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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "compress.h"
#include "stringfmt.h"
#include "exceptions.h"
namespace vespalib::compress {
size_t Integer::compressPositive(uint64_t n, void *destination)
{
uint8_t * d = static_cast<uint8_t *>(destination);
if (n < (0x1 << 6)) {
d[0] = n;
return 1;
} else if (n < (0x1 << 14)) {
d[0] = (n >> 8) | 0x80;
d[1] = n & 0xff;
return 2;
} else if ( n < (0x1 << 30)) {
n = n | 0xc0000000;
d[0] = (n >> 24) & 0xff;
d[1] = (n >> 16) & 0xff;
d[2] = (n >> 8) & 0xff;
d[3] = n & 0xff;
return 4;
} else {
throw_too_big(n);
}
}
void
Integer::throw_too_big(int64_t n) {
throw IllegalArgumentException(make_string("Number '%" PRId64 "' too big, must extend encoding", n));
}
void
Integer::throw_too_big(uint64_t n) {
throw IllegalArgumentException(make_string("Number '%" PRIu64 "' too big, must extend encoding", n));
}
size_t Integer::compress(int64_t n, void *destination)
{
uint8_t * d = static_cast<uint8_t *>(destination);
int negative = n < 0 ? 0x80 : 0x0;
if (negative != 0) {
n = -n;
}
if (n < (0x1 << 5)) {
d[0] = n | negative;
return 1;
} else if (n < (0x1 << 13)) {
d[0] = (n >> 8) | 0x40 | negative;
d[1] = n & 0xff;
return 2;
} else if ( n < (0x1 << 29)) {
d[0] = ((n >> 24) | 0x60 | negative) & 0xff;
d[1] = (n >> 16) & 0xff;
d[2] = (n >> 8) & 0xff;
d[3] = n & 0xff;
return 4;
} else {
throw_too_big(negative ? -n : n);
}
}
}
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