src/lib-mail/quoted-printable.c

	quoted-printable.c revision 2f67f2fbb4b145ce7ba39ef9f15932aeadeb1747
/* Copyright (c) 2002-2012 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "buffer.h"
#include "hex-binary.h"
#include "quoted-printable.h"

#define QP_IS_TRAILING_SPACE(c) \
    ((c) == ' ' || (c) == '\t')

static int
qp_is_end_of_line(const unsigned char *src, size_t *src_pos, size_t size)
{
    size_t i = *src_pos;

    i_assert(src[i] == '=');
    for (i++; i < size; i++) {
        if (QP_IS_TRAILING_SPACE(src[i]) || src[i] == '\r')
            continue;

        if (src[i] != '\n')
            return 0;

        *src_pos = i;
        return 1;
    }
    return -1;
}

void quoted_printable_decode(const unsigned char *src, size_t src_size,
                 size_t *src_pos_r, buffer_t *dest)
{
    char hexbuf[3];
    size_t src_pos, pos, next;
    int ret;

    hexbuf[2] = '\0';

    next = 0;
    for (src_pos = 0; src_pos < src_size; src_pos++) {
        if (src[src_pos] != '=' && src[src_pos] != '\n')
            continue;

        if (src[src_pos] == '\n') {
            /* drop trailing whitespace */
            pos = src_pos;
            if (pos > 0 && src[pos-1] == '\r')
                pos--;
            while (pos > 0 && QP_IS_TRAILING_SPACE(src[pos-1]))
                pos--;
            buffer_append(dest, src + next, pos - next);
            next = src_pos+1;
            buffer_append(dest, "\r\n", 2);
            continue;
        }

        /* '=' */
        buffer_append(dest, src + next, src_pos - next);
        next = src_pos;

        if ((ret = qp_is_end_of_line(src, &src_pos, src_size)) > 0) {
            /* =[whitespace][\r]\n */
            next = src_pos+1;
            continue;
        }
        if (ret < 0) {
            /* unknown yet if this is end of line */
            break;
        }
        if (src_pos+2 >= src_size)
            break;

        /* =<hex> */
        hexbuf[0] = src[src_pos+1];
        hexbuf[1] = src[src_pos+2];

        if (hex_to_binary(hexbuf, dest) == 0) {
            src_pos += 2;
            next = src_pos + 1;
        } else {
            /* non-hex data, show as-is */
            next = src_pos;
        }
    }
    if (src_pos == src_size) {
        /* add everything but trailing spaces */
        if (src_pos > 0 && src[src_pos-1] == '\r')
            src_pos--;
        while (src_pos > 0 && QP_IS_TRAILING_SPACE(src[src_pos-1]))
            src_pos--;
        buffer_append(dest, src + next, src_pos - next);
        next = src_pos;
    }

    *src_pos_r = next;
}

void quoted_printable_q_decode(const unsigned char *src, size_t src_size,
                   buffer_t *dest)
{
    char hexbuf[3];
    size_t src_pos, next;

    hexbuf[2] = '\0';

    next = 0;
    for (src_pos = 0; src_pos < src_size; src_pos++) {
        if (src[src_pos] != '_' && src[src_pos] != '=')
            continue;

        buffer_append(dest, src + next, src_pos - next);
        next = src_pos;

        if (src[src_pos] == '_') {
            buffer_append_c(dest, ' ');
            next++;
            continue;
        }

        if (src_pos+2 >= src_size)
            break;

        /* =<hex> */
        hexbuf[0] = src[src_pos+1];
        hexbuf[1] = src[src_pos+2];

        if (hex_to_binary(hexbuf, dest) == 0) {
            src_pos += 2;
            next = src_pos+1;
        } else {
            /* non-hex data, show as-is */
            next = src_pos;
        }
    }
    buffer_append(dest, src + next, src_size - next);
}