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62 lines
1.1 KiB

#include "varint.h"
size_t varint_put(u8 buf[VARINT_MAX_LEN], varint_t v)
{
u8 *p = buf;
if (v < 0xfd) {
*(p++) = v;
} else if (v <= 0xffff) {
(*p++) = 0xfd;
(*p++) = v;
(*p++) = v >> 8;
} else if (v <= 0xffffffff) {
(*p++) = 0xfe;
(*p++) = v;
(*p++) = v >> 8;
(*p++) = v >> 16;
(*p++) = v >> 24;
} else {
(*p++) = 0xff;
(*p++) = v;
(*p++) = v >> 8;
(*p++) = v >> 16;
(*p++) = v >> 24;
(*p++) = v >> 32;
(*p++) = v >> 40;
(*p++) = v >> 48;
(*p++) = v >> 56;
}
return p - buf;
}
size_t varint_get(const u8 *p, size_t max, varint_t *val)
{
if (max < 1)
return 0;
switch (*p) {
case 0xfd:
if (max < 3)
return 0;
*val = ((u64)p[1] << 8) + p[0];
return 3;
case 0xfe:
if (max < 5)
return 0;
*val = ((u64)p[3] << 24) + ((u64)p[2] << 16)
+ ((u64)p[1] << 8) + p[0];
return 5;
case 0xff:
if (max < 9)
return 0;
*val = ((u64)p[7] << 56) + ((u64)p[6] << 48)
+ ((u64)p[5] << 40) + ((u64)p[4] << 32)
+ ((u64)p[3] << 24) + ((u64)p[2] << 16)
+ ((u64)p[1] << 8) + p[0];
return 9;
default:
*val = *p;
return 1;
}
}