//===-- StdStringExtractor.cpp ----------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "StdStringExtractor.h"
#include <cstdlib>
static inline int xdigit_to_sint(char ch) {
if (ch >= 'a' && ch <= 'f')
return 10 + ch - 'a';
if (ch >= 'A' && ch <= 'F')
return 10 + ch - 'A';
if (ch >= '0' && ch <= '9')
return ch - '0';
return -1;
}
// StdStringExtractor constructor
StdStringExtractor::StdStringExtractor() : m_packet(), m_index(0) {}
StdStringExtractor::StdStringExtractor(const char *packet_cstr)
: m_packet(), m_index(0) {
if (packet_cstr)
m_packet.assign(packet_cstr);
}
// Destructor
StdStringExtractor::~StdStringExtractor() = default;
char StdStringExtractor::GetChar(char fail_value) {
if (m_index < m_packet.size()) {
char ch = m_packet[m_index];
++m_index;
return ch;
}
m_index = UINT64_MAX;
return fail_value;
}
// If a pair of valid hex digits exist at the head of the
// StdStringExtractor they are decoded into an unsigned byte and returned
// by this function
//
// If there is not a pair of valid hex digits at the head of the
// StdStringExtractor, it is left unchanged and -1 is returned
int StdStringExtractor::DecodeHexU8() {
SkipSpaces();
if (GetBytesLeft() < 2) {
return -1;
}
const int hi_nibble = xdigit_to_sint(m_packet[m_index]);
const int lo_nibble = xdigit_to_sint(m_packet[m_index + 1]);
if (hi_nibble == -1 || lo_nibble == -1) {
return -1;
}
m_index += 2;
return (uint8_t)((hi_nibble << 4) + lo_nibble);
}
// Extract an unsigned character from two hex ASCII chars in the packet
// string, or return fail_value on failure
uint8_t StdStringExtractor::GetHexU8(uint8_t fail_value, bool set_eof_on_fail) {
// On success, fail_value will be overwritten with the next
// character in the stream
GetHexU8Ex(fail_value, set_eof_on_fail);
return fail_value;
}
bool StdStringExtractor::GetHexU8Ex(uint8_t &ch, bool set_eof_on_fail) {
int byte = DecodeHexU8();
if (byte == -1) {
if (set_eof_on_fail || m_index >= m_packet.size())
m_index = UINT64_MAX;
// ch should not be changed in case of failure
return false;
}
ch = (uint8_t)byte;
return true;
}
uint32_t StdStringExtractor::GetU32(uint32_t fail_value, int base) {
if (m_index < m_packet.size()) {
char *end = nullptr;
const char *start = m_packet.c_str();
const char *cstr = start + m_index;
uint32_t result = static_cast<uint32_t>(::strtoul(cstr, &end, base));
if (end && end != cstr) {
m_index = end - start;
return result;
}
}
return fail_value;
}
int32_t StdStringExtractor::GetS32(int32_t fail_value, int base) {
if (m_index < m_packet.size()) {
char *end = nullptr;
const char *start = m_packet.c_str();
const char *cstr = start + m_index;
int32_t result = static_cast<int32_t>(::strtol(cstr, &end, base));
if (end && end != cstr) {
m_index = end - start;
return result;
}
}
return fail_value;
}
uint64_t StdStringExtractor::GetU64(uint64_t fail_value, int base) {
if (m_index < m_packet.size()) {
char *end = nullptr;
const char *start = m_packet.c_str();
const char *cstr = start + m_index;
uint64_t result = ::strtoull(cstr, &end, base);
if (end && end != cstr) {
m_index = end - start;
return result;
}
}
return fail_value;
}
int64_t StdStringExtractor::GetS64(int64_t fail_value, int base) {
if (m_index < m_packet.size()) {
char *end = nullptr;
const char *start = m_packet.c_str();
const char *cstr = start + m_index;
int64_t result = ::strtoll(cstr, &end, base);
if (end && end != cstr) {
m_index = end - start;
return result;
}
}
return fail_value;
}
uint32_t StdStringExtractor::GetHexMaxU32(bool little_endian,
uint32_t fail_value) {
uint32_t result = 0;
uint32_t nibble_count = 0;
SkipSpaces();
if (little_endian) {
uint32_t shift_amount = 0;
while (m_index < m_packet.size() && ::isxdigit(m_packet[m_index])) {
// Make sure we don't exceed the size of a uint32_t...
if (nibble_count >= (sizeof(uint32_t) * 2)) {
m_index = UINT64_MAX;
return fail_value;
}
uint8_t nibble_lo;
uint8_t nibble_hi = xdigit_to_sint(m_packet[m_index]);
++m_index;
if (m_index < m_packet.size() && ::isxdigit(m_packet[m_index])) {
nibble_lo = xdigit_to_sint(m_packet[m_index]);
++m_index;
result |= ((uint32_t)nibble_hi << (shift_amount + 4));
result |= ((uint32_t)nibble_lo << shift_amount);
nibble_count += 2;
shift_amount += 8;
} else {
result |= ((uint32_t)nibble_hi << shift_amount);
nibble_count += 1;
shift_amount += 4;
}
}
} else {
while (m_index < m_packet.size() && ::isxdigit(m_packet[m_index])) {
// Make sure we don't exceed the size of a uint32_t...
if (nibble_count >= (sizeof(uint32_t) * 2)) {
m_index = UINT64_MAX;
return fail_value;
}
uint8_t nibble = xdigit_to_sint(m_packet[m_index]);
// Big Endian
result <<= 4;
result |= nibble;
++m_index;
++nibble_count;
}
}
return result;
}
uint64_t StdStringExtractor::GetHexMaxU64(bool little_endian,
uint64_t fail_value) {
uint64_t result = 0;
uint32_t nibble_count = 0;
SkipSpaces();
if (little_endian) {
uint32_t shift_amount = 0;
while (m_index < m_packet.size() && ::isxdigit(m_packet[m_index])) {
// Make sure we don't exceed the size of a uint64_t...
if (nibble_count >= (sizeof(uint64_t) * 2)) {
m_index = UINT64_MAX;
return fail_value;
}
uint8_t nibble_lo;
uint8_t nibble_hi = xdigit_to_sint(m_packet[m_index]);
++m_index;
if (m_index < m_packet.size() && ::isxdigit(m_packet[m_index])) {
nibble_lo = xdigit_to_sint(m_packet[m_index]);
++m_index;
result |= ((uint64_t)nibble_hi << (shift_amount + 4));
result |= ((uint64_t)nibble_lo << shift_amount);
nibble_count += 2;
shift_amount += 8;
} else {
result |= ((uint64_t)nibble_hi << shift_amount);
nibble_count += 1;
shift_amount += 4;
}
}
} else {
while (m_index < m_packet.size() && ::isxdigit(m_packet[m_index])) {
// Make sure we don't exceed the size of a uint64_t...
if (nibble_count >= (sizeof(uint64_t) * 2)) {
m_index = UINT64_MAX;
return fail_value;
}
uint8_t nibble = xdigit_to_sint(m_packet[m_index]);
// Big Endian
result <<= 4;
result |= nibble;
++m_index;
++nibble_count;
}
}
return result;
}
size_t StdStringExtractor::GetHexBytes(void *dst_void, size_t dst_len,
uint8_t fail_fill_value) {
uint8_t *dst = (uint8_t *)dst_void;
size_t bytes_extracted = 0;
while (bytes_extracted < dst_len && GetBytesLeft()) {
dst[bytes_extracted] = GetHexU8(fail_fill_value);
if (IsGood())
++bytes_extracted;
else
break;
}
for (size_t i = bytes_extracted; i < dst_len; ++i)
dst[i] = fail_fill_value;
return bytes_extracted;
}
// Decodes all valid hex encoded bytes at the head of the
// StdStringExtractor, limited by dst_len.
//
// Returns the number of bytes successfully decoded
size_t StdStringExtractor::GetHexBytesAvail(void *dst_void, size_t dst_len) {
uint8_t *dst = (uint8_t *)dst_void;
size_t bytes_extracted = 0;
while (bytes_extracted < dst_len) {
int decode = DecodeHexU8();
if (decode == -1) {
break;
}
dst[bytes_extracted++] = (uint8_t)decode;
}
return bytes_extracted;
}
size_t StdStringExtractor::GetHexByteString(std::string &str) {
str.clear();
str.reserve(GetBytesLeft() / 2);
char ch;
while ((ch = GetHexU8()) != '\0')
str.append(1, ch);
return str.size();
}
size_t StdStringExtractor::GetHexByteStringFixedLength(std::string &str,
uint32_t nibble_length) {
str.clear();
uint32_t nibble_count = 0;
for (const char *pch = Peek();
(nibble_count < nibble_length) && (pch != nullptr);
str.append(1, GetHexU8(0, false)), pch = Peek(), nibble_count += 2) {
}
return str.size();
}
size_t StdStringExtractor::GetHexByteStringTerminatedBy(std::string &str,
char terminator) {
str.clear();
char ch;
while ((ch = GetHexU8(0, false)) != '\0')
str.append(1, ch);
if (Peek() && *Peek() == terminator)
return str.size();
str.clear();
return str.size();
}
bool StdStringExtractor::GetNameColonValue(std::string &name,
std::string &value) {
// Read something in the form of NNNN:VVVV; where NNNN is any character
// that is not a colon, followed by a ':' character, then a value (one or
// more ';' chars), followed by a ';'
if (m_index < m_packet.size()) {
const size_t colon_idx = m_packet.find(':', m_index);
if (colon_idx != std::string::npos) {
const size_t semicolon_idx = m_packet.find(';', colon_idx);
if (semicolon_idx != std::string::npos) {
name.assign(m_packet, m_index, colon_idx - m_index);
value.assign(m_packet, colon_idx + 1, semicolon_idx - (colon_idx + 1));
m_index = semicolon_idx + 1;
return true;
}
}
}
m_index = UINT64_MAX;
return false;
}
void StdStringExtractor::SkipSpaces() {
const size_t n = m_packet.size();
while (m_index < n && isspace(m_packet[m_index]))
++m_index;
}
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