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[core] Deduplicate base64 encode/decode logic (#14143)

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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
J. Nick Koston
2026-02-20 19:20:58 -06:00
committed by GitHub
parent d206c75b0b
commit 35037d1a5b
1 changed files with 40 additions and 48 deletions
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88
esphome/core/helpers.cpp
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@@ -545,38 +545,36 @@ static inline bool is_base64(char c) { return (isalnum(c) || (c == '+') || (c ==
std::string base64_encode(const std::vector<uint8_t> &buf) { return base64_encode(buf.data(), buf.size()); }
// Encode 3 input bytes to 4 base64 characters, append 'count' to ret.
static inline void base64_encode_triple(const char *char_array_3, int count, std::string &ret) {
char char_array_4[4];
char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
char_array_4[3] = char_array_3[2] & 0x3f;
for (int j = 0; j < count; j++)
ret += BASE64_CHARS[static_cast<uint8_t>(char_array_4[j])];
}
std::string base64_encode(const uint8_t *buf, size_t buf_len) {
std::string ret;
int i = 0;
int j = 0;
char char_array_3[3];
char char_array_4[4];
while (buf_len--) {
char_array_3[i++] = *(buf++);
if (i == 3) {
char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
char_array_4[3] = char_array_3[2] & 0x3f;
for (i = 0; (i < 4); i++)
ret += BASE64_CHARS[static_cast<uint8_t>(char_array_4[i])];
base64_encode_triple(char_array_3, 4, ret);
i = 0;
}
}
if (i) {
for (j = i; j < 3; j++)
for (int j = i; j < 3; j++)
char_array_3[j] = '\0';
char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
char_array_4[3] = char_array_3[2] & 0x3f;
for (j = 0; (j < i + 1); j++)
ret += BASE64_CHARS[static_cast<uint8_t>(char_array_4[j])];
base64_encode_triple(char_array_3, i + 1, ret);
while ((i++ < 3))
ret += '=';
@@ -589,13 +587,33 @@ size_t base64_decode(const std::string &encoded_string, uint8_t *buf, size_t buf
return base64_decode(reinterpret_cast<const uint8_t *>(encoded_string.data()), encoded_string.size(), buf, buf_len);
}
// Decode 4 base64 characters to up to 'count' output bytes, returns true if truncated.
static inline bool base64_decode_quad(uint8_t *char_array_4, int count, uint8_t *buf, size_t buf_len, size_t &out) {
for (int i = 0; i < 4; i++)
char_array_4[i] = base64_find_char(char_array_4[i]);
uint8_t char_array_3[3];
char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
bool truncated = false;
for (int j = 0; j < count; j++) {
if (out < buf_len) {
buf[out++] = char_array_3[j];
} else {
truncated = true;
}
}
return truncated;
}
size_t base64_decode(const uint8_t *encoded_data, size_t encoded_len, uint8_t *buf, size_t buf_len) {
size_t in_len = encoded_len;
int i = 0;
int j = 0;
size_t in = 0;
size_t out = 0;
uint8_t char_array_4[4], char_array_3[3];
uint8_t char_array_4[4];
bool truncated = false;
// SAFETY: The loop condition checks is_base64() before processing each character.
@@ -605,42 +623,16 @@ size_t base64_decode(const uint8_t *encoded_data, size_t encoded_len, uint8_t *b
char_array_4[i++] = encoded_data[in];
in++;
if (i == 4) {
for (i = 0; i < 4; i++)
char_array_4[i] = base64_find_char(char_array_4[i]);
char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
for (i = 0; i < 3; i++) {
if (out < buf_len) {
buf[out++] = char_array_3[i];
} else {
truncated = true;
}
}
truncated |= base64_decode_quad(char_array_4, 3, buf, buf_len, out);
i = 0;
}
}
if (i) {
for (j = i; j < 4; j++)
for (int j = i; j < 4; j++)
char_array_4[j] = 0;
for (j = 0; j < 4; j++)
char_array_4[j] = base64_find_char(char_array_4[j]);
char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
for (j = 0; j < i - 1; j++) {
if (out < buf_len) {
buf[out++] = char_array_3[j];
} else {
truncated = true;
}
}
truncated |= base64_decode_quad(char_array_4, i - 1, buf, buf_len, out);
}
if (truncated) {