mirror of https://github.com/BOINC/boinc.git
177 lines
5.3 KiB
C
177 lines
5.3 KiB
C
// Copyright 2003 Regents of the University of California
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#include "parse.h"
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// Table of characters coding the 64 values.
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static char base64_value_to_char[64] =
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{
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', // 0- 9
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'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', // 10-19
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'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', // 20-29
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'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', // 30-39
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'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', // 40-49
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'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', // 50-59
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'8', '9', '+', '/' // 60-63
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};
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// Table of base64 values for first 128 characters.
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static short base64_char_to_value[128] =
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{
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 0- 9
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10- 19
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 20- 29
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 30- 39
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-1, -1, -1, 62, -1, -1, -1, 63, 52, 53, // 40- 49
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54, 55, 56, 57, 58, 59, 60, 61, -1, -1, // 50- 59
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-1, -1, -1, -1, -1, 0, 1, 2, 3, 4, // 60- 69
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5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 70- 79
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 80- 89
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25, -1, -1, -1, -1, -1, -1, 26, 27, 28, // 90- 99
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29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // 100-109
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39, 40, 41, 42, 43, 44, 45, 46, 47, 48, // 110-119
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49, 50, 51, -1, -1, -1, -1, -1 // 120-127
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};
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/* The following diagram shows the logical steps by which three octets
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get transformed into four base64 characters.
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.--------. .--------. .--------.
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|aaaaaabb| |bbbbcccc| |ccdddddd|
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`--------' `--------' `--------'
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6 2 4 4 2 6
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.--------+--------+--------+--------.
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|00aaaaaa|00bbbbbb|00cccccc|00dddddd|
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`--------+--------+--------+--------'
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.--------+--------+--------+--------.
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|AAAAAAAA|BBBBBBBB|CCCCCCCC|DDDDDDDD|
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`--------+--------+--------+--------'
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The octets are divided into 6 bit chunks, which are then encoded into
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base64 characters. */
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string r_base64_encode (const char* from, size_t length) throw(InvalidBase64Exception)
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{
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string result;
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result.reserve(length + length/3 + 1);
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size_t i = 0;
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int c;
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unsigned int value;
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while (i < length)
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{
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c = from[i++];
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// Process first byte of a triplet.
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result += base64_value_to_char[0x3f & c >> 2];
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value = (0x03 & c) << 4;
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// Process second byte of a triplet.
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if (i == length)
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{
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result += base64_value_to_char[value];
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result += '=';
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result += '=';
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break;
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}
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c = from[i++];
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result += base64_value_to_char[value | (0x0f & c >> 4)];
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value = (0x0f & c) << 2;
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// Process third byte of a triplet.
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if (i == length)
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{
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result += base64_value_to_char[value];
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result += '=';
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break;
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}
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c = from[i++];
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result += base64_value_to_char[value | (0x03 & c >> 6)];
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result += base64_value_to_char[0x3f & c];
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}
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return result;
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}
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#define IS_ASCII(Character) \
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((Character) < 128)
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#define IS_BASE64(Character) \
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(IS_ASCII (Character) && base64_char_to_value[Character] >= 0)
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#define IS_BASE64_IGNORABLE(Character) \
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((Character) == ' ' || (Character) == '\t' || (Character) == '\n' \
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|| (Character) == '\f' || (Character) == '\r')
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#define READ_QUADRUPLET_BYTE() \
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do { \
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if (i == length) return result; \
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c = from[i++]; \
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} \
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while (IS_BASE64_IGNORABLE (c))
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string r_base64_decode (const char* from, size_t length) throw(InvalidBase64Exception)
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{
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size_t i = 0;
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string result;
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unsigned char c;
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unsigned long value;
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while (true)
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{
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// Process first byte of a quadruplet.
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READ_QUADRUPLET_BYTE();
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if (!IS_BASE64 (c))
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throw InvalidBase64Exception();
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value = base64_char_to_value[c] << 18;
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// Process second byte of a quadruplet.
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READ_QUADRUPLET_BYTE();
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if (!IS_BASE64 (c))
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throw InvalidBase64Exception();
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value |= base64_char_to_value[c] << 12;
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c = (unsigned char) (value >> 16);
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result += c;
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// Process third byte of a quadruplet.
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READ_QUADRUPLET_BYTE();
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if (c == '=')
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{
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READ_QUADRUPLET_BYTE();
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if (c != '=')
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throw InvalidBase64Exception();
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continue;
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}
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if (!IS_BASE64 (c))
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throw InvalidBase64Exception();
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value |= base64_char_to_value[c] << 6;
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c = (unsigned char) (0xff & value >> 8);
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result += c;
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// Process fourth byte of a quadruplet.
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READ_QUADRUPLET_BYTE();
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if (c == '=')
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continue;
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if (!IS_BASE64 (c))
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throw InvalidBase64Exception();
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value |= base64_char_to_value[c];
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c = (unsigned char) (0xff & value);
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result += c;
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}
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}
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