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#include <stddef.h>
#include <string.h>
#include <stdlib.h>
#include "sfnt.h"
#include "../util.h"
static uint32_t big32(uint8_t *src)
{
uint32_t ret = *(src++) << 24;
ret |= *(src++) << 16;
ret |= *(src++) << 8;
ret |= *src;
return ret;
}
static uint32_t big16(uint8_t *src)
{
uint32_t ret = *(src++) << 8;
ret |= *src;
return ret;
}
#define MIN_RESOURCE_MAP_SIZE (16 + 12 + 2 + 8)
sfnt_container *load_sfnt(uint8_t *buffer, uint32_t size)
{
if (size < 0x100) {
return NULL;
}
uint32_t sfnt_res_count, sfnt_res_offset, res_offset;
uint8_t type;
if (!memcmp(buffer, "true", 4) || !memcmp(buffer, "OTTO", 4) || !memcmp(buffer, "typ1", 4) || !memcmp(buffer, "\0\x01\0\0", 4)) {
type = CONTAINER_TTF;
} else if (!memcmp(buffer, "ttcf", 4)) {
type = CONTAINER_TTC;
} else {
static uint8_t all_zeroes[16];
uint32_t resource_map_off = big32(buffer + 4);
if (resource_map_off + MIN_RESOURCE_MAP_SIZE > size) {
return NULL;
}
//first 16 bytes of map should match header or be all zeroes
if (memcmp(buffer, buffer + resource_map_off, 16) && memcmp(all_zeroes, buffer + resource_map_off, 16)) {
return NULL;
}
uint32_t type_start_off = resource_map_off + big16(buffer + resource_map_off + 24);
if (type_start_off + sizeof(uint16_t) > size) {
return NULL;
}
uint32_t num_types = 1 + big16(buffer + type_start_off);
if (type_start_off + sizeof(uint16_t) + 8 * num_types > size) {
return NULL;
}
res_offset = big32(buffer);
if (res_offset > size) {
return NULL;
}
uint8_t *cur = buffer + type_start_off + 2;
sfnt_res_count = 0;
for (uint32_t i = 0; i < num_types; i++, cur += 8)
{
if (!memcmp("sfnt", cur, 4)) {
sfnt_res_count = 1 + big16(cur + 4);
sfnt_res_offset = type_start_off + big16(cur + 6);
if (sfnt_res_offset + sfnt_res_count * 12 > size) {
return NULL;
}
type = CONTAINER_DFONT;
break;
}
}
if (!sfnt_res_count) {
//No "sfnt" resources in this dfont
return NULL;
}
}
sfnt_container *sfnt = calloc(1, sizeof(sfnt_container));
sfnt->blob = buffer;
sfnt->size = size;
sfnt->container_type = type;
switch (type)
{
case CONTAINER_TTF:
sfnt->num_fonts = 1;
sfnt->tables = calloc(1, sizeof(sfnt_table));
sfnt->tables->container = sfnt;
sfnt->tables->data = buffer + 0xC;
sfnt->tables->num_entries = big16(buffer + 4);
sfnt->tables->offset = 0;
break;
case CONTAINER_TTC: {
sfnt->num_fonts = big32(buffer+8);
sfnt->tables = calloc(sfnt->num_fonts, sizeof(sfnt_table));
uint8_t *offsets = buffer + 0xC;
for (int i = 0; i < sfnt->num_fonts; i++, offsets += sizeof(uint32_t))
{
uint32_t offset = big32(offsets);
sfnt->tables[i].data = buffer + offset + 0xC;
sfnt->tables[i].container = sfnt;
sfnt->tables[i].num_entries = big16(buffer + offset + 4);
sfnt->tables[i].offset = 0;
}
break;
}
case CONTAINER_DFONT:{
sfnt->num_fonts = sfnt_res_count;
sfnt->tables = calloc(sfnt->num_fonts, sizeof(sfnt_table));
uint8_t *cur = buffer + sfnt_res_offset;
for (int i = 0; i < sfnt->num_fonts; i++, cur += 12)
{
uint32_t offset = res_offset + (big32(cur + 4) & 0xFFFFFF);
if (offset + 4 > size) {
sfnt->tables[i].num_entries = 0;
sfnt->tables[i].data = NULL;
continue;
}
uint32_t res_size = big32(buffer + offset);
if (offset + 4 + res_size > size || res_size < 0xC) {
sfnt->tables[i].num_entries = 0;
sfnt->tables[i].data = NULL;
continue;
}
sfnt->tables[i].container = sfnt;
sfnt->tables[i].data = buffer + offset + 4 + 0xC;
sfnt->tables[i].num_entries = big16(buffer + offset + 4 + 4);
sfnt->tables[i].offset = offset + 4;
}
break;
}
}
return sfnt;
}
uint8_t *sfnt_find_table(sfnt_table *sfnt, char *table, uint32_t *size_out)
{
uint8_t *entry = sfnt->data;
for (int i = 0; i < sfnt->num_entries; i++, entry += 16)
{
if (!strncmp(entry, table, 4)) {
if (size_out) {
*size_out = big32(entry + 12);
}
return sfnt->container->blob + sfnt->offset + big32(entry + 8);
}
}
return NULL;
}
char *sfnt_name(sfnt_table *sfnt, uint16_t name_type)
{
uint32_t name_size;
uint8_t *name_table = sfnt_find_table(sfnt, "name", &name_size);
if (!name_table) {
return NULL;
}
uint16_t num_names = big16(name_table + 2);
if ((6 + num_names *12) > name_size) {
//count is too big for the name table size, abort
return NULL;
}
uint8_t *entry = name_table + 6;
uint16_t name_length = 0, name_offset;
uint8_t *unicode_entry = NULL, *macroman_entry = NULL, *winunicode_entry = NULL;
for (uint16_t i = 0; i < num_names; i++, entry += 12)
{
if (big16(entry + 6) != name_type) {
continue;
}
uint16_t language_id = big16(entry + 4);
if (language_id >= 0x8000) {
//ingore language tag records
continue;
}
uint16_t platform_id = big16(entry);
if (platform_id == 0) {
//prefer Unicode first
unicode_entry = entry;
break;
} else if (platform_id == 3 && big16(entry + 2) < 2) {
if (!winunicode_entry || (language_id & 0xFF) == 0x09) {
winunicode_entry = entry;
}
} else if (platform_id == 1 && big16(entry + 2) == 0) {
if (!macroman_entry || (language_id == 0)) {
macroman_entry = entry;
}
}
}
entry = unicode_entry ? unicode_entry : winunicode_entry ? winunicode_entry : macroman_entry;
if (entry) {
name_length = big16(entry + 8);
name_offset = big16(entry + 10);
}
if (!name_length) {
return NULL;
}
uint32_t full_off = name_offset + big16(name_table + 4);
if ((full_off + name_length) > name_size) {
return NULL;
}
if (entry == macroman_entry) {
//TODO: convert these properly to UTF-8
char *ret = malloc(name_length + 1);
memcpy(ret, name_table + full_off, name_length);
ret[name_length] = 0;
return ret;
} else {
return utf16be_to_utf8(name_table + full_off, name_length/2);
}
}
uint8_t *sfnt_flatten(sfnt_table *sfnt, uint32_t *size_out)
{
uint8_t *ret = NULL;;
sfnt_container *cont = sfnt->container;
switch(cont->container_type)
{
case CONTAINER_TTF:
ret = cont->blob;
if (size_out) {
*size_out = cont->size;
}
break;
case CONTAINER_TTC:
memmove(cont->blob, sfnt->data - 0xC, 0xC + sfnt->num_entries * 12);
ret = cont->blob;
if (size_out) {
*size_out = cont->size;
}
break;
case CONTAINER_DFONT:{
uint8_t * start = sfnt->data - 0xC;
uint32_t size = big32(start - 4);
if (size + (start-cont->blob) > cont->size) {
size = cont->size - (start-cont->blob);
}
ret = malloc(size);
memcpy(ret, start, size);
free(cont->blob);
if (size_out) {
*size_out = size;
}
break;
}
}
free(cont->tables);
free(cont);
return ret;
}
sfnt_table *sfnt_subfamily_by_names(sfnt_container *sfnt, const char **names)
{
for (int i = 0; i < sfnt->num_fonts; i++)
{
for (const char **name = names; *name; name++)
{
char *font_subfam = sfnt_name(sfnt->tables + i, SFNT_SUBFAMILY);
if (font_subfam && !strcasecmp(*name, font_subfam)) {
free(font_subfam);
return sfnt->tables + i;
}
free(font_subfam);
}
}
return NULL;
}
void sfnt_free(sfnt_container *sfnt)
{
free(sfnt->tables);
free(sfnt->blob);
free(sfnt);
}
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