minor bug fixes + bmp first try (not working)

src/programs/bmp.c

@@ -0,0 +1,81 @@
+// Bitmap image renderer
+// Author: xamidev
+// Licensed under the Unlicense. See the repo below.
+// https://github.com/xamidev/blankos
+
+#include "../kernel/kmain.h"
+#include <stdint.h>
+#include "../kernel/initrd.h"
+#include "../drivers/framebuffer.h"
+#include "../libc/stdio.h"
+
+typedef struct
+{
+	uint16_t bfType;
+	uint32_t bfSize;
+	uint16_t bfReserved1;
+	uint16_t bfReserved2;
+	uint32_t bfOffBits;
+} BMPHeader;
+
+typedef struct
+{
+	uint32_t biSize;
+	int32_t  biWidth;
+	int32_t  biHeight;
+	uint16_t biPlanes;
+	uint16_t biBitCount;
+	uint32_t biCompression;
+	uint32_t biSizeImage;
+	int32_t  biXPelsPerMeter;
+	int32_t  biYPelsPerMeter;
+	uint32_t biClrUsed;
+	uint32_t biClrImportant;
+} BMPInfoHeader;
+
+void display_bmp(uint32_t* fb, int pitch, int bpp, uint8_t* initrd)
+{
+	char buffer[1024*1024];
+	int file_status = tar_file_to_buffer(initrd, "./flower.bmp", buffer);
+
+	if (file_status != 0)
+	{
+		puts("Error loading BMP\n");
+		return;
+	}
+
+	BMPHeader* bmp_header = (BMPHeader*)buffer;
+	BMPInfoHeader* bmp_info = (BMPInfoHeader*) (buffer+sizeof(BMPHeader));
+
+	if (bmp_header->bfType != 0x4D42)
+	{
+		puts("Not a valid BMP\n");
+		return;
+	}
+
+	int width = bmp_info->biWidth;
+	int height = bmp_info->biHeight;
+	int pixel_offset = bmp_header->bfOffBits;
+
+	if (bmp_info->biBitCount != 24)
+	{
+		puts("Not a 24-bit BMP\n");
+		return;
+	}
+
+	uint8_t* pixel_data = (uint8_t*)(buffer + pixel_offset);
+
+	for (int y=0; y<height; y++)
+	{
+		for (int x=0; x<width; x++)
+		{
+			int index = (x+(height-y-1)*width)*3;
+			uint8_t blue = pixel_data[index];
+			uint8_t green = pixel_data[index+1];
+			uint8_t red = pixel_data[index+2];
+
+			uint32_t color = (red << 16) | (green << 8) | blue;
+			putpixel(fb, pitch, bpp, x, y, color);
+		}
+	}
+}