15f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian/* 25f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * Copyright (c) 2008, 2009, Google Inc. All rights reserved. 35f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * 45f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * Redistribution and use in source and binary forms, with or without 55f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * modification, are permitted provided that the following conditions are 65f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * met: 75f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * 85f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * * Redistributions of source code must retain the above copyright 95f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * notice, this list of conditions and the following disclaimer. 105f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * * Redistributions in binary form must reproduce the above 115f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * copyright notice, this list of conditions and the following disclaimer 125f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * in the documentation and/or other materials provided with the 135f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * distribution. 145f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * * Neither the name of Google Inc. nor the names of its 155f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * contributors may be used to endorse or promote products derived from 165f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * this software without specific prior written permission. 175f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * 185f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 195f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 205f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 215f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 225f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 235f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 245f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 255f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 265f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 275f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 285f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 295f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian */ 305f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 315f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian#include <stdint.h> 325f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian#include <stdlib.h> 335f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian#include <string.h> 345f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 355f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// For htons/ntohs 365f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian#include <arpa/inet.h> 375f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 385f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// Buffer helper class 395f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// 405f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// This class perform some trival buffer operations while checking for 415f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// out-of-bounds errors. As a family they return false if anything is amiss, 425f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// updating the current offset otherwise. 435f1ab04193ad0130ca8204aadaceae083aca9881Feng Qianclass Buffer { 445f1ab04193ad0130ca8204aadaceae083aca9881Feng Qianpublic: 455f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian Buffer(const uint8_t* buffer, size_t length) 465f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian : m_buffer(buffer) 475f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian , m_length(length) 485f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian , m_offset(0) { } 495f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 505f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian bool skip(size_t numBytes) 515f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian { 525f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (m_offset + numBytes > m_length) 535f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 545f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian m_offset += numBytes; 555f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return true; 565f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian } 575f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 585f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian bool readU8(uint8_t* value) 595f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian { 605f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (m_offset + sizeof(uint8_t) > m_length) 615f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 625f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian *value = m_buffer[m_offset]; 635f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian m_offset += sizeof(uint8_t); 645f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return true; 655f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian } 665f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 675f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian bool readU16(uint16_t* value) 685f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian { 695f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (m_offset + sizeof(uint16_t) > m_length) 705f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 715f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian memcpy(value, m_buffer + m_offset, sizeof(uint16_t)); 725f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian *value = ntohs(*value); 735f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian m_offset += sizeof(uint16_t); 745f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return true; 755f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian } 765f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 775f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian bool readS16(int16_t* value) 785f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian { 795f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return readU16(reinterpret_cast<uint16_t*>(value)); 805f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian } 815f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 825f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian size_t offset() const 835f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian { 845f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return m_offset; 855f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian } 865f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 875f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian void setOffset(size_t newoffset) 885f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian { 895f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian m_offset = newoffset; 905f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian } 915f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 925f1ab04193ad0130ca8204aadaceae083aca9881Feng Qianprivate: 935f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian const uint8_t *const m_buffer; 945f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian const size_t m_length; 955f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian size_t m_offset; 965f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian}; 975f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 985f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// VDMX parsing code. 995f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// 1005f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// VDMX tables are found in some TrueType/OpenType fonts and contain 1015f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// ascender/descender overrides for certain (usually small) sizes. This is 1025f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// needed in order to match font metrics on Windows. 1035f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// 1045f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// Freetype does not parse these tables so we do so here. 1055f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1065f1ab04193ad0130ca8204aadaceae083aca9881Feng Qiannamespace WebCore { 1075f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1085f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// Parse a TrueType VDMX table. 1095f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// yMax: (output) the ascender value from the table 1105f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// yMin: (output) the descender value from the table (negative!) 1115f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// vdmx: the table bytes 1125f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// vdmxLength: length of @vdmx, in bytes 1135f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// targetPixelSize: the pixel size of the font (e.g. 16) 1145f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// 1155f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// Returns true iff a suitable match are found. Otherwise, *yMax and *yMin are 1165f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// untouched. size_t must be 32-bits to avoid overflow. 1175f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// 1185f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian// See http://www.microsoft.com/opentype/otspec/vdmx.htm 1195f1ab04193ad0130ca8204aadaceae083aca9881Feng Qianbool parseVDMX(int* yMax, int* yMin, 1205f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian const uint8_t* vdmx, size_t vdmxLength, 1215f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian unsigned targetPixelSize) 1225f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian{ 1235f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian Buffer buf(vdmx, vdmxLength); 1245f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1255f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // We ignore the version. Future tables should be backwards compatible with 1265f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // this layout. 1275f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian uint16_t numRatios; 1285f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (!buf.skip(4) || !buf.readU16(&numRatios)) 1295f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 1305f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1315f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // Now we have two tables. Firstly we have @numRatios Ratio records, then a 1325f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // matching array of @numRatios offsets. We save the offset of the beginning 1335f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // of this second table. 1345f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // 1355f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // Range 6 <= x <= 262146 1365f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian unsigned long offsetTableOffset = 1375f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian buf.offset() + 4 /* sizeof struct ratio */ * numRatios; 1385f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1395f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian unsigned desiredRatio = 0xffffffff; 1405f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // We read 4 bytes per record, so the offset range is 1415f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // 6 <= x <= 524286 1425f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian for (unsigned i = 0; i < numRatios; ++i) { 1435f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian uint8_t xRatio, yRatio1, yRatio2; 1445f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1455f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (!buf.skip(1) 1465f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian || !buf.readU8(&xRatio) 1475f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian || !buf.readU8(&yRatio1) 1485f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian || !buf.readU8(&yRatio2)) 1495f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 1505f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1515f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // This either covers 1:1, or this is the default entry (0, 0, 0) 1525f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if ((xRatio == 1 && yRatio1 <= 1 && yRatio2 >= 1) 1535f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian || (xRatio == 0 && yRatio1 == 0 && yRatio2 == 0)) { 1545f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian desiredRatio = i; 1555f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian break; 1565f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian } 1575f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian } 1585f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1595f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (desiredRatio == 0xffffffff) // no ratio found 1605f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 1615f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1625f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // Range 10 <= x <= 393216 1635f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian buf.setOffset(offsetTableOffset + sizeof(uint16_t) * desiredRatio); 1645f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1655f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // Now we read from the offset table to get the offset of another array 1665f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian uint16_t groupOffset; 1675f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (!buf.readU16(&groupOffset)) 1685f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 1695f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // Range 0 <= x <= 65535 1705f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian buf.setOffset(groupOffset); 1715f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1725f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian uint16_t numRecords; 1735f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (!buf.readU16(&numRecords) || !buf.skip(sizeof(uint16_t))) 1745f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 1755f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1765f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // We read 6 bytes per record, so the offset range is 1775f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // 4 <= x <= 458749 1785f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian for (unsigned i = 0; i < numRecords; ++i) { 1795f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian uint16_t pixelSize; 1805f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (!buf.readU16(&pixelSize)) 1815f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 1825f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian // the entries are sorted, so we can abort early if need be 1835f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (pixelSize > targetPixelSize) 1845f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 1855f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1865f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (pixelSize == targetPixelSize) { 1875f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian int16_t tempYMax, tempYMin; 1885f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (!buf.readS16(&tempYMax) 1895f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian || !buf.readS16(&tempYMin)) 1905f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 1915f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian *yMin = tempYMin; 1925f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian *yMax = tempYMax; 1935f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return true; 1945f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian } 1955f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian if (!buf.skip(2 * sizeof(int16_t))) 1965f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 1975f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian } 1985f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 1995f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian return false; 2005f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian} 2015f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian 2025f1ab04193ad0130ca8204aadaceae083aca9881Feng Qian} // namespace WebCore 203