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LibDraw: Teach PNGLoader to only decode enough of learn the image size

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This commit is contained in:
Andreas Kling 2019-10-16 20:01:11 +02:00
parent 00a7c48d6e
commit 2366c330e3
1 changed files with 78 additions and 35 deletions
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113
Libraries/LibDraw/PNGLoader.cpp
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@ -13,6 +13,8 @@
//#define PNG_STOPWATCH_DEBUG //#define PNG_STOPWATCH_DEBUG
static const u8 png_header[8] = { 0x89, 'P', 'N', 'G', 13, 10, 26, 10 };
struct PNG_IHDR { struct PNG_IHDR {
NetworkOrdered<u32> width; NetworkOrdered<u32> width;
NetworkOrdered<u32> height; NetworkOrdered<u32> height;
@ -61,8 +63,10 @@ struct [[gnu::packed]] Quad16
}; };
struct PNGLoadingContext { struct PNGLoadingContext {
enum class State { enum State {
NotDecoded, NotDecoded = 0,
HeaderDecoded,
SizeDecoded,
ChunksDecoded, ChunksDecoded,
BitmapDecoded, BitmapDecoded,
}; };
@ -139,7 +143,7 @@ private:
}; };
static RefPtr<GraphicsBitmap> load_png_impl(const u8*, int); static RefPtr<GraphicsBitmap> load_png_impl(const u8*, int);
static bool process_chunk(Streamer&, PNGLoadingContext& context); static bool process_chunk(Streamer&, PNGLoadingContext& context, bool decode_size_only);
RefPtr<GraphicsBitmap> load_png(const StringView& path) RefPtr<GraphicsBitmap> load_png(const StringView& path)
{ {
@ -390,35 +394,66 @@ template<bool has_alpha, u8 filter_type>
} }
} }
static bool decode_png_chunks(PNGLoadingContext& context) static bool decode_png_header(PNGLoadingContext& context)
{ {
ASSERT(context.state == PNGLoadingContext::State::NotDecoded); if (context.state >= PNGLoadingContext::HeaderDecoded)
#ifdef PNG_STOPWATCH_DEBUG return true;
Stopwatch sw("load_png_impl: total");
#endif
const u8* data_ptr = context.data;
int data_remaining = context.data_size;
const u8 png_header[8] = { 0x89, 'P', 'N', 'G', 13, 10, 26, 10 }; if (memcmp(context.data, png_header, sizeof(png_header)) != 0) {
if (memcmp(context.data, png_header, sizeof(png_header))) { dbg() << "Invalid PNG header";
dbgprintf("Invalid PNG header\n");
return false; return false;
} }
context.state = PNGLoadingContext::HeaderDecoded;
return true;
}
static bool decode_png_size(PNGLoadingContext& context)
{
if (context.state >= PNGLoadingContext::SizeDecoded)
return true;
if (context.state < PNGLoadingContext::HeaderDecoded) {
if (!decode_png_header(context))
return false;
}
const u8* data_ptr = context.data + sizeof(png_header);
size_t data_remaining = context.data_size - sizeof(png_header);
Streamer streamer(data_ptr, data_remaining);
while (!streamer.at_end()) {
if (!process_chunk(streamer, context, true)) {
return false;
}
if (context.width && context.height) {
context.state = PNGLoadingContext::State::SizeDecoded;
return true;
}
}
return false;
}
static bool decode_png_chunks(PNGLoadingContext& context)
{
if (context.state >= PNGLoadingContext::State::ChunksDecoded)
return true;
if (context.state < PNGLoadingContext::HeaderDecoded) {
if (!decode_png_header(context))
return false;
}
const u8* data_ptr = context.data + sizeof(png_header);
int data_remaining = context.data_size - sizeof(png_header);
context.compressed_data.ensure_capacity(context.data_size); context.compressed_data.ensure_capacity(context.data_size);
data_ptr += sizeof(png_header); Streamer streamer(data_ptr, data_remaining);
data_remaining -= sizeof(png_header); while (!streamer.at_end()) {
if (!process_chunk(streamer, context, false)) {
{ return false;
#ifdef PNG_STOPWATCH_DEBUG
Stopwatch sw("load_png_impl: read chunks");
#endif
Streamer streamer(data_ptr, data_remaining);
while (!streamer.at_end()) {
if (!process_chunk(streamer, context)) {
return false;
}
} }
} }
@ -428,7 +463,14 @@ static bool decode_png_chunks(PNGLoadingContext& context)
static bool decode_png_bitmap(PNGLoadingContext& context) static bool decode_png_bitmap(PNGLoadingContext& context)
{ {
ASSERT(context.state == PNGLoadingContext::State::ChunksDecoded); if (context.state < PNGLoadingContext::State::ChunksDecoded) {
if (!decode_png_chunks(context))
return false;
}
if (context.state >= PNGLoadingContext::State::BitmapDecoded)
return true;
{ {
#ifdef PNG_STOPWATCH_DEBUG #ifdef PNG_STOPWATCH_DEBUG
Stopwatch sw("load_png_impl: uncompress"); Stopwatch sw("load_png_impl: uncompress");
@ -491,7 +533,7 @@ static RefPtr<GraphicsBitmap> load_png_impl(const u8* data, int data_size)
return context.bitmap; return context.bitmap;
} }
static bool process_IHDR(const ByteBuffer& data, PNGLoadingContext& context) static bool process_IHDR(const ByteBuffer& data, PNGLoadingContext& context, bool decode_size_only = false)
{ {
if (data.size() < (int)sizeof(PNG_IHDR)) if (data.size() < (int)sizeof(PNG_IHDR))
return false; return false;
@ -542,8 +584,10 @@ static bool process_IHDR(const ByteBuffer& data, PNGLoadingContext& context)
ASSERT_NOT_REACHED(); ASSERT_NOT_REACHED();
} }
context.decompression_buffer_size = (context.width * context.height * context.bytes_per_pixel + context.height); if (!decode_size_only) {
context.decompression_buffer = (u8*)mmap_with_name(nullptr, context.decompression_buffer_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0, "PNG decompression buffer"); context.decompression_buffer_size = (context.width * context.height * context.bytes_per_pixel + context.height);
context.decompression_buffer = (u8*)mmap_with_name(nullptr, context.decompression_buffer_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0, "PNG decompression buffer");
}
return true; return true;
} }
@ -569,7 +613,7 @@ static bool process_tRNS(const ByteBuffer& data, PNGLoadingContext& context)
return true; return true;
} }
static bool process_chunk(Streamer& streamer, PNGLoadingContext& context) static bool process_chunk(Streamer& streamer, PNGLoadingContext& context, bool decode_size_only)
{ {
u32 chunk_size; u32 chunk_size;
if (!streamer.read(chunk_size)) { if (!streamer.read(chunk_size)) {
@ -597,7 +641,7 @@ static bool process_chunk(Streamer& streamer, PNGLoadingContext& context)
#endif #endif
if (!strcmp((const char*)chunk_type, "IHDR")) if (!strcmp((const char*)chunk_type, "IHDR"))
return process_IHDR(chunk_data, context); return process_IHDR(chunk_data, context, decode_size_only);
if (!strcmp((const char*)chunk_type, "IDAT")) if (!strcmp((const char*)chunk_type, "IDAT"))
return process_IDAT(chunk_data, context); return process_IDAT(chunk_data, context);
if (!strcmp((const char*)chunk_type, "PLTE")) if (!strcmp((const char*)chunk_type, "PLTE"))
@ -620,8 +664,8 @@ PNGImageLoaderPlugin::~PNGImageLoaderPlugin()
Size PNGImageLoaderPlugin::size() Size PNGImageLoaderPlugin::size()
{ {
if (m_context->state == PNGLoadingContext::State::NotDecoded) { if (m_context->state < PNGLoadingContext::State::SizeDecoded) {
bool success = decode_png_chunks(*m_context); bool success = decode_png_size(*m_context);
ASSERT(success); ASSERT(success);
} }
@ -630,9 +674,8 @@ Size PNGImageLoaderPlugin::size()
RefPtr<GraphicsBitmap> PNGImageLoaderPlugin::bitmap() RefPtr<GraphicsBitmap> PNGImageLoaderPlugin::bitmap()
{ {
if (m_context->state != PNGLoadingContext::State::BitmapDecoded) { if (m_context->state < PNGLoadingContext::State::BitmapDecoded) {
// NOTE: This forces the chunk decoding to happen. // NOTE: This forces the chunk decoding to happen.
size();
bool success = decode_png_bitmap(*m_context); bool success = decode_png_bitmap(*m_context);
ASSERT(success); ASSERT(success);
} }