libs/gst/base/gstbitwriter.h

   1 /*
   2  *  gstbitwriter.h - bitstream writer
   3  *
   4  *  Copyright (C) 2013 Intel Corporation
   5  *  Copyright (C) 2018 Igalia, S. L.
   6  *
   7  *  This library is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU Lesser General Public License
   9  *  as published by the Free Software Foundation; either version 2.1
  10  *  of the License, or (at your option) any later version.
  11  *
  12  *  This library is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *  Lesser General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU Lesser General Public
  18  *  License along with this library; if not, write to the Free
  19  *  Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20  *  Boston, MA 02110-1301 USA
  21  */
  22
  23 #ifndef GST_BIT_WRITER_H
  24 #define GST_BIT_WRITER_H
  25
  26 #include <gst/gst.h>
  27 #include <gst/base/base-prelude.h>
  28
  29 #include <string.h>
  30
  31 G_BEGIN_DECLS
  32
  33 #define GST_BIT_WRITER_DATA(writer)     ((writer)->data)
  34 #define GST_BIT_WRITER_BIT_SIZE(writer) ((writer)->bit_size)
  35 #define GST_BIT_WRITER(writer)          ((GstBitWriter *) (writer))
  36
  37 typedef struct _GstBitWriter GstBitWriter;
  38
  39 /**
  40  * GstBitWriter:
  41  * @data: Allocated @data for bit writer to write
  42  * @bit_size: Size of written @data in bits
  43  *
  44  * A bit writer instance.
  45  */
  46 struct _GstBitWriter
  47 {
  48   guint8 *data;
  49   guint bit_size;
  50
  51   /*< private >*/
  52   guint bit_capacity; /* Capacity of the allocated data */
  53   gboolean auto_grow; /* Whether space can auto grow */
  54   gboolean owned;
  55   gpointer _gst_reserved[GST_PADDING];
  56 };
  57
  58 GST_BASE_API
  59 GstBitWriter *  gst_bit_writer_new              (void) G_GNUC_MALLOC;
  60
  61 GST_BASE_API
  62 GstBitWriter *  gst_bit_writer_new_with_size    (guint32 size, gboolean fixed) G_GNUC_MALLOC;
  63
  64 GST_BASE_API
  65 GstBitWriter *  gst_bit_writer_new_with_data    (guint8 *data, guint size,
  66                                                  gboolean initialized) G_GNUC_MALLOC;
  67
  68 GST_BASE_API
  69 void            gst_bit_writer_free             (GstBitWriter *bitwriter);
  70
  71 GST_BASE_API
  72 guint8 *        gst_bit_writer_free_and_get_data (GstBitWriter *bitwriter);
  73
  74 GST_BASE_API
  75 GstBuffer *     gst_bit_writer_free_and_get_buffer (GstBitWriter *bitwriter);
  76
  77 GST_BASE_API
  78 void            gst_bit_writer_init             (GstBitWriter *bitwriter);
  79
  80 GST_BASE_API
  81 void            gst_bit_writer_init_with_size   (GstBitWriter *bitwriter,
  82                                                  guint32 size, gboolean fixed);
  83
  84 GST_BASE_API
  85 void            gst_bit_writer_init_with_data   (GstBitWriter *bitwriter,  guint8 *data,
  86                                                  guint size, gboolean initialized);
  87
  88 GST_BASE_API
  89 void            gst_bit_writer_reset            (GstBitWriter *bitwriter);
  90
  91 GST_BASE_API
  92 guint8 *        gst_bit_writer_reset_and_get_data (GstBitWriter *bitwriter);
  93
  94 GST_BASE_API
  95 GstBuffer *     gst_bit_writer_reset_and_get_buffer (GstBitWriter *bitwriter);
  96
  97 GST_BASE_API
  98 guint           gst_bit_writer_get_size         (const GstBitWriter *bitwriter);
  99
 100 GST_BASE_API
 101 guint8 *        gst_bit_writer_get_data         (const GstBitWriter *bitwriter);
 102
 103 GST_BASE_API
 104 gboolean        gst_bit_writer_set_pos          (GstBitWriter *bitwriter, guint pos);
 105
 106 GST_BASE_API
 107 guint           gst_bit_writer_get_remaining    (const GstBitWriter *bitwriter);
 108
 109 GST_BASE_API
 110 gboolean        gst_bit_writer_put_bits_uint8   (GstBitWriter *bitwriter, guint8 value,
 111                                                  guint nbits);
 112
 113 GST_BASE_API
 114 gboolean        gst_bit_writer_put_bits_uint16  (GstBitWriter *bitwriter, guint16 value,
 115                                                  guint nbits);
 116
 117 GST_BASE_API
 118 gboolean        gst_bit_writer_put_bits_uint32  (GstBitWriter *bitwriter, guint32 value,
 119                                                  guint nbits);
 120
 121 GST_BASE_API
 122 gboolean        gst_bit_writer_put_bits_uint64  (GstBitWriter *bitwriter, guint64 value,
 123                                                  guint nbits);
 124
 125 GST_BASE_API
 126 gboolean        gst_bit_writer_put_bytes        (GstBitWriter *bitwriter, const guint8 *data,
 127                                                  guint nbytes);
 128
 129 GST_BASE_API
 130 gboolean        gst_bit_writer_align_bytes      (GstBitWriter *bitwriter, guint8 trailing_bit);
 131
 132 static const guint8 _gst_bit_writer_bit_filling_mask[9] = {
 133     0x00, 0x01, 0x03, 0x07,
 134     0x0F, 0x1F, 0x3F, 0x7F,
 135     0xFF
 136 };
 137
 138 /* Aligned to 256 bytes */
 139 #define __GST_BITS_WRITER_ALIGNMENT_MASK 2047
 140 #define __GST_BITS_WRITER_ALIGNED(bitsize)                   \
 141     (((bitsize) + __GST_BITS_WRITER_ALIGNMENT_MASK)&(~__GST_BITS_WRITER_ALIGNMENT_MASK))
 142
 143 static inline gboolean
 144 _gst_bit_writer_check_remaining (GstBitWriter * bitwriter, guint32 bits)
 145 {
 146   guint32 new_bit_size = bits + bitwriter->bit_size;
 147   guint32 clear_pos;
 148
 149   g_assert (bitwriter->bit_size <= bitwriter->bit_capacity);
 150   if (new_bit_size <= bitwriter->bit_capacity)
 151     return TRUE;
 152
 153   if (!bitwriter->auto_grow)
 154     return FALSE;
 155
 156   /* auto grow space */
 157   new_bit_size = __GST_BITS_WRITER_ALIGNED (new_bit_size);
 158   g_assert (new_bit_size
 159       && ((new_bit_size & __GST_BITS_WRITER_ALIGNMENT_MASK) == 0));
 160   clear_pos = ((bitwriter->bit_size + 7) >> 3);
 161   bitwriter->data = g_realloc (bitwriter->data, (new_bit_size >> 3));
 162   memset (bitwriter->data + clear_pos, 0, (new_bit_size >> 3) - clear_pos);
 163   bitwriter->bit_capacity = new_bit_size;
 164   return TRUE;
 165 }
 166
 167 #undef __GST_BITS_WRITER_ALIGNMENT_MASK
 168 #undef __GST_BITS_WRITER_ALIGNED
 169
 170 #define __GST_BIT_WRITER_WRITE_BITS_UNCHECKED(bits) \
 171 static inline void \
 172 gst_bit_writer_put_bits_uint##bits##_unchecked( \
 173     GstBitWriter *bitwriter, \
 174     guint##bits value, \
 175     guint nbits \
 176 ) \
 177 { \
 178     guint byte_pos, bit_offset; \
 179     guint8  *cur_byte; \
 180     guint fill_bits; \
 181     \
 182     byte_pos = (bitwriter->bit_size >> 3); \
 183     bit_offset = (bitwriter->bit_size & 0x07); \
 184     cur_byte = bitwriter->data + byte_pos; \
 185     g_assert (nbits <= bits); \
 186     g_assert( bit_offset < 8 && \
 187             bitwriter->bit_size <= bitwriter->bit_capacity); \
 188     \
 189     while (nbits) { \
 190         fill_bits = ((8 - bit_offset) < nbits ? (8 - bit_offset) : nbits); \
 191         nbits -= fill_bits; \
 192         bitwriter->bit_size += fill_bits; \
 193         \
 194         *cur_byte |= (((value >> nbits) & _gst_bit_writer_bit_filling_mask[fill_bits]) \
 195                       << (8 - bit_offset - fill_bits)); \
 196         ++cur_byte; \
 197         bit_offset = 0; \
 198     } \
 199     g_assert(cur_byte <= \
 200            (bitwriter->data + (bitwriter->bit_capacity >> 3))); \
 201 }
 202
 203 __GST_BIT_WRITER_WRITE_BITS_UNCHECKED (8)
 204 __GST_BIT_WRITER_WRITE_BITS_UNCHECKED (16)
 205 __GST_BIT_WRITER_WRITE_BITS_UNCHECKED (32)
 206 __GST_BIT_WRITER_WRITE_BITS_UNCHECKED (64)
 207 #undef __GST_BIT_WRITER_WRITE_BITS_UNCHECKED
 208
 209 static inline guint
 210 gst_bit_writer_get_size_unchecked (const GstBitWriter * bitwriter)
 211 {
 212   return GST_BIT_WRITER_BIT_SIZE (bitwriter);
 213 }
 214
 215 static inline guint8 *
 216 gst_bit_writer_get_data_unchecked (const GstBitWriter * bitwriter)
 217 {
 218   return GST_BIT_WRITER_DATA (bitwriter);
 219 }
 220
 221 static inline gboolean
 222 gst_bit_writer_set_pos_unchecked (GstBitWriter * bitwriter, guint pos)
 223 {
 224   GST_BIT_WRITER_BIT_SIZE (bitwriter) = pos;
 225   return TRUE;
 226 }
 227
 228 static inline guint
 229 gst_bit_writer_get_remaining_unchecked (const GstBitWriter * bitwriter)
 230 {
 231   return bitwriter->bit_capacity - bitwriter->bit_size;
 232 }
 233
 234 static inline void
 235 gst_bit_writer_put_bytes_unchecked (GstBitWriter * bitwriter,
 236     const guint8 * data, guint nbytes)
 237 {
 238   if ((bitwriter->bit_size & 0x07) == 0) {
 239     memcpy (&bitwriter->data[bitwriter->bit_size >> 3], data, nbytes);
 240     bitwriter->bit_size += (nbytes << 3);
 241   } else {
 242     g_assert (0);
 243     while (nbytes) {
 244       gst_bit_writer_put_bits_uint8_unchecked (bitwriter, *data, 8);
 245       --nbytes;
 246       ++data;
 247     }
 248   }
 249 }
 250
 251 static inline void
 252 gst_bit_writer_align_bytes_unchecked (GstBitWriter * bitwriter,
 253     guint8 trailing_bit)
 254 {
 255   guint32 bit_offset, bit_left;
 256   guint8 value = 0;
 257
 258   bit_offset = (bitwriter->bit_size & 0x07);
 259   if (!bit_offset)
 260     return;
 261
 262   bit_left = 8 - bit_offset;
 263   if (trailing_bit)
 264     value = _gst_bit_writer_bit_filling_mask[bit_left];
 265   gst_bit_writer_put_bits_uint8_unchecked (bitwriter, value, bit_left);
 266 }
 267
 268 #define __GST_BIT_WRITER_WRITE_BITS_INLINE(bits) \
 269 static inline gboolean \
 270 _gst_bit_writer_put_bits_uint##bits##_inline( \
 271     GstBitWriter *bitwriter, \
 272     guint##bits value, \
 273     guint nbits \
 274 ) \
 275 { \
 276     g_return_val_if_fail(bitwriter != NULL, FALSE); \
 277     g_return_val_if_fail(nbits != 0, FALSE); \
 278     g_return_val_if_fail(nbits <= bits, FALSE); \
 279     \
 280     if (!_gst_bit_writer_check_remaining(bitwriter, nbits)) \
 281         return FALSE; \
 282     gst_bit_writer_put_bits_uint##bits##_unchecked(bitwriter, value, nbits); \
 283     return TRUE; \
 284 }
 285
 286 __GST_BIT_WRITER_WRITE_BITS_INLINE (8)
 287 __GST_BIT_WRITER_WRITE_BITS_INLINE (16)
 288 __GST_BIT_WRITER_WRITE_BITS_INLINE (32)
 289 __GST_BIT_WRITER_WRITE_BITS_INLINE (64)
 290 #undef __GST_BIT_WRITER_WRITE_BITS_INLINE
 291
 292 static inline guint
 293 _gst_bit_writer_get_size_inline (const GstBitWriter * bitwriter)
 294 {
 295   g_return_val_if_fail (bitwriter != NULL, 0);
 296
 297   return gst_bit_writer_get_size_unchecked (bitwriter);
 298 }
 299
 300 static inline guint8 *
 301 _gst_bit_writer_get_data_inline (const GstBitWriter * bitwriter)
 302 {
 303   g_return_val_if_fail (bitwriter != NULL, NULL);
 304
 305   return gst_bit_writer_get_data_unchecked (bitwriter);
 306 }
 307
 308 static inline gboolean
 309 _gst_bit_writer_set_pos_inline (GstBitWriter * bitwriter, guint pos)
 310 {
 311   g_return_val_if_fail (bitwriter != NULL, FALSE);
 312   g_return_val_if_fail (pos <= bitwriter->bit_capacity, FALSE);
 313
 314   return gst_bit_writer_set_pos_unchecked (bitwriter, pos);
 315 }
 316
 317 static inline guint
 318 _gst_bit_writer_get_remaining_inline (const GstBitWriter * bitwriter)
 319 {
 320   g_return_val_if_fail (bitwriter != NULL, 0);
 321   g_return_val_if_fail (bitwriter->bit_size < bitwriter->bit_capacity, 0);
 322
 323   return gst_bit_writer_get_remaining_unchecked (bitwriter);
 324 }
 325
 326 static inline gboolean
 327 _gst_bit_writer_put_bytes_inline (GstBitWriter * bitwriter,
 328     const guint8 * data, guint nbytes)
 329 {
 330   g_return_val_if_fail (bitwriter != NULL, FALSE);
 331   g_return_val_if_fail (data != NULL, FALSE);
 332   g_return_val_if_fail (nbytes, FALSE);
 333
 334   if (!_gst_bit_writer_check_remaining (bitwriter, nbytes * 8))
 335     return FALSE;
 336
 337   gst_bit_writer_put_bytes_unchecked (bitwriter, data, nbytes);
 338   return TRUE;
 339 }
 340
 341 static inline gboolean
 342 _gst_bit_writer_align_bytes_inline (GstBitWriter * bitwriter,
 343     guint8 trailing_bit)
 344 {
 345   g_return_val_if_fail (bitwriter != NULL, FALSE);
 346   g_return_val_if_fail ((trailing_bit == 0 || trailing_bit == 1), FALSE);
 347   g_return_val_if_fail (((bitwriter->bit_size + 7) & (~7)) <=
 348       bitwriter->bit_capacity, FALSE);
 349
 350   gst_bit_writer_align_bytes_unchecked (bitwriter, trailing_bit);
 351   return TRUE;
 352 }
 353
 354 #ifndef GST_BIT_WRITER_DISABLE_INLINES
 355 #define gst_bit_writer_get_size(bitwriter) \
 356     _gst_bit_writer_get_size_inline(bitwriter)
 357 #define gst_bit_writer_get_data(bitwriter) \
 358     _gst_bit_writer_get_data_inline(bitwriter)
 359 #define gst_bit_writer_set_pos(bitwriter, pos) \
 360     G_LIKELY (_gst_bit_writer_set_pos_inline (bitwriter, pos))
 361 #define gst_bit_writer_get_remaining(bitwriter) \
 362     _gst_bit_writer_get_remaining_inline(bitwriter)
 363
 364 #define gst_bit_writer_put_bits_uint8(bitwriter, value, nbits) \
 365     G_LIKELY (_gst_bit_writer_put_bits_uint8_inline (bitwriter, value, nbits))
 366 #define gst_bit_writer_put_bits_uint16(bitwriter, value, nbits) \
 367     G_LIKELY (_gst_bit_writer_put_bits_uint16_inline (bitwriter, value, nbits))
 368 #define gst_bit_writer_put_bits_uint32(bitwriter, value, nbits) \
 369     G_LIKELY (_gst_bit_writer_put_bits_uint32_inline (bitwriter, value, nbits))
 370 #define gst_bit_writer_put_bits_uint64(bitwriter, value, nbits) \
 371     G_LIKELY (_gst_bit_writer_put_bits_uint64_inline (bitwriter, value, nbits))
 372
 373 #define gst_bit_writer_put_bytes(bitwriter, data, nbytes) \
 374     G_LIKELY (_gst_bit_writer_put_bytes_inline (bitwriter, data, nbytes))
 375
 376 #define gst_bit_writer_align_bytes(bitwriter, trailing_bit) \
 377     G_LIKELY (_gst_bit_writer_align_bytes_inline(bitwriter, trailing_bit))
 378 #endif
 379
 380 G_END_DECLS
 381
 382 #endif /* GST_BIT_WRITER_H */