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Diffstat (limited to 'alarm/node_modules/pako/lib/zlib/inffast.js')
-rw-r--r-- | alarm/node_modules/pako/lib/zlib/inffast.js | 345 |
1 files changed, 345 insertions, 0 deletions
diff --git a/alarm/node_modules/pako/lib/zlib/inffast.js b/alarm/node_modules/pako/lib/zlib/inffast.js new file mode 100644 index 0000000..4cc958f --- /dev/null +++ b/alarm/node_modules/pako/lib/zlib/inffast.js @@ -0,0 +1,345 @@ +'use strict'; + +// (C) 1995-2013 Jean-loup Gailly and Mark Adler +// (C) 2014-2017 Vitaly Puzrin and Andrey Tupitsin +// +// This software is provided 'as-is', without any express or implied +// warranty. In no event will the authors be held liable for any damages +// arising from the use of this software. +// +// Permission is granted to anyone to use this software for any purpose, +// including commercial applications, and to alter it and redistribute it +// freely, subject to the following restrictions: +// +// 1. The origin of this software must not be misrepresented; you must not +// claim that you wrote the original software. If you use this software +// in a product, an acknowledgment in the product documentation would be +// appreciated but is not required. +// 2. Altered source versions must be plainly marked as such, and must not be +// misrepresented as being the original software. +// 3. This notice may not be removed or altered from any source distribution. + +// See state defs from inflate.js +var BAD = 30; /* got a data error -- remain here until reset */ +var TYPE = 12; /* i: waiting for type bits, including last-flag bit */ + +/* + Decode literal, length, and distance codes and write out the resulting + literal and match bytes until either not enough input or output is + available, an end-of-block is encountered, or a data error is encountered. + When large enough input and output buffers are supplied to inflate(), for + example, a 16K input buffer and a 64K output buffer, more than 95% of the + inflate execution time is spent in this routine. + + Entry assumptions: + + state.mode === LEN + strm.avail_in >= 6 + strm.avail_out >= 258 + start >= strm.avail_out + state.bits < 8 + + On return, state.mode is one of: + + LEN -- ran out of enough output space or enough available input + TYPE -- reached end of block code, inflate() to interpret next block + BAD -- error in block data + + Notes: + + - The maximum input bits used by a length/distance pair is 15 bits for the + length code, 5 bits for the length extra, 15 bits for the distance code, + and 13 bits for the distance extra. This totals 48 bits, or six bytes. + Therefore if strm.avail_in >= 6, then there is enough input to avoid + checking for available input while decoding. + + - The maximum bytes that a single length/distance pair can output is 258 + bytes, which is the maximum length that can be coded. inflate_fast() + requires strm.avail_out >= 258 for each loop to avoid checking for + output space. + */ +module.exports = function inflate_fast(strm, start) { + var state; + var _in; /* local strm.input */ + var last; /* have enough input while in < last */ + var _out; /* local strm.output */ + var beg; /* inflate()'s initial strm.output */ + var end; /* while out < end, enough space available */ +//#ifdef INFLATE_STRICT + var dmax; /* maximum distance from zlib header */ +//#endif + var wsize; /* window size or zero if not using window */ + var whave; /* valid bytes in the window */ + var wnext; /* window write index */ + // Use `s_window` instead `window`, avoid conflict with instrumentation tools + var s_window; /* allocated sliding window, if wsize != 0 */ + var hold; /* local strm.hold */ + var bits; /* local strm.bits */ + var lcode; /* local strm.lencode */ + var dcode; /* local strm.distcode */ + var lmask; /* mask for first level of length codes */ + var dmask; /* mask for first level of distance codes */ + var here; /* retrieved table entry */ + var op; /* code bits, operation, extra bits, or */ + /* window position, window bytes to copy */ + var len; /* match length, unused bytes */ + var dist; /* match distance */ + var from; /* where to copy match from */ + var from_source; + + + var input, output; // JS specific, because we have no pointers + + /* copy state to local variables */ + state = strm.state; + //here = state.here; + _in = strm.next_in; + input = strm.input; + last = _in + (strm.avail_in - 5); + _out = strm.next_out; + output = strm.output; + beg = _out - (start - strm.avail_out); + end = _out + (strm.avail_out - 257); +//#ifdef INFLATE_STRICT + dmax = state.dmax; +//#endif + wsize = state.wsize; + whave = state.whave; + wnext = state.wnext; + s_window = state.window; + hold = state.hold; + bits = state.bits; + lcode = state.lencode; + dcode = state.distcode; + lmask = (1 << state.lenbits) - 1; + dmask = (1 << state.distbits) - 1; + + + /* decode literals and length/distances until end-of-block or not enough + input data or output space */ + + top: + do { + if (bits < 15) { + hold += input[_in++] << bits; + bits += 8; + hold += input[_in++] << bits; + bits += 8; + } + + here = lcode[hold & lmask]; + + dolen: + for (;;) { // Goto emulation + op = here >>> 24/*here.bits*/; + hold >>>= op; + bits -= op; + op = (here >>> 16) & 0xff/*here.op*/; + if (op === 0) { /* literal */ + //Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ? + // "inflate: literal '%c'\n" : + // "inflate: literal 0x%02x\n", here.val)); + output[_out++] = here & 0xffff/*here.val*/; + } + else if (op & 16) { /* length base */ + len = here & 0xffff/*here.val*/; + op &= 15; /* number of extra bits */ + if (op) { + if (bits < op) { + hold += input[_in++] << bits; + bits += 8; + } + len += hold & ((1 << op) - 1); + hold >>>= op; + bits -= op; + } + //Tracevv((stderr, "inflate: length %u\n", len)); + if (bits < 15) { + hold += input[_in++] << bits; + bits += 8; + hold += input[_in++] << bits; + bits += 8; + } + here = dcode[hold & dmask]; + + dodist: + for (;;) { // goto emulation + op = here >>> 24/*here.bits*/; + hold >>>= op; + bits -= op; + op = (here >>> 16) & 0xff/*here.op*/; + + if (op & 16) { /* distance base */ + dist = here & 0xffff/*here.val*/; + op &= 15; /* number of extra bits */ + if (bits < op) { + hold += input[_in++] << bits; + bits += 8; + if (bits < op) { + hold += input[_in++] << bits; + bits += 8; + } + } + dist += hold & ((1 << op) - 1); +//#ifdef INFLATE_STRICT + if (dist > dmax) { + strm.msg = 'invalid distance too far back'; + state.mode = BAD; + break top; + } +//#endif + hold >>>= op; + bits -= op; + //Tracevv((stderr, "inflate: distance %u\n", dist)); + op = _out - beg; /* max distance in output */ + if (dist > op) { /* see if copy from window */ + op = dist - op; /* distance back in window */ + if (op > whave) { + if (state.sane) { + strm.msg = 'invalid distance too far back'; + state.mode = BAD; + break top; + } + +// (!) This block is disabled in zlib defaults, +// don't enable it for binary compatibility +//#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR +// if (len <= op - whave) { +// do { +// output[_out++] = 0; +// } while (--len); +// continue top; +// } +// len -= op - whave; +// do { +// output[_out++] = 0; +// } while (--op > whave); +// if (op === 0) { +// from = _out - dist; +// do { +// output[_out++] = output[from++]; +// } while (--len); +// continue top; +// } +//#endif + } + from = 0; // window index + from_source = s_window; + if (wnext === 0) { /* very common case */ + from += wsize - op; + if (op < len) { /* some from window */ + len -= op; + do { + output[_out++] = s_window[from++]; + } while (--op); + from = _out - dist; /* rest from output */ + from_source = output; + } + } + else if (wnext < op) { /* wrap around window */ + from += wsize + wnext - op; + op -= wnext; + if (op < len) { /* some from end of window */ + len -= op; + do { + output[_out++] = s_window[from++]; + } while (--op); + from = 0; + if (wnext < len) { /* some from start of window */ + op = wnext; + len -= op; + do { + output[_out++] = s_window[from++]; + } while (--op); + from = _out - dist; /* rest from output */ + from_source = output; + } + } + } + else { /* contiguous in window */ + from += wnext - op; + if (op < len) { /* some from window */ + len -= op; + do { + output[_out++] = s_window[from++]; + } while (--op); + from = _out - dist; /* rest from output */ + from_source = output; + } + } + while (len > 2) { + output[_out++] = from_source[from++]; + output[_out++] = from_source[from++]; + output[_out++] = from_source[from++]; + len -= 3; + } + if (len) { + output[_out++] = from_source[from++]; + if (len > 1) { + output[_out++] = from_source[from++]; + } + } + } + else { + from = _out - dist; /* copy direct from output */ + do { /* minimum length is three */ + output[_out++] = output[from++]; + output[_out++] = output[from++]; + output[_out++] = output[from++]; + len -= 3; + } while (len > 2); + if (len) { + output[_out++] = output[from++]; + if (len > 1) { + output[_out++] = output[from++]; + } + } + } + } + else if ((op & 64) === 0) { /* 2nd level distance code */ + here = dcode[(here & 0xffff)/*here.val*/ + (hold & ((1 << op) - 1))]; + continue dodist; + } + else { + strm.msg = 'invalid distance code'; + state.mode = BAD; + break top; + } + + break; // need to emulate goto via "continue" + } + } + else if ((op & 64) === 0) { /* 2nd level length code */ + here = lcode[(here & 0xffff)/*here.val*/ + (hold & ((1 << op) - 1))]; + continue dolen; + } + else if (op & 32) { /* end-of-block */ + //Tracevv((stderr, "inflate: end of block\n")); + state.mode = TYPE; + break top; + } + else { + strm.msg = 'invalid literal/length code'; + state.mode = BAD; + break top; + } + + break; // need to emulate goto via "continue" + } + } while (_in < last && _out < end); + + /* return unused bytes (on entry, bits < 8, so in won't go too far back) */ + len = bits >> 3; + _in -= len; + bits -= len << 3; + hold &= (1 << bits) - 1; + + /* update state and return */ + strm.next_in = _in; + strm.next_out = _out; + strm.avail_in = (_in < last ? 5 + (last - _in) : 5 - (_in - last)); + strm.avail_out = (_out < end ? 257 + (end - _out) : 257 - (_out - end)); + state.hold = hold; + state.bits = bits; + return; +}; |