Add files via upload

QRCode/pingout.cpp

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+/* 
+ * Tiny PNG Output (C++)
+ * 
+ * Copyright (c) 2018 Project Nayuki
+ * https://www.nayuki.io/page/tiny-png-output
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program (see COPYING.txt and COPYING.LESSER.txt).
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma warning(disable:4146)
+
+#include <algorithm>
+#include <cassert>
+#include <limits>
+#include <stdexcept>
+#include "pngout.hpp"
+
+#pragma warning(disable:C4146)
+
+using std::uint8_t;
+using std::uint16_t;
+using std::uint32_t;
+using std::uint64_t;
+using std::size_t;
+
+
+TinyPngOut::TinyPngOut(uint32_t w, uint32_t h, std::ostream &out) :
+		// Set most of the fields
+		width(w),
+		height(h),
+		output(out),
+		positionX(0),
+		positionY(0),
+		deflateFilled(0),
+		adler(1) {
+
+	// Check arguments
+	if (width == 0 || height == 0)
+		throw std::domain_error("Zero width or height");
+
+	// Compute and check data siezs
+	uint64_t lineSz = static_cast<uint64_t>(width) * 3 + 1;
+	if (lineSz > UINT32_MAX)
+		throw std::length_error("Image too large");
+	lineSize = static_cast<uint32_t>(lineSz);
+
+	uint64_t uncompRm = lineSize * height;
+	if (uncompRm > UINT32_MAX)
+		throw std::length_error("Image too large");
+	uncompRemain = static_cast<uint32_t>(uncompRm);
+
+	uint32_t numBlocks = uncompRemain / DEFLATE_MAX_BLOCK_SIZE;
+	if (uncompRemain % DEFLATE_MAX_BLOCK_SIZE != 0)
+		numBlocks++;  // Round up
+	// 5 bytes per DEFLATE uncompressed block header, 2 bytes for zlib header, 4 bytes for zlib Adler-32 footer
+	uint64_t idatSize = static_cast<uint64_t>(numBlocks) * 5 + 6;
+	idatSize += uncompRemain;
+	if (idatSize > static_cast<uint32_t>(INT32_MAX))
+		throw std::length_error("Image too large");
+
+	// Write header (not a pure header, but a couple of things concatenated together)
+	uint8_t header[] = {  // 43 bytes long
+		// PNG header
+		0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A,
+		// IHDR chunk
+		0x00, 0x00, 0x00, 0x0D,
+		0x49, 0x48, 0x44, 0x52,
+		0, 0, 0, 0,  // 'width' placeholder
+		0, 0, 0, 0,  // 'height' placeholder
+		0x08, 0x02, 0x00, 0x00, 0x00,
+		0, 0, 0, 0,  // IHDR CRC-32 placeholder
+		// IDAT chunk
+		0, 0, 0, 0,  // 'idatSize' placeholder
+		0x49, 0x44, 0x41, 0x54,
+		// DEFLATE data
+		0x08, 0x1D,
+	};
+	putBigUint32(width, &header[16]);
+	putBigUint32(height, &header[20]);
+	putBigUint32(idatSize, &header[33]);
+	crc = 0;
+	crc32(&header[12], 17);
+	putBigUint32(crc, &header[29]);
+	write(header);
+
+	crc = 0;
+	crc32(&header[37], 6);  // 0xD7245B6B
+}
+
+
+void TinyPngOut::write(const uint8_t pixels[], size_t count) {
+	if (count > SIZE_MAX / 3)
+		throw std::length_error("Invalid argument");
+	count *= 3;  // Convert pixel count to byte count
+	while (count > 0) {
+		if (pixels == nullptr)
+			throw std::invalid_argument("Null pointer");
+		if (positionY >= height)
+			throw std::logic_error("All image pixels already written");
+
+		if (deflateFilled == 0) {  // Start DEFLATE block
+			uint16_t size = DEFLATE_MAX_BLOCK_SIZE;
+			if (uncompRemain < size)
+				size = static_cast<uint16_t>(uncompRemain);
+			const uint8_t header[] = {  // 5 bytes long
+				static_cast<uint8_t>(uncompRemain <= DEFLATE_MAX_BLOCK_SIZE ? 1 : 0),
+				static_cast<uint8_t>(size >> 0),
+				static_cast<uint8_t>(size >> 8),
+				static_cast<uint8_t>((size >> 0) ^ 0xFF),
+				static_cast<uint8_t>((size >> 8) ^ 0xFF),
+			};
+			write(header);
+			crc32(header, sizeof(header) / sizeof(header[0]));
+		}
+		assert(positionX < lineSize && deflateFilled < DEFLATE_MAX_BLOCK_SIZE);
+
+		if (positionX == 0) {  // Beginning of line - write filter method byte
+			uint8_t b[] = {0};
+			write(b);
+			crc32(b, 1);
+			adler32(b, 1);
+			positionX++;
+			uncompRemain--;
+			deflateFilled++;
+
+		} else {  // Write some pixel bytes for current line
+			uint16_t n = DEFLATE_MAX_BLOCK_SIZE - deflateFilled;
+			if (lineSize - positionX < n)
+				n = static_cast<uint16_t>(lineSize - positionX);
+			if (count < n)
+				n = static_cast<uint16_t>(count);
+			if (static_cast<std::make_unsigned<std::streamsize>::type>(std::numeric_limits<std::streamsize>::max()) < std::numeric_limits<decltype(n)>::max())
+				n = std::min(n, static_cast<decltype(n)>(std::numeric_limits<std::streamsize>::max()));
+			assert(n > 0);
+			output.write(reinterpret_cast<const char*>(pixels), static_cast<std::streamsize>(n));
+
+			// Update checksums
+			crc32(pixels, n);
+			adler32(pixels, n);
+
+			// Increment positions
+			count -= n;
+			pixels += n;
+			positionX += n;
+			uncompRemain -= n;
+			deflateFilled += n;
+		}
+
+		if (deflateFilled >= DEFLATE_MAX_BLOCK_SIZE)
+			deflateFilled = 0;  // End current block
+
+		if (positionX == lineSize) {  // Increment line
+			positionX = 0;
+			positionY++;
+			if (positionY == height) {  // Reached end of pixels
+				uint8_t footer[] = {  // 20 bytes long
+					0, 0, 0, 0,  // DEFLATE Adler-32 placeholder
+					0, 0, 0, 0,  // IDAT CRC-32 placeholder
+					// IEND chunk
+					0x00, 0x00, 0x00, 0x00,
+					0x49, 0x45, 0x4E, 0x44,
+					0xAE, 0x42, 0x60, 0x82,
+				};
+				putBigUint32(adler, &footer[0]);
+				crc32(&footer[0], 4);
+				putBigUint32(crc, &footer[4]);
+				write(footer);
+			}
+		}
+	}
+}
+
+
+void TinyPngOut::crc32(const uint8_t data[], size_t len) {
+	crc = ~crc;
+	for (size_t i = 0; i < len; i++) {
+		for (int j = 0; j < 8; j++) {  // Inefficient bitwise implementation, instead of table-based
+			uint32_t bit = (crc ^ (data[i] >> j)) & 1;
+			crc = (crc >> 1) ^ ((-bit) & UINT32_C(0xEDB88320));
+		}
+	}
+	crc = ~crc;
+}
+
+
+void TinyPngOut::adler32(const uint8_t data[], size_t len) {
+	uint32_t s1 = adler & 0xFFFF;
+	uint32_t s2 = adler >> 16;
+	for (size_t i = 0; i < len; i++) {
+		s1 = (s1 + data[i]) % 65521;
+		s2 = (s2 + s1) % 65521;
+	}
+	adler = s2 << 16 | s1;
+}
+
+
+void TinyPngOut::putBigUint32(uint32_t val, uint8_t array[4]) {
+	for (int i = 0; i < 4; i++)
+		array[i] = static_cast<uint8_t>(val >> ((3 - i) * 8));
+}
+

QRCode/pngout.hpp

@@ -0,0 +1,98 @@
+/* 
+ * Tiny PNG Output (C++)
+ * 
+ * Copyright (c) 2018 Project Nayuki
+ * https://www.nayuki.io/page/tiny-png-output
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program (see COPYING.txt and COPYING.LESSER.txt).
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <ostream>
+
+
+/* 
+ * Takes image pixel data in raw RGB8.8.8 format and writes a PNG file to a byte output stream.
+ */
+class TinyPngOut final {
+
+    /*---- Fields ----*/
+
+	// Immutable configuration
+	private: std::uint32_t width;   // Measured in pixels
+	private: std::uint32_t height;  // Measured in pixels
+	private: std::uint32_t lineSize;  // Measured in bytes, equal to (width * 3 + 1)
+
+	// Running state
+	private: std::ostream &output;
+	private: std::uint32_t positionX;      // Next byte index in current line
+	private: std::uint32_t positionY;      // Line index of next byte
+	private: std::uint32_t uncompRemain;   // Number of uncompressed bytes remaining
+	private: std::uint16_t deflateFilled;  // Bytes filled in the current block (0 <= n < DEFLATE_MAX_BLOCK_SIZE)
+	private: std::uint32_t crc;    // Primarily for IDAT chunk
+	private: std::uint32_t adler;  // For DEFLATE data within IDAT
+
+
+
+	/*---- Public constructor and method ----*/
+
+	/* 
+	 * Creates a PNG writer with the given width and height (both non-zero) and byte output stream.
+	 * TinyPngOut will leave the output stream still open once it finishes writing the PNG file data.
+	 * Throws an exception if the dimensions exceed certain limits (e.g. w * h > 700 million).
+	 */
+	public: explicit TinyPngOut(std::uint32_t w, std::uint32_t h, std::ostream &out);
+
+
+	/* 
+	 * Writes 'count' pixels from the given array to the output stream. This reads count*3
+	 * bytes from the array. Pixels are presented from top to bottom, left to right, and with
+	 * subpixels in RGB order. This object keeps track of how many pixels were written and
+	 * various position variables. It is an error to write more pixels in total than width*height.
+	 * Once exactly width*height pixels have been written with this TinyPngOut object,
+	 * there are no more valid operations on the object and it should be discarded.
+	 */
+	public: void write(const std::uint8_t pixels[], size_t count);
+
+
+
+	/*---- Private checksum methods ----*/
+
+	// Reads the 'crc' field and updates its value based on the given array of new data.
+	private: void crc32(const std::uint8_t data[], size_t len);
+
+
+	// Reads the 'adler' field and updates its value based on the given array of new data.
+	private: void adler32(const std::uint8_t data[], size_t len);
+
+
+
+	/*---- Private utility members ----*/
+
+	private: template <std::size_t N>
+	void write(const std::uint8_t (&data)[N]) {
+		output.write(reinterpret_cast<const char*>(data), sizeof(data));
+	}
+
+
+	private: static void putBigUint32(std::uint32_t val, std::uint8_t array[4]);
+
+
+	private: static constexpr std::uint16_t DEFLATE_MAX_BLOCK_SIZE = 65535;
+
+};