--- /dev/null
+/*
+ LZ4 - Fast LZ compression algorithm
+ Copyright (C) 2011-2015, Yann Collet.
+
+ SPDX-License-Identifier: BSD-2-Clause
+
+ You can contact the author at :
+ - LZ4 source repository : https://github.com/Cyan4973/lz4
+ - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c
+*/
+
+
+/**************************************
+* Reading and writing into memory
+**************************************/
+
+/* customized version of memcpy, which may overwrite up to 7 bytes beyond dstEnd */
+static void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd)
+{
+ BYTE* d = (BYTE*)dstPtr;
+ const BYTE* s = (const BYTE*)srcPtr;
+ BYTE* e = (BYTE*)dstEnd;
+ do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e);
+}
+
+
+/**************************************
+* Common Constants
+**************************************/
+#define MINMATCH 4
+
+#define COPYLENGTH 8
+#define LASTLITERALS 5
+#define MFLIMIT (COPYLENGTH+MINMATCH)
+static const int LZ4_minLength = (MFLIMIT+1);
+
+#define KB *(1 <<10)
+#define MB *(1 <<20)
+#define GB *(1U<<30)
+
+#define MAXD_LOG 16
+#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
+
+#define ML_BITS 4
+#define ML_MASK ((1U<<ML_BITS)-1)
+#define RUN_BITS (8-ML_BITS)
+#define RUN_MASK ((1U<<RUN_BITS)-1)
+
+
+/**************************************
+* Local Structures and types
+**************************************/
+typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive;
+typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive;
+typedef enum { full = 0, partial = 1 } earlyEnd_directive;
+
+
+
+/*******************************
+* Decompression functions
+*******************************/
+/*
+ * This generic decompression function cover all use cases.
+ * It shall be instantiated several times, using different sets of directives
+ * Note that it is essential this generic function is really inlined,
+ * in order to remove useless branches during compilation optimization.
+ */
+FORCE_INLINE int LZ4_decompress_generic(
+ const char* const source,
+ char* const dest,
+ int inputSize,
+ int outputSize, /* If endOnInput==endOnInputSize, this value is the max size of Output Buffer. */
+
+ int endOnInput, /* endOnOutputSize, endOnInputSize */
+ int partialDecoding, /* full, partial */
+ int targetOutputSize, /* only used if partialDecoding==partial */
+ int dict, /* noDict, withPrefix64k, usingExtDict */
+ const BYTE* const lowPrefix, /* == dest if dict == noDict */
+ const BYTE* const dictStart, /* only if dict==usingExtDict */
+ const size_t dictSize /* note : = 0 if noDict */
+ )
+{
+ /* Local Variables */
+ const BYTE* ip = (const BYTE*) source;
+ const BYTE* const iend = ip + inputSize;
+
+ BYTE* op = (BYTE*) dest;
+ BYTE* const oend = op + outputSize;
+ BYTE* cpy;
+ BYTE* oexit = op + targetOutputSize;
+ const BYTE* const lowLimit = lowPrefix - dictSize;
+
+ const BYTE* const dictEnd = (const BYTE*)dictStart + dictSize;
+ const size_t dec32table[] = {4, 1, 2, 1, 4, 4, 4, 4};
+ const size_t dec64table[] = {0, 0, 0, (size_t)-1, 0, 1, 2, 3};
+
+ const int safeDecode = (endOnInput==endOnInputSize);
+ const int checkOffset = ((safeDecode) && (dictSize < (int)(64 KB)));
+
+
+ /* Special cases */
+ if ((partialDecoding) && (oexit> oend-MFLIMIT)) oexit = oend-MFLIMIT; /* targetOutputSize too high => decode everything */
+ if ((endOnInput) && (unlikely(outputSize==0))) return ((inputSize==1) && (*ip==0)) ? 0 : -1; /* Empty output buffer */
+ if ((!endOnInput) && (unlikely(outputSize==0))) return (*ip==0?1:-1);
+
+
+ /* Main Loop */
+ while (1)
+ {
+ unsigned token;
+ size_t length;
+ const BYTE* match;
+
+ /* get literal length */
+ token = *ip++;
+ if ((length=(token>>ML_BITS)) == RUN_MASK)
+ {
+ unsigned s;
+ do
+ {
+ s = *ip++;
+ length += s;
+ }
+ while (likely((endOnInput)?ip<iend-RUN_MASK:1) && (s==255));
+ if ((safeDecode) && unlikely((size_t)(op+length)<(size_t)(op))) goto _output_error; /* overflow detection */
+ if ((safeDecode) && unlikely((size_t)(ip+length)<(size_t)(ip))) goto _output_error; /* overflow detection */
+ }
+
+ /* copy literals */
+ cpy = op+length;
+ if (((endOnInput) && ((cpy>(partialDecoding?oexit:oend-MFLIMIT)) || (ip+length>iend-(2+1+LASTLITERALS))) )
+ || ((!endOnInput) && (cpy>oend-COPYLENGTH)))
+ {
+ if (partialDecoding)
+ {
+ if (cpy > oend) goto _output_error; /* Error : write attempt beyond end of output buffer */
+ if ((endOnInput) && (ip+length > iend)) goto _output_error; /* Error : read attempt beyond end of input buffer */
+ }
+ else
+ {
+ if ((!endOnInput) && (cpy != oend)) goto _output_error; /* Error : block decoding must stop exactly there */
+ if ((endOnInput) && ((ip+length != iend) || (cpy > oend))) goto _output_error; /* Error : input must be consumed */
+ }
+ memcpy(op, ip, length);
+ ip += length;
+ op += length;
+ break; /* Necessarily EOF, due to parsing restrictions */
+ }
+ LZ4_wildCopy(op, ip, cpy);
+ ip += length; op = cpy;
+
+ /* get offset */
+ match = cpy - LZ4_readLE16(ip); ip+=2;
+ if ((checkOffset) && (unlikely(match < lowLimit))) goto _output_error; /* Error : offset outside destination buffer */
+
+ /* get matchlength */
+ length = token & ML_MASK;
+ if (length == ML_MASK)
+ {
+ unsigned s;
+ do
+ {
+ if ((endOnInput) && (ip > iend-LASTLITERALS)) goto _output_error;
+ s = *ip++;
+ length += s;
+ } while (s==255);
+ if ((safeDecode) && unlikely((size_t)(op+length)<(size_t)op)) goto _output_error; /* overflow detection */
+ }
+ length += MINMATCH;
+
+ /* check external dictionary */
+ if ((dict==usingExtDict) && (match < lowPrefix))
+ {
+ if (unlikely(op+length > oend-LASTLITERALS)) goto _output_error; /* doesn't respect parsing restriction */
+
+ if (length <= (size_t)(lowPrefix-match))
+ {
+ /* match can be copied as a single segment from external dictionary */
+ match = dictEnd - (lowPrefix-match);
+ memmove(op, match, length); op += length;
+ }
+ else
+ {
+ /* match encompass external dictionary and current segment */
+ size_t copySize = (size_t)(lowPrefix-match);
+ memcpy(op, dictEnd - copySize, copySize);
+ op += copySize;
+ copySize = length - copySize;
+ if (copySize > (size_t)(op-lowPrefix)) /* overlap within current segment */
+ {
+ BYTE* const endOfMatch = op + copySize;
+ const BYTE* copyFrom = lowPrefix;
+ while (op < endOfMatch) *op++ = *copyFrom++;
+ }
+ else
+ {
+ memcpy(op, lowPrefix, copySize);
+ op += copySize;
+ }
+ }
+ continue;
+ }
+
+ /* copy repeated sequence */
+ cpy = op + length;
+ if (unlikely((op-match)<8))
+ {
+ const size_t dec64 = dec64table[op-match];
+ op[0] = match[0];
+ op[1] = match[1];
+ op[2] = match[2];
+ op[3] = match[3];
+ match += dec32table[op-match];
+ LZ4_copy4(op+4, match);
+ op += 8; match -= dec64;
+ } else { LZ4_copy8(op, match); op+=8; match+=8; }
+
+ if (unlikely(cpy>oend-12))
+ {
+ if (cpy > oend-LASTLITERALS) goto _output_error; /* Error : last LASTLITERALS bytes must be literals */
+ if (op < oend-8)
+ {
+ LZ4_wildCopy(op, match, oend-8);
+ match += (oend-8) - op;
+ op = oend-8;
+ }
+ while (op<cpy) *op++ = *match++;
+ }
+ else
+ LZ4_wildCopy(op, match, cpy);
+ op=cpy; /* correction */
+ }
+
+ /* end of decoding */
+ if (endOnInput)
+ return (int) (((char*)op)-dest); /* Nb of output bytes decoded */
+ else
+ return (int) (((const char*)ip)-source); /* Nb of input bytes read */
+
+ /* Overflow error detected */
+_output_error:
+ return (int) (-(((const char*)ip)-source))-1;
+}
projects / oweals / u-boot.git / blobdiff