src/lib-mail/quoted-printable.c

/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */

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

int quoted_printable_q_decode(const unsigned char *src, size_t src_size,
                  buffer_t *dest)
{
    char hexbuf[3];
    size_t src_pos, next;
    bool errors = FALSE;

    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 */
            errors = TRUE;
            next = src_pos;
        }
    }
    buffer_append(dest, src + next, src_size - next);
    return errors ? -1 : 0;
}