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/* |
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* base64.c -- base-64 conversion routines. |
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* |
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* For license terms, see the file COPYING in this directory. |
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* |
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* This base 64 encoding is defined in RFC2045 section 6.8, |
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* "Base64 Content-Transfer-Encoding", but lines must not be broken in the |
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* scheme used here. |
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*/ |
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#include "config.h" |
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#include "fetchmail.h" |
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#include <ctype.h> |
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|
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static const char base64digits[] = |
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
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|
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#define BAD -1 |
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static const char base64val[] = { |
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BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, |
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BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, |
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BAD,BAD,BAD,BAD, BAD,BAD,BAD,BAD, BAD,BAD,BAD, 62, BAD,BAD,BAD, 63, |
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61,BAD,BAD, BAD,BAD,BAD,BAD, |
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BAD, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, |
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,BAD, BAD,BAD,BAD,BAD, |
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BAD, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, |
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41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,BAD, BAD,BAD,BAD,BAD |
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}; |
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#define DECODE64(c) (isascii((unsigned char)(c)) ? base64val[c] : BAD) |
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|
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void to64frombits(char *out, const void *in_, int inlen) |
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/* raw bytes in quasi-big-endian order to base 64 string (NUL-terminated) */ |
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{ |
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const unsigned char *in = (const unsigned char *)in_; |
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|
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for (; inlen >= 3; inlen -= 3) |
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{ |
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*out++ = base64digits[in[0] >> 2]; |
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*out++ = base64digits[((in[0] << 4) & 0x30) | (in[1] >> 4)]; |
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*out++ = base64digits[((in[1] << 2) & 0x3c) | (in[2] >> 6)]; |
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*out++ = base64digits[in[2] & 0x3f]; |
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in += 3; |
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} |
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if (inlen > 0) |
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{ |
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unsigned char fragment; |
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|
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*out++ = base64digits[in[0] >> 2]; |
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fragment = (in[0] << 4) & 0x30; |
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if (inlen > 1) |
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fragment |= in[1] >> 4; |
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*out++ = base64digits[fragment]; |
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*out++ = (inlen < 2) ? '=' : base64digits[(in[1] << 2) & 0x3c]; |
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*out++ = '='; |
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} |
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*out = '\0'; |
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} |
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|
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int from64tobits(void *out_, const char *in, int maxlen) |
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/* base 64 to raw bytes in quasi-big-endian order, returning count of bytes */ |
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/* maxlen limits output buffer size, set to zero to ignore */ |
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{ |
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int len = 0; |
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register unsigned char digit1, digit2, digit3, digit4; |
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unsigned char *out = (unsigned char *)out_; |
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|
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if (in[0] == '+' && in[1] == ' ') |
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in += 2; |
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if (*in == '\r') |
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return(0); |
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|
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do { |
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digit1 = in[0]; |
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if (DECODE64(digit1) == BAD) |
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return(-1); |
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digit2 = in[1]; |
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if (DECODE64(digit2) == BAD) |
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return(-1); |
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digit3 = in[2]; |
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if (digit3 != '=' && DECODE64(digit3) == BAD) |
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return(-1); |
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digit4 = in[3]; |
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if (digit4 != '=' && DECODE64(digit4) == BAD) |
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return(-1); |
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in += 4; |
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++len; |
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if (maxlen && len > maxlen) |
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return(-1); |
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*out++ = (DECODE64(digit1) << 2) | (DECODE64(digit2) >> 4); |
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if (digit3 != '=') |
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{ |
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++len; |
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if (maxlen && len > maxlen) |
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return(-1); |
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*out++ = ((DECODE64(digit2) << 4) & 0xf0) | (DECODE64(digit3) >> 2); |
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if (digit4 != '=') |
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{ |
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++len; |
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if (maxlen && len > maxlen) |
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return(-1); |
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*out++ = ((DECODE64(digit3) << 6) & 0xc0) | DECODE64(digit4); |
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} |
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} |
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} while |
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(*in && *in != '\r' && digit4 != '='); |
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|
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return (len); |
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} |
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|
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/* base64.c ends here */ |
