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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-03-09 13:19:48 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-03-09 13:20:02 +0000 |
commit | 58daab21cd043e1dc37024a7f99b396788372918 (patch) | |
tree | 96771e43bb69f7c1c2b0b4f7374cb74d7866d0cb /web/server/h2o/libh2o/deps/golombset/golombset.h | |
parent | Releasing debian version 1.43.2-1. (diff) | |
download | netdata-58daab21cd043e1dc37024a7f99b396788372918.tar.xz netdata-58daab21cd043e1dc37024a7f99b396788372918.zip |
Merging upstream version 1.44.3.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'web/server/h2o/libh2o/deps/golombset/golombset.h')
-rw-r--r-- | web/server/h2o/libh2o/deps/golombset/golombset.h | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/web/server/h2o/libh2o/deps/golombset/golombset.h b/web/server/h2o/libh2o/deps/golombset/golombset.h new file mode 100644 index 000000000..207f0d61c --- /dev/null +++ b/web/server/h2o/libh2o/deps/golombset/golombset.h @@ -0,0 +1,162 @@ +/* + * Copyright (c) 2015 Kazuho Oku + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to + * deal in the Software without restriction, including without limitation the + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or + * sell copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + */ +#ifndef GOLOMBSET_H +#define GOLOMBSET_H + +#include <inttypes.h> + +struct st_golombset_encode_t { + unsigned char *dst; + unsigned char *dst_max; + unsigned dst_shift; +}; + +struct st_golombset_decode_t { + const unsigned char *src; + const unsigned char *src_max; + unsigned src_shift; +}; + +static int golombset_encode_bit(struct st_golombset_encode_t *ctx, int bit) +{ + if (ctx->dst_shift == 0) { + if (++ctx->dst == ctx->dst_max) + return -1; + *ctx->dst = 0; + ctx->dst_shift = 8; + } + --ctx->dst_shift; + if (bit) + *ctx->dst |= 1 << ctx->dst_shift; + return 0; +} + +static int golombset_encode_bits(struct st_golombset_encode_t *ctx, unsigned bits, uint64_t value) +{ + if (bits != 0) { + do { + --bits; + if (golombset_encode_bit(ctx, (value >> bits) & 1) != 0) + return -1; + } while (bits != 0); + } + return 0; +} + +static int golombset_decode_bit(struct st_golombset_decode_t *ctx) +{ + if (ctx->src_shift == 0) { + if (++ctx->src == ctx->src_max) + return -1; + ctx->src_shift = 8; + } + return (*ctx->src >> --ctx->src_shift) & 1; +} + +static int golombset_decode_bits(struct st_golombset_decode_t *ctx, unsigned bits, uint64_t *value) +{ + int bit; + + *value = 0; + for (; bits != 0; --bits) { + if ((bit = golombset_decode_bit(ctx)) == -1) + return -1; + *value = (*value * 2) + bit; + } + + return 0; +} + +static int golombset_encode_value(struct st_golombset_encode_t *ctx, unsigned fixed_bits, uint64_t value) +{ + /* emit quontient */ + uint64_t unary_bits = value >> fixed_bits; + for (; unary_bits != 0; --unary_bits) + if (golombset_encode_bit(ctx, 0) != 0) + return -1; + if (golombset_encode_bit(ctx, 1) != 0) + return -1; + /* emit remainder */ + return golombset_encode_bits(ctx, fixed_bits, value); +} + +static int golombset_decode_value(struct st_golombset_decode_t *ctx, unsigned fixed_bits, uint64_t *value) +{ + uint64_t q; + int bit; + + /* decode quontient */ + for (q = 0; ; ++q) { + if ((bit = golombset_decode_bit(ctx)) == -1) + return -1; + if (bit) + break; + } + /* decode remainder */ + if (golombset_decode_bits(ctx, fixed_bits, value) == -1) + return -1; + /* merge q and r */ + *value += q << fixed_bits; + + return 0; +} + +static int golombset_encode(unsigned fixed_bits, uint64_t *keys, size_t num_keys, void *buf, size_t *bufsize) +{ + struct st_golombset_encode_t ctx = {(unsigned char *)buf - 1, (unsigned char *)buf + *bufsize}; + size_t i; + uint64_t next_min = 0; + + for (i = 0; i != num_keys; ++i) { + if (golombset_encode_value(&ctx, fixed_bits, keys[i] - next_min) != 0) + return -1; + next_min = keys[i] + 1; + } + + *bufsize = ctx.dst + 1 - (unsigned char *)buf; + + return 0; +} + +static int golombset_decode(unsigned fixed_bits, const void *buf, size_t bufsize, uint64_t *keys, size_t *num_keys) +{ + struct st_golombset_decode_t ctx = {buf, (unsigned char *)buf + bufsize, 8}; + size_t index = 0; + uint64_t next_min = 0; + + while (1) { + uint64_t value; + if (golombset_decode_value(&ctx, fixed_bits, &value) != 0) + break; + if (index == *num_keys) { + /* not enough space */ + return -1; + } + value += next_min; + keys[index++] = value; + next_min = value + 1; + } + *num_keys = index; + return 0; +} + +#endif |