partial.c

#include <curl/curl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include <zlib.h>
#include <libgen.h>

#include "common.h"
#include "partial/partial.h"

static size_t dummyReceive(void* data, size_t size, size_t nmemb, void* info) {
	return size * nmemb;
}

static size_t receiveCentralDirectoryEnd(void* data, size_t size, size_t nmemb, ZipInfo* info) {
	memcpy(info->centralDirectoryEnd + info->centralDirectoryEndRecvd, data, size * nmemb);
	info->centralDirectoryEndRecvd += size * nmemb;
	return size * nmemb;
}

static size_t receiveCentralDirectory(void* data, size_t size, size_t nmemb, ZipInfo* info) {
	memcpy(info->centralDirectory + info->centralDirectoryRecvd, data, size * nmemb);
	info->centralDirectoryRecvd += size * nmemb;
	return size * nmemb;
}

static size_t receiveData(void* data, size_t size, size_t nmemb, void** pFileData) {
	memcpy(pFileData[0], data, size * nmemb);
	pFileData[0] = ((char*)pFileData[0]) + (size * nmemb);
	ZipInfo* info = ((ZipInfo*)pFileData[1]);
	CDFile* file = ((CDFile*)pFileData[2]);
	size_t* progress = ((size_t*)pFileData[3]);

	if(progress) {
		*progress += size * nmemb;
	}

	if(info && info->progressCallback && file) {
		info->progressCallback(info, file, *progress);
	}

	return size * nmemb;
}

static void flipFiles(ZipInfo* info)
{
	char* cur = info->centralDirectory;

	unsigned int i;
	for(i = 0; i < info->centralDirectoryDesc->CDEntries; i++)
	{
		CDFile* candidate = (CDFile*) cur;
		FLIPENDIANLE(candidate->signature);
		FLIPENDIANLE(candidate->version);
		FLIPENDIANLE(candidate->versionExtract);
		// FLIPENDIANLE(candidate->flags);
		FLIPENDIANLE(candidate->method);
		FLIPENDIANLE(candidate->modTime);
		FLIPENDIANLE(candidate->modDate);
		// FLIPENDIANLE(candidate->crc32);
		FLIPENDIANLE(candidate->compressedSize);
		FLIPENDIANLE(candidate->size);
		FLIPENDIANLE(candidate->lenFileName);
		FLIPENDIANLE(candidate->lenExtra);
		FLIPENDIANLE(candidate->lenComment);
		FLIPENDIANLE(candidate->diskStart);
		// FLIPENDIANLE(candidate->internalAttr);
		// FLIPENDIANLE(candidate->externalAttr);
		FLIPENDIANLE(candidate->offset);

		cur += sizeof(CDFile) + candidate->lenFileName + candidate->lenExtra + candidate->lenComment;
	}
}

ZipInfo* PartialZipInit(const char* url)
{
	ZipInfo* info = (ZipInfo*) calloc(1, sizeof(ZipInfo));
	info->url = strdup(url);
	info->centralDirectoryRecvd = 0;
	info->centralDirectoryEndRecvd = 0;
	info->centralDirectoryDesc = NULL;
	info->progressCallback = NULL;

	info->hCurl = curl_easy_init();

	curl_easy_setopt(info->hCurl, CURLOPT_URL, info->url);
	curl_easy_setopt(info->hCurl, CURLOPT_FOLLOWLOCATION, 1);
	curl_easy_setopt(info->hCurl, CURLOPT_NOBODY, 1);
	curl_easy_setopt(info->hCurl, CURLOPT_WRITEFUNCTION, dummyReceive);

	if(strncmp(info->url, "file://", 7) == 0)
	{
		char* filePath = (char*) curl_easy_unescape(info->hCurl, info->url + 7, 0,  NULL);
		FILE* f = fopen(filePath, "rb");
		if(!f)
		{
			curl_free(filePath);
			curl_easy_cleanup(info->hCurl);
			free(info->url);
			free(info);

			return NULL;
		}

		fseek(f, 0, SEEK_END);
		info->length = ftell(f);
		fclose(f);

		curl_free(filePath);
	}
	else
	{
		curl_easy_perform(info->hCurl);

		double dFileLength;
		curl_easy_getinfo(info->hCurl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &dFileLength);
		info->length = dFileLength;
	}

	char sRange[100];
	uint64_t start;

	if(info->length > (0xffff + sizeof(EndOfCD)))
		start = info->length - 0xffff - sizeof(EndOfCD);
	else
		start = 0;

	uint64_t end = info->length - 1;

	sprintf(sRange, "%" PRIu64 "-%" PRIu64, start, end);

	curl_easy_setopt(info->hCurl, CURLOPT_WRITEFUNCTION, receiveCentralDirectoryEnd);
	curl_easy_setopt(info->hCurl, CURLOPT_WRITEDATA, info);
	curl_easy_setopt(info->hCurl, CURLOPT_RANGE, sRange);
	curl_easy_setopt(info->hCurl, CURLOPT_HTTPGET, 1);

	curl_easy_perform(info->hCurl);

	char* cur;
	for(cur = info->centralDirectoryEnd; cur < (info->centralDirectoryEnd + (end - start - 1)); cur++)
	{
		EndOfCD* candidate = (EndOfCD*) cur;
		uint32_t signature = candidate->signature;
		FLIPENDIANLE(signature);
		if(signature == 0x06054b50)
		{
			uint16_t lenComment = candidate->lenComment;
			FLIPENDIANLE(lenComment);
			if((cur + lenComment + sizeof(EndOfCD)) == (info->centralDirectoryEnd + info->centralDirectoryEndRecvd))
			{
				FLIPENDIANLE(candidate->diskNo);
				FLIPENDIANLE(candidate->CDDiskNo);
				FLIPENDIANLE(candidate->CDDiskEntries);
				FLIPENDIANLE(candidate->CDEntries);
				FLIPENDIANLE(candidate->CDSize);
				FLIPENDIANLE(candidate->CDOffset);
				FLIPENDIANLE(candidate->lenComment);
				info->centralDirectoryDesc = candidate;
				break;
			}
		}

	}

	if(info->centralDirectoryDesc)
	{
		info->centralDirectory = malloc(info->centralDirectoryDesc->CDSize);
		start = info->centralDirectoryDesc->CDOffset;
		end = start + info->centralDirectoryDesc->CDSize - 1;
		sprintf(sRange, "%" PRIu64 "-%" PRIu64, start, end);
		curl_easy_setopt(info->hCurl, CURLOPT_WRITEFUNCTION, receiveCentralDirectory);
		curl_easy_setopt(info->hCurl, CURLOPT_WRITEDATA, info);
		curl_easy_setopt(info->hCurl, CURLOPT_RANGE, sRange);
		curl_easy_setopt(info->hCurl, CURLOPT_HTTPGET, 1);
		curl_easy_perform(info->hCurl);

		flipFiles(info);

		return info;
	}
	else
	{
		curl_easy_cleanup(info->hCurl);
		free(info->url);
		free(info);
		return NULL;
	}
}

CDFile* PartialZipFindFile(ZipInfo* info, const char* fileName)
{
	char* cur = info->centralDirectory;
	unsigned int i;
	for(i = 0; i < info->centralDirectoryDesc->CDEntries; i++)
	{
		CDFile* candidate = (CDFile*) cur;
		const char* curFileName = cur + sizeof(CDFile);

		if(strlen(fileName) == candidate->lenFileName && strncmp(fileName, curFileName, candidate->lenFileName) == 0)
			return candidate;

		cur += sizeof(CDFile) + candidate->lenFileName + candidate->lenExtra + candidate->lenComment;
	}

	return NULL;
}

CDFile* PartialZipListFiles(ZipInfo* info)
{
	char* cur = info->centralDirectory;
	unsigned int i;
	for(i = 0; i < info->centralDirectoryDesc->CDEntries; i++)
	{
		CDFile* candidate = (CDFile*) cur;
		const char* curFileName = cur + sizeof(CDFile);
		char* myFileName = (char*) malloc(candidate->lenFileName + 1);
		memcpy(myFileName, curFileName, candidate->lenFileName);
		myFileName[candidate->lenFileName] = '\0';

		printf("%s: method: %d, compressed size: %d, size: %d\n", myFileName, candidate->method,
				candidate->compressedSize, candidate->size);

		free(myFileName);

		cur += sizeof(CDFile) + candidate->lenFileName + candidate->lenExtra + candidate->lenComment;
	}

	return NULL;
}

unsigned char* PartialZipGetFile(ZipInfo* info, CDFile* file, char* sizeToDownload)
{
	LocalFile localHeader;
	LocalFile* pLocalHeader = &localHeader;

	uint64_t start = file->offset;
	uint64_t end = file->offset + sizeof(LocalFile) - 1;
	char sRange[100];
	sprintf(sRange, "%" PRIu64 "-%" PRIu64, start, end);

	void* pFileHeader[] = {pLocalHeader, NULL, NULL, NULL};

    curl_easy_setopt(info->hCurl, CURLOPT_URL, info->url);
	curl_easy_setopt(info->hCurl, CURLOPT_FOLLOWLOCATION, 1);
	curl_easy_setopt(info->hCurl, CURLOPT_WRITEFUNCTION, receiveData);
	curl_easy_setopt(info->hCurl, CURLOPT_WRITEDATA, &pFileHeader);
	curl_easy_setopt(info->hCurl, CURLOPT_RANGE, sRange);
	curl_easy_setopt(info->hCurl, CURLOPT_HTTPGET, 1);
	curl_easy_perform(info->hCurl);

	FLIPENDIANLE(localHeader.signature);
	FLIPENDIANLE(localHeader.versionExtract);
	// FLIPENDIANLE(localHeader.flags);
	FLIPENDIANLE(localHeader.method);
	FLIPENDIANLE(localHeader.modTime);
	FLIPENDIANLE(localHeader.modDate);
	// FLIPENDIANLE(localHeader.crc32);
	FLIPENDIANLE(localHeader.compressedSize);
	FLIPENDIANLE(localHeader.size);
	FLIPENDIANLE(localHeader.lenFileName);
	FLIPENDIANLE(localHeader.lenExtra);

	if(sizeToDownload != NULL) {
		file->compressedSize = atoi(sizeToDownload);
		file->size = atoi(sizeToDownload);
	}

	unsigned char* fileData = (unsigned char*) malloc(file->compressedSize);
	size_t progress = 0;
	void* pFileData[] = {fileData, info, file, &progress};

	start = file->offset + sizeof(LocalFile) + localHeader.lenFileName + localHeader.lenExtra;
	end = start + file->compressedSize - 1;
	sprintf(sRange, "%" PRIu64 "-%" PRIu64, start, end);

	curl_easy_setopt(info->hCurl, CURLOPT_WRITEFUNCTION, receiveData);
	curl_easy_setopt(info->hCurl, CURLOPT_WRITEDATA, pFileData);
	curl_easy_setopt(info->hCurl, CURLOPT_RANGE, sRange);
	curl_easy_setopt(info->hCurl, CURLOPT_HTTPGET, 1);
	curl_easy_perform(info->hCurl);

	if(file->method == 8)
	{
		unsigned char* uncData = (unsigned char*) malloc(file->size);
		z_stream strm;
		strm.zalloc = Z_NULL;
		strm.zfree = Z_NULL;
		strm.opaque = Z_NULL;
		strm.avail_in = 0;
		strm.next_in = NULL;

		inflateInit2(&strm, -MAX_WBITS);
		strm.avail_in = file->compressedSize;
		strm.next_in = fileData;
		strm.avail_out = file->size;
		strm.next_out = uncData;
		inflate(&strm, Z_FINISH);
		inflateEnd(&strm);
		free(fileData);
		fileData = uncData;
	}
	return fileData;
}

void PartialZipSetProgressCallback(ZipInfo* info, PartialZipProgressCallback progressCallback)
{
	info->progressCallback = progressCallback;
}

void PartialZipRelease(ZipInfo* info)
{
	curl_easy_cleanup(info->hCurl);
	free(info->centralDirectory);
	free(info->url);
	free(info);

	curl_global_cleanup();
}