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-rw-r--r--absl/strings/escaping.cc188
1 files changed, 13 insertions, 175 deletions
diff --git a/absl/strings/escaping.cc b/absl/strings/escaping.cc
index d2fcd9c1..7adc1b65 100644
--- a/absl/strings/escaping.cc
+++ b/absl/strings/escaping.cc
@@ -26,6 +26,7 @@
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/unaligned_access.h"
#include "absl/strings/internal/char_map.h"
+#include "absl/strings/internal/escaping.h"
#include "absl/strings/internal/resize_uninitialized.h"
#include "absl/strings/internal/utf8.h"
#include "absl/strings/str_cat.h"
@@ -764,177 +765,10 @@ constexpr signed char kUnWebSafeBase64[] = {
};
/* clang-format on */
-size_t CalculateBase64EscapedLenInternal(size_t input_len, bool do_padding) {
- // Base64 encodes three bytes of input at a time. If the input is not
- // divisible by three, we pad as appropriate.
- //
- // (from https://tools.ietf.org/html/rfc3548)
- // Special processing is performed if fewer than 24 bits are available
- // at the end of the data being encoded. A full encoding quantum is
- // always completed at the end of a quantity. When fewer than 24 input
- // bits are available in an input group, zero bits are added (on the
- // right) to form an integral number of 6-bit groups. Padding at the
- // end of the data is performed using the '=' character. Since all base
- // 64 input is an integral number of octets, only the following cases
- // can arise:
-
- // Base64 encodes each three bytes of input into four bytes of output.
- size_t len = (input_len / 3) * 4;
-
- if (input_len % 3 == 0) {
- // (from https://tools.ietf.org/html/rfc3548)
- // (1) the final quantum of encoding input is an integral multiple of 24
- // bits; here, the final unit of encoded output will be an integral
- // multiple of 4 characters with no "=" padding,
- } else if (input_len % 3 == 1) {
- // (from https://tools.ietf.org/html/rfc3548)
- // (2) the final quantum of encoding input is exactly 8 bits; here, the
- // final unit of encoded output will be two characters followed by two
- // "=" padding characters, or
- len += 2;
- if (do_padding) {
- len += 2;
- }
- } else { // (input_len % 3 == 2)
- // (from https://tools.ietf.org/html/rfc3548)
- // (3) the final quantum of encoding input is exactly 16 bits; here, the
- // final unit of encoded output will be three characters followed by one
- // "=" padding character.
- len += 3;
- if (do_padding) {
- len += 1;
- }
- }
-
- assert(len >= input_len); // make sure we didn't overflow
- return len;
-}
-
-size_t Base64EscapeInternal(const unsigned char* src, size_t szsrc, char* dest,
- size_t szdest, const char* base64,
- bool do_padding) {
- static const char kPad64 = '=';
-
- if (szsrc * 4 > szdest * 3) return 0;
-
- char* cur_dest = dest;
- const unsigned char* cur_src = src;
-
- char* const limit_dest = dest + szdest;
- const unsigned char* const limit_src = src + szsrc;
-
- // Three bytes of data encodes to four characters of cyphertext.
- // So we can pump through three-byte chunks atomically.
- if (szsrc >= 3) { // "limit_src - 3" is UB if szsrc < 3.
- while (cur_src < limit_src - 3) { // While we have >= 32 bits.
- uint32_t in = absl::big_endian::Load32(cur_src) >> 8;
-
- cur_dest[0] = base64[in >> 18];
- in &= 0x3FFFF;
- cur_dest[1] = base64[in >> 12];
- in &= 0xFFF;
- cur_dest[2] = base64[in >> 6];
- in &= 0x3F;
- cur_dest[3] = base64[in];
-
- cur_dest += 4;
- cur_src += 3;
- }
- }
- // To save time, we didn't update szdest or szsrc in the loop. So do it now.
- szdest = limit_dest - cur_dest;
- szsrc = limit_src - cur_src;
-
- /* now deal with the tail (<=3 bytes) */
- switch (szsrc) {
- case 0:
- // Nothing left; nothing more to do.
- break;
- case 1: {
- // One byte left: this encodes to two characters, and (optionally)
- // two pad characters to round out the four-character cypherblock.
- if (szdest < 2) return 0;
- uint32_t in = cur_src[0];
- cur_dest[0] = base64[in >> 2];
- in &= 0x3;
- cur_dest[1] = base64[in << 4];
- cur_dest += 2;
- szdest -= 2;
- if (do_padding) {
- if (szdest < 2) return 0;
- cur_dest[0] = kPad64;
- cur_dest[1] = kPad64;
- cur_dest += 2;
- szdest -= 2;
- }
- break;
- }
- case 2: {
- // Two bytes left: this encodes to three characters, and (optionally)
- // one pad character to round out the four-character cypherblock.
- if (szdest < 3) return 0;
- uint32_t in = absl::big_endian::Load16(cur_src);
- cur_dest[0] = base64[in >> 10];
- in &= 0x3FF;
- cur_dest[1] = base64[in >> 4];
- in &= 0x00F;
- cur_dest[2] = base64[in << 2];
- cur_dest += 3;
- szdest -= 3;
- if (do_padding) {
- if (szdest < 1) return 0;
- cur_dest[0] = kPad64;
- cur_dest += 1;
- szdest -= 1;
- }
- break;
- }
- case 3: {
- // Three bytes left: same as in the big loop above. We can't do this in
- // the loop because the loop above always reads 4 bytes, and the fourth
- // byte is past the end of the input.
- if (szdest < 4) return 0;
- uint32_t in = (cur_src[0] << 16) + absl::big_endian::Load16(cur_src + 1);
- cur_dest[0] = base64[in >> 18];
- in &= 0x3FFFF;
- cur_dest[1] = base64[in >> 12];
- in &= 0xFFF;
- cur_dest[2] = base64[in >> 6];
- in &= 0x3F;
- cur_dest[3] = base64[in];
- cur_dest += 4;
- szdest -= 4;
- break;
- }
- default:
- // Should not be reached: blocks of 4 bytes are handled
- // in the while loop before this switch statement.
- ABSL_RAW_LOG(FATAL, "Logic problem? szsrc = %zu", szsrc);
- break;
- }
- return (cur_dest - dest);
-}
-
-constexpr char kBase64Chars[] =
- "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
-
constexpr char kWebSafeBase64Chars[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
template <typename String>
-void Base64EscapeInternal(const unsigned char* src, size_t szsrc, String* dest,
- bool do_padding, const char* base64_chars) {
- const size_t calc_escaped_size =
- CalculateBase64EscapedLenInternal(szsrc, do_padding);
- strings_internal::STLStringResizeUninitialized(dest, calc_escaped_size);
-
- const size_t escaped_len = Base64EscapeInternal(
- src, szsrc, &(*dest)[0], dest->size(), base64_chars, do_padding);
- assert(calc_escaped_size == escaped_len);
- dest->erase(escaped_len);
-}
-
-template <typename String>
bool Base64UnescapeInternal(const char* src, size_t slen, String* dest,
const signed char* unbase64) {
// Determine the size of the output std::string. Base64 encodes every 3 bytes into
@@ -1068,26 +902,30 @@ bool WebSafeBase64Unescape(absl::string_view src, std::string* dest) {
}
void Base64Escape(absl::string_view src, std::string* dest) {
- Base64EscapeInternal(reinterpret_cast<const unsigned char*>(src.data()),
- src.size(), dest, true, kBase64Chars);
+ strings_internal::Base64EscapeInternal(
+ reinterpret_cast<const unsigned char*>(src.data()), src.size(), dest,
+ true, strings_internal::kBase64Chars);
}
void WebSafeBase64Escape(absl::string_view src, std::string* dest) {
- Base64EscapeInternal(reinterpret_cast<const unsigned char*>(src.data()),
- src.size(), dest, false, kWebSafeBase64Chars);
+ strings_internal::Base64EscapeInternal(
+ reinterpret_cast<const unsigned char*>(src.data()), src.size(), dest,
+ false, kWebSafeBase64Chars);
}
std::string Base64Escape(absl::string_view src) {
std::string dest;
- Base64EscapeInternal(reinterpret_cast<const unsigned char*>(src.data()),
- src.size(), &dest, true, kBase64Chars);
+ strings_internal::Base64EscapeInternal(
+ reinterpret_cast<const unsigned char*>(src.data()), src.size(), &dest,
+ true, strings_internal::kBase64Chars);
return dest;
}
std::string WebSafeBase64Escape(absl::string_view src) {
std::string dest;
- Base64EscapeInternal(reinterpret_cast<const unsigned char*>(src.data()),
- src.size(), &dest, false, kWebSafeBase64Chars);
+ strings_internal::Base64EscapeInternal(
+ reinterpret_cast<const unsigned char*>(src.data()), src.size(), &dest,
+ false, kWebSafeBase64Chars);
return dest;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-01 03:28:16 +0000