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Diffstat (limited to 'subversion/libsvn_subr/base64.c')
| -rw-r--r-- | subversion/libsvn_subr/base64.c | 567 |
1 files changed, 567 insertions, 0 deletions
diff --git a/subversion/libsvn_subr/base64.c b/subversion/libsvn_subr/base64.c new file mode 100644 index 0000000..97ee3d2 --- /dev/null +++ b/subversion/libsvn_subr/base64.c @@ -0,0 +1,567 @@ +/* + * base64.c: base64 encoding and decoding functions + * + * ==================================================================== + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + * ==================================================================== + */ + + + +#include <string.h> + +#include <apr.h> +#include <apr_pools.h> +#include <apr_general.h> /* for APR_INLINE */ + +#include "svn_pools.h" +#include "svn_io.h" +#include "svn_error.h" +#include "svn_base64.h" +#include "private/svn_string_private.h" +#include "private/svn_subr_private.h" + +/* When asked to format the base64-encoded output as multiple lines, + we put this many chars in each line (plus one new line char) unless + we run out of data. + It is vital for some of the optimizations below that this value is + a multiple of 4. */ +#define BASE64_LINELEN 76 + +/* This number of bytes is encoded in a line of base64 chars. */ +#define BYTES_PER_LINE (BASE64_LINELEN / 4 * 3) + +/* Value -> base64 char mapping table (2^6 entries) */ +static const char base64tab[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \ + "abcdefghijklmnopqrstuvwxyz0123456789+/"; + + +/* Binary input --> base64-encoded output */ + +struct encode_baton { + svn_stream_t *output; + unsigned char buf[3]; /* Bytes waiting to be encoded */ + size_t buflen; /* Number of bytes waiting */ + size_t linelen; /* Bytes output so far on this line */ + apr_pool_t *scratch_pool; +}; + + +/* Base64-encode a group. IN needs to have three bytes and OUT needs + to have room for four bytes. The input group is treated as four + six-bit units which are treated as lookups into base64tab for the + bytes of the output group. */ +static APR_INLINE void +encode_group(const unsigned char *in, char *out) +{ + /* Expand input bytes to machine word length (with zero extra cost + on x86/x64) ... */ + apr_size_t part0 = in[0]; + apr_size_t part1 = in[1]; + apr_size_t part2 = in[2]; + + /* ... to prevent these arithmetic operations from being limited to + byte size. This saves non-zero cost conversions of the result when + calculating the addresses within base64tab. */ + out[0] = base64tab[part0 >> 2]; + out[1] = base64tab[((part0 & 3) << 4) | (part1 >> 4)]; + out[2] = base64tab[((part1 & 0xf) << 2) | (part2 >> 6)]; + out[3] = base64tab[part2 & 0x3f]; +} + +/* Base64-encode a line, i.e. BYTES_PER_LINE bytes from DATA into + BASE64_LINELEN chars and append it to STR. It does not assume that + a new line char will be appended, though. + The code in this function will simply transform the data without + performing any boundary checks. Therefore, DATA must have at least + BYTES_PER_LINE left and space for at least another BASE64_LINELEN + chars must have been pre-allocated in STR before calling this + function. */ +static void +encode_line(svn_stringbuf_t *str, const char *data) +{ + /* Translate directly from DATA to STR->DATA. */ + const unsigned char *in = (const unsigned char *)data; + char *out = str->data + str->len; + char *end = out + BASE64_LINELEN; + + /* We assume that BYTES_PER_LINE is a multiple of 3 and BASE64_LINELEN + a multiple of 4. */ + for ( ; out != end; in += 3, out += 4) + encode_group(in, out); + + /* Expand and terminate the string. */ + *out = '\0'; + str->len += BASE64_LINELEN; +} + +/* (Continue to) Base64-encode the byte string DATA (of length LEN) + into STR. Include newlines every so often if BREAK_LINES is true. + INBUF, INBUFLEN, and LINELEN are used internally; the caller shall + make INBUF have room for three characters and initialize *INBUFLEN + and *LINELEN to 0. + + INBUF and *INBUFLEN carry the leftover data from call to call, and + *LINELEN carries the length of the current output line. */ +static void +encode_bytes(svn_stringbuf_t *str, const void *data, apr_size_t len, + unsigned char *inbuf, size_t *inbuflen, size_t *linelen, + svn_boolean_t break_lines) +{ + char group[4]; + const char *p = data, *end = p + len; + apr_size_t buflen; + + /* Resize the stringbuf to make room for the (approximate) size of + output, to avoid repeated resizes later. + Please note that our optimized code relies on the fact that STR + never needs to be resized until we leave this function. */ + buflen = len * 4 / 3 + 4; + if (break_lines) + { + /* Add an extra space for line breaks. */ + buflen += buflen / BASE64_LINELEN; + } + svn_stringbuf_ensure(str, str->len + buflen); + + /* Keep encoding three-byte groups until we run out. */ + while (*inbuflen + (end - p) >= 3) + { + /* May we encode BYTES_PER_LINE bytes without caring about + line breaks, data in the temporary INBUF or running out + of data? */ + if ( *inbuflen == 0 + && (*linelen == 0 || !break_lines) + && (end - p >= BYTES_PER_LINE)) + { + /* Yes, we can encode a whole chunk of data at once. */ + encode_line(str, p); + p += BYTES_PER_LINE; + *linelen += BASE64_LINELEN; + } + else + { + /* No, this is one of a number of special cases. + Encode the data byte by byte. */ + memcpy(inbuf + *inbuflen, p, 3 - *inbuflen); + p += (3 - *inbuflen); + encode_group(inbuf, group); + svn_stringbuf_appendbytes(str, group, 4); + *inbuflen = 0; + *linelen += 4; + } + + /* Add line breaks as necessary. */ + if (break_lines && *linelen == BASE64_LINELEN) + { + svn_stringbuf_appendbyte(str, '\n'); + *linelen = 0; + } + } + + /* Tack any extra input onto *INBUF. */ + memcpy(inbuf + *inbuflen, p, end - p); + *inbuflen += (end - p); +} + + +/* Encode leftover data, if any, and possibly a final newline (if + there has been any data and BREAK_LINES is set), appending to STR. + LEN must be in the range 0..2. */ +static void +encode_partial_group(svn_stringbuf_t *str, const unsigned char *extra, + size_t len, size_t linelen, svn_boolean_t break_lines) +{ + unsigned char ingroup[3]; + char outgroup[4]; + + if (len > 0) + { + memcpy(ingroup, extra, len); + memset(ingroup + len, 0, 3 - len); + encode_group(ingroup, outgroup); + memset(outgroup + (len + 1), '=', 4 - (len + 1)); + svn_stringbuf_appendbytes(str, outgroup, 4); + linelen += 4; + } + if (break_lines && linelen > 0) + svn_stringbuf_appendbyte(str, '\n'); +} + + +/* Write handler for svn_base64_encode. */ +static svn_error_t * +encode_data(void *baton, const char *data, apr_size_t *len) +{ + struct encode_baton *eb = baton; + svn_stringbuf_t *encoded = svn_stringbuf_create_empty(eb->scratch_pool); + apr_size_t enclen; + svn_error_t *err = SVN_NO_ERROR; + + /* Encode this block of data and write it out. */ + encode_bytes(encoded, data, *len, eb->buf, &eb->buflen, &eb->linelen, TRUE); + enclen = encoded->len; + if (enclen != 0) + err = svn_stream_write(eb->output, encoded->data, &enclen); + svn_pool_clear(eb->scratch_pool); + return err; +} + + +/* Close handler for svn_base64_encode(). */ +static svn_error_t * +finish_encoding_data(void *baton) +{ + struct encode_baton *eb = baton; + svn_stringbuf_t *encoded = svn_stringbuf_create_empty(eb->scratch_pool); + apr_size_t enclen; + svn_error_t *err = SVN_NO_ERROR; + + /* Encode a partial group at the end if necessary, and write it out. */ + encode_partial_group(encoded, eb->buf, eb->buflen, eb->linelen, TRUE); + enclen = encoded->len; + if (enclen != 0) + err = svn_stream_write(eb->output, encoded->data, &enclen); + + /* Pass on the close request and clean up the baton. */ + if (err == SVN_NO_ERROR) + err = svn_stream_close(eb->output); + svn_pool_destroy(eb->scratch_pool); + return err; +} + + +svn_stream_t * +svn_base64_encode(svn_stream_t *output, apr_pool_t *pool) +{ + struct encode_baton *eb = apr_palloc(pool, sizeof(*eb)); + svn_stream_t *stream; + + eb->output = output; + eb->buflen = 0; + eb->linelen = 0; + eb->scratch_pool = svn_pool_create(pool); + stream = svn_stream_create(eb, pool); + svn_stream_set_write(stream, encode_data); + svn_stream_set_close(stream, finish_encoding_data); + return stream; +} + + +const svn_string_t * +svn_base64_encode_string2(const svn_string_t *str, + svn_boolean_t break_lines, + apr_pool_t *pool) +{ + svn_stringbuf_t *encoded = svn_stringbuf_create_empty(pool); + unsigned char ingroup[3]; + size_t ingrouplen = 0; + size_t linelen = 0; + + encode_bytes(encoded, str->data, str->len, ingroup, &ingrouplen, &linelen, + break_lines); + encode_partial_group(encoded, ingroup, ingrouplen, linelen, + break_lines); + return svn_stringbuf__morph_into_string(encoded); +} + +const svn_string_t * +svn_base64_encode_string(const svn_string_t *str, apr_pool_t *pool) +{ + return svn_base64_encode_string2(str, TRUE, pool); +} + + + +/* Base64-encoded input --> binary output */ + +struct decode_baton { + svn_stream_t *output; + unsigned char buf[4]; /* Bytes waiting to be decoded */ + int buflen; /* Number of bytes waiting */ + svn_boolean_t done; /* True if we already saw an '=' */ + apr_pool_t *scratch_pool; +}; + + +/* Base64-decode a group. IN needs to have four bytes and OUT needs + to have room for three bytes. The input bytes must already have + been decoded from base64tab into the range 0..63. The four + six-bit values are pasted together to form three eight-bit bytes. */ +static APR_INLINE void +decode_group(const unsigned char *in, char *out) +{ + out[0] = (char)((in[0] << 2) | (in[1] >> 4)); + out[1] = (char)(((in[1] & 0xf) << 4) | (in[2] >> 2)); + out[2] = (char)(((in[2] & 0x3) << 6) | in[3]); +} + +/* Lookup table for base64 characters; reverse_base64[ch] gives a + negative value if ch is not a valid base64 character, or otherwise + the value of the byte represented; 'A' => 0 etc. */ +static const signed char reverse_base64[256] = { +-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, +52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, +-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, +15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, +-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, +41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, +-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 +}; + +/* Similar to decode_group but this function also translates the + 6-bit values from the IN buffer before translating them. + Return FALSE if a non-base64 char (e.g. '=' or new line) + has been encountered. */ +static APR_INLINE svn_boolean_t +decode_group_directly(const unsigned char *in, char *out) +{ + /* Translate the base64 chars in values [0..63, 0xff] */ + apr_size_t part0 = (unsigned char)reverse_base64[(unsigned char)in[0]]; + apr_size_t part1 = (unsigned char)reverse_base64[(unsigned char)in[1]]; + apr_size_t part2 = (unsigned char)reverse_base64[(unsigned char)in[2]]; + apr_size_t part3 = (unsigned char)reverse_base64[(unsigned char)in[3]]; + + /* Pack 4x6 bits into 3x8.*/ + out[0] = (char)((part0 << 2) | (part1 >> 4)); + out[1] = (char)(((part1 & 0xf) << 4) | (part2 >> 2)); + out[2] = (char)(((part2 & 0x3) << 6) | part3); + + /* FALSE, iff any part is 0xff. */ + return (part0 | part1 | part2 | part3) != (unsigned char)(-1); +} + +/* Base64-encode up to BASE64_LINELEN chars from *DATA and append it to + STR. After the function returns, *DATA will point to the first char + that has not been translated, yet. Returns TRUE if all BASE64_LINELEN + chars could be translated, i.e. no special char has been encountered + in between. + The code in this function will simply transform the data without + performing any boundary checks. Therefore, DATA must have at least + BASE64_LINELEN left and space for at least another BYTES_PER_LINE + chars must have been pre-allocated in STR before calling this + function. */ +static svn_boolean_t +decode_line(svn_stringbuf_t *str, const char **data) +{ + /* Decode up to BYTES_PER_LINE bytes directly from *DATA into STR->DATA. */ + const unsigned char *p = *(const unsigned char **)data; + char *out = str->data + str->len; + char *end = out + BYTES_PER_LINE; + + /* We assume that BYTES_PER_LINE is a multiple of 3 and BASE64_LINELEN + a multiple of 4. Stop translation as soon as we encounter a special + char. Leave the entire group untouched in that case. */ + for (; out < end; p += 4, out += 3) + if (!decode_group_directly(p, out)) + break; + + /* Update string sizes and positions. */ + str->len = out - str->data; + *out = '\0'; + *data = (const char *)p; + + /* Return FALSE, if the caller should continue the decoding process + using the slow standard method. */ + return out == end; +} + + +/* (Continue to) Base64-decode the byte string DATA (of length LEN) + into STR. INBUF, INBUFLEN, and DONE are used internally; the + caller shall have room for four bytes in INBUF and initialize + *INBUFLEN to 0 and *DONE to FALSE. + + INBUF and *INBUFLEN carry the leftover bytes from call to call, and + *DONE keeps track of whether we've seen an '=' which terminates the + encoded data. */ +static void +decode_bytes(svn_stringbuf_t *str, const char *data, apr_size_t len, + unsigned char *inbuf, int *inbuflen, svn_boolean_t *done) +{ + const char *p = data; + char group[3]; + signed char find; + const char *end = data + len; + + /* Resize the stringbuf to make room for the maximum size of output, + to avoid repeated resizes later. The optimizations in + decode_line rely on no resizes being necessary! + + (*inbuflen+len) is encoded data length + (*inbuflen+len)/4 is the number of complete 4-bytes sets + (*inbuflen+len)/4*3 is the number of decoded bytes + svn_stringbuf_ensure will add an additional byte for the terminating 0. + */ + svn_stringbuf_ensure(str, str->len + ((*inbuflen + len) / 4) * 3); + + while ( !*done && p < end ) + { + /* If no data is left in temporary INBUF and there is at least + one line-sized chunk left to decode, we may use the optimized + code path. */ + if ((*inbuflen == 0) && (p + BASE64_LINELEN <= end)) + if (decode_line(str, &p)) + continue; + + /* A special case or decode_line encountered a special char. */ + if (*p == '=') + { + /* We are at the end and have to decode a partial group. */ + if (*inbuflen >= 2) + { + memset(inbuf + *inbuflen, 0, 4 - *inbuflen); + decode_group(inbuf, group); + svn_stringbuf_appendbytes(str, group, *inbuflen - 1); + } + *done = TRUE; + } + else + { + find = reverse_base64[(unsigned char)*p]; + ++p; + + if (find >= 0) + inbuf[(*inbuflen)++] = find; + if (*inbuflen == 4) + { + decode_group(inbuf, group); + svn_stringbuf_appendbytes(str, group, 3); + *inbuflen = 0; + } + } + } +} + + +/* Write handler for svn_base64_decode. */ +static svn_error_t * +decode_data(void *baton, const char *data, apr_size_t *len) +{ + struct decode_baton *db = baton; + svn_stringbuf_t *decoded; + apr_size_t declen; + svn_error_t *err = SVN_NO_ERROR; + + /* Decode this block of data. */ + decoded = svn_stringbuf_create_empty(db->scratch_pool); + decode_bytes(decoded, data, *len, db->buf, &db->buflen, &db->done); + + /* Write the output, clean up, go home. */ + declen = decoded->len; + if (declen != 0) + err = svn_stream_write(db->output, decoded->data, &declen); + svn_pool_clear(db->scratch_pool); + return err; +} + + +/* Close handler for svn_base64_decode(). */ +static svn_error_t * +finish_decoding_data(void *baton) +{ + struct decode_baton *db = baton; + svn_error_t *err; + + /* Pass on the close request and clean up the baton. */ + err = svn_stream_close(db->output); + svn_pool_destroy(db->scratch_pool); + return err; +} + + +svn_stream_t * +svn_base64_decode(svn_stream_t *output, apr_pool_t *pool) +{ + struct decode_baton *db = apr_palloc(pool, sizeof(*db)); + svn_stream_t *stream; + + db->output = output; + db->buflen = 0; + db->done = FALSE; + db->scratch_pool = svn_pool_create(pool); + stream = svn_stream_create(db, pool); + svn_stream_set_write(stream, decode_data); + svn_stream_set_close(stream, finish_decoding_data); + return stream; +} + + +const svn_string_t * +svn_base64_decode_string(const svn_string_t *str, apr_pool_t *pool) +{ + svn_stringbuf_t *decoded = svn_stringbuf_create_empty(pool); + unsigned char ingroup[4]; + int ingrouplen = 0; + svn_boolean_t done = FALSE; + + decode_bytes(decoded, str->data, str->len, ingroup, &ingrouplen, &done); + return svn_stringbuf__morph_into_string(decoded); +} + + +/* Return a base64-encoded representation of CHECKSUM, allocated in POOL. + If CHECKSUM->kind is not recognized, return NULL. + ### That 'NULL' claim was in the header file when this was public, but + doesn't look true in the implementation. + + ### This is now only used as a new implementation of svn_base64_from_md5(); + it would probably be safer to revert that to its old implementation. */ +static svn_stringbuf_t * +base64_from_checksum(const svn_checksum_t *checksum, apr_pool_t *pool) +{ + svn_stringbuf_t *checksum_str; + unsigned char ingroup[3]; + size_t ingrouplen = 0; + size_t linelen = 0; + checksum_str = svn_stringbuf_create_empty(pool); + + encode_bytes(checksum_str, checksum->digest, + svn_checksum_size(checksum), ingroup, &ingrouplen, + &linelen, TRUE); + encode_partial_group(checksum_str, ingroup, ingrouplen, linelen, TRUE); + + /* Our base64-encoding routines append a final newline if any data + was created at all, so let's hack that off. */ + if (checksum_str->len) + { + checksum_str->len--; + checksum_str->data[checksum_str->len] = 0; + } + + return checksum_str; +} + + +svn_stringbuf_t * +svn_base64_from_md5(unsigned char digest[], apr_pool_t *pool) +{ + svn_checksum_t *checksum + = svn_checksum__from_digest_md5(digest, pool); + + return base64_from_checksum(checksum, pool); +} |