pdvzip update

src/adjustZip.cpp

@@ -0,0 +1,67 @@
+// ZIP file has been moved to another location. We need to find and adjust the ZIP file record offsets to their new location.
+
+#include "adjustZip.h"
+#include "searchFunc.h"
+#include "getByteValue.h"    
+#include <iterator>         
+
+void adjustZipOffsets(std::vector<uint8_t>& vec, const uint32_t VEC_SIZE, const uint32_t LAST_IDAT_INDEX) {
+	auto valueUpdater = [](std::vector<uint8_t>& vec, uint32_t value_insert_index, const uint32_t NEW_VALUE, uint8_t bits) {
+		while (bits) { vec[value_insert_index--] = (NEW_VALUE >> (bits -= 8)) & 0xff; }
+	};
+
+	constexpr uint8_t
+		SIG_LENGTH 			= 4,
+		CENTRAL_LOCAL_INDEX_DIFF 	= 45,
+		END_CENTRAL_START_INDEX_DIFF 	= 19,
+		ZIP_COMMENT_LENGTH_INDEX_DIFF 	= 21,
+		ZIP_RECORDS_INDEX_DIFF 		= 11,
+		ZIP_LOCAL_INDEX_DIFF 		= 4,
+		INCREMENT_SEARCH_INDEX 		= 1,
+		PNG_IEND_LENGTH 		= 16,
+		BYTE_LENGTH 			= 2;
+
+	constexpr std::array<uint8_t, SIG_LENGTH>
+		ZIP_LOCAL_SIG		{ 0x50, 0x4B, 0x03, 0x04 },
+		END_CENTRAL_DIR_SIG	{ 0x50, 0x4B, 0x05, 0x06 },
+		START_CENTRAL_DIR_SIG	{ 0x50, 0x4B, 0x01, 0x02 };
+
+	// Starting from the end of the vector storing the archive, a single reverse search of the contents finds the "end_central directory" index. 	
+	const uint32_t END_CENTRAL_DIR_INDEX = VEC_SIZE - static_cast<uint32_t>(std::distance(vec.rbegin(), std::search(vec.rbegin(), vec.rend(), 
+			END_CENTRAL_DIR_SIG.rbegin(), END_CENTRAL_DIR_SIG.rend()))) - SIG_LENGTH;
+	uint32_t 
+		total_zip_records_index = END_CENTRAL_DIR_INDEX + ZIP_RECORDS_INDEX_DIFF,
+		end_central_start_index = END_CENTRAL_DIR_INDEX + END_CENTRAL_START_INDEX_DIFF,
+		zip_comment_length_index = END_CENTRAL_DIR_INDEX + ZIP_COMMENT_LENGTH_INDEX_DIFF,
+		zip_record_local_index = LAST_IDAT_INDEX + ZIP_LOCAL_INDEX_DIFF,
+		start_central_dir_index = VEC_SIZE;
+
+	bool isBigEndian = false;
+
+	uint16_t 
+		total_zip_records = getByteValue(vec, total_zip_records_index, BYTE_LENGTH, isBigEndian),
+		zip_comment_length = getByteValue(vec, zip_comment_length_index, BYTE_LENGTH, isBigEndian) + PNG_IEND_LENGTH, // Extend comment length to include end bytes of PNG. Important for JAR files.
+		record_count = 0;
+
+	uint8_t value_bit_length = 16;
+	valueUpdater(vec, zip_comment_length_index, zip_comment_length, value_bit_length); 
+
+	// Find the 1st / main "start_central directory" index location by iterating over the vector, working backwards from the vector's content.
+	// By starting the search from the end of the vector, we know we are already within the record section data of the archive and this
+	// avoids the possibility of a "false-positive" signature match, if we were to search the vector from the beginning and read through the image and file data first.
+	while (record_count++ != total_zip_records) {
+		start_central_dir_index = VEC_SIZE - static_cast<uint32_t>(std::distance(vec.rbegin(), std::search(vec.rbegin() + (VEC_SIZE - start_central_dir_index + SIG_LENGTH),
+			vec.rend(), START_CENTRAL_DIR_SIG.rbegin(), START_CENTRAL_DIR_SIG.rend()))) - SIG_LENGTH;
+	}
+
+	uint32_t central_dir_local_index = start_central_dir_index + CENTRAL_LOCAL_INDEX_DIFF;
+
+	value_bit_length = 32;
+	valueUpdater(vec, end_central_start_index, start_central_dir_index, value_bit_length);  // Update end_central index location with start_central directory offset.
+
+	while (total_zip_records--) {
+		valueUpdater(vec, central_dir_local_index, zip_record_local_index, value_bit_length); // Write the new zip_record index/offset to the central_dir_local index location.
+		zip_record_local_index = searchFunc(vec, zip_record_local_index, INCREMENT_SEARCH_INDEX, ZIP_LOCAL_SIG); // Get the next zip_record index/offset.
+		central_dir_local_index = searchFunc(vec, central_dir_local_index, INCREMENT_SEARCH_INDEX, START_CENTRAL_DIR_SIG) + CENTRAL_LOCAL_INDEX_DIFF; // Get the next central_dir index location.
+	}
+}

src/adjustZip.h

@@ -0,0 +1,6 @@
+#pragma once
+
+#include <vector>
+#include <cstdint>
+
+void adjustZipOffsets(std::vector<uint8_t>&, const uint32_t, const uint32_t);

src/compile_pdvzip.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+# compile_pdvzip.sh
+
+g++ main.cpp lodepng/lodepng.cpp programArgs.cpp fileChecks.cpp copyChunks.cpp \
+    information.cpp adjustZip.cpp writeFile.cpp getByteValue.cpp valueUpdater.cpp \
+    crc32.cpp resizeImage.cpp extractionScripts.cpp pdvZip.cpp \
+    -Wall -O2 -s -o pdvzip
+
+if [ $? -eq 0 ]; then
+    echo "Compilation successful. Executable 'pdvzip' created."
+else
+    echo "Compilation failed."
+    exit 1
+fi

src/copyChunks.cpp

@@ -0,0 +1,84 @@
+
+#include "copyChunks.h"
+#include "searchFunc.h"
+#include "getByteValue.h"     
+#include <iterator>     
+#include <stdexcept>    
+#include <utility>            
+
+void copyEssentialChunks(std::vector<uint8_t>& image_vec) {
+	constexpr uint8_t SIG_LENGTH = 4;
+
+	constexpr std::array<uint8_t, SIG_LENGTH> 
+		PLTE_SIG {0x50, 0x4C, 0x54, 0x45},
+		TRNS_SIG {0x74, 0x52, 0x4E, 0x53},
+		IDAT_SIG {0x49, 0x44, 0x41, 0x54};
+
+    	constexpr uint8_t
+		PNG_FIRST_BYTES = 33,
+		PNG_IEND_BYTES = 12,
+		PNG_COLOR_TYPE_INDEX = 0x19,
+		PNG_TRUECOLOR_VAL = 2,
+		PNG_INDEXED_COLOR_VAL = 3;
+
+    	const size_t IMAGE_VEC_SIZE = image_vec.size();
+
+    	const uint32_t FIRST_IDAT_INDEX = searchFunc(image_vec, 0, 0, IDAT_SIG);
+
+    	if (FIRST_IDAT_INDEX == IMAGE_VEC_SIZE) {
+    		throw std::runtime_error("Image Error: Invalid or corrupt image file. IDAT chunk not found.");
+    	}
+
+    	std::vector<uint8_t> copied_image_vec;
+    	copied_image_vec.reserve(IMAGE_VEC_SIZE);     
+
+    	std::copy_n(image_vec.begin(), PNG_FIRST_BYTES, std::back_inserter(copied_image_vec));	
+
+    	auto copy_chunk_type = [&](const auto& chunk_signature) {
+		constexpr uint8_t 
+			PNG_CHUNK_FIELDS_COMBINED_LENGTH = 12, // Size_field + Name_field + CRC_field.
+			PNG_CHUNK_LENGTH_FIELD_SIZE = 4,
+			SEARCH_INCREMENT = 5;
+
+        	uint32_t 
+			chunk_search_pos = 0,
+			chunk_length_pos = 0,
+			chunk_count = 0,
+			chunk_length = 0;
+
+		bool isBigEndian = true;
+
+        	while (true) {
+            		chunk_search_pos = searchFunc(image_vec, chunk_search_pos, SEARCH_INCREMENT, chunk_signature);
+
+			if (chunk_signature != IDAT_SIG && chunk_search_pos > FIRST_IDAT_INDEX) {
+				if (chunk_signature == PLTE_SIG && !chunk_count) {
+					throw std::runtime_error("Image Error: Invalid or corrupt image file. PLTE chunk not found.");
+				} else {
+					break;
+				}
+			} else if (chunk_search_pos == IMAGE_VEC_SIZE) {
+				break;
+			}
+
+			++chunk_count;
+			chunk_length_pos = chunk_search_pos - PNG_CHUNK_LENGTH_FIELD_SIZE;
+            		chunk_length = getByteValue(image_vec, chunk_length_pos, PNG_CHUNK_LENGTH_FIELD_SIZE, isBigEndian) + PNG_CHUNK_FIELDS_COMBINED_LENGTH;
+	    		std::copy_n(image_vec.begin() + chunk_length_pos, chunk_length, std::back_inserter(copied_image_vec));
+        	}
+    	};
+
+	if (image_vec[PNG_COLOR_TYPE_INDEX] == PNG_INDEXED_COLOR_VAL) {
+    		copy_chunk_type(PLTE_SIG);
+    		copy_chunk_type(TRNS_SIG);
+	}
+
+	if (image_vec[PNG_COLOR_TYPE_INDEX] == PNG_TRUECOLOR_VAL) {
+		copy_chunk_type(TRNS_SIG);
+	}
+
+    	copy_chunk_type(IDAT_SIG);
+
+    	std::copy_n(image_vec.end() - PNG_IEND_BYTES, PNG_IEND_BYTES, std::back_inserter(copied_image_vec));
+    	image_vec = std::move(copied_image_vec);
+}

src/copyChunks.h

@@ -0,0 +1,6 @@
+#pragma once
+
+#include <vector>
+#include <cstdint>
+
+void copyEssentialChunks(std::vector<uint8_t>&);

src/crc32.cpp

@@ -0,0 +1,36 @@
+// The following function (slightly modified) to compute CRC32 for PNG chunks is taken from: https://www.w3.org/TR/2003/REC-PNG-20031110/#D-CRCAppendix 
+
+#include "crc32.h"
+#include <array>   
+
+uint32_t crcUpdate(uint8_t* buf, uint32_t buf_length) {
+	constexpr uint16_t TABLE_LENGTH = 256;
+
+	constexpr std::array<uint32_t, TABLE_LENGTH> CRC_TABLE {
+		0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x76DC419,  0x706AF48F, 0xE963A535, 0x9E6495A3, 0xEDB8832,  0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x9B64C2B,  0x7EB17CBD,
+		0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
+		0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 0x35B5A8FA, 0x42B2986C,
+		0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
+		0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190, 0x1DB7106,  0x98D220BC, 0xEFD5102A, 0x71B18589, 0x6B6B51F,
+		0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0xF00F934,  0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x86D3D2D,  0x91646C97, 0xE6635C01, 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
+		0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65, 0x4DB26158, 0x3AB551CE,
+		0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
+		0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F, 0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81,
+		0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6, 0x3B6E20C,  0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x4DB2615,  0x73DC1683, 0xE3630B12, 0x94643B84, 0xD6D6A3E,  0x7A6A5AA8,
+		0xE40ECF0B, 0x9309FF9D, 0xA00AE27,  0x7D079EB1, 0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0,
+		0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
+		0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703,
+		0x220216B9, 0x5505262F, 0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x26D930A,
+		0x9C0906A9, 0xEB0E363F, 0x72076785, 0x5005713,  0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0xCB61B38,  0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0xBDBDF21,  0x86D3D2D4, 0xF1D4E242,
+		0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
+		0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5,
+		0x47B2CF7F, 0x30B5FFE9, 0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
+		0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D };
+
+	uint32_t 
+		buf_index{},
+		crc_value = 0xffffffffL;
+
+	while (buf_length--) { crc_value = CRC_TABLE[(crc_value ^ buf[buf_index++]) & 0xff] ^ (crc_value >> 8); }
+	return (crc_value) ^ 0xffffffffL;
+}

src/crc32.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include <cstdint>
+
+uint32_t crcUpdate(uint8_t*, uint32_t);