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/*
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rtc_base/string_encode.h"
#include <cstdio>
#include <string>
#include <vector>
#include "absl/strings/string_view.h"
#include "api/array_view.h"
#include "rtc_base/checks.h"
namespace webrtc {
/////////////////////////////////////////////////////////////////////////////
// String Encoding Utilities
/////////////////////////////////////////////////////////////////////////////
namespace {
const char HEX[] = "0123456789abcdef";
// Convert an unsigned value from 0 to 15 to the hex character equivalent...
char hex_encode(unsigned char val) {
RTC_DCHECK_LT(val, 16);
return (val < 16) ? HEX[val] : '!';
}
// ...and vice-versa.
bool hex_decode(char ch, unsigned char* val) {
if ((ch >= '0') && (ch <= '9')) {
*val = ch - '0';
} else if ((ch >= 'A') && (ch <= 'F')) {
*val = (ch - 'A') + 10;
} else if ((ch >= 'a') && (ch <= 'f')) {
*val = (ch - 'a') + 10;
} else {
return false;
}
return true;
}
size_t hex_encode_output_length(size_t srclen, char delimiter) {
return delimiter && srclen > 0 ? (srclen * 3 - 1) : (srclen * 2);
}
// hex_encode shows the hex representation of binary data in ascii, with
// `delimiter` between bytes, or none if `delimiter` == 0.
void hex_encode_with_delimiter(char* buffer,
absl::string_view source,
char delimiter) {
RTC_DCHECK(buffer);
// Init and check bounds.
const unsigned char* bsource =
reinterpret_cast<const unsigned char*>(source.data());
size_t srcpos = 0, bufpos = 0;
size_t srclen = source.length();
while (srcpos < srclen) {
unsigned char ch = bsource[srcpos++];
buffer[bufpos] = hex_encode((ch >> 4) & 0xF);
buffer[bufpos + 1] = hex_encode((ch) & 0xF);
bufpos += 2;
// Don't write a delimiter after the last byte.
if (delimiter && (srcpos < srclen)) {
buffer[bufpos] = delimiter;
++bufpos;
}
}
}
} // namespace
std::string hex_encode(absl::string_view str) {
return hex_encode_with_delimiter(str, 0);
}
std::string hex_encode_with_delimiter(absl::string_view source,
char delimiter) {
std::string s(hex_encode_output_length(source.length(), delimiter), 0);
hex_encode_with_delimiter(&s[0], source, delimiter);
return s;
}
size_t hex_decode_with_delimiter(ArrayView<char> cbuffer,
absl::string_view source,
char delimiter) {
if (cbuffer.empty())
return 0;
// Init and bounds check.
unsigned char* bbuffer = reinterpret_cast<unsigned char*>(cbuffer.data());
size_t srcpos = 0, bufpos = 0;
size_t srclen = source.length();
size_t needed = (delimiter) ? (srclen + 1) / 3 : srclen / 2;
if (cbuffer.size() < needed)
return 0;
while (srcpos < srclen) {
if ((srclen - srcpos) < 2) {
// This means we have an odd number of bytes.
return 0;
}
unsigned char h1, h2;
if (!hex_decode(source[srcpos], &h1) ||
!hex_decode(source[srcpos + 1], &h2))
return 0;
bbuffer[bufpos++] = (h1 << 4) | h2;
srcpos += 2;
// Remove the delimiter if needed.
if (delimiter && (srclen - srcpos) > 1) {
if (source[srcpos] != delimiter)
return 0;
++srcpos;
}
}
return bufpos;
}
size_t hex_decode(ArrayView<char> buffer, absl::string_view source) {
return hex_decode_with_delimiter(buffer, source, 0);
}
size_t tokenize(absl::string_view source,
char delimiter,
std::vector<std::string>* fields) {
fields->clear();
size_t last = 0;
for (size_t i = 0; i < source.length(); ++i) {
if (source[i] == delimiter) {
if (i != last) {
fields->emplace_back(source.substr(last, i - last));
}
last = i + 1;
}
}
if (last != source.length()) {
fields->emplace_back(source.substr(last, source.length() - last));
}
return fields->size();
}
bool tokenize_first(absl::string_view source,
const char delimiter,
std::string* token,
std::string* rest) {
// Find the first delimiter
size_t left_pos = source.find(delimiter);
if (left_pos == absl::string_view::npos) {
return false;
}
// Look for additional occurrances of delimiter.
size_t right_pos = left_pos + 1;
while (right_pos < source.size() && source[right_pos] == delimiter) {
right_pos++;
}
*token = std::string(source.substr(0, left_pos));
*rest = std::string(source.substr(right_pos));
return true;
}
std::vector<absl::string_view> split(absl::string_view source, char delimiter) {
std::vector<absl::string_view> fields;
size_t last = 0;
for (size_t i = 0; i < source.length(); ++i) {
if (source[i] == delimiter) {
fields.push_back(source.substr(last, i - last));
last = i + 1;
}
}
fields.push_back(source.substr(last));
return fields;
}
bool FromString(absl::string_view s, bool* b) {
if (s == "false") {
*b = false;
return true;
}
if (s == "true") {
*b = true;
return true;
}
return false;
}
} // namespace webrtc
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