#include "lib.h"

#include "base32.h"

#include "buffer.h"

static const char b32enc[] =

"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";

static const char b32hexenc[] =

"0123456789ABCDEFGHIJKLMNOPQRSTUV";

static const unsigned char b32dec[256] = {

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0-7 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 8-15 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 16-23 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 24-31 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 32-39 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 40-47 */

0xff, 0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, /* 48-55 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 56-63 */

0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, /* 64-71 */

0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, /* 72-79 */

0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, /* 80-87 */

0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff, /* 88-95 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 96-103 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 104-111 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 112-119 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 120-127 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 128-255 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

};

static const unsigned char b32hexdec[256] = {

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0-7 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 8-15 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 16-23 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 24-31 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 32-39 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 40-47 */

0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 48-55 */

0x08, 0x09, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 56-63 */

0xff, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, /* 64-71 */

0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, /* 72-79 */

0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0xff, /* 80-87 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 88-95 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 96-103 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 104-111 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 112-119 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 120-127 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 128-255 */

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,

};

static void

base32_encode_with_alphabet(const char *alph,

bool pad, const void *src, size_t src_size, buffer_t *dest)

{

const unsigned char *src_c = src;

unsigned char tmp[8], endb;

size_t src_pos;

/* [5 3][2 5 1][4 4][1 5 2][3 5]

/* encode main part */

for (src_pos = 0; src_pos + 4 < src_size; src_pos += 5) {

tmp[0] = alph[src_c[src_pos] >> 3];

tmp[1] = alph[((src_c[src_pos] & 0x07) << 2) |

((src_c[src_pos+1] >> 6) & 0x03)];

tmp[2] = alph[((src_c[src_pos+1] >> 1) & 0x1f)];

tmp[3] = alph[((src_c[src_pos+1] & 0x01) << 4) |

(src_c[src_pos+2] >> 4)];

tmp[4] = alph[((src_c[src_pos+2] & 0x0f) << 1) |

(src_c[src_pos+3] >> 7)];

tmp[5] = alph[((src_c[src_pos+3] >> 2) & 0x1f)];

tmp[6] = alph[((src_c[src_pos+3] & 0x03) << 3) |

(src_c[src_pos+4] >> 5)];

tmp[7] = alph[src_c[src_pos+4] & 0x1f];

buffer_append(dest, tmp, 8);

}

/* encode last < 5 bytes if any */

if (src_pos < src_size) {

tmp[0] = alph[src_c[src_pos] >> 3];

switch (src_size - src_pos) {

case 1:

tmp[1] = alph[((src_c[src_pos] & 0x07) << 2)];

endb = 2;

break;

case 2:

tmp[1] = alph[((src_c[src_pos] & 0x07) << 2) |

((src_c[src_pos+1] >> 6) & 0x03)];

tmp[2] = alph[((src_c[src_pos+1] >> 1) & 0x1f)];

tmp[3] = alph[((src_c[src_pos+1] & 0x01) << 4)];

endb = 4;

break;

case 3:

tmp[1] = alph[((src_c[src_pos] & 0x07) << 2) |

((src_c[src_pos+1] >> 6) & 0x03)];

tmp[2] = alph[((src_c[src_pos+1] >> 1) & 0x1f)];

tmp[3] = alph[((src_c[src_pos+1] & 0x01) << 4) |

(src_c[src_pos+2] >> 4)];

tmp[4] = alph[((src_c[src_pos+2] & 0x0f) << 1)];

endb = 5;

break;

case 4:

tmp[1] = alph[((src_c[src_pos] & 0x07) << 2) |

((src_c[src_pos+1] >> 6) & 0x03)];

tmp[2] = alph[((src_c[src_pos+1] >> 1) & 0x1f)];

tmp[3] = alph[((src_c[src_pos+1] & 0x01) << 4) |

(src_c[src_pos+2] >> 4)];

tmp[4] = alph[((src_c[src_pos+2] & 0x0f) << 1) |

(src_c[src_pos+3] >> 7)];

tmp[5] = alph[((src_c[src_pos+3] >> 2) & 0x1f)];

tmp[6] = alph[((src_c[src_pos+3] & 0x03) << 3)];

endb = 7;

break;

default:

i_unreached();

}

/* add padding if required */

if (pad) {

memset(&tmp[endb], '=', sizeof(tmp)-endb);

buffer_append(dest, tmp, 8);

} else {

buffer_append(dest, tmp, endb);

}

}

}

void base32_encode(bool pad, const void *src, size_t src_size,

buffer_t *dest)

{

base32_encode_with_alphabet(b32enc, pad, src, src_size, dest);

}

void base32hex_encode(bool pad, const void *src, size_t src_size,

buffer_t *dest)

{

base32_encode_with_alphabet(b32hexenc, pad, src, src_size, dest);

}

#define IS_EMPTY(c) \

((c) == '\n' || (c) == '\r' || (c) == ' ' || (c) == '\t')

static int

base32_decode_with_alphabet(const unsigned char *alph,

const void *src, size_t src_size, size_t *src_pos_r,

buffer_t *dest)

{

const unsigned char *src_c = src;

size_t block_pos, src_pos;

unsigned char output[5], ipos, opos;

int ret = 1;

/* (5)(3 2)(5)(1 4)(4 1)(5)(2 3)(5)

ipos = opos = 0;

block_pos = 0;

for (src_pos = 0; src_pos < src_size; src_pos++) {

unsigned char input = alph[src_c[src_pos]];

if (input == 0xff) {

if (unlikely(!IS_EMPTY(src_c[src_pos])))

break;

continue;

}

ipos++;

switch (ipos) {

case 1:

output[0] = input << 3;

opos = 0;

break;

case 2:

output[0] |= input >> 2;

output[1] = (input & 0x03) << 6;

opos = 1;

break;

case 3:

output[1] |= input << 1;

opos = 1;

break;

case 4:

output[1] |= input >> 4;

output[2] = (input & 0x0f) << 4;

opos = 2;

break;

case 5:

output[2] |= input >> 1;

output[3] = (input & 0x01) << 7;

opos = 3;

break;

case 6:

output[3] |= input << 2;

opos = 3;

break;

case 7:

output[3] |= input >> 3;

output[4] = ((input & 0x07) << 5);

opos = 4;

break;

case 8:

output[4] |= input;

buffer_append(dest, output, 5);

ipos = 0;

opos = 0;

block_pos = src_pos;

break;

default:

i_unreached();

}

}

if (ipos > 0) {

for (; src_pos < src_size; src_pos++) {

if (src_c[src_pos] != '=') {

if (unlikely(!IS_EMPTY(src_c[src_pos]))) {

ret = -1;

break;

}

continue;

}

if (++ipos >= 8) {

buffer_append(dest, output, opos);

ipos = 0;

ret = 0;

src_pos++;

break;

}

}

}

if (src_pos_r != NULL) {

if (ipos == 0) {

for (; src_pos < src_size; src_pos++) {

if (!IS_EMPTY(src_c[src_pos]))

break;

}

*src_pos_r = src_pos;

} else {

*src_pos_r = block_pos;

}

}

return ret;

}

int base32_decode(const void *src, size_t src_size,

size_t *src_pos_r, buffer_t *dest)

{

return base32_decode_with_alphabet

(b32dec, src, src_size, src_pos_r, dest);

}

int base32hex_decode(const void *src, size_t src_size,

size_t *src_pos_r, buffer_t *dest)

{

return base32_decode_with_alphabet

(b32hexdec, src, src_size, src_pos_r, dest);

}

buffer_t *t_base32_decode_str(const char *str)

{

buffer_t *buf;

size_t len = strlen(str);

buf = t_buffer_create(MAX_BASE32_DECODED_SIZE(len));

(void)base32_decode(str, len, NULL, buf);

return buf;

}

buffer_t *t_base32hex_decode_str(const char *str)

{

buffer_t *buf;

size_t len = strlen(str);

buf = t_buffer_create(MAX_BASE32_DECODED_SIZE(len));

(void)base32hex_decode(str, len, NULL, buf);

return buf;

}

bool base32_is_valid_char(char c)

{

return b32dec[(uint8_t)c] != 0xff;

}

bool base32hex_is_valid_char(char c)

{

return b32hexdec[(uint8_t)c] != 0xff;

}