Function bs_read

AnyCore/plydecoder.cc:56–163

    s->i_left  = 8;                              //��û�п�ʼ��д����ǰ�ֽ�ʣ��δ��ȡ��λ��8
}
int bs_read( bs_t *s, int i_count )
{
    static uint32_t i_mask[33] ={0x00,
        0x01,      0x03,      0x07,      0x0f,
        0x1f,      0x3f,      0x7f,      0xff,
        0x1ff,     0x3ff,     0x7ff,     0xfff,
        0x1fff,    0x3fff,    0x7fff,    0xffff,
        0x1ffff,   0x3ffff,   0x7ffff,   0xfffff,
        0x1fffff,  0x3fffff,  0x7fffff,  0xffffff,
        0x1ffffff, 0x3ffffff, 0x7ffffff, 0xfffffff,
        0x1fffffff,0x3fffffff,0x7fffffff,0xffffffff};
    /*
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     �ֽ�:       1       2       3       4
     00000000 00000000 00000000 00000000      �±�
     
     0x00:                           00000000      x[0]
     
     0x01:                           00000001      x[1]
     0x03:                           00000011      x[2]
     0x07:                           00000111      x[3]
     0x0f:                           00001111      x[4]
     
     0x1f:                           00011111      x[5]
     0x3f:                           00111111      x[6]
     0x7f:                           01111111      x[7]
     0xff:                           11111111      x[8]    1�ֽ�
     
     0x1ff:                      0001 11111111      x[9]
     0x3ff:                      0011 11111111      x[10]   i_mask[s->i_left]
     0x7ff:                      0111 11111111      x[11]
     0xfff:                      1111 11111111      x[12]   1.5�ֽ�
     
     0x1fff:                  00011111 11111111      x[13]
     0x3fff:                  00111111 11111111      x[14]
     0x7fff:                  01111111 11111111      x[15]
     0xffff:                  11111111 11111111      x[16]   2�ֽ�
     
     0x1ffff:             0001 11111111 11111111      x[17]
     0x3ffff:             0011 11111111 11111111      x[18]
     0x7ffff:             0111 11111111 11111111      x[19]
     0xfffff:             1111 11111111 11111111      x[20]   2.5�ֽ�
     
     0x1fffff:         00011111 11111111 11111111      x[21]
     0x3fffff:         00111111 11111111 11111111      x[22]
     0x7fffff:         01111111 11111111 11111111      x[23]
     0xffffff:         11111111 11111111 11111111      x[24]   3�ֽ�
     
     0x1ffffff:    0001 11111111 11111111 11111111      x[25]
     0x3ffffff:    0011 11111111 11111111 11111111      x[26]
     0x7ffffff:    0111 11111111 11111111 11111111      x[27]
     0xfffffff:    1111 11111111 11111111 11111111      x[28]   3.5�ֽ�
     
     0x1fffffff:00011111 11111111 11111111 11111111      x[29]
     0x3fffffff:00111111 11111111 11111111 11111111      x[30]