/*
  Additional tools for Minizip
  Code: Xavier Roche '2004
  License: Same as ZLIB (www.gzip.org)
*/

/* Code */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "zlib.h"
#include "unzip.h"

#define READ_8(adr)  ((unsigned char)*(adr))
#define READ_16(adr) ( READ_8(adr) | (READ_8(adr+1) << 8) )
#define READ_32(adr) ( READ_16(adr) | (READ_16((adr)+2) << 16) )

#define WRITE_8(buff, n) do { \
  *((unsigned char*)(buff)) = (unsigned char) ((n) & 0xff); \
} while(0)
#define WRITE_16(buff, n) do { \
  WRITE_8((unsigned char*)(buff), n); \
  WRITE_8(((unsigned char*)(buff)) + 1, (n) >> 8); \
} while(0)
#define WRITE_32(buff, n) do { \
  WRITE_16((unsigned char*)(buff), (n) & 0xffff); \
  WRITE_16((unsigned char*)(buff) + 2, (n) >> 16); \
} while(0)

extern int ZEXPORT unzRepair(file, fileOut, fileOutTmp, nRecovered, bytesRecovered)
const char* file;
const char* fileOut;
const char* fileOutTmp;
uLong* nRecovered;
uLong* bytesRecovered;
{
	int err = Z_OK;
	FILE* fpZip = fopen(file, "rb");
	FILE* fpOut = fopen(fileOut, "wb");
	FILE* fpOutCD = fopen(fileOutTmp, "wb");
	if (fpZip != NULL &&  fpOut != NULL) {
		int entries = 0;
		uLong totalBytes = 0;
		char header[30];
		char filename[1024];
		char extra[1024];
		int offset = 0;
		int offsetCD = 0;
		while (fread(header, 1, 30, fpZip) == 30) {
			int currentOffset = offset;

			/* File entry */
			if (READ_32(header) == 0x04034b50) {
				unsigned int version = READ_16(header + 4);
				unsigned int gpflag = READ_16(header + 6);
				unsigned int method = READ_16(header + 8);
				unsigned int filetime = READ_16(header + 10);
				unsigned int filedate = READ_16(header + 12);
				unsigned int crc = READ_32(header + 14); /* crc */
				unsigned int cpsize = READ_32(header + 18); /* compressed size */
				unsigned int uncpsize = READ_32(header + 22); /* uncompressed sz */
				unsigned int fnsize = READ_16(header + 26); /* file name length */
				unsigned int extsize = READ_16(header + 28); /* extra field length */
				filename[0] = extra[0] = '\0';

				/* Header */
				if (fwrite(header, 1, 30, fpOut) == 30) {
					offset += 30;
				}
				else {
					err = Z_ERRNO;
					break;
				}

				/* Filename */
				if (fnsize > 0) {
					if (fnsize < sizeof(filename)) {
						if (fread(filename, 1, fnsize, fpZip) == fnsize) {
							if (fwrite(filename, 1, fnsize, fpOut) == fnsize) {
								offset += fnsize;
							}
							else {
								err = Z_ERRNO;
								break;
							}
						}
						else {
							err = Z_ERRNO;
							break;
						}
					}
					else {
						err = Z_ERRNO;
						break;
					}
				}
				else {
					err = Z_STREAM_ERROR;
					break;
				}

				/* Extra field */
				if (extsize > 0) {
					if (extsize < sizeof(extra)) {
						if (fread(extra, 1, extsize, fpZip) == extsize) {
							if (fwrite(extra, 1, extsize, fpOut) == extsize) {
								offset += extsize;
							}
							else {
								err = Z_ERRNO;
								break;
							}
						}
						else {
							err = Z_ERRNO;
							break;
						}
					}
					else {
						err = Z_ERRNO;
						break;
					}
				}

				/* Data */
				{
					int dataSize = cpsize;
					if (dataSize == 0) {
						dataSize = uncpsize;
					}
					if (dataSize > 0) {
						char* data = malloc(dataSize);
						if (data != NULL) {
							if ((int)fread(data, 1, dataSize, fpZip) == dataSize) {
								if ((int)fwrite(data, 1, dataSize, fpOut) == dataSize) {
									offset += dataSize;
									totalBytes += dataSize;
								}
								else {
									err = Z_ERRNO;
								}
							}
							else {
								err = Z_ERRNO;
							}
							free(data);
							if (err != Z_OK) {
								break;
							}
						}
						else {
							err = Z_MEM_ERROR;
							break;
						}
					}
				}

				/* Central directory entry */
				{
					char hdr[46];
					char* comment = "";
					int comsize = (int)strlen(comment);
					WRITE_32(hdr, 0x02014b50);
					WRITE_16(hdr + 4, version);
					WRITE_16(hdr + 6, version);
					WRITE_16(hdr + 8, gpflag);
					WRITE_16(hdr + 10, method);
					WRITE_16(hdr + 12, filetime);
					WRITE_16(hdr + 14, filedate);
					WRITE_32(hdr + 16, crc);
					WRITE_32(hdr + 20, cpsize);
					WRITE_32(hdr + 24, uncpsize);
					WRITE_16(hdr + 28, fnsize);
					WRITE_16(hdr + 30, extsize);
					WRITE_16(hdr + 32, comsize);
					WRITE_16(hdr + 34, 0);     /* disk # */
					WRITE_16(hdr + 36, 0);     /* int attrb */
					WRITE_32(hdr + 38, 0);     /* ext attrb */
					WRITE_32(hdr + 42, currentOffset);
					/* Header */
					if (fwrite(hdr, 1, 46, fpOutCD) == 46) {
						offsetCD += 46;

						/* Filename */
						if (fnsize > 0) {
							if (fwrite(filename, 1, fnsize, fpOutCD) == fnsize) {
								offsetCD += fnsize;
							}
							else {
								err = Z_ERRNO;
								break;
							}
						}
						else {
							err = Z_STREAM_ERROR;
							break;
						}

						/* Extra field */
						if (extsize > 0) {
							if (fwrite(extra, 1, extsize, fpOutCD) == extsize) {
								offsetCD += extsize;
							}
							else {
								err = Z_ERRNO;
								break;
							}
						}

						/* Comment field */
						if (comsize > 0) {
							if ((int)fwrite(comment, 1, comsize, fpOutCD) == comsize) {
								offsetCD += comsize;
							}
							else {
								err = Z_ERRNO;
								break;
							}
						}


					}
					else {
						err = Z_ERRNO;
						break;
					}
				}

				/* Success */
				entries++;

			}
			else {
				break;
			}
		}

		/* Final central directory  */
		{
			int entriesZip = entries;
			char hdr[22];
			char* comment = ""; // "ZIP File recovered by zlib/minizip/mztools";
			int comsize = (int)strlen(comment);
			if (entriesZip > 0xffff) {
				entriesZip = 0xffff;
			}
			WRITE_32(hdr, 0x06054b50);
			WRITE_16(hdr + 4, 0);    /* disk # */
			WRITE_16(hdr + 6, 0);    /* disk # */
			WRITE_16(hdr + 8, entriesZip);   /* hack */
			WRITE_16(hdr + 10, entriesZip);  /* hack */
			WRITE_32(hdr + 12, offsetCD);    /* size of CD */
			WRITE_32(hdr + 16, offset);      /* offset to CD */
			WRITE_16(hdr + 20, comsize);     /* comment */

			/* Header */
			if (fwrite(hdr, 1, 22, fpOutCD) == 22) {

				/* Comment field */
				if (comsize > 0) {
					if ((int)fwrite(comment, 1, comsize, fpOutCD) != comsize) {
						err = Z_ERRNO;
					}
				}

			}
			else {
				err = Z_ERRNO;
			}
		}

		/* Final merge (file + central directory) */
		fclose(fpOutCD);
		if (err == Z_OK) {
			fpOutCD = fopen(fileOutTmp, "rb");
			if (fpOutCD != NULL) {
				int nRead;
				char buffer[8192];
				while ((nRead = (int)fread(buffer, 1, sizeof(buffer), fpOutCD)) > 0) {
					if ((int)fwrite(buffer, 1, nRead, fpOut) != nRead) {
						err = Z_ERRNO;
						break;
					}
				}
				fclose(fpOutCD);
			}
		}

		/* Close */
		fclose(fpZip);
		fclose(fpOut);

		/* Wipe temporary file */
		(void)remove(fileOutTmp);

		/* Number of recovered entries */
		if (err == Z_OK) {
			if (nRecovered != NULL) {
				*nRecovered = entries;
			}
			if (bytesRecovered != NULL) {
				*bytesRecovered = totalBytes;
			}
		}
	}
	else {
		err = Z_STREAM_ERROR;
	}
	return err;
}