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author | Minteck <contact@minteck.org> | 2023-01-10 14:54:04 +0100 |
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committer | Minteck <contact@minteck.org> | 2023-01-10 14:54:04 +0100 |
commit | 99c1d9af689e5325f3cf535c4007b3aeb8325229 (patch) | |
tree | e663b3c2ebdbd67c818ac0c5147f0ce1d2463cda /school/node_modules/pako/lib/utils/strings.js | |
parent | 9871b03912fc28ad38b4037ebf26a78aa937baba (diff) | |
download | pluralconnect-99c1d9af689e5325f3cf535c4007b3aeb8325229.tar.gz pluralconnect-99c1d9af689e5325f3cf535c4007b3aeb8325229.tar.bz2 pluralconnect-99c1d9af689e5325f3cf535c4007b3aeb8325229.zip |
Update - This is an automated commit
Diffstat (limited to 'school/node_modules/pako/lib/utils/strings.js')
-rw-r--r-- | school/node_modules/pako/lib/utils/strings.js | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/school/node_modules/pako/lib/utils/strings.js b/school/node_modules/pako/lib/utils/strings.js new file mode 100644 index 0000000..b07a732 --- /dev/null +++ b/school/node_modules/pako/lib/utils/strings.js @@ -0,0 +1,187 @@ +// String encode/decode helpers +'use strict'; + + +var utils = require('./common'); + + +// Quick check if we can use fast array to bin string conversion +// +// - apply(Array) can fail on Android 2.2 +// - apply(Uint8Array) can fail on iOS 5.1 Safari +// +var STR_APPLY_OK = true; +var STR_APPLY_UIA_OK = true; + +try { String.fromCharCode.apply(null, [ 0 ]); } catch (__) { STR_APPLY_OK = false; } +try { String.fromCharCode.apply(null, new Uint8Array(1)); } catch (__) { STR_APPLY_UIA_OK = false; } + + +// Table with utf8 lengths (calculated by first byte of sequence) +// Note, that 5 & 6-byte values and some 4-byte values can not be represented in JS, +// because max possible codepoint is 0x10ffff +var _utf8len = new utils.Buf8(256); +for (var q = 0; q < 256; q++) { + _utf8len[q] = (q >= 252 ? 6 : q >= 248 ? 5 : q >= 240 ? 4 : q >= 224 ? 3 : q >= 192 ? 2 : 1); +} +_utf8len[254] = _utf8len[254] = 1; // Invalid sequence start + + +// convert string to array (typed, when possible) +exports.string2buf = function (str) { + var buf, c, c2, m_pos, i, str_len = str.length, buf_len = 0; + + // count binary size + for (m_pos = 0; m_pos < str_len; m_pos++) { + c = str.charCodeAt(m_pos); + if ((c & 0xfc00) === 0xd800 && (m_pos + 1 < str_len)) { + c2 = str.charCodeAt(m_pos + 1); + if ((c2 & 0xfc00) === 0xdc00) { + c = 0x10000 + ((c - 0xd800) << 10) + (c2 - 0xdc00); + m_pos++; + } + } + buf_len += c < 0x80 ? 1 : c < 0x800 ? 2 : c < 0x10000 ? 3 : 4; + } + + // allocate buffer + buf = new utils.Buf8(buf_len); + + // convert + for (i = 0, m_pos = 0; i < buf_len; m_pos++) { + c = str.charCodeAt(m_pos); + if ((c & 0xfc00) === 0xd800 && (m_pos + 1 < str_len)) { + c2 = str.charCodeAt(m_pos + 1); + if ((c2 & 0xfc00) === 0xdc00) { + c = 0x10000 + ((c - 0xd800) << 10) + (c2 - 0xdc00); + m_pos++; + } + } + if (c < 0x80) { + /* one byte */ + buf[i++] = c; + } else if (c < 0x800) { + /* two bytes */ + buf[i++] = 0xC0 | (c >>> 6); + buf[i++] = 0x80 | (c & 0x3f); + } else if (c < 0x10000) { + /* three bytes */ + buf[i++] = 0xE0 | (c >>> 12); + buf[i++] = 0x80 | (c >>> 6 & 0x3f); + buf[i++] = 0x80 | (c & 0x3f); + } else { + /* four bytes */ + buf[i++] = 0xf0 | (c >>> 18); + buf[i++] = 0x80 | (c >>> 12 & 0x3f); + buf[i++] = 0x80 | (c >>> 6 & 0x3f); + buf[i++] = 0x80 | (c & 0x3f); + } + } + + return buf; +}; + +// Helper (used in 2 places) +function buf2binstring(buf, len) { + // On Chrome, the arguments in a function call that are allowed is `65534`. + // If the length of the buffer is smaller than that, we can use this optimization, + // otherwise we will take a slower path. + if (len < 65534) { + if ((buf.subarray && STR_APPLY_UIA_OK) || (!buf.subarray && STR_APPLY_OK)) { + return String.fromCharCode.apply(null, utils.shrinkBuf(buf, len)); + } + } + + var result = ''; + for (var i = 0; i < len; i++) { + result += String.fromCharCode(buf[i]); + } + return result; +} + + +// Convert byte array to binary string +exports.buf2binstring = function (buf) { + return buf2binstring(buf, buf.length); +}; + + +// Convert binary string (typed, when possible) +exports.binstring2buf = function (str) { + var buf = new utils.Buf8(str.length); + for (var i = 0, len = buf.length; i < len; i++) { + buf[i] = str.charCodeAt(i); + } + return buf; +}; + + +// convert array to string +exports.buf2string = function (buf, max) { + var i, out, c, c_len; + var len = max || buf.length; + + // Reserve max possible length (2 words per char) + // NB: by unknown reasons, Array is significantly faster for + // String.fromCharCode.apply than Uint16Array. + var utf16buf = new Array(len * 2); + + for (out = 0, i = 0; i < len;) { + c = buf[i++]; + // quick process ascii + if (c < 0x80) { utf16buf[out++] = c; continue; } + + c_len = _utf8len[c]; + // skip 5 & 6 byte codes + if (c_len > 4) { utf16buf[out++] = 0xfffd; i += c_len - 1; continue; } + + // apply mask on first byte + c &= c_len === 2 ? 0x1f : c_len === 3 ? 0x0f : 0x07; + // join the rest + while (c_len > 1 && i < len) { + c = (c << 6) | (buf[i++] & 0x3f); + c_len--; + } + + // terminated by end of string? + if (c_len > 1) { utf16buf[out++] = 0xfffd; continue; } + + if (c < 0x10000) { + utf16buf[out++] = c; + } else { + c -= 0x10000; + utf16buf[out++] = 0xd800 | ((c >> 10) & 0x3ff); + utf16buf[out++] = 0xdc00 | (c & 0x3ff); + } + } + + return buf2binstring(utf16buf, out); +}; + + +// Calculate max possible position in utf8 buffer, +// that will not break sequence. If that's not possible +// - (very small limits) return max size as is. +// +// buf[] - utf8 bytes array +// max - length limit (mandatory); +exports.utf8border = function (buf, max) { + var pos; + + max = max || buf.length; + if (max > buf.length) { max = buf.length; } + + // go back from last position, until start of sequence found + pos = max - 1; + while (pos >= 0 && (buf[pos] & 0xC0) === 0x80) { pos--; } + + // Very small and broken sequence, + // return max, because we should return something anyway. + if (pos < 0) { return max; } + + // If we came to start of buffer - that means buffer is too small, + // return max too. + if (pos === 0) { return max; } + + return (pos + _utf8len[buf[pos]] > max) ? pos : max; +}; |