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trezor-firmware/crypto/buffer.c

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/**
* Copyright (c) 2023 Trezor Company s.r.o.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT HMAC_SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
* OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include <stdlib.h>
#include <string.h>
#include "buffer.h"
void buffer_reader_init(BUFFER_READER *reader, const uint8_t *data,
size_t size) {
reader->data = data;
reader->size = size;
reader->pos = 0;
}
void buffer_writer_init(BUFFER_WRITER *writer, uint8_t *data, size_t size) {
writer->data = data;
writer->size = size;
writer->pos = 0;
}
size_t buffer_remaining(BUFFER_READER *buf) {
if ((buf->data == NULL) || (buf->pos > buf->size)) {
return 0;
}
return buf->size - buf->pos;
}
bool buffer_ptr(BUFFER_READER *buf, const uint8_t **ptr) {
if ((buf->data == NULL) || (buf->pos > buf->size)) {
return false;
}
*ptr = &buf->data[buf->pos];
return true;
}
bool buffer_peek(const BUFFER_READER *buf, uint8_t *byte) {
if ((buf->data == NULL) || (buf->pos >= buf->size)) {
return false;
}
*byte = buf->data[buf->pos];
return true;
}
bool buffer_get(BUFFER_READER *buf, uint8_t *byte) {
if (!buffer_peek(buf, byte)) {
return false;
}
buf->pos += 1;
return true;
}
bool buffer_seek(BUFFER_READER *buf, size_t pos) {
if ((buf->data == NULL) || (pos > buf->size)) {
return false;
}
buf->pos = pos;
return true;
}
bool buffer_read_buffer(BUFFER_READER *src, BUFFER_READER *dest, size_t size) {
if ((src->data == NULL) || (src->pos + size > src->size)) {
return false;
}
buffer_reader_init(dest, &src->data[src->pos], size);
src->pos += size;
return true;
}
void buffer_lstrip(BUFFER_READER *buf, uint8_t byte) {
if (buf->data == NULL) {
return;
}
while ((buf->pos < buf->size) && (buf->data[buf->pos] == byte)) {
buf->pos += 1;
}
return;
}
bool buffer_put(BUFFER_WRITER *writer, uint8_t byte) {
if ((writer->data == NULL) || (writer->pos >= writer->size)) {
return false;
}
writer->data[writer->pos] = byte;
writer->pos += 1;
return true;
}
bool buffer_write_array(BUFFER_WRITER *writer, const uint8_t *src,
size_t size) {
if ((writer->data == NULL) || (writer->pos + size > writer->size)) {
return false;
}
memcpy(&writer->data[writer->pos], src, size);
writer->pos += size;
return true;
}
bool buffer_write_buffer(BUFFER_WRITER *dest, BUFFER_READER *src) {
if ((src->data == NULL) || (src->pos > src->size)) {
return false;
}
if (!buffer_write_array(dest, &src->data[src->pos], src->size - src->pos)) {
return false;
}
src->pos = src->size;
return true;
}
size_t buffer_written_size(BUFFER_WRITER *writer) { return writer->pos; }