diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/base64.c | 81 | ||||
| -rw-r--r-- | src/base64.h | 27 | ||||
| -rw-r--r-- | src/local.mk | 2 |
3 files changed, 110 insertions, 0 deletions
diff --git a/src/base64.c b/src/base64.c new file mode 100644 index 0000000..dacd03e --- /dev/null +++ b/src/base64.c @@ -0,0 +1,81 @@ +/* + * Copyright (C) 2013 P. J. McDermott + * + * This file is part of Dodge Balls + * + * Dodge Balls 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. + * + * Dodge Balls 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 Dodge Balls. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <stddef.h> +#include "base64.h" + +static void +_db_base64_decode_block(const char *src, char *dest) +{ + int i; + /* GCC's SSP won't wrap functions with arrays smaller than 8 bytes. */ + char buf[8]; + + /* Convert base 64 characters into values. */ + /* Supports ASCII and EBCDIC systems. */ + for (i = 0; i < 4; ++i) { + if (src[i] >= 'A' && src[i] <= 'I') { + buf[i] = src[i] - 'A' + 0; + } else if (src[i] >= 'J' && src[i] <= 'R') { + buf[i] = src[i] - 'J' + 9; + } else if (src[i] >= 'S' && src[i] <= 'Z') { + buf[i] = src[i] - 'S' + 18; + } else if (src[i] >= 'a' && src[i] <= 'i') { + buf[i] = src[i] - 'a' + 26; + } else if (src[i] >= 'j' && src[i] <= 'r') { + buf[i] = src[i] - 'j' + 35; + } else if (src[i] >= 's' && src[i] <= 'z') { + buf[i] = src[i] - 's' + 44; + } else if (src[i] >= '0' && src[i] <= '9') { + buf[i] = src[i] - '0' + 52; + } else if (src[i] == '+') { + buf[i] = 62; + } else if (src[i] == '/') { + buf[i] = 63; + } else { + buf[i] = '\0'; + } + } + + /* Map four decoded value bytes into three output bytes. */ + dest[0] = (buf[0] << 2) | (buf[1] >> 4); + dest[1] = (buf[1] << 4) | (buf[2] >> 2); + dest[2] = (buf[2] << 6) | (buf[3] >> 0); +} + +void +db_base64_decode(const char *src, char *dest, size_t dest_len) +{ + size_t i; + + /* Decode the input one entire block at a time. */ + for (i = 0; i < (dest_len - 1) / 3; ++i) { + if (src[i * 4] == '\0' || + src[i * 4 + 1] == '\0' || + src[i * 4 + 2] == '\0' || + src[i * 4 + 3] == '\0') { + dest[i * 3] = '\0'; + break; + } + _db_base64_decode_block(src + i * 4, dest + i * 3); + } + + /* Ensure NUL termination. */ + dest[dest_len - 1] = '\0'; +} diff --git a/src/base64.h b/src/base64.h new file mode 100644 index 0000000..361a563 --- /dev/null +++ b/src/base64.h @@ -0,0 +1,27 @@ +/* + * Copyright (C) 2013 P. J. McDermott + * + * This file is part of Dodge Balls + * + * Dodge Balls 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. + * + * Dodge Balls 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 Dodge Balls. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef DB_BASE64_H_ +#define DB_BASE64_H_ + +#include <stddef.h> + +void db_base64_decode(const char *src, char *dest, size_t dest_len); + +#endif /* DB_BASE64_H_ */ diff --git a/src/local.mk b/src/local.mk index c796ae7..4b6f55d 100644 --- a/src/local.mk +++ b/src/local.mk @@ -1,4 +1,6 @@ dodge_balls_SOURCES += \ + %reldir%/base64.c \ + %reldir%/base64.h \ %reldir%/collision.c \ %reldir%/collision.h \ %reldir%/defs.h \ |