michael@0: // Copyright (c) 2009 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #include "hdmx.h"
michael@0: #include "head.h"
michael@0: #include "maxp.h"
michael@0: 
michael@0: // hdmx - Horizontal Device Metrics
michael@0: // http://www.microsoft.com/typography/otspec/hdmx.htm
michael@0: 
michael@0: #define TABLE_NAME "hdmx"
michael@0: 
michael@0: #define DROP_THIS_TABLE \
michael@0:   do { \
michael@0:     delete file->hdmx; \
michael@0:     file->hdmx = 0; \
michael@0:     OTS_FAILURE_MSG("Table discarded"); \
michael@0:   } while (0)
michael@0: 
michael@0: namespace ots {
michael@0: 
michael@0: bool ots_hdmx_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
michael@0:   Buffer table(data, length);
michael@0:   file->hdmx = new OpenTypeHDMX;
michael@0:   OpenTypeHDMX * const hdmx = file->hdmx;
michael@0: 
michael@0:   if (!file->head || !file->maxp) {
michael@0:     return OTS_FAILURE_MSG("Missing maxp or head tables in font, needed by hdmx");
michael@0:   }
michael@0: 
michael@0:   if ((file->head->flags & 0x14) == 0) {
michael@0:     // http://www.microsoft.com/typography/otspec/recom.htm
michael@0:     OTS_WARNING("the table should not be present when bit 2 and 4 of the "
michael@0:                 "head->flags are not set");
michael@0:     DROP_THIS_TABLE;
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   int16_t num_recs;
michael@0:   if (!table.ReadU16(&hdmx->version) ||
michael@0:       !table.ReadS16(&num_recs) ||
michael@0:       !table.ReadS32(&hdmx->size_device_record)) {
michael@0:     return OTS_FAILURE_MSG("Failed to read hdmx header");
michael@0:   }
michael@0:   if (hdmx->version != 0) {
michael@0:     OTS_WARNING("bad version: %u", hdmx->version);
michael@0:     DROP_THIS_TABLE;
michael@0:     return true;
michael@0:   }
michael@0:   if (num_recs <= 0) {
michael@0:     OTS_WARNING("bad num_recs: %d", num_recs);
michael@0:     DROP_THIS_TABLE;
michael@0:     return true;
michael@0:   }
michael@0:   const int32_t actual_size_device_record = file->maxp->num_glyphs + 2;
michael@0:   if (hdmx->size_device_record < actual_size_device_record) {
michael@0:     OTS_WARNING("bad hdmx->size_device_record: %d", hdmx->size_device_record);
michael@0:     DROP_THIS_TABLE;
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   hdmx->pad_len = hdmx->size_device_record - actual_size_device_record;
michael@0:   if (hdmx->pad_len > 3) {
michael@0:     return OTS_FAILURE_MSG("Bad padding %d", hdmx->pad_len);
michael@0:   }
michael@0: 
michael@0:   uint8_t last_pixel_size = 0;
michael@0:   hdmx->records.reserve(num_recs);
michael@0:   for (int i = 0; i < num_recs; ++i) {
michael@0:     OpenTypeHDMXDeviceRecord rec;
michael@0: 
michael@0:     if (!table.ReadU8(&rec.pixel_size) ||
michael@0:         !table.ReadU8(&rec.max_width)) {
michael@0:       return OTS_FAILURE_MSG("Failed to read hdmx record %d", i);
michael@0:     }
michael@0:     if ((i != 0) &&
michael@0:         (rec.pixel_size <= last_pixel_size)) {
michael@0:       OTS_WARNING("records are not sorted");
michael@0:       DROP_THIS_TABLE;
michael@0:       return true;
michael@0:     }
michael@0:     last_pixel_size = rec.pixel_size;
michael@0: 
michael@0:     rec.widths.reserve(file->maxp->num_glyphs);
michael@0:     for (unsigned j = 0; j < file->maxp->num_glyphs; ++j) {
michael@0:       uint8_t width;
michael@0:       if (!table.ReadU8(&width)) {
michael@0:         return OTS_FAILURE_MSG("Failed to read glyph width %d in record %d", j, i);
michael@0:       }
michael@0:       rec.widths.push_back(width);
michael@0:     }
michael@0: 
michael@0:     if ((hdmx->pad_len > 0) &&
michael@0:         !table.Skip(hdmx->pad_len)) {
michael@0:       return OTS_FAILURE_MSG("Failed to skip padding %d", hdmx->pad_len);
michael@0:     }
michael@0: 
michael@0:     hdmx->records.push_back(rec);
michael@0:   }
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool ots_hdmx_should_serialise(OpenTypeFile *file) {
michael@0:   if (!file->hdmx) return false;
michael@0:   if (!file->glyf) return false;  // this table is not for CFF fonts.
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool ots_hdmx_serialise(OTSStream *out, OpenTypeFile *file) {
michael@0:   OpenTypeHDMX * const hdmx = file->hdmx;
michael@0: 
michael@0:   if (!out->WriteU16(hdmx->version) ||
michael@0:       !out->WriteS16(hdmx->records.size()) ||
michael@0:       !out->WriteS32(hdmx->size_device_record)) {
michael@0:     return OTS_FAILURE_MSG("Failed to write hdmx header");
michael@0:   }
michael@0: 
michael@0:   for (unsigned i = 0; i < hdmx->records.size(); ++i) {
michael@0:     const OpenTypeHDMXDeviceRecord& rec = hdmx->records[i];
michael@0:     if (!out->Write(&rec.pixel_size, 1) ||
michael@0:         !out->Write(&rec.max_width, 1) ||
michael@0:         !out->Write(&rec.widths[0], rec.widths.size())) {
michael@0:       return OTS_FAILURE_MSG("Failed to write hdmx record %d", i);
michael@0:     }
michael@0:     if ((hdmx->pad_len > 0) &&
michael@0:         !out->Write((const uint8_t *)"\x00\x00\x00", hdmx->pad_len)) {
michael@0:       return OTS_FAILURE_MSG("Failed to write hdmx padding of length %d", hdmx->pad_len);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: void ots_hdmx_free(OpenTypeFile *file) {
michael@0:   delete file->hdmx;
michael@0: }
michael@0: 
michael@0: }  // namespace ots