unleashed-firmware/lib/mjs/common/cs_varint.c
Nikolay Minaylov 0154018363
[FL-3579, FL-3601, FL-3714] JavaScript runner (#3286)
* FBT: cdefines to env, libs order
* API: strtod, modf, itoa, calloc
* Apps: elk js
* Apps: mjs
* JS: scripts as assets
* mjs: composite resolver
* mjs: stack trace
* ELK JS example removed
* MJS thread, MJS lib modified to support script interruption
* JS console UI
* Module system, BadUSB bindings rework
* JS notifications, simple dialog, BadUSB demo
* Custom dialogs, dialog demo
* MJS as system library, some dirty hacks to make it compile
* Plugin-based js modules
* js_uart(BadUART) module
* js_uart: support for byte array arguments
* Script icon and various fixes
* File browser: multiple extensions filter, running js scripts from app loader
* Running js scripts from archive browser
* JS Runner as system app
* Example scripts moved to /ext/apps/Scripts
* JS bytecode listing generation
* MJS builtin printf cleanup
* JS examples cleanup
* mbedtls version fix
* Unused lib cleanup
* Making PVS happy & TODOs cleanup
* TODOs cleanup #2
* MJS: initial typed arrays support
* JS: fix mem leak in uart destructor

Co-authored-by: SG <who.just.the.doctor@gmail.com>
Co-authored-by: Aleksandr Kutuzov <alleteam@gmail.com>
2024-02-12 15:54:32 +07:00

76 lines
1.9 KiB
C

/*
* Copyright (c) 2014-2018 Cesanta Software Limited
* All rights reserved
*
* Licensed under the Apache License, Version 2.0 (the ""License"");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an ""AS IS"" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "cs_varint.h"
size_t cs_varint_llen(uint64_t num) {
size_t llen = 0;
do {
llen++;
} while (num >>= 7);
return llen;
}
size_t cs_varint_encode(uint64_t num, uint8_t *buf, size_t buf_size) {
size_t llen = 0;
do {
uint8_t byte = num & 0x7f;
num >>= 7;
if (num != 0) byte |= 0x80;
if (llen < buf_size) *buf++ = byte;
llen++;
} while (num != 0);
return llen;
}
bool cs_varint_decode(const uint8_t *buf, size_t buf_size, uint64_t *num,
size_t *llen) {
size_t i = 0, shift = 0;
uint64_t n = 0;
do {
if (i == buf_size || i == (8 * sizeof(*num) / 7 + 1)) return false;
/*
* Each byte of varint contains 7 bits, in little endian order.
* MSB is a continuation bit: it tells whether next byte is used.
*/
n |= ((uint64_t)(buf[i] & 0x7f)) << shift;
/*
* First we increment i, then check whether it is within boundary and
* whether decoded byte had continuation bit set.
*/
i++;
shift += 7;
} while (shift < sizeof(uint64_t) * 8 && (buf[i - 1] & 0x80));
*num = n;
*llen = i;
return true;
}
uint64_t cs_varint_decode_unsafe(const uint8_t *buf, int *llen) {
uint64_t v;
size_t l;
cs_varint_decode(buf, ~0, &v, &l);
*llen = l;
return v;
}