• file
• revisions
• annotate
• diff
• comparison
• raw

gfx/ots/src/hdmx.cc@97036ab72558 (annotated)

gfx/ots/src/hdmx.cc

Tue, 06 Jan 2015 21:39:09 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Tue, 06 Jan 2015 21:39:09 +0100

branch

TOR_BUG_9701

changeset 8

97036ab72558

permissions

-rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

michael@0	1	// Copyright (c) 2009 The Chromium Authors. All rights reserved.
michael@0	2	// Use of this source code is governed by a BSD-style license that can be
michael@0	3	// found in the LICENSE file.
michael@0	4
michael@0	5	#include "hdmx.h"
michael@0	6	#include "head.h"
michael@0	7	#include "maxp.h"
michael@0	8
michael@0	9	// hdmx - Horizontal Device Metrics
michael@0	10	// http://www.microsoft.com/typography/otspec/hdmx.htm
michael@0	11
michael@0	12	#define TABLE_NAME "hdmx"
michael@0	13
michael@0	14	#define DROP_THIS_TABLE \
michael@0	15	do { \
michael@0	16	delete file->hdmx; \
michael@0	17	file->hdmx = 0; \
michael@0	18	OTS_FAILURE_MSG("Table discarded"); \
michael@0	19	} while (0)
michael@0	20
michael@0	21	namespace ots {
michael@0	22
michael@0	23	bool ots_hdmx_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
michael@0	24	Buffer table(data, length);
michael@0	25	file->hdmx = new OpenTypeHDMX;
michael@0	26	OpenTypeHDMX * const hdmx = file->hdmx;
michael@0	27
michael@0	28	if (!file->head || !file->maxp) {
michael@0	29	return OTS_FAILURE_MSG("Missing maxp or head tables in font, needed by hdmx");
michael@0	30	}
michael@0	31
michael@0	32	if ((file->head->flags & 0x14) == 0) {
michael@0	33	// http://www.microsoft.com/typography/otspec/recom.htm
michael@0	34	OTS_WARNING("the table should not be present when bit 2 and 4 of the "
michael@0	35	"head->flags are not set");
michael@0	36	DROP_THIS_TABLE;
michael@0	37	return true;
michael@0	38	}
michael@0	39
michael@0	40	int16_t num_recs;
michael@0	41	if (!table.ReadU16(&hdmx->version) ||
michael@0	42	!table.ReadS16(&num_recs) ||
michael@0	43	!table.ReadS32(&hdmx->size_device_record)) {
michael@0	44	return OTS_FAILURE_MSG("Failed to read hdmx header");
michael@0	45	}
michael@0	46	if (hdmx->version != 0) {
michael@0	47	OTS_WARNING("bad version: %u", hdmx->version);
michael@0	48	DROP_THIS_TABLE;
michael@0	49	return true;
michael@0	50	}
michael@0	51	if (num_recs <= 0) {
michael@0	52	OTS_WARNING("bad num_recs: %d", num_recs);
michael@0	53	DROP_THIS_TABLE;
michael@0	54	return true;
michael@0	55	}
michael@0	56	const int32_t actual_size_device_record = file->maxp->num_glyphs + 2;
michael@0	57	if (hdmx->size_device_record < actual_size_device_record) {
michael@0	58	OTS_WARNING("bad hdmx->size_device_record: %d", hdmx->size_device_record);
michael@0	59	DROP_THIS_TABLE;
michael@0	60	return true;
michael@0	61	}
michael@0	62
michael@0	63	hdmx->pad_len = hdmx->size_device_record - actual_size_device_record;
michael@0	64	if (hdmx->pad_len > 3) {
michael@0	65	return OTS_FAILURE_MSG("Bad padding %d", hdmx->pad_len);
michael@0	66	}
michael@0	67
michael@0	68	uint8_t last_pixel_size = 0;
michael@0	69	hdmx->records.reserve(num_recs);
michael@0	70	for (int i = 0; i < num_recs; ++i) {
michael@0	71	OpenTypeHDMXDeviceRecord rec;
michael@0	72
michael@0	73	if (!table.ReadU8(&rec.pixel_size) ||
michael@0	74	!table.ReadU8(&rec.max_width)) {
michael@0	75	return OTS_FAILURE_MSG("Failed to read hdmx record %d", i);
michael@0	76	}
michael@0	77	if ((i != 0) &&
michael@0	78	(rec.pixel_size <= last_pixel_size)) {
michael@0	79	OTS_WARNING("records are not sorted");
michael@0	80	DROP_THIS_TABLE;
michael@0	81	return true;
michael@0	82	}
michael@0	83	last_pixel_size = rec.pixel_size;
michael@0	84
michael@0	85	rec.widths.reserve(file->maxp->num_glyphs);
michael@0	86	for (unsigned j = 0; j < file->maxp->num_glyphs; ++j) {
michael@0	87	uint8_t width;
michael@0	88	if (!table.ReadU8(&width)) {
michael@0	89	return OTS_FAILURE_MSG("Failed to read glyph width %d in record %d", j, i);
michael@0	90	}
michael@0	91	rec.widths.push_back(width);
michael@0	92	}
michael@0	93
michael@0	94	if ((hdmx->pad_len > 0) &&
michael@0	95	!table.Skip(hdmx->pad_len)) {
michael@0	96	return OTS_FAILURE_MSG("Failed to skip padding %d", hdmx->pad_len);
michael@0	97	}
michael@0	98
michael@0	99	hdmx->records.push_back(rec);
michael@0	100	}
michael@0	101
michael@0	102	return true;
michael@0	103	}
michael@0	104
michael@0	105	bool ots_hdmx_should_serialise(OpenTypeFile *file) {
michael@0	106	if (!file->hdmx) return false;
michael@0	107	if (!file->glyf) return false; // this table is not for CFF fonts.
michael@0	108	return true;
michael@0	109	}
michael@0	110
michael@0	111	bool ots_hdmx_serialise(OTSStream *out, OpenTypeFile *file) {
michael@0	112	OpenTypeHDMX * const hdmx = file->hdmx;
michael@0	113
michael@0	114	if (!out->WriteU16(hdmx->version) ||
michael@0	115	!out->WriteS16(hdmx->records.size()) ||
michael@0	116	!out->WriteS32(hdmx->size_device_record)) {
michael@0	117	return OTS_FAILURE_MSG("Failed to write hdmx header");
michael@0	118	}
michael@0	119
michael@0	120	for (unsigned i = 0; i < hdmx->records.size(); ++i) {
michael@0	121	const OpenTypeHDMXDeviceRecord& rec = hdmx->records[i];
michael@0	122	if (!out->Write(&rec.pixel_size, 1) ||
michael@0	123	!out->Write(&rec.max_width, 1) ||
michael@0	124	!out->Write(&rec.widths[0], rec.widths.size())) {
michael@0	125	return OTS_FAILURE_MSG("Failed to write hdmx record %d", i);
michael@0	126	}
michael@0	127	if ((hdmx->pad_len > 0) &&
michael@0	128	!out->Write((const uint8_t *)"\x00\x00\x00", hdmx->pad_len)) {
michael@0	129	return OTS_FAILURE_MSG("Failed to write hdmx padding of length %d", hdmx->pad_len);
michael@0	130	}
michael@0	131	}
michael@0	132
michael@0	133	return true;
michael@0	134	}
michael@0	135
michael@0	136	void ots_hdmx_free(OpenTypeFile *file) {
michael@0	137	delete file->hdmx;
michael@0	138	}
michael@0	139
michael@0	140	} // namespace ots