git/git

#include "git-compat-util.h"
#include "varint.h"

uintmax_t decode_varint(const unsigned char **bufp)
{
    const unsigned char *buf = *bufp;
    unsigned char c = *buf++;
    uintmax_t val = c & 127;
    while (c & 128) {
        val += 1;
        if (!val || MSB(val, 7))
            return 0; /* overflow */
        c = *buf++;
        val = (val << 7) + (c & 127);
    }
    *bufp = buf;
    return val;
}

int encode_varint(uintmax_t value, unsigned char *buf)
{
    unsigned char varint[16];
    unsigned pos = sizeof(varint) - 1;
    varint[pos] = value & 127;
    while (value >>= 7)
        varint[--pos] = 128 | (--value & 127);
    if (buf)
        memcpy(buf, varint + pos, sizeof(varint) - pos);
    return sizeof(varint) - pos;
}