173 lines
5.2 KiB
C
173 lines
5.2 KiB
C
/* base64.h
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Base-64 encoding and decoding.
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Copyright (C) 2002 Niels Möller, Dan Egnor
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This file is part of GNU Nettle.
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GNU Nettle is free software: you can redistribute it and/or
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modify it under the terms of either:
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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or
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* the GNU General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at your
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option) any later version.
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or both in parallel, as here.
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GNU Nettle is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received copies of the GNU General Public License and
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the GNU Lesser General Public License along with this program. If
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not, see http://www.gnu.org/licenses/.
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*/
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#ifndef NETTLE_BASE64_H_INCLUDED
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#define NETTLE_BASE64_H_INCLUDED
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#include "nettle-types.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Name mangling */
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#define base64_encode_init nettle_base64_encode_init
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#define base64url_encode_init nettle_base64url_encode_init
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#define base64_encode_single nettle_base64_encode_single
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#define base64_encode_update nettle_base64_encode_update
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#define base64_encode_final nettle_base64_encode_final
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#define base64_encode_raw nettle_base64_encode_raw
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#define base64_encode_group nettle_base64_encode_group
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#define base64_decode_init nettle_base64_decode_init
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#define base64url_decode_init nettle_base64url_decode_init
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#define base64_decode_single nettle_base64_decode_single
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#define base64_decode_update nettle_base64_decode_update
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#define base64_decode_final nettle_base64_decode_final
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#define BASE64_BINARY_BLOCK_SIZE 3
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#define BASE64_TEXT_BLOCK_SIZE 4
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/* Base64 encoding */
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/* Maximum length of output for base64_encode_update. NOTE: Doesn't
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* include any padding that base64_encode_final may add. */
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/* We have at most 4 buffered bits, and a total of (4 + length * 8) bits. */
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#define BASE64_ENCODE_LENGTH(length) (((length) * 8 + 4)/6)
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/* Maximum length of output generated by base64_encode_final. */
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#define BASE64_ENCODE_FINAL_LENGTH 3
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/* Exact length of output generated by base64_encode_raw, including
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* padding. */
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#define BASE64_ENCODE_RAW_LENGTH(length) ((((length) + 2)/3)*4)
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struct base64_encode_ctx
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{
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const char *alphabet; /* Alphabet to use for encoding */
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unsigned short word; /* Leftover bits */
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unsigned char bits; /* Number of bits, always 0, 2, or 4. */
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};
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/* Initialize encoding context for base-64 */
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void
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base64_encode_init(struct base64_encode_ctx *ctx);
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/* Initialize encoding context for URL safe alphabet, RFC 4648. */
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void
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base64url_encode_init(struct base64_encode_ctx *ctx);
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/* Encodes a single byte. Returns amount of output (always 1 or 2). */
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size_t
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base64_encode_single(struct base64_encode_ctx *ctx,
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char *dst,
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uint8_t src);
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/* Returns the number of output characters. DST should point to an
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* area of size at least BASE64_ENCODE_LENGTH(length). */
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size_t
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base64_encode_update(struct base64_encode_ctx *ctx,
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char *dst,
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size_t length,
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const uint8_t *src);
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/* DST should point to an area of size at least
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* BASE64_ENCODE_FINAL_LENGTH */
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size_t
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base64_encode_final(struct base64_encode_ctx *ctx,
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char *dst);
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/* Lower level functions */
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/* Encodes a string in one go, including any padding at the end.
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* Generates exactly BASE64_ENCODE_RAW_LENGTH(length) bytes of output.
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* Supports overlapped operation, if src <= dst. FIXME: Use of overlap
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* is deprecated, if needed there should be a separate public fucntion
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* to do that.*/
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void
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base64_encode_raw(char *dst, size_t length, const uint8_t *src);
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void
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base64_encode_group(char *dst, uint32_t group);
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/* Base64 decoding */
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/* Maximum length of output for base64_decode_update. */
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/* We have at most 6 buffered bits, and a total of (length + 1) * 6 bits. */
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#define BASE64_DECODE_LENGTH(length) ((((length) + 1) * 6) / 8)
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struct base64_decode_ctx
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{
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const signed char *table; /* Decoding table */
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unsigned short word; /* Leftover bits */
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unsigned char bits; /* Number buffered bits */
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/* Number of padding characters encountered */
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unsigned char padding;
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};
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/* Initialize decoding context for base-64 */
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void
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base64_decode_init(struct base64_decode_ctx *ctx);
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/* Initialize encoding context for URL safe alphabet, RFC 4648. */
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void
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base64url_decode_init(struct base64_decode_ctx *ctx);
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/* Decodes a single byte. Returns amount of output (0 or 1), or -1 on
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* errors. */
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int
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base64_decode_single(struct base64_decode_ctx *ctx,
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uint8_t *dst,
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char src);
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/* Returns 1 on success, 0 on error. DST should point to an area of
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* size at least BASE64_DECODE_LENGTH(length). The amount of data
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* generated is returned in *DST_LENGTH. */
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int
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base64_decode_update(struct base64_decode_ctx *ctx,
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size_t *dst_length,
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uint8_t *dst,
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size_t src_length,
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const char *src);
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/* Returns 1 on success. */
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int
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base64_decode_final(struct base64_decode_ctx *ctx);
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#ifdef __cplusplus
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}
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#endif
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#endif /* NETTLE_BASE64_H_INCLUDED */
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