From 847962910f0bff071f3bf07c9abb87764fb6cac3 Mon Sep 17 00:00:00 2001
From: claude-bot <claude@ancap.in.ua>
Date: Mon, 13 Jul 2026 12:40:03 +0000
Subject: Import aap/librw @ master

Snapshot for re3/reVC vendoring, per @lzcnt.
Source: https://github.com/aap/librw (master).
---
 src/png.cpp | 151 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)
 create mode 100644 src/png.cpp

(limited to 'src/png.cpp')

diff --git a/src/png.cpp b/src/png.cpp
new file mode 100644
index 0000000..45aa102
--- /dev/null
+++ b/src/png.cpp
@@ -0,0 +1,151 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include "rwbase.h"
+#include "rwerror.h"
+#include "rwplg.h"
+#include "rwpipeline.h"
+#include "rwobjects.h"
+#include "rwengine.h"
+
+#include "lodepng/lodepng.h"
+
+#define PLUGIN_ID 0
+
+namespace rw {
+
+
+Image*
+readPNG(const char *filename)
+{
+	Image *image = nil;
+	uint32 length;
+	uint8 *data = getFileContents(filename, &length);
+	assert(data != nil);
+
+	LodePNGState state;
+	lodepng_state_init(&state);
+	uint8 *raw = nil;
+	uint32 w, h;
+
+	// First try: decode without conversion to see if we understand the format
+	state.decoder.color_convert = 0;
+	uint32 error = lodepng_decode(&raw, &w, &h, &state, data, length);
+	if(error){
+		RWERROR((ERR_GENERAL, lodepng_error_text(error)));
+		return nil;
+	}
+
+	if(state.info_raw.bitdepth == 4 && state.info_raw.colortype == LCT_PALETTE){
+		image = Image::create(w, h, 4);
+		image->allocate();
+		memcpy(image->palette, state.info_raw.palette, state.info_raw.palettesize*4);
+		expandPal4_BE(image->pixels, image->stride, raw, w/2, w, h);
+	}else if(state.info_raw.bitdepth == 8){
+		switch(state.info_raw.colortype){
+		case LCT_PALETTE:
+			image = Image::create(w, h, state.info_raw.palettesize <= 16 ? 4 : 8);
+			image->allocate();
+			memcpy(image->palette, state.info_raw.palette, state.info_raw.palettesize*4);
+			memcpy(image->pixels, raw, w*h);
+			break;
+		case LCT_RGB:
+			image = Image::create(w, h, 24);
+			image->allocate();
+			memcpy(image->pixels, raw, w*h*3);
+			break;
+		default:
+			// Second try: just load as 32 bit
+			free(raw);
+			lodepng_state_init(&state);
+			error = lodepng_decode(&raw, &w, &h, &state, data, length);
+			if(error){
+				RWERROR((ERR_GENERAL, lodepng_error_text(error)));
+				return nil;
+			}
+			// fall through
+		case LCT_RGBA:
+			image = Image::create(w, h, 32);
+			image->allocate();
+			memcpy(image->pixels, raw, w*h*4);
+			break;
+		}
+	}
+
+	free(raw);	// TODO: maybe override lodepng allocator
+
+	return image;
+}
+
+void
+writePNG(Image *image, const char *filename)
+{
+	int32 i;
+	StreamFile file;
+	if(!file.open(filename, "wb")){
+		RWERROR((ERR_FILE, filename));
+		return;
+	}
+
+	size_t rawsize;
+	uint8 *raw = nil;
+	uint8 *pixels;
+	LodePNGState state;
+	lodepng_state_init(&state);
+
+	pixels = image->pixels;
+	switch(image->depth){
+	case 4:
+		state.info_raw.bitdepth = 4;
+		state.info_raw.colortype = LCT_PALETTE;
+		state.info_png.color.bitdepth = 4;
+		state.info_png.color.colortype = LCT_PALETTE;
+		state.encoder.auto_convert = 0;
+		for(i = 0; i < (1<<image->depth); i++){
+			uint8 *col = &image->palette[i*4];
+			lodepng_palette_add(&state.info_png.color, col[0], col[1], col[2], col[3]);
+			lodepng_palette_add(&state.info_raw, col[0], col[1], col[2], col[3]);
+		}
+		pixels = rwNewT(uint8, image->width/2*image->height, ID_IMAGE | MEMDUR_FUNCTION);
+		compressPal4_BE(pixels, image->width/2, image->pixels, image->width, image->width, image->height);
+		break;
+	case 8:
+		state.info_raw.colortype = LCT_PALETTE;
+		state.info_png.color.colortype = LCT_PALETTE;
+		state.encoder.auto_convert = 0;
+		for(i = 0; i < (1<<image->depth); i++){
+			uint8 *col = &image->palette[i*4];
+			lodepng_palette_add(&state.info_png.color, col[0], col[1], col[2], col[3]);
+			lodepng_palette_add(&state.info_raw, col[0], col[1], col[2], col[3]);
+		}
+		break;
+	case 16:
+		// Don't think we can have 16 bits with PNG
+		// TODO: don't change original image
+		image->convertTo32();
+		break;
+	case 24:
+		state.info_raw.colortype = LCT_RGB;
+		state.info_png.color.colortype = LCT_RGB;
+		state.encoder.auto_convert = 0;
+		break;
+	case 32:
+		// already done
+		break;
+	}
+
+	uint32 error = lodepng_encode(&raw, &rawsize, pixels, image->width, image->height, &state);
+	if(error){
+		RWERROR((ERR_GENERAL, lodepng_error_text(error)));
+		return;
+	}
+	if(pixels != image->pixels)
+		rwFree(pixels);
+	file.write8(raw, rawsize);
+	file.close();
+	free(raw);
+}
+
+}
-- 
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