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// Base32 implementation
//
// Copyright 2010 Google Inc.
// Author: Markus Gutschke
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License 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 "base32.h"
int base32_decode(const uint8_t *encoded, uint8_t *result, int bufSize) {
int buffer = 0;
int bitsLeft = 0;
int count = 0;
for (const uint8_t *ptr = encoded; count < bufSize && *ptr; ++ptr) {
uint8_t ch = *ptr;
if (ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n' || ch == '-') {
continue;
}
buffer <<= 5;
// Deal with commonly mistyped characters
if (ch == '0') {
ch = 'O';
} else if (ch == '1') {
ch = 'L';
} else if (ch == '8') {
ch = 'B';
}
// Look up one base32 digit
if ((ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z')) {
ch = (ch & 0x1F) - 1;
} else if (ch >= '2' && ch <= '7') {
ch -= '2' - 26;
} else {
return -1;
}
buffer |= ch;
bitsLeft += 5;
if (bitsLeft >= 8) {
result[count++] = buffer >> (bitsLeft - 8);
bitsLeft -= 8;
}
}
if (count < bufSize) {
result[count] = '\000';
}
return count;
}
int base32_encode(const uint8_t *data, int length, uint8_t *result,
int bufSize) {
if (length < 0 || length > (1 << 28)) {
return -1;
}
int count = 0;
if (length > 0) {
int buffer = data[0];
int next = 1;
int bitsLeft = 8;
while (count < bufSize && (bitsLeft > 0 || next < length)) {
if (bitsLeft < 5) {
if (next < length) {
buffer <<= 8;
buffer |= data[next++] & 0xFF;
bitsLeft += 8;
} else {
int pad = 5 - bitsLeft;
buffer <<= pad;
bitsLeft += pad;
}
}
int index = 0x1F & (buffer >> (bitsLeft - 5));
bitsLeft -= 5;
result[count++] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"[index];
}
}
if (count < bufSize) {
result[count] = '\000';
}
return count;
}
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