/* * Copyright (c) 2006-2014 Erik Ekman , * 2006-2009 Bjorn Andersson * Mostly rewritten 2009 J.A.Bezemer@opensourcepartners.nl * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include #include #include #include "encoding.h" #define BASE32_BLKSIZE_RAW 5 #define BASE32_BLKSIZE_ENC 8 static const char cb32[] = "abcdefghijklmnopqrstuvwxyz012345"; static const char cb32_ucase[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ012345"; static unsigned char rev32[256]; static int reverse_init = 0; inline static void base32_reverse_init(void) { int i; unsigned char c; if (!reverse_init) { memset(rev32, 0, 256); for (i = 0; i < 32; i++) { c = cb32[i]; rev32[(int) c] = i; c = cb32_ucase[i]; rev32[(int) c] = i; } reverse_init = 1; } } int b32_5to8(int in) { return cb32[in & 31]; } int b32_8to5(int in) { base32_reverse_init(); return rev32[in]; } /* * Fills *buf with max. *buflen characters, encoding size bytes of *data. * * NOTE: *buf space should be at least 1 byte _more_ than *buflen * to hold the trailing '\0'. * * return value : #bytes filled in buf (excluding \0) * sets *buflen to : #bytes encoded from data */ static int base32_encode(char *buf, size_t *buflen, const void *data, size_t size) { unsigned char *udata = (unsigned char *) data; int iout = 0; /* to-be-filled output char */ int iin = 0; /* one more than last input byte that can be successfully decoded */ /* Note: Don't bother to optimize manually. GCC optimizes better(!) when using simplistic array indexing. */ while (1) { if (iout >= *buflen || iin >= size) break; buf[iout] = cb32[((udata[iin] & 0xf8) >> 3)]; iout++; if (iout >= *buflen || iin >= size) { iout--; /* previous char is useless */ break; } buf[iout] = cb32[((udata[iin] & 0x07) << 2) | ((iin + 1 < size) ? ((udata[iin + 1] & 0xc0) >> 6) : 0)]; iin++; /* 0 complete, iin=1 */ iout++; if (iout >= *buflen || iin >= size) break; buf[iout] = cb32[((udata[iin] & 0x3e) >> 1)]; iout++; if (iout >= *buflen || iin >= size) { iout--; /* previous char is useless */ break; } buf[iout] = cb32[((udata[iin] & 0x01) << 4) | ((iin + 1 < size) ? ((udata[iin + 1] & 0xf0) >> 4) : 0)]; iin++; /* 1 complete, iin=2 */ iout++; if (iout >= *buflen || iin >= size) break; buf[iout] = cb32[((udata[iin] & 0x0f) << 1) | ((iin + 1 < size) ? ((udata[iin + 1] & 0x80) >> 7) : 0)]; iin++; /* 2 complete, iin=3 */ iout++; if (iout >= *buflen || iin >= size) break; buf[iout] = cb32[((udata[iin] & 0x7c) >> 2)]; iout++; if (iout >= *buflen || iin >= size) { iout--; /* previous char is useless */ break; } buf[iout] = cb32[((udata[iin] & 0x03) << 3) | ((iin + 1 < size) ? ((udata[iin + 1] & 0xe0) >> 5) : 0)]; iin++; /* 3 complete, iin=4 */ iout++; if (iout >= *buflen || iin >= size) break; buf[iout] = cb32[((udata[iin] & 0x1f))]; iin++; /* 4 complete, iin=5 */ iout++; } buf[iout] = '\0'; /* store number of bytes from data that was used */ *buflen = iin; return iout; } #define REV32(x) rev32[(int) (x)] /* * Fills *buf with max. *buflen bytes, decoded from slen chars in *str. * Decoding stops early when *str contains \0. * Illegal encoded chars are assumed to decode to zero. * * NOTE: *buf space should be at least 1 byte _more_ than *buflen * to hold a trailing '\0' that is added (though *buf will usually * contain full-binary data). * * return value : #bytes filled in buf (excluding \0) */ static int base32_decode(void *buf, size_t *buflen, const char *str, size_t slen) { unsigned char *ubuf = (unsigned char *) buf; int iout = 0; /* to-be-filled output byte */ int iin = 0; /* next input char to use in decoding */ base32_reverse_init(); /* Note: Don't bother to optimize manually. GCC optimizes better(!) when using simplistic array indexing. */ while (1) { if (iout >= *buflen || iin + 1 >= slen || str[iin] == '\0' || str[iin + 1] == '\0') break; ubuf[iout] = ((REV32(str[iin]) & 0x1f) << 3) | ((REV32(str[iin + 1]) & 0x1c) >> 2); iin++; /* 0 used up, iin=1 */ iout++; if (iout >= *buflen || iin + 2 >= slen || str[iin] == '\0' || str[iin + 1] == '\0' || str[iin + 2] == '\0') break; ubuf[iout] = ((REV32(str[iin]) & 0x03) << 6) | ((REV32(str[iin + 1]) & 0x1f) << 1) | ((REV32(str[iin + 2]) & 0x10) >> 4); iin += 2; /* 1,2 used up, iin=3 */ iout++; if (iout >= *buflen || iin + 1 >= slen || str[iin] == '\0' || str[iin + 1] == '\0') break; ubuf[iout] = ((REV32(str[iin]) & 0x0f) << 4) | ((REV32(str[iin + 1]) & 0x1e) >> 1); iin++; /* 3 used up, iin=4 */ iout++; if (iout >= *buflen || iin + 2 >= slen || str[iin] == '\0' || str[iin + 1] == '\0' || str[iin + 2] == '\0') break; ubuf[iout] = ((REV32(str[iin]) & 0x01) << 7) | ((REV32(str[iin + 1]) & 0x1f) << 2) | ((REV32(str[iin + 2]) & 0x18) >> 3); iin += 2; /* 4,5 used up, iin=6 */ iout++; if (iout >= *buflen || iin + 1 >= slen || str[iin] == '\0' || str[iin + 1] == '\0') break; ubuf[iout] = ((REV32(str[iin]) & 0x07) << 5) | ((REV32(str[iin + 1]) & 0x1f)); iin += 2; /* 6,7 used up, iin=8 */ iout++; } ubuf[iout] = '\0'; return iout; } const struct encoder base32_ops = { .name = "Base32", .encode = base32_encode, .decode = base32_decode, .places_dots = false, .eats_dots = false, .blocksize_raw = BASE32_BLKSIZE_RAW, .blocksize_encoded = BASE32_BLKSIZE_ENC, };