core/PdfFile/SrcWriter/Utils.cpp

/*
 * Copyright (C) Ascensio System SIA, 2009-2026
 *
 * This program is a free software product. You can redistribute it and/or
 * modify it under the terms of the GNU Affero General Public License (AGPL)
 * version 3 as published by the Free Software Foundation, together with the
 * additional terms provided in the LICENSE file.
 *
 * This program is distributed WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. For
 * details, see the GNU AGPL at: https://www.gnu.org/licenses/agpl-3.0.html
 *
 * You can contact Ascensio System SIA by email at info@onlyoffice.com
 * or by postal mail at 20A-6 Ernesta Birznieka-Upisha Street, Riga,
 * LV-1050, Latvia, European Union.
 *
 * The interactive user interfaces in modified versions of the Program
 * are required to display Appropriate Legal Notices in accordance with
 * Section 5 of the GNU AGPL version 3.
 *
 * No trademark rights are granted under this License.
 *
 * All non-code elements of the Product, including illustrations,
 * icon sets, and technical writing content, are licensed under the
 * Creative Commons Attribution-ShareAlike 4.0 International License:
 * https://creativecommons.org/licenses/by-sa/4.0/legalcode
 *
 * This license applies only to such non-code elements and does not
 * modify or replace the licensing terms applicable to the Program's
 * source code, which remains licensed under the GNU Affero General
 * Public License v3.
 *
 * SPDX-License-Identifier: AGPL-3.0-only
 */
#include "Utils.h"
#include <vector>
#include <ctime>
#include <cwctype>

namespace PdfWriter
{
	BYTE* MemCpy(BYTE* pDst, const BYTE *pSrc, unsigned int unLen)
	{
		if (unLen > 0)
			memcpy(pDst, pSrc, unLen);

		return pDst;
	}
	int   StrLen(const char* sString, int nMaxLen)
	{
		int nLen = 0;

		if (!sString)
			return 0;

		while (*sString != 0 && (nMaxLen < 0 || nLen < nMaxLen))
		{
			sString++;
			nLen++;
		}

		return nLen;
	}
	BYTE* StrCpy(char* sDst, const char* sSrc, char* pEnd)
	{
		if (NULL != sSrc)
		{
			while (pEnd > sDst && *sSrc != 0)
				*sDst++ = *sSrc++;
		}

		*sDst = 0;

		return (BYTE*)sDst;
	}
	void  MemSet(void *pBuf, BYTE nChar, unsigned int unLen)
	{
		memset(pBuf, nChar, unLen);
	}
	char* ItoA  (char *str, int nVal, char *eptr)
	{
		char* sTemp;
		char sBuf[INT_LEN + 1];

		if (nVal < 0)
		{
			if (nVal < LIMIT_MIN_INT)
				nVal = LIMIT_MIN_INT;
			*str++ = '-';
			nVal = -nVal;
		}
		else if (nVal > LIMIT_MAX_INT)
		{
			nVal = LIMIT_MAX_INT;
		}
		else if (nVal == 0)
		{
			*str++ = '0';
		}

		sTemp = sBuf + INT_LEN;
		*sTemp-- = 0;

		while (nVal > 0)
		{
			*sTemp = (char)(nVal % 10) + '0';
			nVal /= 10;
			sTemp--;
		}

		sTemp++;
		while (str < eptr && *sTemp != 0)
			*str++ = *sTemp++;

		*str = 0;

		return str;
	}
	char* ItoA2 (char  *str, unsigned int nVal, unsigned int nLen)
	{
		char* sT;
		char* sU;

		if (nVal > LIMIT_MAX_INT)
			nVal = LIMIT_MAX_INT;

		sU = str + nLen - 1;
		*sU = 0;
		sT = sU - 1;
		while (nVal > 0 && sT >= str)
		{
			*sT = (char)(nVal % 10) + '0';
			nVal /= 10;
			sT--;
		}

		while (str <= sT)
			*sT-- = '0';

		return str + nLen - 1;
	}
	int   StrCmp(const char* s1, const char* s2)
	{
		if (!s1 || !s2)
		{
			if (!s1 && !s2)
				return 0;
			if (!s1 && s2)
				return -1;
			else
				return 1;
		}

		while (*s1 == *s2)
		{
			s1++;
			s2++;
			if (*s1 == 0 || *s2 == 0)
				break;
		}

		return (BYTE)*s1 - (BYTE)*s2;
	}
	char* FtoA  (char* sDst, double dVal, char* pEnd)
	{
		int nNPartVal = 0;
		int nFPartVal = 0;
		char sBuf[REAL_LEN + 1];
		char* sptr = sDst;
		char* sTemp;

		unsigned int nIndex = 0;

		if (dVal > LIMIT_MAX_REAL)
			dVal = LIMIT_MAX_REAL;
		else if (dVal < LIMIT_MIN_REAL)
			dVal = LIMIT_MIN_REAL;

		sTemp = sBuf + REAL_LEN;
		*sTemp-- = 0;

		if (dVal < 0)
		{
			*sDst++ = '-';
			dVal = -dVal;
		}

		// Separate integer and fractional parts
		nNPartVal = (int)(dVal + 0.000005);
		nFPartVal = (int)((float)(dVal - nNPartVal + 0.000005) * 100000);

		// Write fractional part
		for (nIndex = 0; nIndex < 5; nIndex++)
		{
			*sTemp = (char)(nFPartVal % 10) + '0';
			nFPartVal /= 10;
			sTemp--;
		}

		// Write integer part
		*sTemp-- = '.';
		*sTemp = '0';
		if (nNPartVal == 0)
			sTemp--;

		while (nNPartVal > 0)
		{
			*sTemp = (char)(nNPartVal % 10) + '0';
			nNPartVal /= 10;
			sTemp--;
		}

		sTemp++;

		while (sDst <= pEnd && *sTemp != 0)
			*sDst++ = *sTemp++;
		sDst--;


		// TODO: when removing zeros during shift, the end of the string also needs to be cleaned
		// example number -00.90123 result "-0.901234"

		while (sDst > sptr)
		{
			if (*sDst == '0')
				*sDst = 0;
			else {
				if (*sDst == '.')
					*sDst = 0;
				break;
			}
			sDst--;
		}

		return (*sDst == 0) ? sDst : ++sDst;
	}
	void  UIntChangeBit(unsigned int& nValue, short nBit)
	{
		// Work only with 4-byte numbers
		if (nBit < 0 || nBit > 31)
			return;

		unsigned int unBitNum = 1 << nBit;
		if (nValue & unBitNum)
			nValue ^= unBitNum;
		else
			nValue |= unBitNum;
	}
	std::string DateNow()
	{
		char sTemp[DATE_TIME_STR_LEN + 1];
		char* pTemp = NULL;

		MemSet(sTemp, 0, DATE_TIME_STR_LEN + 1);
		time_t oTime = time(0);
		struct tm* oNow = gmtime(&oTime);

		pTemp = (char*)MemCpy((BYTE*)sTemp, (BYTE*)"D:", 2);
		*pTemp++;
		*pTemp++;
		pTemp = ItoA2(pTemp, oNow->tm_year + 1900, 5);
		pTemp = ItoA2(pTemp, oNow->tm_mon + 1, 3);
		pTemp = ItoA2(pTemp, oNow->tm_mday, 3);
		pTemp = ItoA2(pTemp, oNow->tm_hour, 3);
		pTemp = ItoA2(pTemp, oNow->tm_min, 3);
		pTemp = ItoA2(pTemp, oNow->tm_sec, 3);
		*pTemp++ = '+';
		pTemp = ItoA2(pTemp, 0, 3);
		*pTemp++ = '\'';
		pTemp = ItoA2(pTemp, 0, 3);
		*pTemp++ = '\'';
		*pTemp = 0;

		std::string sRes(sTemp);
		return sRes;
	}
	std::wstring NormalizeWhitespace(const std::wstring& s)
	{
		std::wstring sRes;
		sRes.reserve(s.size());

		for (wchar_t c : s)
		{
			switch(c)
			{
			/*
			case 0x0009:   // Character tabulation
			case 0x000A:   // Line feed
			case 0x000B:   // Line tabulation
			case 0x000C:   // Form feed
			case 0x000D:   // Carriage return
			*/
			case 0x00A0:   // No-break space
			case 0x1680:   // Ogham space mark
			case 0x2000:   // En quad
			case 0x2001:   // Em quad
			case 0x2002:   // En space
			case 0x2003:   // Em space
			case 0x2004:   // Three-per-em space
			case 0x2005:   // Four-per-em space
			case 0x2006:   // Six-per-em space
			case 0x2007:   // Figure space
			case 0x2008:   // Punctuation space
			case 0x2009:   // Thin space
			case 0x200A:   // Hair space
			case 0x2028:   // Line separator
			case 0x2029:   // Paragraph separator
			case 0x202F:   // Narrow no-break space
			case 0x205F:   // Medium mathematical space
			case 0x2060:   // Word joiner
			case 0x3000:   // Ideographic space
			case 0xFEFF:   // Zero width no-break space
				sRes += L' ';
				break;
			default:
				sRes += c;
			}
		}

		return sRes;
	}
	void projectPolygon(const std::vector<CPoint>& polygon, const CPoint& axis, double& min, double& max)
	{
		min = std::numeric_limits<double>::max();
		max = std::numeric_limits<double>::lowest();

		for (const auto& point : polygon)
		{
			double projection = (point.x * axis.x + point.y * axis.y) / (axis.x * axis.x + axis.y * axis.y);
			projection *= (axis.x * axis.x + axis.y * axis.y);

			if (projection < min) min = projection;
			if (projection > max) max = projection;
		}
	}
	bool SAT(const std::vector<CPoint>& poly1, const std::vector<CPoint>& poly2)
	{
		std::vector<CPoint> axes;
		for (size_t i = 0; i < poly1.size(); i++)
		{
			CPoint p1 = poly1[i];
			CPoint p2 = poly1[(i + 1) % poly1.size()];
			CPoint edge(p2.x - p1.x, p2.y - p1.y);
			CPoint normal(-edge.y, edge.x); // Perpendicular to edge
			axes.push_back(normal);
		}

		for (size_t i = 0; i < poly2.size(); i++)
		{
			CPoint p1 = poly2[i];
			CPoint p2 = poly2[(i + 1) % poly2.size()];
			CPoint edge(p2.x - p1.x, p2.y - p1.y);
			CPoint normal(-edge.y, edge.x); // Perpendicular to edge
			axes.push_back(normal);
		}

		// Check all axes for separation
		for (const auto& axis : axes)
		{
			double min1, max1, min2, max2;
			projectPolygon(poly1, axis, min1, max1);
			projectPolygon(poly2, axis, min2, max2);

			if (max1 < min2 || max2 < min1)
				return false; // Separating axis found
		}
		return true; // Intersecting
	}
	bool isPolygonInsidePolygon(const std::vector<CPoint>& inner, const std::vector<CPoint>& outer)
	{
		for (const CPoint& point : inner)
		{
			if (!isPointInQuad(point.x, point.y, outer[0].x, outer[0].y, outer[1].x, outer[1].y, outer[2].x, outer[2].y, outer[3].x, outer[3].y))
				return false;
		}
		return true;
	}
	double crossProduct(double x1, double y1, double x2, double y2, double x3, double y3)
	{
		return (x2 - x1) * (y3 - y1) - (y2 - y1) * (x3 - x1);
	}
	bool isPointInQuad(double px, double py, double x1, double y1, double x2, double y2, double x3, double y3, double x4, double y4)
	{
		if (x1 == x2 && x2 == x3 && x3 == x4 && y1 == y2 && y2 == y3 && y3 == y4)
			return (px == x1 && py == y1);

		// Check cross product signs for all sides
		double cross1 = crossProduct(x1, y1, x2, y2, px, py);
		double cross2 = crossProduct(x2, y2, x3, y3, px, py);
		double cross3 = crossProduct(x3, y3, x4, y4, px, py);
		double cross4 = crossProduct(x4, y4, x1, y1, px, py);

		// Point is inside if all cross products have the same sign
		bool allPositive = (cross1 >= 0 && cross2 >= 0 && cross3 >= 0 && cross4 >= 0);
		bool allNegative = (cross1 <= 0 && cross2 <= 0 && cross3 <= 0 && cross4 <= 0);

		return (allNegative || allPositive) && !(cross1 == 0 && cross2 == 0 && cross3 == 0 && cross4 == 0);
	}
	bool RectangleIntersection::segmentsIntersect(const CPoint& a, const CPoint& b, const CPoint& c, const CPoint& d, CPoint& intersection)
	{
		double x1 = a.x, y1 = a.y;
		double x2 = b.x, y2 = b.y;
		double x3 = c.x, y3 = c.y;
		double x4 = d.x, y4 = d.y;

		double denom = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);

		if (std::abs(denom) < 1e-10) return false;

		double t = ((x1 - x3) * (y3 - y4) - (y1 - y3) * (x3 - x4)) / denom;
		double u = -((x1 - x2) * (y1 - y3) - (y1 - y2) * (x1 - x3)) / denom;

		if (t >= 0 && t <= 1 && u >= 0 && u <= 1)
		{
			intersection.x = x1 + t * (x2 - x1);
			intersection.y = y1 + t * (y2 - y1);
			return true;
		}
		return false;
	}
	bool RectangleIntersection::pointInRectangle(const CPoint& p, const std::vector<CPoint>& rect)
	{
		double totalAngle = 0;
		int n = rect.size();

		for (int i = 0; i < n; i++)
		{
			CPoint v1 = { rect[i].x - p.x, rect[i].y - p.y };
			CPoint v2 = { rect[(i + 1) % n].x - p.x, rect[(i + 1) % n].y - p.y };

			double dot = v1.x * v2.x + v1.y * v2.y;
			double cross = v1.x * v2.y - v1.y * v2.x;
			double angle = std::atan2(cross, dot);
			totalAngle += angle;
		}

		return std::abs(totalAngle) > 1;
	}
	double RectangleIntersection::distanceAlongLine(const CPoint& start, const CPoint& end, const CPoint& point)
	{
		double dx = end.x - start.x;
		double dy = end.y - start.y;
		double length = std::sqrt(dx * dx + dy * dy);

		if (length < 1e-10) return 0;

		// Project vector (point - start) onto segment direction
		double proj = ((point.x - start.x) * dx + (point.y - start.y) * dy) / length;
		return proj;
	}
	std::vector<CSegment> RectangleIntersection::findSegmentsOutsideRectangles(const CSegment& line, const std::vector<std::vector<CPoint>>& rectangles)
	{
		std::vector<CPoint> allIntersections;

		// Collect all intersection points with all rectangles
		for (const auto& rect : rectangles)
		{
			for (int i = 0; i < rect.size(); i++)
			{
				CPoint intersection;
				if (segmentsIntersect(line.start, line.end, rect[i], rect[(i + 1) % rect.size()], intersection))
					allIntersections.push_back(intersection);
			}
		}

		// Add segment endpoints
		allIntersections.push_back(line.start);
		allIntersections.push_back(line.end);

		// Remove duplicates
		std::sort(allIntersections.begin(), allIntersections.end(), [&line](const CPoint& a, const CPoint& b)
		{
			return distanceAlongLine(line.start, line.end, a) < distanceAlongLine(line.start, line.end, b);
		});

		auto last = std::unique(allIntersections.begin(), allIntersections.end());
		allIntersections.erase(last, allIntersections.end());

		// Check each segment between intersection points
		std::vector<CSegment> result;

		for (size_t i = 0; i < allIntersections.size() - 1; i++) {
			CPoint start = allIntersections[i];
			CPoint end = allIntersections[i + 1];

			// Find segment midpoint
			CPoint mid =
			{
				(start.x + end.x) / 2,
				(start.y + end.y) / 2
			};

			// Check if midpoint is inside any rectangle
			bool isInsideAnyRectangle = false;
			for (const auto& rect : rectangles)
			{
				if (pointInRectangle(mid, rect))
				{
					isInsideAnyRectangle = true;
					break;
				}
			}

			// If midpoint is not inside any rectangle - this is an external segment
			if (!isInsideAnyRectangle)
				result.push_back(CSegment(start, end));
		}

		return result;
	}
	std::vector<CSegment> RectangleIntersection::findSegmentsOutsideRectanglesSequential(const CSegment& line, const std::vector<std::vector<CPoint>>& rectangles)
	{
		// Start with full segment
		std::vector<CSegment> currentSegments = {line};

		// Sequentially subtract each rectangle
		for (const auto& rect : rectangles) {
			std::vector<CSegment> newSegments;

			for (const auto& segment : currentSegments) {
				auto segmentsOutside = findSegmentsOutsideRectangles(segment, {rect});
				newSegments.insert(newSegments.end(), segmentsOutside.begin(), segmentsOutside.end());
			}

			currentSegments = newSegments;
		}

		return currentSegments;
	}
}