| // Copyright (c) 2009 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "vdmx.h" |
| |
| // VDMX - Vertical Device Metrics |
| // http://www.microsoft.com/typography/otspec/vdmx.htm |
| |
| #define TABLE_NAME "VDMX" |
| |
| #define DROP_THIS_TABLE(...) \ |
| do { \ |
| OTS_FAILURE_MSG_(file, TABLE_NAME ": " __VA_ARGS__); \ |
| OTS_FAILURE_MSG("Table discarded"); \ |
| delete file->vdmx; \ |
| file->vdmx = 0; \ |
| } while (0) |
| |
| namespace ots { |
| |
| bool ots_vdmx_parse(OpenTypeFile *file, const uint8_t *data, size_t length) { |
| Buffer table(data, length); |
| file->vdmx = new OpenTypeVDMX; |
| OpenTypeVDMX * const vdmx = file->vdmx; |
| |
| if (!table.ReadU16(&vdmx->version) || |
| !table.ReadU16(&vdmx->num_recs) || |
| !table.ReadU16(&vdmx->num_ratios)) { |
| return OTS_FAILURE_MSG("Failed to read table header"); |
| } |
| |
| if (vdmx->version > 1) { |
| DROP_THIS_TABLE("bad version: %u", vdmx->version); |
| return true; // continue transcoding |
| } |
| |
| vdmx->rat_ranges.reserve(vdmx->num_ratios); |
| for (unsigned i = 0; i < vdmx->num_ratios; ++i) { |
| OpenTypeVDMXRatioRecord rec; |
| |
| if (!table.ReadU8(&rec.charset) || |
| !table.ReadU8(&rec.x_ratio) || |
| !table.ReadU8(&rec.y_start_ratio) || |
| !table.ReadU8(&rec.y_end_ratio)) { |
| return OTS_FAILURE_MSG("Failed to read ratio header %d", i); |
| } |
| |
| if (rec.charset > 1) { |
| DROP_THIS_TABLE("bad charset: %u", rec.charset); |
| return true; |
| } |
| |
| if (rec.y_start_ratio > rec.y_end_ratio) { |
| DROP_THIS_TABLE("bad y ratio"); |
| return true; |
| } |
| |
| // All values set to zero signal the default grouping to use; |
| // if present, this must be the last Ratio group in the table. |
| if ((i < vdmx->num_ratios - 1u) && |
| (rec.x_ratio == 0) && |
| (rec.y_start_ratio == 0) && |
| (rec.y_end_ratio == 0)) { |
| // workaround for fonts which have 2 or more {0, 0, 0} terminators. |
| DROP_THIS_TABLE("superfluous terminator found"); |
| return true; |
| } |
| |
| vdmx->rat_ranges.push_back(rec); |
| } |
| |
| vdmx->offsets.reserve(vdmx->num_ratios); |
| const size_t current_offset = table.offset(); |
| // current_offset is less than (2 bytes * 3) + (4 bytes * USHRT_MAX) = 256k. |
| for (unsigned i = 0; i < vdmx->num_ratios; ++i) { |
| uint16_t offset; |
| if (!table.ReadU16(&offset)) { |
| return OTS_FAILURE_MSG("Failed to read ratio offset %d", i); |
| } |
| if (current_offset + offset >= length) { // thus doesn't overflow. |
| return OTS_FAILURE_MSG("Bad ratio offset %d for ration %d", offset, i); |
| } |
| |
| vdmx->offsets.push_back(offset); |
| } |
| |
| vdmx->groups.reserve(vdmx->num_recs); |
| for (unsigned i = 0; i < vdmx->num_recs; ++i) { |
| OpenTypeVDMXGroup group; |
| if (!table.ReadU16(&group.recs) || |
| !table.ReadU8(&group.startsz) || |
| !table.ReadU8(&group.endsz)) { |
| return OTS_FAILURE_MSG("Failed to read record header %d", i); |
| } |
| group.entries.reserve(group.recs); |
| for (unsigned j = 0; j < group.recs; ++j) { |
| OpenTypeVDMXVTable vt; |
| if (!table.ReadU16(&vt.y_pel_height) || |
| !table.ReadS16(&vt.y_max) || |
| !table.ReadS16(&vt.y_min)) { |
| return OTS_FAILURE_MSG("Failed to read reacord %d group %d", i, j); |
| } |
| if (vt.y_max < vt.y_min) { |
| DROP_THIS_TABLE("bad y min/max"); |
| return true; |
| } |
| |
| // This table must appear in sorted order (sorted by yPelHeight), |
| // but need not be continuous. |
| if ((j != 0) && (group.entries[j - 1].y_pel_height >= vt.y_pel_height)) { |
| DROP_THIS_TABLE("the table is not sorted"); |
| return true; |
| } |
| |
| group.entries.push_back(vt); |
| } |
| vdmx->groups.push_back(group); |
| } |
| |
| return true; |
| } |
| |
| bool ots_vdmx_should_serialise(OpenTypeFile *file) { |
| if (!file->glyf) return false; // this table is not for CFF fonts. |
| return file->vdmx != NULL; |
| } |
| |
| bool ots_vdmx_serialise(OTSStream *out, OpenTypeFile *file) { |
| OpenTypeVDMX * const vdmx = file->vdmx; |
| |
| if (!out->WriteU16(vdmx->version) || |
| !out->WriteU16(vdmx->num_recs) || |
| !out->WriteU16(vdmx->num_ratios)) { |
| return OTS_FAILURE_MSG("Failed to write table header"); |
| } |
| |
| for (unsigned i = 0; i < vdmx->rat_ranges.size(); ++i) { |
| const OpenTypeVDMXRatioRecord& rec = vdmx->rat_ranges[i]; |
| if (!out->Write(&rec.charset, 1) || |
| !out->Write(&rec.x_ratio, 1) || |
| !out->Write(&rec.y_start_ratio, 1) || |
| !out->Write(&rec.y_end_ratio, 1)) { |
| return OTS_FAILURE_MSG("Failed to write ratio %d", i); |
| } |
| } |
| |
| for (unsigned i = 0; i < vdmx->offsets.size(); ++i) { |
| if (!out->WriteU16(vdmx->offsets[i])) { |
| return OTS_FAILURE_MSG("Failed to write ratio offset %d", i); |
| } |
| } |
| |
| for (unsigned i = 0; i < vdmx->groups.size(); ++i) { |
| const OpenTypeVDMXGroup& group = vdmx->groups[i]; |
| if (!out->WriteU16(group.recs) || |
| !out->Write(&group.startsz, 1) || |
| !out->Write(&group.endsz, 1)) { |
| return OTS_FAILURE_MSG("Failed to write group %d", i); |
| } |
| for (unsigned j = 0; j < group.entries.size(); ++j) { |
| const OpenTypeVDMXVTable& vt = group.entries[j]; |
| if (!out->WriteU16(vt.y_pel_height) || |
| !out->WriteS16(vt.y_max) || |
| !out->WriteS16(vt.y_min)) { |
| return OTS_FAILURE_MSG("Failed to write group %d entry %d", i, j); |
| } |
| } |
| } |
| |
| return true; |
| } |
| |
| void ots_vdmx_free(OpenTypeFile *file) { |
| delete file->vdmx; |
| } |
| |
| } // namespace ots |
| |
| #undef TABLE_NAME |
| #undef DROP_THIS_TABLE |