diff options
| -rw-r--r-- | bitstream.c | 310 |
1 files changed, 155 insertions, 155 deletions
diff --git a/bitstream.c b/bitstream.c index 71e8bb6..fae619f 100644 --- a/bitstream.c +++ b/bitstream.c @@ -5,21 +5,21 @@ #include "bitstream.h" /***************************************************************************** -* -* bit_stream.c package -* Author: Jean-Georges Fritsch, C-Cube Microsystems -* Changes -* Apr 2000 - removed all the file input routines. MFC -*****************************************************************************/ + * + * bit_stream.c package + * Author: Jean-Georges Fritsch, C-Cube Microsystems + * Changes + * Apr 2000 - removed all the file input routines. MFC + *****************************************************************************/ /******************************************************************** This package provides functions to write (exclusive or read) information from (exclusive or to) the bit stream. - + If the bit stream is opened in read mode only the get functions are available. If the bit stream is opened in write mode only the put functions are available. -********************************************************************/ + ********************************************************************/ /*open_bit_stream_w(); open the device to write the bit stream into it */ /*close_bit_stream(); close the device containing the bit stream */ @@ -43,140 +43,140 @@ int minimum = MINIMUM; int refill_buffer (Bit_stream_struc * bs) { - register int i = bs->buf_size - 2 - bs->buf_byte_idx; - register unsigned long n = 1; - register int index = 0; - char val[2]; - - while ((i >= 0) && (!bs->eob)) { - - if (bs->format == BINARY) - n = fread (&bs->buf[i--], sizeof (unsigned char), 1, bs->pt); - - else { - while ((index < 2) && n) { - n = fread (&val[index], sizeof (char), 1, bs->pt); - switch (val[index]) { - case 0x30: - case 0x31: - case 0x32: - case 0x33: - case 0x34: - case 0x35: - case 0x36: - case 0x37: - case 0x38: - case 0x39: - case 0x41: - case 0x42: - case 0x43: - case 0x44: - case 0x45: - case 0x46: - index++; - break; - default: - break; - } - } - - if (val[0] <= 0x39) - bs->buf[i] = (val[0] - 0x30) << 4; - else - bs->buf[i] = (val[0] - 0x37) << 4; - if (val[1] <= 0x39) - bs->buf[i--] |= (val[1] - 0x30); - else - bs->buf[i--] |= (val[1] - 0x37); - index = 0; - } + register int i = bs->buf_size - 2 - bs->buf_byte_idx; + register unsigned long n = 1; + register int index = 0; + char val[2]; + + while ((i >= 0) && (!bs->eob)) { + + if (bs->format == BINARY) + n = fread (&bs->buf[i--], sizeof (unsigned char), 1, bs->pt); + + else { + while ((index < 2) && n) { + n = fread (&val[index], sizeof (char), 1, bs->pt); + switch (val[index]) { + case 0x30: + case 0x31: + case 0x32: + case 0x33: + case 0x34: + case 0x35: + case 0x36: + case 0x37: + case 0x38: + case 0x39: + case 0x41: + case 0x42: + case 0x43: + case 0x44: + case 0x45: + case 0x46: + index++; + break; + default: + break; + } + } + + if (val[0] <= 0x39) + bs->buf[i] = (val[0] - 0x30) << 4; + else + bs->buf[i] = (val[0] - 0x37) << 4; + if (val[1] <= 0x39) + bs->buf[i--] |= (val[1] - 0x30); + else + bs->buf[i--] |= (val[1] - 0x37); + index = 0; + } + + if (!n) { + bs->eob = i + 1; + } - if (!n) { - bs->eob = i + 1; } - - } - return 0; + return 0; } /* empty the buffer to the output device when the buffer becomes full */ void empty_buffer (Bit_stream_struc * bs, int minimum) { - register int i; + register int i; - for (i = bs->buf_size - 1; i >= minimum; i--) - fwrite (&bs->buf[i], sizeof (unsigned char), 1, bs->pt); + for (i = bs->buf_size - 1; i >= minimum; i--) + fwrite (&bs->buf[i], sizeof (unsigned char), 1, bs->pt); - fflush (bs->pt); /* NEW SS to assist in debugging */ + fflush (bs->pt); /* NEW SS to assist in debugging */ - for (i = minimum - 1; i >= 0; i--) - bs->buf[bs->buf_size - minimum + i] = bs->buf[i]; + for (i = minimum - 1; i >= 0; i--) + bs->buf[bs->buf_size - minimum + i] = bs->buf[i]; - bs->buf_byte_idx = bs->buf_size - 1 - minimum; - bs->buf_bit_idx = 8; + bs->buf_byte_idx = bs->buf_size - 1 - minimum; + bs->buf_bit_idx = 8; } /* open the device to write the bit stream into it */ void open_bit_stream_w (Bit_stream_struc * bs, char *bs_filenam, int size) { - if (bs_filenam[0] == '-') - bs->pt = stdout; - else if ((bs->pt = fopen (bs_filenam, "wb")) == NULL) { - fprintf (stderr, "Could not create \"%s\".\n", bs_filenam); - exit (1); - } - alloc_buffer (bs, size); - bs->buf_byte_idx = size - 1; - bs->buf_bit_idx = 8; - bs->totbit = 0; - bs->mode = WRITE_MODE; - bs->eob = FALSE; - bs->eobs = FALSE; + if (bs_filenam[0] == '-') + bs->pt = stdout; + else if ((bs->pt = fopen (bs_filenam, "wb")) == NULL) { + fprintf (stderr, "Could not create \"%s\".\n", bs_filenam); + exit (1); + } + alloc_buffer (bs, size); + bs->buf_byte_idx = size - 1; + bs->buf_bit_idx = 8; + bs->totbit = 0; + bs->mode = WRITE_MODE; + bs->eob = FALSE; + bs->eobs = FALSE; } /*close the device containing the bit stream after a write process*/ void close_bit_stream_w (Bit_stream_struc * bs) { - putbits (bs, 0, 7); - empty_buffer (bs, bs->buf_byte_idx + 1); - fclose (bs->pt); - desalloc_buffer (bs); + putbits (bs, 0, 7); + empty_buffer (bs, bs->buf_byte_idx + 1); + fclose (bs->pt); + desalloc_buffer (bs); } /*open and initialize the buffer; */ void alloc_buffer (Bit_stream_struc * bs, int size) { - bs->buf = - (unsigned char *) mem_alloc (size * sizeof (unsigned char), "buffer"); - bs->buf_size = size; + bs->buf = + (unsigned char *) mem_alloc (size * sizeof (unsigned char), "buffer"); + bs->buf_size = size; } /*empty and close the buffer */ void desalloc_buffer (Bit_stream_struc * bs) { - free (bs->buf); + free (bs->buf); } int putmask[9] = { 0x0, 0x1, 0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff }; int clearmask[9] = { 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x0 }; void back_track_buffer (Bit_stream_struc * bs, int N) -/* goes back N bits in the buffer */ + /* goes back N bits in the buffer */ { - int tmp = N - (N / 8) * 8; - register int i; - - bs->totbit -= N; - for (i = bs->buf_byte_idx; i < bs->buf_byte_idx + N / 8 - 1; i++) - bs->buf[i] = 0; - bs->buf_byte_idx += N / 8; - if ((tmp + bs->buf_bit_idx) <= 8) { - bs->buf_bit_idx += tmp; - } else { - bs->buf_byte_idx++; - bs->buf_bit_idx += (tmp - 8); - } - bs->buf[bs->buf_byte_idx] &= clearmask[bs->buf_bit_idx]; + int tmp = N - (N / 8) * 8; + register int i; + + bs->totbit -= N; + for (i = bs->buf_byte_idx; i < bs->buf_byte_idx + N / 8 - 1; i++) + bs->buf[i] = 0; + bs->buf_byte_idx += N / 8; + if ((tmp + bs->buf_bit_idx) <= 8) { + bs->buf_bit_idx += tmp; + } else { + bs->buf_byte_idx++; + bs->buf_bit_idx += (tmp - 8); + } + bs->buf[bs->buf_byte_idx] &= clearmask[bs->buf_bit_idx]; } int mask[8] = { 0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80 }; @@ -184,64 +184,64 @@ int mask[8] = { 0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80 }; /*write 1 bit from the bit stream */ void put1bit (Bit_stream_struc * bs, int bit) { - bs->totbit++; + bs->totbit++; - bs->buf[bs->buf_byte_idx] |= (bit & 0x1) << (bs->buf_bit_idx - 1); - bs->buf_bit_idx--; - if (!bs->buf_bit_idx) { - bs->buf_bit_idx = 8; - bs->buf_byte_idx--; - if (bs->buf_byte_idx < 0) - empty_buffer (bs, minimum); - bs->buf[bs->buf_byte_idx] = 0; - } + bs->buf[bs->buf_byte_idx] |= (bit & 0x1) << (bs->buf_bit_idx - 1); + bs->buf_bit_idx--; + if (!bs->buf_bit_idx) { + bs->buf_bit_idx = 8; + bs->buf_byte_idx--; + if (bs->buf_byte_idx < 0) + empty_buffer (bs, minimum); + bs->buf[bs->buf_byte_idx] = 0; + } } /*write N bits into the bit stream */ INLINE void putbits (Bit_stream_struc * bs, unsigned int val, int N) { - register int j = N; - register int k, tmp; - - /* if (N > MAX_LENGTH) - fprintf(stderr, "Cannot read or write more than %d bits at a time.\n", MAX_LENGTH); ignore check!! MFC Apr 00 */ - - bs->totbit += N; - while (j > 0) { - k = MIN (j, bs->buf_bit_idx); - tmp = val >> (j - k); - bs->buf[bs->buf_byte_idx] |= (tmp & putmask[k]) << (bs->buf_bit_idx - k); - bs->buf_bit_idx -= k; - if (!bs->buf_bit_idx) { - bs->buf_bit_idx = 8; - bs->buf_byte_idx--; - if (bs->buf_byte_idx < 0) - empty_buffer (bs, minimum); - bs->buf[bs->buf_byte_idx] = 0; + register int j = N; + register int k, tmp; + + /* if (N > MAX_LENGTH) + fprintf(stderr, "Cannot read or write more than %d bits at a time.\n", MAX_LENGTH); ignore check!! MFC Apr 00 */ + + bs->totbit += N; + while (j > 0) { + k = MIN (j, bs->buf_bit_idx); + tmp = val >> (j - k); + bs->buf[bs->buf_byte_idx] |= (tmp & putmask[k]) << (bs->buf_bit_idx - k); + bs->buf_bit_idx -= k; + if (!bs->buf_bit_idx) { + bs->buf_bit_idx = 8; + bs->buf_byte_idx--; + if (bs->buf_byte_idx < 0) + empty_buffer (bs, minimum); + bs->buf[bs->buf_byte_idx] = 0; + } + j -= k; } - j -= k; - } } /*write N bits byte aligned into the bit stream */ void byte_ali_putbits (Bit_stream_struc * bs, unsigned int val, int N) { - unsigned long aligning; + unsigned long aligning; - if (N > MAX_LENGTH) - fprintf (stderr, "Cannot read or write more than %d bits at a time.\n", - MAX_LENGTH); - aligning = sstell (bs) % 8; - if (aligning) - putbits (bs, (unsigned int) 0, (int) (8 - aligning)); + if (N > MAX_LENGTH) + fprintf (stderr, "Cannot read or write more than %d bits at a time.\n", + MAX_LENGTH); + aligning = sstell (bs) % 8; + if (aligning) + putbits (bs, (unsigned int) 0, (int) (8 - aligning)); - putbits (bs, val, N); + putbits (bs, val, N); } /*return the current bit stream length (in bits)*/ unsigned long sstell (Bit_stream_struc * bs) { - return (bs->totbit); + return (bs->totbit); } /*return the status of the bit stream*/ @@ -249,14 +249,14 @@ unsigned long sstell (Bit_stream_struc * bs) /* returns 0 if end of bit stream was not reached */ int end_bs (Bit_stream_struc * bs) { - return (bs->eobs); + return (bs->eobs); } /***************************************************************************** -* -* End of bit_stream.c package -* -*****************************************************************************/ + * + * End of bit_stream.c package + * + *****************************************************************************/ #define BUFSIZE 4096 static unsigned long offset, totbit = 0; @@ -265,7 +265,7 @@ static unsigned int buf[BUFSIZE]; /*return the current bit stream length (in bits)*/ unsigned long hsstell () { - return (totbit); + return (totbit); } /* int putmask[9]={0x0, 0x1, 0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff}; */ @@ -274,10 +274,10 @@ unsigned long hsstell () /*write N bits into the bit stream */ void hputbuf (unsigned int val, int N) { - if (N != 8) { - fprintf (stderr, "Not Supported yet!!\n"); - exit (-3); - } - buf[offset % BUFSIZE] = val; - offset++; + if (N != 8) { + fprintf (stderr, "Not Supported yet!!\n"); + exit (-3); + } + buf[offset % BUFSIZE] = val; + offset++; } |