| /* |
| * Copyright (C) the libgit2 contributors. All rights reserved. |
| * |
| * This file is part of libgit2, distributed under the GNU GPL v2 with |
| * a Linking Exception. For full terms see the included COPYING file. |
| */ |
| |
| #include "common.h" |
| #include "varint.h" |
| |
| uintmax_t git_decode_varint(const unsigned char *bufp, size_t *varint_len) |
| { |
| const unsigned char *buf = bufp; |
| unsigned char c = *buf++; |
| uintmax_t val = c & 127; |
| while (c & 128) { |
| val += 1; |
| if (!val || MSB(val, 7)) { |
| /* This is not a valid varint_len, so it signals |
| the error */ |
| *varint_len = 0; |
| return 0; /* overflow */ |
| } |
| c = *buf++; |
| val = (val << 7) + (c & 127); |
| } |
| *varint_len = buf - bufp; |
| return val; |
| } |
| |
| int git_encode_varint(unsigned char *buf, size_t bufsize, uintmax_t value) |
| { |
| unsigned char varint[16]; |
| unsigned pos = sizeof(varint) - 1; |
| varint[pos] = value & 127; |
| while (value >>= 7) |
| varint[--pos] = 128 | (--value & 127); |
| if (buf) { |
| if (bufsize < pos) |
| return -1; |
| memcpy(buf, varint + pos, sizeof(varint) - pos); |
| } |
| return sizeof(varint) - pos; |
| } |