diff options
Diffstat (limited to 'common/base32.c')
| -rw-r--r-- | common/base32.c | 175 |
1 files changed, 0 insertions, 175 deletions
diff --git a/common/base32.c b/common/base32.c deleted file mode 100644 index a6be8409b1..0000000000 --- a/common/base32.c +++ /dev/null @@ -1,175 +0,0 @@ -/* Copyright 2017 The Chromium OS Authors. All rights reserved. - * Use of this source code is governed by a BSD-style license that can be - * found in the LICENSE file. - */ - -/* Base-32 encoding/decoding */ - -#include "common.h" -#include "base32.h" -#include "util.h" - -static const unsigned char crc5_table1[] = { - 0x00, 0x0E, 0x1C, 0x12, 0x11, 0x1F, 0x0D, 0x03, - 0x0B, 0x05, 0x17, 0x19, 0x1A, 0x14, 0x06, 0x08 -}; - -static const unsigned char crc5_table0[] = { - 0x00, 0x16, 0x05, 0x13, 0x0A, 0x1C, 0x0F, 0x19, - 0x14, 0x02, 0x11, 0x07, 0x1E, 0x08, 0x1B, 0x0D -}; - -uint8_t crc5_sym(uint8_t sym, uint8_t previous_crc) -{ - uint8_t tmp = sym ^ previous_crc; - return crc5_table1[tmp & 0x0F] ^ crc5_table0[(tmp >> 4) & 0x0F]; -} - -/* A-Z0-9 with I,O,0,1 removed */ -const char base32_map[33] = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789"; - -/** - * Decode a base32 symbol. - * - * @param sym Input symbol - * @return The symbol value or -1 if error. - */ -static int decode_sym(int sym) -{ - int i = 0; - - for (i = 0; i < 32; i++) { - if (sym == base32_map[i]) - return i; - } - - return -1; -} - -int base32_encode(char *dest, int destlen_chars, - const void *srcbits, int srclen_bits, - int add_crc_every) -{ - const uint8_t *src = srcbits; - int destlen_needed; - int crc = 0, crc_count = 0; - int didx = 0; - int i; - - *dest = 0; - - /* Make sure destination is big enough */ - destlen_needed = (srclen_bits + 4) / 5; /* Symbols before adding CRC */ - if (add_crc_every) { - /* Must be an exact number of groups to add CRC */ - if (destlen_needed % add_crc_every) - return EC_ERROR_INVAL; - destlen_needed += destlen_needed / add_crc_every; - } - destlen_needed++; /* For terminating null */ - if (destlen_chars < destlen_needed) - return EC_ERROR_INVAL; - - for (i = 0; i < srclen_bits; i += 5) { - int sym; - int sidx = i / 8; - int bit_offs = i % 8; - - if (bit_offs <= 3) { - /* Entire symbol fits in that byte */ - sym = src[sidx] >> (3 - bit_offs); - } else { - /* Use the bits we have left */ - sym = src[sidx] << (bit_offs - 3); - - /* Use the bits from the next byte, if any */ - if (i + 1 < srclen_bits) - sym |= src[sidx + 1] >> (11 - bit_offs); - } - - sym &= 0x1f; - - /* Pad incomplete symbol with 0 bits */ - if (srclen_bits - i < 5) - sym &= 0x1f << (5 + i - srclen_bits); - - dest[didx++] = base32_map[sym]; - - /* Add CRC if needed */ - if (add_crc_every) { - crc = crc5_sym(sym, crc); - if (++crc_count == add_crc_every) { - dest[didx++] = base32_map[crc]; - crc_count = crc = 0; - } - } - } - - /* Terminate string and return */ - dest[didx] = 0; - return EC_SUCCESS; -} - -int base32_decode(uint8_t *dest, int destlen_bits, const char *src, - int crc_after_every) -{ - int crc = 0, crc_count = 0; - int out_bits = 0; - - for (; *src; src++) { - int sym, sbits, dbits, b; - - if (isspace((unsigned char)*src) || *src == '-') - continue; - - sym = decode_sym(*src); - if (sym < 0) - return -1; /* Bad input symbol */ - - /* Check CRC if needed */ - if (crc_after_every) { - if (crc_count == crc_after_every) { - if (crc != sym) - return -1; - crc_count = crc = 0; - continue; - } else { - crc = crc5_sym(sym, crc); - crc_count++; - } - } - - /* - * Stop if we're out of space. Have to do this after checking - * the CRC, or we might not check the last CRC. - */ - if (out_bits >= destlen_bits) - break; - - /* See how many bits we get to use from this symbol */ - sbits = MIN(5, destlen_bits - out_bits); - if (sbits < 5) - sym >>= (5 - sbits); - - /* Fill up the rest of the current byte */ - dbits = 8 - (out_bits & 7); - b = MIN(dbits, sbits); - if (dbits == 8) - dest[out_bits / 8] = 0; /* Starting a new byte */ - dest[out_bits / 8] |= (sym << (dbits - b)) >> (sbits - b); - out_bits += b; - sbits -= b; - - /* Start the next byte if there's space */ - if (sbits > 0) { - dest[out_bits / 8] = sym << (8 - sbits); - out_bits += sbits; - } - } - - /* If we have CRCs, should have a full group */ - if (crc_after_every && crc_count) - return -1; - - return out_bits; -} |