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Diffstat (limited to 'libmailutils/base64.c')
-rw-r--r-- | libmailutils/base64.c | 273 |
1 files changed, 273 insertions, 0 deletions
diff --git a/libmailutils/base64.c b/libmailutils/base64.c new file mode 100644 index 000000000..7a8c62282 --- /dev/null +++ b/libmailutils/base64.c @@ -0,0 +1,273 @@ +/* GNU Mailutils -- a suite of utilities for electronic mail + Copyright (C) 2002, 2009, 2010 Free Software Foundation, Inc. + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 3 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with GNU Mailutils. If not, see <http://www.gnu.org/licenses/>. */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <stdlib.h> +#include <string.h> +#include <mailutils/errno.h> +#include <mailutils/filter.h> + +static char b64tab[] = + "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; +static int b64val[128] = { + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, + 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, + -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, + 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, + -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, + 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 +}; + +int +mu_base64_encode (const unsigned char *input, size_t input_len, + unsigned char **output, size_t *output_len) +{ + size_t olen = 4 * (input_len + 2) / 3 + 1; + unsigned char *out = malloc (olen); + + if (!out) + return ENOMEM; + *output = out; + while (input_len >= 3) + { + *out++ = b64tab[input[0] >> 2]; + *out++ = b64tab[((input[0] << 4) & 0x30) | (input[1] >> 4)]; + *out++ = b64tab[((input[1] << 2) & 0x3c) | (input[2] >> 6)]; + *out++ = b64tab[input[2] & 0x3f]; + input_len -= 3; + input += 3; + } + + if (input_len > 0) + { + unsigned char c = (input[0] << 4) & 0x30; + *out++ = b64tab[input[0] >> 2]; + if (input_len > 1) + c |= input[1] >> 4; + *out++ = b64tab[c]; + *out++ = (input_len < 2) ? '=' : b64tab[(input[1] << 2) & 0x3c]; + *out++ = '='; + } + *output_len = out - *output; + *out = 0; + return 0; +} + +int +mu_base64_decode (const unsigned char *input, size_t input_len, + unsigned char **output, size_t *output_len) +{ + int olen = input_len; + unsigned char *out = malloc (olen); + + if (!out) + return ENOMEM; + *output = out; + do + { + if (input[0] > 127 || b64val[input[0]] == -1 + || input[1] > 127 || b64val[input[1]] == -1 + || input[2] > 127 || ((input[2] != '=') && (b64val[input[2]] == -1)) + || input[3] > 127 || ((input[3] != '=') + && (b64val[input[3]] == -1))) + return EINVAL; + *out++ = (b64val[input[0]] << 2) | (b64val[input[1]] >> 4); + if (input[2] != '=') + { + *out++ = ((b64val[input[1]] << 4) & 0xf0) | (b64val[input[2]] >> 2); + if (input[3] != '=') + *out++ = ((b64val[input[2]] << 6) & 0xc0) | b64val[input[3]]; + } + input += 4; + input_len -= 4; + } + while (input_len > 0); + *output_len = out - *output; + return 0; +} + + +static enum mu_filter_result +_base64_decoder (void *xd MU_ARG_UNUSED, + enum mu_filter_command cmd, + struct mu_filter_io *iobuf) +{ + int i = 0, tmp = 0, pad = 0; + size_t consumed = 0; + unsigned char data[4]; + size_t nbytes = 0; + const char *iptr; + size_t isize; + char *optr; + size_t osize; + + switch (cmd) + { + case mu_filter_init: + case mu_filter_done: + return mu_filter_ok; + default: + break; + } + + if (osize <= 3) + { + iobuf->osize = 3; + return mu_filter_moreoutput; + } + + iptr = iobuf->input; + isize = iobuf->isize; + optr = iobuf->output; + osize = iobuf->osize; + + while (consumed < isize && nbytes + 3 < osize) + { + while (i < 4 && consumed < isize) + { + tmp = b64val[*(const unsigned char*)iptr++]; + consumed++; + if (tmp != -1) + data[i++] = tmp; + else if (*(iptr-1) == '=') + { + data[i++] = 0; + pad++; + } + } + + /* I have a entire block of data 32 bits get the output data. */ + if (i == 4) + { + *optr++ = (data[0] << 2) | ((data[1] & 0x30) >> 4); + *optr++ = ((data[1] & 0xf) << 4) | ((data[2] & 0x3c) >> 2); + *optr++ = ((data[2] & 0x3) << 6) | data[3]; + nbytes += 3 - pad; + } + else + { + /* I did not get all the data. */ + consumed -= i; + break; + } + i = 0; + } + iobuf->isize = consumed; + iobuf->osize = nbytes; + return mu_filter_ok; +} + +static enum mu_filter_result +_base64_encoder (void *xd MU_ARG_UNUSED, + enum mu_filter_command cmd, + struct mu_filter_io *iobuf) +{ + size_t consumed = 0; + int pad = 0; + const unsigned char *ptr = (const unsigned char*) iobuf->input; + size_t nbytes = 0; + size_t isize; + char *optr; + size_t osize; + + switch (cmd) + { + case mu_filter_init: + case mu_filter_done: + return mu_filter_ok; + default: + break; + } + + if (iobuf->isize <= 3) + { + if (cmd == mu_filter_lastbuf) + pad = 1; + else + { + iobuf->isize = 4; + return mu_filter_moreinput; + } + } + if (osize < 4) + { + iobuf->osize = 4; + return mu_filter_moreoutput; + } + + isize = iobuf->isize; + optr = iobuf->output; + osize = iobuf->osize; + + while ((consumed + 3 <= isize && nbytes + 4 <= osize) || pad) + { + unsigned char c1 = 0, c2 = 0, x = '=', y = '='; + + *optr++ = b64tab[ptr[0] >> 2]; + consumed++; + switch (isize - consumed) + { + default: + consumed++; + y = b64tab[ptr[2] & 0x3f]; + c2 = ptr[2] >> 6; + case 1: + consumed++; + x = b64tab[((ptr[1] << 2) + c2) & 0x3f]; + c1 = (ptr[1] >> 4); + case 0: + *optr++ = b64tab[((ptr[0] << 4) + c1) & 0x3f]; + *optr++ = x; + *optr++ = y; + } + + ptr += 3; + nbytes += 4; + pad = 0; + } + + /* Consumed may grow bigger than isize if cmd is mu_filter_lastbuf */ + if (consumed > iobuf->isize) + consumed = iobuf->isize; + iobuf->isize = consumed; + iobuf->osize = nbytes; + return mu_filter_ok; +} + +static struct _mu_filter_record _base64_filter = { + "base64", + 76, + NULL, + _base64_encoder, + _base64_decoder +}; + +mu_filter_record_t mu_base64_filter = &_base64_filter; + +static struct _mu_filter_record _B_filter = { + "B", + 0, + NULL, + _base64_encoder, + _base64_decoder +}; + +mu_filter_record_t mu_rfc_2047_B_filter = &_B_filter; |