76 lines
1.3 KiB
C
76 lines
1.3 KiB
C
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#include "varint.h"
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size_t varint_size(uint64_t v)
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{
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if (v < 0xfd)
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return 1;
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if (v <= 0xffff)
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return 3;
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if (v <= 0xffffffff)
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return 5;
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return 9;
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}
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size_t varint_put(unsigned char buf[VARINT_MAX_LEN], uint64_t v)
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{
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unsigned char *p = buf;
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if (v < 0xfd) {
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*(p++) = v;
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} else if (v <= 0xffff) {
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(*p++) = 0xfd;
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(*p++) = v;
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(*p++) = v >> 8;
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} else if (v <= 0xffffffff) {
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(*p++) = 0xfe;
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(*p++) = v;
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(*p++) = v >> 8;
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(*p++) = v >> 16;
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(*p++) = v >> 24;
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} else {
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(*p++) = 0xff;
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(*p++) = v;
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(*p++) = v >> 8;
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(*p++) = v >> 16;
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(*p++) = v >> 24;
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(*p++) = v >> 32;
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(*p++) = v >> 40;
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(*p++) = v >> 48;
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(*p++) = v >> 56;
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}
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return p - buf;
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}
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size_t varint_get(const unsigned char *p, size_t max, int64_t *val)
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{
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if (max < 1)
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return 0;
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switch (*p) {
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case 0xfd:
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if (max < 3)
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return 0;
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*val = ((uint64_t)p[2] << 8) + p[1];
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return 3;
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case 0xfe:
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if (max < 5)
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return 0;
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*val = ((uint64_t)p[4] << 24) + ((uint64_t)p[3] << 16)
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+ ((uint64_t)p[2] << 8) + p[1];
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return 5;
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case 0xff:
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if (max < 9)
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return 0;
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*val = ((uint64_t)p[8] << 56) + ((uint64_t)p[7] << 48)
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+ ((uint64_t)p[6] << 40) + ((uint64_t)p[5] << 32)
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+ ((uint64_t)p[4] << 24) + ((uint64_t)p[3] << 16)
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+ ((uint64_t)p[2] << 8) + p[1];
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return 9;
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default:
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*val = *p;
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return 1;
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}
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}
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