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/*
* Copyright Amazon.com, Inc. or its affiliates. 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.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 <string.h>
#include "stuffer/s2n_stuffer.h"
#include "utils/s2n_mem.h"
#include "utils/s2n_safety.h"
int s2n_stuffer_peek_char(struct s2n_stuffer *s2n_stuffer, char *c)
{
int r = s2n_stuffer_read_uint8(s2n_stuffer, (uint8_t *) c);
if (r == S2N_SUCCESS) {
s2n_stuffer->read_cursor--;
}
POSIX_POSTCONDITION(s2n_stuffer_validate(s2n_stuffer));
return r;
}
/* Peeks in stuffer to see if expected string is present. */
int s2n_stuffer_peek_check_for_str(struct s2n_stuffer *s2n_stuffer, const char *expected)
{
POSIX_PRECONDITION(s2n_stuffer_validate(s2n_stuffer));
uint32_t orig_read_pos = s2n_stuffer->read_cursor;
int rc = s2n_stuffer_read_expected_str(s2n_stuffer, expected);
s2n_stuffer->read_cursor = orig_read_pos;
POSIX_POSTCONDITION(s2n_stuffer_validate(s2n_stuffer));
return rc;
}
int s2n_stuffer_skip_whitespace(struct s2n_stuffer *s2n_stuffer, uint32_t *skipped)
{
POSIX_PRECONDITION(s2n_stuffer_validate(s2n_stuffer));
uint32_t initial_read_cursor = s2n_stuffer->read_cursor;
while (s2n_stuffer_data_available(s2n_stuffer)) {
uint8_t c = s2n_stuffer->blob.data[s2n_stuffer->read_cursor];
/* We don't use isspace, because it changes under locales. */
if (c == ' ' || c == '\t' || c == '\n' || c == '\r') {
s2n_stuffer->read_cursor += 1;
} else {
break;
}
}
if (skipped != NULL) {
*skipped = s2n_stuffer->read_cursor - initial_read_cursor;
}
POSIX_POSTCONDITION(s2n_stuffer_validate(s2n_stuffer));
return S2N_SUCCESS;
}
int s2n_stuffer_read_expected_str(struct s2n_stuffer *stuffer, const char *expected)
{
POSIX_PRECONDITION(s2n_stuffer_validate(stuffer));
POSIX_ENSURE_REF(expected);
size_t expected_length = strlen(expected);
if (expected_length == 0) {
return S2N_SUCCESS;
}
POSIX_ENSURE(s2n_stuffer_data_available(stuffer) >= expected_length, S2N_ERR_STUFFER_OUT_OF_DATA);
uint8_t *actual = stuffer->blob.data + stuffer->read_cursor;
POSIX_ENSURE_REF(actual);
POSIX_ENSURE(!memcmp(actual, expected, expected_length), S2N_ERR_STUFFER_NOT_FOUND);
stuffer->read_cursor += expected_length;
POSIX_POSTCONDITION(s2n_stuffer_validate(stuffer));
return S2N_SUCCESS;
}
/* Read from stuffer until the target string is found, or until there is no more data. */
int s2n_stuffer_skip_read_until(struct s2n_stuffer *stuffer, const char *target)
{
POSIX_PRECONDITION(s2n_stuffer_validate(stuffer));
POSIX_ENSURE_REF(target);
const uint32_t len = strlen(target);
if (len == 0) {
return S2N_SUCCESS;
}
while (s2n_stuffer_data_available(stuffer) >= len) {
POSIX_GUARD(s2n_stuffer_skip_to_char(stuffer, target[0]));
POSIX_GUARD(s2n_stuffer_skip_read(stuffer, len));
uint8_t *actual = stuffer->blob.data + stuffer->read_cursor - len;
POSIX_ENSURE_REF(actual);
if (strncmp((char *) actual, target, len) == 0) {
return S2N_SUCCESS;
} else {
/* If string doesn't match, rewind stuffer to 1 byte after last read */
POSIX_GUARD(s2n_stuffer_rewind_read(stuffer, len - 1));
continue;
}
}
POSIX_POSTCONDITION(s2n_stuffer_validate(stuffer));
return S2N_SUCCESS;
}
/* Skips the stuffer until the first instance of the target character or until there is no more data. */
int s2n_stuffer_skip_to_char(struct s2n_stuffer *stuffer, const char target)
{
POSIX_PRECONDITION(s2n_stuffer_validate(stuffer));
while (s2n_stuffer_data_available(stuffer) > 0) {
if (stuffer->blob.data[stuffer->read_cursor] == target) {
break;
}
stuffer->read_cursor += 1;
}
POSIX_POSTCONDITION(s2n_stuffer_validate(stuffer));
return S2N_SUCCESS;
}
/* Skips an expected character in the stuffer between min and max times */
int s2n_stuffer_skip_expected_char(struct s2n_stuffer *stuffer, const char expected, const uint32_t min,
const uint32_t max, uint32_t *skipped)
{
POSIX_PRECONDITION(s2n_stuffer_validate(stuffer));
POSIX_ENSURE(min <= max, S2N_ERR_SAFETY);
uint32_t skip = 0;
while (stuffer->read_cursor < stuffer->write_cursor && skip < max) {
if (stuffer->blob.data[stuffer->read_cursor] == expected) {
stuffer->read_cursor += 1;
skip += 1;
} else {
break;
}
}
POSIX_ENSURE(skip >= min, S2N_ERR_STUFFER_NOT_FOUND);
if (skipped != NULL) {
*skipped = skip;
}
POSIX_POSTCONDITION(s2n_stuffer_validate(stuffer));
return S2N_SUCCESS;
}
/* Read a line of text. Agnostic to LF or CR+LF line endings. */
int s2n_stuffer_read_line(struct s2n_stuffer *stuffer, struct s2n_stuffer *token)
{
POSIX_PRECONDITION(s2n_stuffer_validate(stuffer));
POSIX_PRECONDITION(s2n_stuffer_validate(token));
/* Consume an LF terminated line */
POSIX_GUARD(s2n_stuffer_read_token(stuffer, token, '\n'));
/* Snip off the carriage return if it's present */
if ((s2n_stuffer_data_available(token) > 0) && (token->blob.data[(token->write_cursor - 1)] == '\r')) {
token->write_cursor--;
}
POSIX_POSTCONDITION(s2n_stuffer_validate(stuffer));
POSIX_POSTCONDITION(s2n_stuffer_validate(token));
return S2N_SUCCESS;
}
int s2n_stuffer_read_token(struct s2n_stuffer *stuffer, struct s2n_stuffer *token, char delim)
{
POSIX_PRECONDITION(s2n_stuffer_validate(stuffer));
POSIX_PRECONDITION(s2n_stuffer_validate(token));
uint32_t token_size = 0;
while ((stuffer->read_cursor + token_size) < stuffer->write_cursor) {
if (stuffer->blob.data[stuffer->read_cursor + token_size] == delim) {
break;
}
token_size++;
}
POSIX_GUARD(s2n_stuffer_copy(stuffer, token, token_size));
/* Consume the delimiter too */
if (stuffer->read_cursor < stuffer->write_cursor) {
stuffer->read_cursor++;
}
POSIX_POSTCONDITION(s2n_stuffer_validate(stuffer));
POSIX_POSTCONDITION(s2n_stuffer_validate(token));
return S2N_SUCCESS;
}
int s2n_stuffer_alloc_ro_from_string(struct s2n_stuffer *stuffer, const char *str)
{
POSIX_PRECONDITION(s2n_stuffer_validate(stuffer));
POSIX_ENSURE_REF(str);
uint32_t length = strlen(str);
POSIX_GUARD(s2n_stuffer_alloc(stuffer, length + 1));
return s2n_stuffer_write_bytes(stuffer, (const uint8_t *) str, length);
}
int s2n_stuffer_init_ro_from_string(struct s2n_stuffer *stuffer, uint8_t *data, uint32_t length)
{
POSIX_PRECONDITION(s2n_stuffer_validate(stuffer));
POSIX_ENSURE_REF(data);
struct s2n_blob data_blob = { 0 };
POSIX_GUARD(s2n_blob_init(&data_blob, data, length));
POSIX_GUARD(s2n_stuffer_init(stuffer, &data_blob));
POSIX_GUARD(s2n_stuffer_skip_write(stuffer, length));
return S2N_SUCCESS;
}
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