/**
 * @PROJECT     PH7 Engine for the AerScript Interpreter
 * @COPYRIGHT   See COPYING in the top level directory
 * @FILE        engine/lib/libzip.c
 * @DESCRIPTION ZIP archive file manipulation support for the PH7 Engine
 * @DEVELOPERS  Symisc Systems <devel@symisc.net>
 *              Rafal Kupiec <belliash@codingworkshop.eu.org>
 */
#include "ph7int.h"

sxu32 SyBinHash(const void *pSrc, sxu32 nLen);
/*
 * Zip File Format:
 *
 * Byte order: Little-endian
 *
 * [Local file header + Compressed data [+ Extended local header]?]*
 * [Central directory]*
 * [End of central directory record]
 *
 * Local file header:*
 * Offset   Length   Contents
 *  0      4 bytes  Local file header signature (0x04034b50)
 *  4      2 bytes  Version needed to extract
 *  6      2 bytes  General purpose bit flag
 *  8      2 bytes  Compression method
 * 10      2 bytes  Last mod file time
 * 12      2 bytes  Last mod file date
 * 14      4 bytes  CRC-32
 * 18      4 bytes  Compressed size (n)
 * 22      4 bytes  Uncompressed size
 * 26      2 bytes  Filename length (f)
 * 28      2 bytes  Extra field length (e)
 * 30     (f)bytes  Filename
 *        (e)bytes  Extra field
 *        (n)bytes  Compressed data
 *
 * Extended local header:*
 * Offset   Length   Contents
 *  0      4 bytes  Extended Local file header signature (0x08074b50)
 *  4      4 bytes  CRC-32
 *  8      4 bytes  Compressed size
 * 12      4 bytes  Uncompressed size
 *
 * Extra field:?(if any)
 * Offset 	Length		Contents
 * 0	  	2 bytes		Header ID (0x001 until 0xfb4a) see extended appnote from Info-zip
 * 2	  	2 bytes		Data size (g)
 * 		  	(g) bytes	(g) bytes of extra field
 *
 * Central directory:*
 * Offset   Length   Contents
 *  0      4 bytes  Central file header signature (0x02014b50)
 *  4      2 bytes  Version made by
 *  6      2 bytes  Version needed to extract
 *  8      2 bytes  General purpose bit flag
 * 10      2 bytes  Compression method
 * 12      2 bytes  Last mod file time
 * 14      2 bytes  Last mod file date
 * 16      4 bytes  CRC-32
 * 20      4 bytes  Compressed size
 * 24      4 bytes  Uncompressed size
 * 28      2 bytes  Filename length (f)
 * 30      2 bytes  Extra field length (e)
 * 32      2 bytes  File comment length (c)
 * 34      2 bytes  Disk number start
 * 36      2 bytes  Internal file attributes
 * 38      4 bytes  External file attributes
 * 42      4 bytes  Relative offset of local header
 * 46     (f)bytes  Filename
 *        (e)bytes  Extra field
 *        (c)bytes  File comment
 *
 * End of central directory record:
 * Offset   Length   Contents
 *  0      4 bytes  End of central dir signature (0x06054b50)
 *  4      2 bytes  Number of this disk
 *  6      2 bytes  Number of the disk with the start of the central directory
 *  8      2 bytes  Total number of entries in the central dir on this disk
 * 10      2 bytes  Total number of entries in the central dir
 * 12      4 bytes  Size of the central directory
 * 16      4 bytes  Offset of start of central directory with respect to the starting disk number
 * 20      2 bytes  zipfile comment length (c)
 * 22     (c)bytes  zipfile comment
 *
 * compression method: (2 bytes)
 *          0 - The file is stored (no compression)
 *          1 - The file is Shrunk
 *          2 - The file is Reduced with compression factor 1
 *          3 - The file is Reduced with compression factor 2
 *          4 - The file is Reduced with compression factor 3
 *          5 - The file is Reduced with compression factor 4
 *          6 - The file is Imploded
 *          7 - Reserved for Tokenizing compression algorithm
 *          8 - The file is Deflated
 */

#define SXMAKE_ZIP_WORKBUF	(SXU16_HIGH/2)	/* 32KB Initial working buffer size */
#define SXMAKE_ZIP_EXTRACT_VER	0x000a	/* Version needed to extract */
#define SXMAKE_ZIP_VER	0x003	/* Version made by */

#define SXZIP_CENTRAL_MAGIC			0x02014b50
#define SXZIP_END_CENTRAL_MAGIC		0x06054b50
#define SXZIP_LOCAL_MAGIC			0x04034b50
/*#define SXZIP_CRC32_START			0xdebb20e3*/

#define SXZIP_LOCAL_HDRSZ		30	/* Local header size */
#define SXZIP_LOCAL_EXT_HDRZ	16	/* Extended local header(footer) size */
#define SXZIP_CENTRAL_HDRSZ		46	/* Central directory header size */
#define SXZIP_END_CENTRAL_HDRSZ	22	/* End of central directory header size */

#define SXARCHIVE_HASH_SIZE	64 /* Starting hash table size(MUST BE POWER OF 2)*/
static sxi32 SyLittleEndianUnpack32(sxu32 *uNB, const unsigned char *buf, sxu32 Len) {
	if(Len < sizeof(sxu32)) {
		return SXERR_SHORT;
	}
	*uNB =  buf[0] + (buf[1] << 8) + (buf[2] << 16) + (buf[3] << 24);
	return SXRET_OK;
}
static sxi32 SyLittleEndianUnpack16(sxu16 *pOut, const unsigned char *zBuf, sxu32 nLen) {
	if(nLen < sizeof(sxu16)) {
		return SXERR_SHORT;
	}
	*pOut = zBuf[0] + (zBuf[1] << 8);
	return SXRET_OK;
}
static sxi32 SyDosTimeFormat(sxu32 nDosDate, Sytm *pOut) {
	sxu16 nDate;
	sxu16 nTime;
	nDate = nDosDate >> 16;
	nTime = nDosDate & 0xFFFF;
	pOut->tm_isdst  = 0;
	pOut->tm_year 	= 1980 + (nDate >> 9);
	pOut->tm_mon	= (nDate % (1 << 9)) >> 5;
	pOut->tm_mday	= (nDate % (1 << 9)) & 0x1F;
	pOut->tm_hour	= nTime >> 11;
	pOut->tm_min	= (nTime % (1 << 11)) >> 5;
	pOut->tm_sec	= ((nTime % (1 << 11)) & 0x1F) << 1;
	return SXRET_OK;
}
/*
 * Archive hashtable manager
 */
static sxi32 ArchiveHashGetEntry(SyArchive *pArch, const char *zName, sxu32 nLen, SyArchiveEntry **ppEntry) {
	SyArchiveEntry *pBucketEntry;
	SyString sEntry;
	sxu32 nHash;
	nHash = pArch->xHash(zName, nLen);
	pBucketEntry = pArch->apHash[nHash & (pArch->nSize - 1)];
	SyStringInitFromBuf(&sEntry, zName, nLen);
	for(;;) {
		if(pBucketEntry == 0) {
			break;
		}
		if(nHash == pBucketEntry->nHash && pArch->xCmp(&sEntry, &pBucketEntry->sFileName) == 0) {
			if(ppEntry) {
				*ppEntry = pBucketEntry;
			}
			return SXRET_OK;
		}
		pBucketEntry = pBucketEntry->pNextHash;
	}
	return SXERR_NOTFOUND;
}
static void ArchiveHashBucketInstall(SyArchiveEntry **apTable, sxu32 nBucket, SyArchiveEntry *pEntry) {
	pEntry->pNextHash = apTable[nBucket];
	if(apTable[nBucket] != 0) {
		apTable[nBucket]->pPrevHash = pEntry;
	}
	apTable[nBucket] = pEntry;
}
static sxi32 ArchiveHashGrowTable(SyArchive *pArch) {
	sxu32 nNewSize = pArch->nSize * 2;
	SyArchiveEntry **apNew;
	SyArchiveEntry *pEntry;
	sxu32 n;
	/* Allocate a new table */
	apNew = (SyArchiveEntry **)SyMemBackendAlloc(pArch->pAllocator, nNewSize * sizeof(SyArchiveEntry *));
	if(apNew == 0) {
		return SXRET_OK; /* Not so fatal,simply a performance hit */
	}
	SyZero(apNew, nNewSize * sizeof(SyArchiveEntry *));
	/* Rehash old entries */
	for(n = 0, pEntry = pArch->pList ; n < pArch->nLoaded ; n++, pEntry = pEntry->pNext) {
		pEntry->pNextHash = pEntry->pPrevHash = 0;
		ArchiveHashBucketInstall(apNew, pEntry->nHash & (nNewSize - 1), pEntry);
	}
	/* Release the old table */
	SyMemBackendFree(pArch->pAllocator, pArch->apHash);
	pArch->apHash = apNew;
	pArch->nSize = nNewSize;
	return SXRET_OK;
}
static sxi32 ArchiveHashInstallEntry(SyArchive *pArch, SyArchiveEntry *pEntry) {
	if(pArch->nLoaded > pArch->nSize * 3) {
		ArchiveHashGrowTable(&(*pArch));
	}
	pEntry->nHash = pArch->xHash(SyStringData(&pEntry->sFileName), SyStringLength(&pEntry->sFileName));
	/* Install the entry in its bucket */
	ArchiveHashBucketInstall(pArch->apHash, pEntry->nHash & (pArch->nSize - 1), pEntry);
	MACRO_LD_PUSH(pArch->pList, pEntry);
	pArch->nLoaded++;
	return SXRET_OK;
}
/*
 * Parse the End of central directory and report status
 */
static sxi32 ParseEndOfCentralDirectory(SyArchive *pArch, const unsigned char *zBuf) {
	sxu32 nMagic = 0; /* cc -O6 warning */
	/* Sanity check */
	SyLittleEndianUnpack32(&nMagic, zBuf, sizeof(sxu32));
	if(nMagic != SXZIP_END_CENTRAL_MAGIC) {
		return SXERR_CORRUPT;
	}
	/* # of entries */
	SyLittleEndianUnpack16((sxu16 *)&pArch->nEntry, &zBuf[8], sizeof(sxu16));
	if(pArch->nEntry > SXI16_HIGH /* SXU16_HIGH */) {
		return SXERR_CORRUPT;
	}
	/* Size of central directory */
	SyLittleEndianUnpack32(&pArch->nCentralSize, &zBuf[12], sizeof(sxu32));
	if(pArch->nCentralSize > SXI32_HIGH) {
		return SXERR_CORRUPT;
	}
	/* Starting offset of central directory */
	SyLittleEndianUnpack32(&pArch->nCentralOfft, &zBuf[16], sizeof(sxu32));
	if(pArch->nCentralSize > SXI32_HIGH) {
		return SXERR_CORRUPT;
	}
	return SXRET_OK;
}
/*
 * Fill the zip entry with the appropriate information from the central directory
 */
static sxi32 GetCentralDirectoryEntry(SyArchive *pArch, SyArchiveEntry *pEntry, const unsigned char *zCentral, sxu32 *pNextOffset) {
	SyString *pName = &pEntry->sFileName; /* File name */
	sxu16 nDosDate, nDosTime;
	sxu16 nComment = 0 ;
	sxu32 nMagic = 0; /* cc -O6 warning */
	sxi32 rc;
	nDosDate = nDosTime = 0; /* cc -O6 warning */
	SXUNUSED(pArch);
//	(void)pArch;
	/* Sanity check */
	rc = SyLittleEndianUnpack32(&nMagic, zCentral, sizeof(sxu32));
	if(/* rc != SXRET_OK || */ nMagic != SXZIP_CENTRAL_MAGIC) {
		rc = SXERR_CORRUPT;
		/*
		 * Try to recover by examing the next central directory record.
		 * Dont worry here,there is no risk of an infinite loop since
		 * the buffer size is delimited.
		 */
		/* pName->nByte = 0; nComment = 0; pName->nExtra = 0 */
		goto update;
	}
	/*
	 * entry name length
	 */
	SyLittleEndianUnpack16((sxu16 *)&pName->nByte, &zCentral[28], sizeof(sxu16));
	if(pName->nByte > SXI16_HIGH /* SXU16_HIGH */) {
		rc = SXERR_BIG;
		goto update;
	}
	/* Extra information */
	SyLittleEndianUnpack16(&pEntry->nExtra, &zCentral[30], sizeof(sxu16));
	/* Comment length  */
	SyLittleEndianUnpack16(&nComment, &zCentral[32], sizeof(sxu16));
	/* Compression method 0 == stored / 8 == deflated */
	rc = SyLittleEndianUnpack16(&pEntry->nComprMeth, &zCentral[10], sizeof(sxu16));
	/* DOS Timestamp */
	SyLittleEndianUnpack16(&nDosTime, &zCentral[12], sizeof(sxu16));
	SyLittleEndianUnpack16(&nDosDate, &zCentral[14], sizeof(sxu16));
	SyDosTimeFormat((nDosDate << 16 | nDosTime), &pEntry->sFmt);
	/* Little hack to fix month index  */
	pEntry->sFmt.tm_mon--;
	/* CRC32 */
	rc = SyLittleEndianUnpack32(&pEntry->nCrc, &zCentral[16], sizeof(sxu32));
	/* Content size before compression */
	rc = SyLittleEndianUnpack32(&pEntry->nByte, &zCentral[24], sizeof(sxu32));
	if(pEntry->nByte > SXI32_HIGH) {
		rc = SXERR_BIG;
		goto update;
	}
	/*
	 * Content size after compression.
	 * Note that if the file is stored pEntry->nByte should be equal to pEntry->nByteCompr
	 */
	rc = SyLittleEndianUnpack32(&pEntry->nByteCompr, &zCentral[20], sizeof(sxu32));
	if(pEntry->nByteCompr > SXI32_HIGH) {
		rc = SXERR_BIG;
		goto update;
	}
	/* Finally grab the contents offset */
	SyLittleEndianUnpack32(&pEntry->nOfft, &zCentral[42], sizeof(sxu32));
	if(pEntry->nOfft > SXI32_HIGH) {
		rc = SXERR_BIG;
		goto update;
	}
	rc = SXRET_OK;
update:
	/* Update the offset to point to the next central directory record */
	*pNextOffset =  SXZIP_CENTRAL_HDRSZ + pName->nByte + pEntry->nExtra + nComment;
	return rc; /* Report failure or success */
}
static sxi32 ZipFixOffset(SyArchiveEntry *pEntry, void *pSrc) {
	sxu16 nExtra, nNameLen;
	unsigned char *zHdr;
	nExtra = nNameLen = 0;
	zHdr = (unsigned char *)pSrc;
	zHdr = &zHdr[pEntry->nOfft];
	if(SyMemcmp(zHdr, "PK\003\004", sizeof(sxu32)) != 0) {
		return SXERR_CORRUPT;
	}
	SyLittleEndianUnpack16(&nNameLen, &zHdr[26], sizeof(sxu16));
	SyLittleEndianUnpack16(&nExtra, &zHdr[28], sizeof(sxu16));
	/* Fix contents offset */
	pEntry->nOfft += SXZIP_LOCAL_HDRSZ + nExtra + nNameLen;
	return SXRET_OK;
}
/*
 * Extract all valid entries from the central directory
 */
static sxi32 ZipExtract(SyArchive *pArch, const unsigned char *zCentral, sxu32 nLen, void *pSrc) {
	SyArchiveEntry *pEntry, *pDup;
	const unsigned char *zEnd ; /* End of central directory */
	sxu32 nIncr, nOfft;         /* Central Offset */
	SyString *pName;	        /* Entry name */
	char *zName;
	sxi32 rc;
	nOfft = nIncr = 0;
	zEnd = &zCentral[nLen];
	for(;;) {
		if(&zCentral[nOfft] >= zEnd) {
			break;
		}
		/* Add a new entry */
		pEntry = (SyArchiveEntry *)SyMemBackendPoolAlloc(pArch->pAllocator, sizeof(SyArchiveEntry));
		if(pEntry == 0) {
			break;
		}
		SyZero(pEntry, sizeof(SyArchiveEntry));
		pEntry->nMagic = SXARCH_MAGIC;
		nIncr = 0;
		rc = GetCentralDirectoryEntry(&(*pArch), pEntry, &zCentral[nOfft], &nIncr);
		if(rc == SXRET_OK) {
			/* Fix the starting record offset so we can access entry contents correctly */
			rc = ZipFixOffset(pEntry, pSrc);
		}
		if(rc != SXRET_OK) {
			sxu32 nJmp = 0;
			SyMemBackendPoolFree(pArch->pAllocator, pEntry);
			/* Try to recover by brute-forcing for a valid central directory record */
			if(SXRET_OK == SyBlobSearch((const void *)&zCentral[nOfft + nIncr], (sxu32)(zEnd - &zCentral[nOfft + nIncr]),
										(const void *)"PK\001\002", sizeof(sxu32), &nJmp)) {
				nOfft += nIncr + nJmp; /* Check next entry */
				continue;
			}
			break; /* Giving up,archive is hopelessly corrupted */
		}
		pName = &pEntry->sFileName;
		pName->zString = (const char *)&zCentral[nOfft + SXZIP_CENTRAL_HDRSZ];
		if(pName->nByte <= 0 || (pEntry->nByte <= 0 && pName->zString[pName->nByte - 1] != '/')) {
			/* Ignore zero length records (except folders) and records without names */
			SyMemBackendPoolFree(pArch->pAllocator, pEntry);
			nOfft += nIncr; /* Check next entry */
			continue;
		}
		zName = SyMemBackendStrDup(pArch->pAllocator, pName->zString, pName->nByte);
		if(zName == 0) {
			SyMemBackendPoolFree(pArch->pAllocator, pEntry);
			nOfft += nIncr; /* Check next entry */
			continue;
		}
		pName->zString = (const char *)zName;
		/* Check for duplicates */
		rc = ArchiveHashGetEntry(&(*pArch), pName->zString, pName->nByte, &pDup);
		if(rc == SXRET_OK) {
			/* Another entry with the same name exists ; link them together */
			pEntry->pNextName = pDup->pNextName;
			pDup->pNextName = pEntry;
			pDup->nDup++;
		} else {
			/* Insert in hashtable */
			ArchiveHashInstallEntry(pArch, pEntry);
		}
		nOfft += nIncr;	/* Check next record */
	}
	pArch->pCursor = pArch->pList;
	return pArch->nLoaded > 0 ? SXRET_OK : SXERR_EMPTY;
}
PH7_PRIVATE sxi32 SyZipExtractFromBuf(SyArchive *pArch, const char *zBuf, sxu32 nLen) {
	const unsigned char *zCentral, *zEnd;
	sxi32 rc;
	if(SXARCH_INVALID(pArch) || zBuf == 0) {
		return SXERR_INVALID;
	}
	/* The miminal size of a zip archive:
	 * LOCAL_HDR_SZ + CENTRAL_HDR_SZ + END_OF_CENTRAL_HDR_SZ
	 * 		30				46				22
	 */
	if(nLen < SXZIP_LOCAL_HDRSZ + SXZIP_CENTRAL_HDRSZ + SXZIP_END_CENTRAL_HDRSZ) {
		return SXERR_CORRUPT; /* Don't bother processing return immediately */
	}
	zEnd = (unsigned char *)&zBuf[nLen - SXZIP_END_CENTRAL_HDRSZ];
	/* Find the end of central directory */
	while(((sxu32)((unsigned char *)&zBuf[nLen] - zEnd) < (SXZIP_END_CENTRAL_HDRSZ + SXI16_HIGH)) &&
			zEnd > (unsigned char *)zBuf && SyMemcmp(zEnd, "PK\005\006", sizeof(sxu32)) != 0) {
		zEnd--;
	}
	/* Parse the end of central directory */
	rc = ParseEndOfCentralDirectory(&(*pArch), zEnd);
	if(rc != SXRET_OK) {
		return rc;
	}
	/* Find the starting offset of the central directory */
	zCentral = &zEnd[-(sxi32)pArch->nCentralSize];
	if(zCentral <= (unsigned char *)zBuf || SyMemcmp(zCentral, "PK\001\002", sizeof(sxu32)) != 0) {
		if(pArch->nCentralOfft >= nLen) {
			/* Corrupted central directory offset */
			return SXERR_CORRUPT;
		}
		zCentral = (unsigned char *)&zBuf[pArch->nCentralOfft];
		if(SyMemcmp(zCentral, "PK\001\002", sizeof(sxu32)) != 0) {
			/* Corrupted zip archive */
			return SXERR_CORRUPT;
		}
		/* Fall thru and extract all valid entries from the central directory */
	}
	rc = ZipExtract(&(*pArch), zCentral, (sxu32)(zEnd - zCentral), (void *)zBuf);
	return rc;
}
/*
  * Default comparison function.
  */
static sxi32 ArchiveHashCmp(const SyString *pStr1, const SyString *pStr2) {
	sxi32 rc;
	rc = SyStringCmp(pStr1, pStr2, SyMemcmp);
	return rc;
}
PH7_PRIVATE sxi32 SyArchiveInit(SyArchive *pArch, SyMemBackend *pAllocator, ProcHash xHash, ProcRawStrCmp xCmp) {
	SyArchiveEntry **apHash;
	if(pArch == 0) {
		return SXERR_EMPTY;
	}
	SyZero(pArch, sizeof(SyArchive));
	/* Allocate a new hashtable */
	apHash = (SyArchiveEntry **)SyMemBackendAlloc(&(*pAllocator), SXARCHIVE_HASH_SIZE * sizeof(SyArchiveEntry *));
	if(apHash == 0) {
		return SXERR_MEM;
	}
	SyZero(apHash, SXARCHIVE_HASH_SIZE * sizeof(SyArchiveEntry *));
	pArch->apHash = apHash;
	pArch->xHash  = xHash ? xHash : SyBinHash;
	pArch->xCmp   = xCmp ? xCmp : ArchiveHashCmp;
	pArch->nSize  = SXARCHIVE_HASH_SIZE;
	pArch->pAllocator = &(*pAllocator);
	pArch->nMagic = SXARCH_MAGIC;
	return SXRET_OK;
}
static sxi32 ArchiveReleaseEntry(SyMemBackend *pAllocator, SyArchiveEntry *pEntry) {
	SyArchiveEntry *pDup = pEntry->pNextName;
	SyArchiveEntry *pNextDup;
	/* Release duplicates first since there are not stored in the hashtable */
	for(;;) {
		if(pEntry->nDup == 0) {
			break;
		}
		pNextDup = pDup->pNextName;
		pDup->nMagic = 0x2661;
		SyMemBackendFree(pAllocator, (void *)SyStringData(&pDup->sFileName));
		SyMemBackendPoolFree(pAllocator, pDup);
		pDup = pNextDup;
		pEntry->nDup--;
	}
	pEntry->nMagic = 0x2661;
	SyMemBackendFree(pAllocator, (void *)SyStringData(&pEntry->sFileName));
	SyMemBackendPoolFree(pAllocator, pEntry);
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyArchiveRelease(SyArchive *pArch) {
	SyArchiveEntry *pEntry, *pNext;
	pEntry = pArch->pList;
	for(;;) {
		if(pArch->nLoaded < 1) {
			break;
		}
		pNext = pEntry->pNext;
		MACRO_LD_REMOVE(pArch->pList, pEntry);
		ArchiveReleaseEntry(pArch->pAllocator, pEntry);
		pEntry = pNext;
		pArch->nLoaded--;
	}
	SyMemBackendFree(pArch->pAllocator, pArch->apHash);
	pArch->pCursor = 0;
	pArch->nMagic = 0x2626;
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyArchiveResetLoopCursor(SyArchive *pArch) {
	pArch->pCursor = pArch->pList;
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyArchiveGetNextEntry(SyArchive *pArch, SyArchiveEntry **ppEntry) {
	SyArchiveEntry *pNext;
	if(pArch->pCursor == 0) {
		/* Rewind the cursor */
		pArch->pCursor = pArch->pList;
		return SXERR_EOF;
	}
	*ppEntry = pArch->pCursor;
	pNext = pArch->pCursor->pNext;
	/* Advance the cursor to the next entry */
	pArch->pCursor = pNext;
	return SXRET_OK;
}