From c5714400662fdc285166addc626d0d1d34fdc414 Mon Sep 17 00:00:00 2001 From: Anton Khirnov Date: Thu, 28 Jan 2021 13:23:23 +0100 Subject: lavc/bitstream: templatize for BE/LE Allows using both BE and LE bitstream readers in the same file. --- libavcodec/bitstream.h | 379 +++----------------------------------- libavcodec/bitstream_template.h | 392 ++++++++++++++++++++++++++++++++++++++++ tests/ref/fate/source | 1 + 3 files changed, 415 insertions(+), 357 deletions(-) create mode 100644 libavcodec/bitstream_template.h diff --git a/libavcodec/bitstream.h b/libavcodec/bitstream.h index 85f1af28c8..3fa63695d3 100644 --- a/libavcodec/bitstream.h +++ b/libavcodec/bitstream.h @@ -49,88 +49,6 @@ typedef struct BitstreamContext { unsigned size_in_bits; } BitstreamContext; -static inline void refill_64(BitstreamContext *bc) -{ -#if !UNCHECKED_BITSTREAM_READER - if (bc->ptr >= bc->buffer_end) - return; -#endif - -#ifdef BITSTREAM_READER_LE - bc->bits = AV_RL64(bc->ptr); -#else - bc->bits = AV_RB64(bc->ptr); -#endif - bc->ptr += 8; - bc->bits_left = 64; -} - -static inline void refill_32(BitstreamContext *bc) -{ -#if !UNCHECKED_BITSTREAM_READER - if (bc->ptr >= bc->buffer_end) - return; -#endif - -#ifdef BITSTREAM_READER_LE - bc->bits = (uint64_t)AV_RL32(bc->ptr) << bc->bits_left | bc->bits; -#else - bc->bits = bc->bits | (uint64_t)AV_RB32(bc->ptr) << (32 - bc->bits_left); -#endif - bc->ptr += 4; - bc->bits_left += 32; -} - -/** - * Initialize BitstreamContext. - * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes - * larger than the actual read bits because some optimized bitstream - * readers read 32 or 64 bits at once and could read over the end - * @param bit_size the size of the buffer in bits - * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow. - */ -static inline int bitstream_init(BitstreamContext *bc, const uint8_t *buffer, - unsigned int bit_size) -{ - unsigned int buffer_size; - - if (bit_size > INT_MAX - 7 || !buffer) { - bc->buffer = NULL; - bc->ptr = NULL; - bc->bits_left = 0; - return AVERROR_INVALIDDATA; - } - - buffer_size = (bit_size + 7) >> 3; - - bc->buffer = buffer; - bc->buffer_end = buffer + buffer_size; - bc->ptr = bc->buffer; - bc->size_in_bits = bit_size; - bc->bits_left = 0; - bc->bits = 0; - - refill_64(bc); - - return 0; -} - -/** - * Initialize BitstreamContext. - * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes - * larger than the actual read bits because some optimized bitstream - * readers read 32 or 64 bits at once and could read over the end - * @param byte_size the size of the buffer in bytes - * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow - */ -static inline int bitstream_init8(BitstreamContext *bc, const uint8_t *buffer, - unsigned int byte_size) -{ - if (byte_size > INT_MAX / 8) - return AVERROR_INVALIDDATA; - return bitstream_init(bc, buffer, byte_size * 8); -} - /** * Return number of bits already read. */ @@ -155,235 +73,6 @@ static inline int bitstream_bits_left(const BitstreamContext *bc) return (bc->buffer - bc->ptr) * 8 + bc->size_in_bits + bc->bits_left; } -static inline uint64_t get_val(BitstreamContext *bc, unsigned int n) -{ - uint64_t ret; - -#ifdef BITSTREAM_READER_LE - ret = bc->bits & ((UINT64_C(1) << n) - 1); - bc->bits >>= n; -#else - ret = bc->bits >> (64 - n); - bc->bits <<= n; -#endif - bc->bits_left -= n; - - return ret; -} - -/** - * Return one bit from the buffer. - */ -static inline unsigned int bitstream_read_bit(BitstreamContext *bc) -{ - if (!bc->bits_left) - refill_64(bc); - - return get_val(bc, 1); -} - -/** - * Return n bits from the buffer, n has to be in the 0-63 range. - */ -static inline uint64_t bitstream_read_63(BitstreamContext *bc, unsigned int n) -{ - uint64_t ret = 0; -#ifdef BITSTREAM_READER_LE - uint64_t left = 0; -#endif - - if (!n) - return 0; - - if (n > bc->bits_left) { - n -= bc->bits_left; -#ifdef BITSTREAM_READER_LE - left = bc->bits_left; -#endif - ret = get_val(bc, bc->bits_left); - refill_64(bc); - } - -#ifdef BITSTREAM_READER_LE - ret = get_val(bc, n) << left | ret; -#else - ret = get_val(bc, n) | ret << n; -#endif - - return ret; -} - -/** - * Return n bits from the buffer, n has to be in the 0-32 range. - */ -static inline uint32_t bitstream_read(BitstreamContext *bc, unsigned int n) -{ - if (!n) - return 0; - - if (n > bc->bits_left) { - refill_32(bc); - if (bc->bits_left < 32) - bc->bits_left = n; - } - - return get_val(bc, n); -} - -/** - * Return n bits from the buffer as a signed integer. - * n has to be in the 0-32 range. - */ -static inline int32_t bitstream_read_signed(BitstreamContext *bc, unsigned int n) -{ - return sign_extend(bitstream_read(bc, n), n); -} - -static inline unsigned int show_val(BitstreamContext *bc, unsigned int n) -{ -#ifdef BITSTREAM_READER_LE - return bc->bits & ((UINT64_C(1) << n) - 1); -#else - return bc->bits >> (64 - n); -#endif -} - -/** - * Return n bits from the buffer but do not change the buffer state. - * n has to be in the 0-32 range. - */ -static inline unsigned int bitstream_peek(BitstreamContext *bc, unsigned int n) -{ - if (n > bc->bits_left) - refill_32(bc); - - return show_val(bc, n); -} - -/** - * Return n bits from the buffer as a signed integer, - * do not change the buffer state. - * n has to be in the 0-32 range. - */ -static inline int bitstream_peek_signed(BitstreamContext *bc, unsigned int n) -{ - return sign_extend(bitstream_peek(bc, n), n); -} - -static inline void skip_remaining(BitstreamContext *bc, unsigned int n) -{ -#ifdef BITSTREAM_READER_LE - bc->bits >>= n; -#else - bc->bits <<= n; -#endif - bc->bits_left -= n; -} - -/** - * Skip n bits in the buffer. - */ -static inline void bitstream_skip(BitstreamContext *bc, unsigned int n) -{ - if (n < bc->bits_left) - skip_remaining(bc, n); - else { - n -= bc->bits_left; - bc->bits = 0; - bc->bits_left = 0; - - if (n >= 64) { - unsigned int skip = n / 8; - - n -= skip * 8; - bc->ptr += skip; - } - refill_64(bc); - if (n) - skip_remaining(bc, n); - } -} - -/** - * Seek to the given bit position. - */ -static inline void bitstream_seek(BitstreamContext *bc, unsigned pos) -{ - bc->ptr = bc->buffer; - bc->bits = 0; - bc->bits_left = 0; - - bitstream_skip(bc, pos); -} - -/** - * Skip bits to a byte boundary. - */ -static inline const uint8_t *bitstream_align(BitstreamContext *bc) -{ - unsigned int n = -bitstream_tell(bc) & 7; - if (n) - bitstream_skip(bc, n); - return bc->buffer + (bitstream_tell(bc) >> 3); -} - -/** - * Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB). - * If MSB not set it is negative. - * @param n length in bits - */ -static inline int bitstream_read_xbits(BitstreamContext *bc, unsigned int n) -{ - int32_t cache = bitstream_peek(bc, 32); - int sign = ~cache >> 31; - skip_remaining(bc, n); - - return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign; -} - -/** - * Return decoded truncated unary code for the values 0, 1, 2. - */ -static inline int bitstream_decode012(BitstreamContext *bc) -{ - if (!bitstream_read_bit(bc)) - return 0; - else - return bitstream_read_bit(bc) + 1; -} - -/** - * Return decoded truncated unary code for the values 2, 1, 0. - */ -static inline int bitstream_decode210(BitstreamContext *bc) -{ - if (bitstream_read_bit(bc)) - return 0; - else - return 2 - bitstream_read_bit(bc); -} - -/* Read sign bit and flip the sign of the provided value accordingly. */ -static inline int bitstream_apply_sign(BitstreamContext *bc, int val) -{ - int sign = bitstream_read_signed(bc, 1); - return (val ^ sign) - sign; -} - -static inline int bitstream_skip_1stop_8data(BitstreamContext *s) -{ - if (bitstream_bits_left(s) <= 0) - return AVERROR_INVALIDDATA; - - while (bitstream_read(s, 1)) { - bitstream_skip(s, 8); - if (bitstream_bits_left(s) <= 0) - return AVERROR_INVALIDDATA; - } - - return 0; -} - /* Unwind the cache so a refill_32 can fill it again. */ static inline void bitstream_unwind(BitstreamContext *bc) { @@ -412,52 +101,28 @@ static inline void bitstream_unget(BitstreamContext *bc, uint64_t value, bc->bits_left += amount; } -/** - * Return the LUT element for the given bitstream configuration. - */ -static inline int set_idx(BitstreamContext *bc, int code, int *n, int *nb_bits, - VLC_TYPE (*table)[2]) -{ - unsigned idx; - - *nb_bits = -*n; - idx = bitstream_peek(bc, *nb_bits) + code; - *n = table[idx][1]; - - return table[idx][0]; -} - -/** - * Parse a vlc code. - * @param bits is the number of bits which will be read at once, must be - * identical to nb_bits in init_vlc() - * @param max_depth is the number of times bits bits must be read to completely - * read the longest vlc code - * = (max_vlc_length + bits - 1) / bits - * If the vlc code is invalid and max_depth=1, then no bits will be removed. - * If the vlc code is invalid and max_depth>1, then the number of bits removed - * is undefined. - */ -static inline int bitstream_read_vlc(BitstreamContext *bc, VLC_TYPE (*table)[2], - int bits, int max_depth) -{ - int nb_bits; - unsigned idx = bitstream_peek(bc, bits); - int code = table[idx][0]; - int n = table[idx][1]; - - if (max_depth > 1 && n < 0) { - skip_remaining(bc, bits); - code = set_idx(bc, code, &n, &nb_bits, table); - if (max_depth > 2 && n < 0) { - skip_remaining(bc, nb_bits); - code = set_idx(bc, code, &n, &nb_bits, table); - } - } - skip_remaining(bc, n); - - return code; -} +#define BITSTREAM_LE +#include "bitstream_template.h" + +#undef BITSTREAM_LE +#include "bitstream_template.h" + +#define bitstream_init bitstream_init_be +#define bitstream_init8 bitstream_init8_be +#define bitstream_read_bit bitstream_read_bit_be +#define bitstream_read_63 bitstream_read_63_be +#define bitstream_read bitstream_read_be +#define bitstream_read_signed bitstream_read_signed_be +#define bitstream_peek bitstream_peek_be +#define bitstream_peek_signed bitstream_peek_signed_be +#define bitstream_skip bitstream_skip_be +#define bitstream_seek bitstream_seek_be +#define bitstream_align bitstream_align_be +#define bitstream_read_xbits bitstream_read_xbits_be +#define bitstream_decode012 bitstream_decode012_be +#define bitstream_decode210 bitstream_decode210_be +#define bitstream_apply_sign bitstream_apply_sign_be +#define bitstream_read_vlc bitstream_read_vlc_be #define BITSTREAM_RL_VLC(level, run, bc, table, bits, max_depth) \ do { \ diff --git a/libavcodec/bitstream_template.h b/libavcodec/bitstream_template.h new file mode 100644 index 0000000000..14a420139c --- /dev/null +++ b/libavcodec/bitstream_template.h @@ -0,0 +1,392 @@ +/* + * Copyright (c) 2016 Alexandra Hájková + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifdef BITSTREAM_LE +# define BS_SUFFIX le +#else +# define BS_SUFFIX be +#endif + +#define BS_JOIN(x, y) x ## _ ## y +#define BS_FUNC2(x, y) BS_JOIN(x, y) +#define BS_FUNC(x) BS_FUNC2(x, BS_SUFFIX) + +static inline void BS_FUNC(refill_64)(BitstreamContext *bc) +{ +#if !UNCHECKED_BITSTREAM_READER + if (bc->ptr >= bc->buffer_end) + return; +#endif + +#ifdef BITSTREAM_LE + bc->bits = AV_RL64(bc->ptr); +#else + bc->bits = AV_RB64(bc->ptr); +#endif + bc->ptr += 8; + bc->bits_left = 64; +} + +static inline void BS_FUNC(refill_32)(BitstreamContext *bc) +{ +#if !UNCHECKED_BITSTREAM_READER + if (bc->ptr >= bc->buffer_end) + return; +#endif + +#ifdef BITSTREAM_LE + bc->bits = (uint64_t)AV_RL32(bc->ptr) << bc->bits_left | bc->bits; +#else + bc->bits = bc->bits | (uint64_t)AV_RB32(bc->ptr) << (32 - bc->bits_left); +#endif + bc->ptr += 4; + bc->bits_left += 32; +} + +/** + * Initialize BitstreamContext. + * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes + * larger than the actual read bits because some optimized bitstream + * readers read 32 or 64 bits at once and could read over the end + * @param bit_size the size of the buffer in bits + * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow. + */ +static inline int BS_FUNC(bitstream_init)(BitstreamContext *bc, const uint8_t *buffer, + unsigned int bit_size) +{ + unsigned int buffer_size; + + if (bit_size > INT_MAX - 7 || !buffer) { + bc->buffer = NULL; + bc->ptr = NULL; + bc->bits_left = 0; + return AVERROR_INVALIDDATA; + } + + buffer_size = (bit_size + 7) >> 3; + + bc->buffer = buffer; + bc->buffer_end = buffer + buffer_size; + bc->ptr = bc->buffer; + bc->size_in_bits = bit_size; + bc->bits_left = 0; + bc->bits = 0; + + BS_FUNC(refill_64)(bc); + + return 0; +} + +/** + * Initialize BitstreamContext. + * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes + * larger than the actual read bits because some optimized bitstream + * readers read 32 or 64 bits at once and could read over the end + * @param byte_size the size of the buffer in bytes + * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow + */ +static inline int BS_FUNC(bitstream_init8)(BitstreamContext *bc, const uint8_t *buffer, + unsigned int byte_size) +{ + if (byte_size > INT_MAX / 8) + return AVERROR_INVALIDDATA; + return BS_FUNC(bitstream_init)(bc, buffer, byte_size * 8); +} + +static inline uint64_t BS_FUNC(get_val)(BitstreamContext *bc, unsigned int n) +{ + uint64_t ret; + +#ifdef BITSTREAM_LE + ret = bc->bits & ((UINT64_C(1) << n) - 1); + bc->bits >>= n; +#else + ret = bc->bits >> (64 - n); + bc->bits <<= n; +#endif + bc->bits_left -= n; + + return ret; +} + +/** + * Return one bit from the buffer. + */ +static inline unsigned int BS_FUNC(bitstream_read_bit)(BitstreamContext *bc) +{ + if (!bc->bits_left) + BS_FUNC(refill_64)(bc); + + return BS_FUNC(get_val)(bc, 1); +} + +/** + * Return n bits from the buffer, n has to be in the 0-63 range. + */ +static inline uint64_t BS_FUNC(bitstream_read_63)(BitstreamContext *bc, unsigned int n) +{ + uint64_t ret = 0; +#ifdef BITSTREAM_LE + uint64_t left = 0; +#endif + + if (!n) + return 0; + + if (n > bc->bits_left) { + n -= bc->bits_left; +#ifdef BITSTREAM_LE + left = bc->bits_left; +#endif + ret = BS_FUNC(get_val)(bc, bc->bits_left); + BS_FUNC(refill_64)(bc); + } + +#ifdef BITSTREAM_LE + ret = get_val_le(bc, n) << left | ret; +#else + ret = get_val_be(bc, n) | ret << n; +#endif + + return ret; +} + +/** + * Return n bits from the buffer, n has to be in the 0-32 range. + */ +static inline uint32_t BS_FUNC(bitstream_read)(BitstreamContext *bc, unsigned int n) +{ + if (!n) + return 0; + + if (n > bc->bits_left) { + BS_FUNC(refill_32)(bc); + if (bc->bits_left < 32) + bc->bits_left = n; + } + + return BS_FUNC(get_val)(bc, n); +} + +/** + * Return n bits from the buffer as a signed integer. + * n has to be in the 0-32 range. + */ +static inline int32_t BS_FUNC(bitstream_read_signed)(BitstreamContext *bc, unsigned int n) +{ + return sign_extend(BS_FUNC(bitstream_read)(bc, n), n); +} + +static inline unsigned int BS_FUNC(show_val)(BitstreamContext *bc, unsigned int n) +{ +#ifdef BITSTREAM_LE + return bc->bits & ((UINT64_C(1) << n) - 1); +#else + return bc->bits >> (64 - n); +#endif +} + +/** + * Return n bits from the buffer but do not change the buffer state. + * n has to be in the 0-32 range. + */ +static inline unsigned int BS_FUNC(bitstream_peek)(BitstreamContext *bc, unsigned int n) +{ + if (n > bc->bits_left) + BS_FUNC(refill_32)(bc); + + return BS_FUNC(show_val)(bc, n); +} + +/** + * Return n bits from the buffer as a signed integer, + * do not change the buffer state. + * n has to be in the 0-32 range. + */ +static inline int BS_FUNC(bitstream_peek_signed)(BitstreamContext *bc, unsigned int n) +{ + return sign_extend(BS_FUNC(bitstream_peek)(bc, n), n); +} + +static inline void BS_FUNC(skip_remaining)(BitstreamContext *bc, unsigned int n) +{ +#ifdef BITSTREAM_LE + bc->bits >>= n; +#else + bc->bits <<= n; +#endif + bc->bits_left -= n; +} + +/** + * Skip n bits in the buffer. + */ +static inline void BS_FUNC(bitstream_skip)(BitstreamContext *bc, unsigned int n) +{ + if (n < bc->bits_left) + BS_FUNC(skip_remaining)(bc, n); + else { + n -= bc->bits_left; + bc->bits = 0; + bc->bits_left = 0; + + if (n >= 64) { + unsigned int skip = n / 8; + + n -= skip * 8; + bc->ptr += skip; + } + BS_FUNC(refill_64)(bc); + if (n) + BS_FUNC(skip_remaining)(bc, n); + } +} + +/** + * Seek to the given bit position. + */ +static inline void BS_FUNC(bitstream_seek)(BitstreamContext *bc, unsigned pos) +{ + bc->ptr = bc->buffer; + bc->bits = 0; + bc->bits_left = 0; + + BS_FUNC(bitstream_skip)(bc, pos); +} + +/** + * Skip bits to a byte boundary. + */ +static inline const uint8_t *BS_FUNC(bitstream_align)(BitstreamContext *bc) +{ + unsigned int n = -bitstream_tell(bc) & 7; + if (n) + BS_FUNC(bitstream_skip)(bc, n); + return bc->buffer + (bitstream_tell(bc) >> 3); +} + +/** + * Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB). + * If MSB not set it is negative. + * @param n length in bits + */ +static inline int BS_FUNC(bitstream_read_xbits)(BitstreamContext *bc, unsigned int n) +{ + int32_t cache = BS_FUNC(bitstream_peek)(bc, 32); + int sign = ~cache >> 31; + BS_FUNC(skip_remaining)(bc, n); + + return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign; +} + +/** + * Return decoded truncated unary code for the values 0, 1, 2. + */ +static inline int BS_FUNC(bitstream_decode012)(BitstreamContext *bc) +{ + if (!BS_FUNC(bitstream_read_bit)(bc)) + return 0; + else + return BS_FUNC(bitstream_read_bit)(bc) + 1; +} + +/** + * Return decoded truncated unary code for the values 2, 1, 0. + */ +static inline int BS_FUNC(bitstream_decode210)(BitstreamContext *bc) +{ + if (BS_FUNC(bitstream_read_bit)(bc)) + return 0; + else + return 2 - BS_FUNC(bitstream_read_bit)(bc); +} + +/* Read sign bit and flip the sign of the provided value accordingly. */ +static inline int BS_FUNC(bitstream_apply_sign)(BitstreamContext *bc, int val) +{ + int sign = BS_FUNC(bitstream_read_signed)(bc, 1); + return (val ^ sign) - sign; +} + +static inline int BS_FUNC(bitstream_skip_1stop_8data)(BitstreamContext *s) +{ + if (bitstream_bits_left(s) <= 0) + return AVERROR_INVALIDDATA; + + while (BS_FUNC(bitstream_read)(s, 1)) { + BS_FUNC(bitstream_skip)(s, 8); + if (bitstream_bits_left(s) <= 0) + return AVERROR_INVALIDDATA; + } + + return 0; +} + +/** + * Return the LUT element for the given bitstream configuration. + */ +static inline int BS_FUNC(set_idx)(BitstreamContext *bc, int code, int *n, int *nb_bits, + VLC_TYPE (*table)[2]) +{ + unsigned idx; + + *nb_bits = -*n; + idx = BS_FUNC(bitstream_peek)(bc, *nb_bits) + code; + *n = table[idx][1]; + + return table[idx][0]; +} + +/** + * Parse a vlc code. + * @param bits is the number of bits which will be read at once, must be + * identical to nb_bits in init_vlc() + * @param max_depth is the number of times bits bits must be read to completely + * read the longest vlc code + * = (max_vlc_length + bits - 1) / bits + * If the vlc code is invalid and max_depth=1, then no bits will be removed. + * If the vlc code is invalid and max_depth>1, then the number of bits removed + * is undefined. + */ +static inline int BS_FUNC(bitstream_read_vlc)(BitstreamContext *bc, VLC_TYPE (*table)[2], + int bits, int max_depth) +{ + int nb_bits; + unsigned idx = BS_FUNC(bitstream_peek)(bc, bits); + int code = table[idx][0]; + int n = table[idx][1]; + + if (max_depth > 1 && n < 0) { + BS_FUNC(skip_remaining)(bc, bits); + code = BS_FUNC(set_idx)(bc, code, &n, &nb_bits, table); + if (max_depth > 2 && n < 0) { + BS_FUNC(skip_remaining)(bc, nb_bits); + code = BS_FUNC(set_idx)(bc, code, &n, &nb_bits, table); + } + } + BS_FUNC(skip_remaining)(bc, n); + + return code; +} + +#undef BS_FUNC +#undef BS_FUNC2 +#undef BS_JOIN +#undef BS_SUFFIX diff --git a/tests/ref/fate/source b/tests/ref/fate/source index 69dcdc4f27..497f296196 100644 --- a/tests/ref/fate/source +++ b/tests/ref/fate/source @@ -20,6 +20,7 @@ Headers without standard inclusion guards: compat/djgpp/math.h compat/float/float.h compat/float/limits.h +libavcodec/bitstream_template.h tools/decode_simple.h Use of av_clip() where av_clip_uintp2() could be used: Use of av_clip() where av_clip_intp2() could be used: -- cgit v1.2.3