diff options
Diffstat (limited to 'plugins/encodings/base64.c')
-rw-r--r-- | plugins/encodings/base64.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/plugins/encodings/base64.c b/plugins/encodings/base64.c new file mode 100644 index 0000000..c749a87 --- /dev/null +++ b/plugins/encodings/base64.c @@ -0,0 +1,139 @@ + +/* Chrysalide - Outil d'analyse de fichiers binaires + * base64.c - calculs d'encodages en base 64 + * + * Copyright (C) 2020 Cyrille Bagard + * + * This file is part of Chrysalide. + * + * Chrysalide is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * Chrysalide 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with Chrysalide. If not, see <http://www.gnu.org/licenses/>. + */ + + +#include "base64.h" + + + +/****************************************************************************** +* * +* Paramètres : input = données d'entrée à traiter. * +* output = données sortantes constituées. [OUT] * +* alphabet = alphabet d'encodage mis à disposition. * +* * +* Description : Procède à l'encodage d'un contenu en base 64. * +* * +* Retour : Bilan de l'opération : true en cas de réussite, false sinon. * +* * +* Remarques : - * +* * +******************************************************************************/ + +bool _base64_encode(const sized_binary_t *input, sized_string_t *output, const sized_string_t *alphabet) +{ + bool result; /* Bilan à retourner */ + const bin_t *src; /* Tête de lecture #1 */ + const bin_t *alpha; /* Tête de lecture #2 */ + bin_t *iter; /* Tête d'écriture */ + size_t i; /* Boucle de parcours */ + + result = (alphabet->len == 64); + if (!result) goto exit; + + /* Création du réceptacle */ + + output->len = input->len * 4 / 3; + + if (output->len % 4 != 0) + output->len += (4 - output->len % 4); + + output->data = malloc((output->len + 1) * sizeof(bin_t)); + + /* Encodage du corps du message */ + + src = input->static_bin_data; + alpha = alphabet->static_bin_data; + + iter = output->bin_data; + + if (input->len > 2) + for (i = 0; i < (input->len - 2); i += 3) + { + *iter++ = alpha[(src[i] >> 2) & 0x3f]; + + *iter++ = alpha[((src[i] & 0x03) << 4) | ((src[i + 1] & 0xf0) >> 4)]; + + *iter++ = alpha[((src[i + 1] & 0x0f) << 2) | ((src[i + 2] & 0xc0) >> 6)]; + + *iter++ = alpha[src[i + 2] & 0x3f]; + + } + else + i = 0; + + /* Bourrage final ? */ + + if (i < input->len) + { + *iter++ = alpha[(src[i] >> 2) & 0x3f]; + + if (i == (input->len - 1)) + { + *iter++ = alpha[((src[i] & 0x03) << 4)]; + *iter++ = '='; + } + else + { + *iter++ = alpha[((src[i] & 0x03) << 4) | ((src[i + 1] & 0xf0) >> 4)]; + *iter++ = alpha[((src[i + 1] & 0x0f) << 2)]; + } + + *iter++ = '='; + } + + *iter = 0x00; + + exit: + + return result; + +} + + +/****************************************************************************** +* * +* Paramètres : input = données d'entrée à traiter. * +* output = données sortantes constituées. [OUT] * +* * +* Description : Procède à l'encodage par défaut d'un contenu en base 64. * +* * +* Retour : Bilan de l'opération : true en cas de réussite, false sinon. * +* * +* Remarques : - * +* * +******************************************************************************/ + +bool base64_encode(const sized_binary_t *input, sized_string_t *output) +{ + bool result; /* Bilan à retourner */ + + const sized_string_t alphabet = { + .static_data = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/", + .len = 64 + }; + + result = _base64_encode(input, output, &alphabet); + + return result; + +} |