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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
commit | 6bf0a5cb5034a7e684dcc3500e841785237ce2dd (patch) | |
tree | a68f146d7fa01f0134297619fbe7e33db084e0aa /netwerk/dns/punycode.c | |
parent | Initial commit. (diff) | |
download | thunderbird-upstream.tar.xz thunderbird-upstream.zip |
Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | netwerk/dns/punycode.c | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/netwerk/dns/punycode.c b/netwerk/dns/punycode.c new file mode 100644 index 0000000000..4653216507 --- /dev/null +++ b/netwerk/dns/punycode.c @@ -0,0 +1,325 @@ +/* +punycode.c from RFC 3492 +http://www.nicemice.net/idn/ +Adam M. Costello +http://www.nicemice.net/amc/ + +This is ANSI C code (C89) implementing Punycode (RFC 3492). + + +C. Disclaimer and license + + Regarding this entire document or any portion of it (including + the pseudocode and C code), the author makes no guarantees and + is not responsible for any damage resulting from its use. The + author grants irrevocable permission to anyone to use, modify, + and distribute it in any way that does not diminish the rights + of anyone else to use, modify, and distribute it, provided that + redistributed derivative works do not contain misleading author or + version information. Derivative works need not be licensed under + similar terms. +*/ + +#include "punycode.h" + +/**********************************************************/ +/* Implementation (would normally go in its own .c file): */ + +#include <string.h> + +/*** Bootstring parameters for Punycode ***/ + +enum { + base = 36, + tmin = 1, + tmax = 26, + skew = 38, + damp = 700, + initial_bias = 72, + initial_n = 0x80, + delimiter = 0x2D +}; + +/* basic(cp) tests whether cp is a basic code point: */ +#define basic(cp) ((punycode_uint)(cp) < 0x80) + +/* delim(cp) tests whether cp is a delimiter: */ +#define delim(cp) ((cp) == delimiter) + +/* decode_digit(cp) returns the numeric value of a basic code */ +/* point (for use in representing integers) in the range 0 to */ +/* base-1, or base if cp is does not represent a value. */ + +static punycode_uint decode_digit(punycode_uint cp) { + return cp - 48 < 10 ? cp - 22 + : cp - 65 < 26 ? cp - 65 + : cp - 97 < 26 ? cp - 97 + : base; +} + +/* encode_digit(d,flag) returns the basic code point whose value */ +/* (when used for representing integers) is d, which needs to be in */ +/* the range 0 to base-1. The lowercase form is used unless flag is */ +/* nonzero, in which case the uppercase form is used. The behavior */ +/* is undefined if flag is nonzero and digit d has no uppercase form. */ + +static char encode_digit(punycode_uint d, int flag) { + return d + 22 + 75 * (d < 26) - ((flag != 0) << 5); + /* 0..25 map to ASCII a..z or A..Z */ + /* 26..35 map to ASCII 0..9 */ +} + +/* flagged(bcp) tests whether a basic code point is flagged */ +/* (uppercase). The behavior is undefined if bcp is not a */ +/* basic code point. */ + +#define flagged(bcp) ((punycode_uint)(bcp)-65 < 26) + +/* encode_basic(bcp,flag) forces a basic code point to lowercase */ +/* if flag is zero, uppercase if flag is nonzero, and returns */ +/* the resulting code point. The code point is unchanged if it */ +/* is caseless. The behavior is undefined if bcp is not a basic */ +/* code point. */ + +static char encode_basic(punycode_uint bcp, int flag) { + bcp -= (bcp - 97 < 26) << 5; + return bcp + ((!flag && (bcp - 65 < 26)) << 5); +} + +/*** Platform-specific constants ***/ + +/* maxint is the maximum value of a punycode_uint variable: */ +static const punycode_uint maxint = (punycode_uint)-1; +/* Because maxint is unsigned, -1 becomes the maximum value. */ + +/*** Bias adaptation function ***/ + +static punycode_uint adapt(punycode_uint delta, punycode_uint numpoints, + int firsttime) { + punycode_uint k; + + delta = firsttime ? delta / damp : delta >> 1; + /* delta >> 1 is a faster way of doing delta / 2 */ + delta += delta / numpoints; + + for (k = 0; delta > ((base - tmin) * tmax) / 2; k += base) { + delta /= base - tmin; + } + + return k + (base - tmin + 1) * delta / (delta + skew); +} + +/*** Main encode function ***/ + +enum punycode_status punycode_encode(punycode_uint input_length, + const punycode_uint input[], + const unsigned char case_flags[], + punycode_uint* output_length, + char output[]) { + punycode_uint n, delta, h, b, out, max_out, bias, j, m, q, k, t; + + /* Initialize the state: */ + + n = initial_n; + delta = out = 0; + max_out = *output_length; + bias = initial_bias; + + /* Handle the basic code points: */ + + for (j = 0; j < input_length; ++j) { + if (basic(input[j])) { + if (max_out - out < 2) { + return punycode_big_output; + } + output[out++] = + case_flags ? encode_basic(input[j], case_flags[j]) : (char)input[j]; + } + /* else if (input[j] < n) return punycode_bad_input; */ + /* (not needed for Punycode with unsigned code points) */ + } + + h = b = out; + + /* h is the number of code points that have been handled, b is the */ + /* number of basic code points, and out is the number of characters */ + /* that have been output. */ + + if (b > 0) { + output[out++] = delimiter; + } + + /* Main encoding loop: */ + + while (h < input_length) { + /* All non-basic code points < n have been */ + /* handled already. Find the next larger one: */ + + for (m = maxint, j = 0; j < input_length; ++j) { + /* if (basic(input[j])) continue; */ + /* (not needed for Punycode) */ + if (input[j] >= n && input[j] < m) { + m = input[j]; + } + } + + /* Increase delta enough to advance the decoder's */ + /* <n,i> state to <m,0>, but guard against overflow: */ + + if (m - n > (maxint - delta) / (h + 1)) { + return punycode_overflow; + } + delta += (m - n) * (h + 1); + n = m; + + for (j = 0; j < input_length; ++j) { + /* Punycode does not need to check whether input[j] is basic: */ + if (input[j] < n /* || basic(input[j]) */) { + if (++delta == 0) { + return punycode_overflow; + } + } + + if (input[j] == n) { + /* Represent delta as a generalized variable-length integer: */ + + for (q = delta, k = base;; k += base) { + if (out >= max_out) { + return punycode_big_output; + } + t = k <= bias /* + tmin */ ? tmin : /* +tmin not needed */ + k >= bias + tmax ? tmax + : k - bias; + if (q < t) { + break; + } + output[out++] = encode_digit(t + (q - t) % (base - t), 0); + q = (q - t) / (base - t); + } + + output[out++] = encode_digit(q, case_flags && case_flags[j]); + bias = adapt(delta, h + 1, h == b); + delta = 0; + ++h; + } + } + + ++delta, ++n; + } + + *output_length = out; + return punycode_success; +} + +/*** Main decode function ***/ + +enum punycode_status punycode_decode(punycode_uint input_length, + const char input[], + punycode_uint* output_length, + punycode_uint output[], + unsigned char case_flags[]) { + punycode_uint n, out, i, max_out, bias, b, j, in, oldi, w, k, digit, t; + + if (!input_length) { + return punycode_bad_input; + } + + /* Initialize the state: */ + + n = initial_n; + out = i = 0; + max_out = *output_length; + bias = initial_bias; + + /* Handle the basic code points: Let b be the number of input code */ + /* points before the last delimiter, or 0 if there is none, then */ + /* copy the first b code points to the output. */ + + for (b = 0, j = input_length - 1; j > 0; --j) { + if (delim(input[j])) { + b = j; + break; + } + } + if (b > max_out) { + return punycode_big_output; + } + + for (j = 0; j < b; ++j) { + if (case_flags) { + case_flags[out] = flagged(input[j]); + } + if (!basic(input[j])) { + return punycode_bad_input; + } + output[out++] = input[j]; + } + + /* Main decoding loop: Start just after the last delimiter if any */ + /* basic code points were copied; start at the beginning otherwise. */ + + for (in = b > 0 ? b + 1 : 0; in < input_length; ++out) { + /* in is the index of the next character to be consumed, and */ + /* out is the number of code points in the output array. */ + + /* Decode a generalized variable-length integer into delta, */ + /* which gets added to i. The overflow checking is easier */ + /* if we increase i as we go, then subtract off its starting */ + /* value at the end to obtain delta. */ + + for (oldi = i, w = 1, k = base;; k += base) { + if (in >= input_length) { + return punycode_bad_input; + } + digit = decode_digit(input[in++]); + if (digit >= base) { + return punycode_bad_input; + } + if (digit > (maxint - i) / w) { + return punycode_overflow; + } + i += digit * w; + t = k <= bias /* + tmin */ ? tmin : /* +tmin not needed */ + k >= bias + tmax ? tmax + : k - bias; + if (digit < t) { + break; + } + if (w > maxint / (base - t)) { + return punycode_overflow; + } + w *= (base - t); + } + + bias = adapt(i - oldi, out + 1, oldi == 0); + + /* i was supposed to wrap around from out+1 to 0, */ + /* incrementing n each time, so we'll fix that now: */ + + if (i / (out + 1) > maxint - n) { + return punycode_overflow; + } + n += i / (out + 1); + i %= (out + 1); + + /* Insert n at position i of the output: */ + + /* not needed for Punycode: */ + /* if (decode_digit(n) <= base) return punycode_invalid_input; */ + if (out >= max_out) { + return punycode_big_output; + } + + if (case_flags) { + memmove(case_flags + i + 1, case_flags + i, out - i); + /* Case of last character determines uppercase flag: */ + case_flags[i] = flagged(input[in - 1]); + } + + memmove(output + i + 1, output + i, (out - i) * sizeof *output); + output[i++] = n; + } + + *output_length = out; + return punycode_success; +} |