr == 0) m_file->read_object(&m_buffer,1,p_abort);
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m_buffer_ptr = (m_buffer_ptr+1) & 7;
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}
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}
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inline void byte_align() {m_buffer_ptr = 0;}
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private:
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service_ptr_t<file> m_file;
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t_size m_buffer_ptr;
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t_uint8 m_buffer;
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};
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class bitreader_limited
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{
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public:
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inline bitreader_limited(const t_uint8 * p_ptr,t_size p_base,t_size p_remaining) : m_reader(p_ptr,p_base), m_remaining(p_remaining) {}
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inline t_size get_bitptr() const {return m_reader.get_bitptr();}
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inline t_size get_remaining() const {return m_remaining;}
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inline void skip(t_size p_bits) {
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if (p_bits > m_remaining) throw exception_io_data_truncation();
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m_remaining -= p_bits;
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m_reader.skip(p_bits);
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}
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size_t peek(size_t bits) {
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if (bits > m_remaining) throw exception_io_data_truncation();
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return m_reader.peek(bits);
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}
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t_size read(t_size p_bits)
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{
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if (p_bits > m_remaining) throw exception_io_data_truncation();
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m_remaining -= p_bits;
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return m_reader.read(p_bits);
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}
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private:
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bitreader m_reader;
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t_size m_remaining;
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};
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inline static t_size extract_bits(const t_uint8 * p_buffer,t_size p_base,t_size p_count) {
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return bitreader(p_buffer,p_base).read(p_count);
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}
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}
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