/* GNU Mailutils -- a suite of utilities for electronic mail Copyright (C) 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, 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> #define ISWS(c) ((c)==' ' || (c)=='\t') static enum mu_filter_result _qp_decoder (void *xd MU_ARG_UNUSED, enum mu_filter_command cmd, struct mu_filter_io *iobuf) { char c; size_t consumed = 0; size_t wscount = 0; 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; } iptr = iobuf->input; isize = iobuf->isize; optr = iobuf->output; osize = iobuf->osize; while (consumed < isize && nbytes < osize) { c = *iptr++; if (ISWS(c)) { wscount++; consumed++; } else { /* Octets with values of 9 and 32 MAY be represented as US-ASCII TAB (HT) and SPACE characters, respectively, but MUST NOT be so represented at the end of an encoded line. Any TAB (HT) or SPACE characters on an encoded line MUST thus be followed on that line by a printable character. */ if (wscount) { if (c != '\r' && c != '\n') { size_t sz; if (consumed >= isize) break; if (nbytes + wscount > osize) sz = osize - nbytes; else sz = wscount; memcpy(optr, iptr - wscount - 1, sz); optr += sz; nbytes += sz; if (wscount > sz) { wscount -= sz; break; } } wscount = 0; if (nbytes == osize) break; } if (c == '=') { /* There must be 2 more characters before I consume this. */ if (consumed + 2 >= isize) break; else { /* you get =XX where XX are hex characters. */ char chr[3]; int new_c; chr[2] = 0; chr[0] = *iptr++; /* Ignore LF. */ if (chr[0] != '\n') { chr[1] = *iptr++; new_c = strtoul (chr, NULL, 16); *optr++ = new_c; nbytes++; consumed += 3; } else consumed += 2; } } /* CR character. */ else if (c == '\r') { /* There must be at least 1 more character before I consume this. */ if (consumed + 1 >= isize) { if (cmd == mu_filter_lastbuf) consumed++; break; } else { iptr++; /* Skip the CR character. */ *optr++ = '\n'; nbytes++; consumed += 2; } } else if (c == '_') { *optr++ = ' '; nbytes++; consumed++; } else { *optr++ = c; nbytes++; consumed++; } } } iobuf->isize = consumed - wscount; iobuf->osize = nbytes; return mu_filter_ok; } static enum mu_filter_result _qp_encoder (void *xd MU_ARG_UNUSED, enum mu_filter_command cmd, struct mu_filter_io *iobuf) { unsigned int c; size_t consumed = 0; size_t nbytes = 0; static const char _hexdigits[] = "0123456789ABCDEF"; 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; } iptr = iobuf->input; isize = iobuf->isize; optr = iobuf->output; osize = iobuf->osize; nbytes = 0; /* Strategy: check if we have enough room in the output buffer only once the required size has been computed. If there is not enough, return and hope that the caller will free up the output buffer a bit. */ while (consumed < isize) { int simple_char; /* candidate byte to convert */ c = *(unsigned char*) iptr; simple_char = (c >= 32 && c <= 60) || (c >= 62 && c <= 126) || c == '\t' || c == '\n'; if (simple_char) { /* a non-quoted character uses up one byte */ if (nbytes + 1 > osize) break; *optr++ = c; nbytes++; iptr++; consumed++; } else { /* a quoted character uses up three bytes */ if (nbytes + 3 > osize) break; *optr++ = '='; *optr++ = _hexdigits[(c >> 4) & 0xf]; *optr++ = _hexdigits[c & 0xf]; nbytes += 3; /* we've actuall used up one byte of input */ iptr++; consumed++; } } iobuf->isize = consumed; iobuf->osize = nbytes; return mu_filter_ok; } static struct _mu_filter_record _qp_filter = { "quoted-printable", NULL, _qp_encoder, _qp_decoder }; mu_filter_record_t mu_qp_filter = &_qp_filter; static struct _mu_filter_record _Q_filter = { "Q", NULL, _qp_encoder, _qp_decoder }; mu_filter_record_t mu_rfc_2047_Q_filter = &_Q_filter;