Merge imported librosprite onto trunk

svn path=/trunk/librosprite/; revision=10029

1 files changed, 0 insertions, 840 deletions

diff --git a/trunk/librosprite.c b/trunk/librosprite.c
deleted file mode 100644
index e21b8cb..0000000
--- a/trunk/librosprite.c
+++ /dev/null
@@ -1,840 +0,0 @@
-/*
- * This file is part of librosprite.
- * Licensed under the MIT License,
- *                http://www.opensource.org/licenses/mit-license.php
- * Copyright 2008 James Shaw <js102@zepler.net>
- */
-
-/**
- * \file
- */
-
-#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <stdbool.h>
-#include <string.h>
-
-#include "librosprite.h"
-
-/**
- * Reads four bytes, 00, 11, 22 and 33, of a byte array b to give 0x33221100.
- */
-#define BTUINT(b) (b[0] | (b[1] << 8) | (b[2] << 16) | (b[3] << 24))
-
-/**
- * Reverse the byte order of a word such that 0xAABBCCDD becomes 0xDDCCBBAA.
- */
-#define BSWAP(word) (((word & (0x000000ff)) << 24) | ((word & 0x0000ff00) << 8) | ((word & 0x00ff0000) >> 8) | ((word & 0xff000000) >> 24))
-
-#define ERRCHK(x) do { \
-	rosprite_error err = x; \
-	if (err != ROSPRITE_OK) return err; \
-} while(0)
-
-struct rosprite_header {
-	uint32_t width_words; /* width in words */
-	/* height defined in sprite struct */
-	uint32_t first_used_bit; /* old format only (spriteType = 0) */
-	uint32_t last_used_bit;
-
-	/**
-	 * Image size in bytes
-	 */
-	uint32_t image_size;
-
-	/**
-	 * Mask size in bytes
-	 */
-	uint32_t mask_size;
-};
-
-struct rosprite_mask_state {
-	uint32_t x;
-	uint32_t y;
-	uint32_t first_used_bit;
-	uint32_t row_max_bit;
-	uint32_t height;
-	uint32_t current_byte_index;
-	uint32_t current_word;
-	uint32_t bpp;
-};
-
-struct rosprite_file_context {
-	FILE* f;
-};
-
-struct rosprite_mem_context {
-	uint8_t* base;
-	unsigned long offset;
-	bool known_size;
-	unsigned long size;
-};
-
-static const struct rosprite_mode oldmodes[] = {
-/*0*/{ .colorbpp = 1, .maskbpp = 1, .mask_width = 1, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*1*/{ .colorbpp = 2, .maskbpp = 1, .mask_width = 2, .xdpi = 45, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*2*/{ .colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 22, .ydpi = 45, .color_model = ROSPRITE_RGB },
-
-/*3*/{ .colorbpp = 0, .maskbpp = 0, .mask_width = 0, .xdpi = 0,  .ydpi = 0,  .color_model = ROSPRITE_RGB },
-
-/*4*/{ .colorbpp = 1, .maskbpp = 1, .mask_width = 1, .xdpi = 45, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*5*/{ .colorbpp = 2, .maskbpp = 1, .mask_width = 2, .xdpi = 22, .ydpi = 45, .color_model = ROSPRITE_RGB },
-
-/*6*/{ .colorbpp = 0, .maskbpp = 0, .mask_width = 0, .xdpi = 0,  .ydpi = 0,  .color_model = ROSPRITE_RGB },
-/*7*/{ .colorbpp = 0, .maskbpp = 0, .mask_width = 0, .xdpi = 0,  .ydpi = 0,  .color_model = ROSPRITE_RGB },
-
-/*8*/{ .colorbpp = 2, .maskbpp = 1, .mask_width = 2, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*9*/{ .colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 45, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*10*/{.colorbpp = 8, .maskbpp = 1, .mask_width = 8, .xdpi = 22, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*11*/{.colorbpp = 2, .maskbpp = 1, .mask_width = 2, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*12*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*13*/{.colorbpp = 8, .maskbpp = 1, .mask_width = 8, .xdpi = 45, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*14*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*15*/{.colorbpp = 8, .maskbpp = 1, .mask_width = 8, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*16*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*17*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*18*/{.colorbpp = 1, .maskbpp = 1, .mask_width = 1, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*19*/{.colorbpp = 2, .maskbpp = 1, .mask_width = 2, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*20*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*21*/{.colorbpp = 8, .maskbpp = 1, .mask_width = 8, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*22*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi =180, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*23*/{.colorbpp = 1, .maskbpp = 1, .mask_width = 1, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*24*/{.colorbpp = 8, .maskbpp = 1, .mask_width = 8, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*25*/{.colorbpp = 1, .maskbpp = 1, .mask_width = 1, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*26*/{.colorbpp = 2, .maskbpp = 1, .mask_width = 2, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*27*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*28*/{.colorbpp = 8, .maskbpp = 1, .mask_width = 8, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*29*/{.colorbpp = 1, .maskbpp = 1, .mask_width = 1, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*30*/{.colorbpp = 2, .maskbpp = 1, .mask_width = 2, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*31*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*32*/{.colorbpp = 8, .maskbpp = 1, .mask_width = 8, .xdpi = 90, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*33*/{.colorbpp = 1, .maskbpp = 1, .mask_width = 1, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*34*/{.colorbpp = 2, .maskbpp = 1, .mask_width = 2, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*35*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*36*/{.colorbpp = 8, .maskbpp = 1, .mask_width = 8, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*37*/{.colorbpp = 1, .maskbpp = 1, .mask_width = 1, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*38*/{.colorbpp = 2, .maskbpp = 1, .mask_width = 2, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*39*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*40*/{.colorbpp = 8, .maskbpp = 1, .mask_width = 8, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*41*/{.colorbpp = 1, .maskbpp = 1, .mask_width = 1, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*42*/{.colorbpp = 2, .maskbpp = 1, .mask_width = 2, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*43*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*44*/{.colorbpp = 1, .maskbpp = 1, .mask_width = 1, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*45*/{.colorbpp = 2, .maskbpp = 1, .mask_width = 2, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*46*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 90, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*47*/{.colorbpp = 8, .maskbpp = 1, .mask_width = 8, .xdpi = 45, .ydpi = 45, .color_model = ROSPRITE_RGB },
-/*48*/{.colorbpp = 4, .maskbpp = 1, .mask_width = 4, .xdpi = 45, .ydpi = 90, .color_model = ROSPRITE_RGB },
-/*49*/{.colorbpp = 8, .maskbpp = 1, .mask_width = 8, .xdpi = 45, .ydpi = 90, .color_model = ROSPRITE_RGB }
-};
-
-/* table for converting a 5bit channel into an 8bit channel (used for 16bpp to 32bpp conversion) */
-static const uint8_t sprite_16bpp_translate[] = {
-	0x00, 0x08, 0x10, 0x18, 0x20, 0x29, 0x31, 0x39,
-	0x41, 0x4a, 0x52, 0x5a, 0x62, 0x6a, 0x73, 0x7b,
-	0x83, 0x8b, 0x94, 0x9c, 0xa4, 0xac, 0xb4, 0xbd,
-	0xc5, 0xcd, 0xd5, 0xde, 0xe6, 0xee, 0xf6, 0xff
-};
-
-/* palettes generated with palette2c.c
- * which in turn requires rosprite_load_palette(FILE* f)
- * defined in this file
- */
-static const uint32_t sprite_1bpp_palette[] = { 0xffffffff, 0xff };
-
-static const uint32_t sprite_2bpp_palette[] = { 0xffffffff, 0xbbbbbbff, 0x777777ff, 0xff };
-
-static const uint32_t sprite_4bpp_palette[] = {
-0xffffffff, 0xddddddff, 0xbbbbbbff, 0x999999ff,
-0x777777ff, 0x555555ff, 0x333333ff, 0xff,
-0x4499ff, 0xeeee00ff, 0xcc00ff, 0xdd0000ff,
-0xeeeebbff, 0x558800ff, 0xffbb00ff, 0xbbffff
-};
-
-static const uint32_t sprite_8bpp_palette[] = {
-0xff, 0x111111ff, 0x222222ff, 0x333333ff,
-0x440000ff, 0x551111ff, 0x662222ff, 0x773333ff,
-0x44ff, 0x111155ff, 0x222266ff, 0x333377ff,
-0x440044ff, 0x551155ff, 0x662266ff, 0x773377ff,
-0x880000ff, 0x991111ff, 0xaa2222ff, 0xbb3333ff,
-0xcc0000ff, 0xdd1111ff, 0xee2222ff, 0xff3333ff,
-0x880044ff, 0x991155ff, 0xaa2266ff, 0xbb3377ff,
-0xcc0044ff, 0xdd1155ff, 0xee2266ff, 0xff3377ff,
-0x4400ff, 0x115511ff, 0x226622ff, 0x337733ff,
-0x444400ff, 0x555511ff, 0x666622ff, 0x777733ff,
-0x4444ff, 0x115555ff, 0x226666ff, 0x337777ff,
-0x444444ff, 0x555555ff, 0x666666ff, 0x777777ff,
-0x884400ff, 0x995511ff, 0xaa6622ff, 0xbb7733ff,
-0xcc4400ff, 0xdd5511ff, 0xee6622ff, 0xff7733ff,
-0x884444ff, 0x995555ff, 0xaa6666ff, 0xbb7777ff,
-0xcc4444ff, 0xdd5555ff, 0xee6666ff, 0xff7777ff,
-0x8800ff, 0x119911ff, 0x22aa22ff, 0x33bb33ff,
-0x448800ff, 0x559911ff, 0x66aa22ff, 0x77bb33ff,
-0x8844ff, 0x119955ff, 0x22aa66ff, 0x33bb77ff,
-0x448844ff, 0x559955ff, 0x66aa66ff, 0x77bb77ff,
-0x888800ff, 0x999911ff, 0xaaaa22ff, 0xbbbb33ff,
-0xcc8800ff, 0xdd9911ff, 0xeeaa22ff, 0xffbb33ff,
-0x888844ff, 0x999955ff, 0xaaaa66ff, 0xbbbb77ff,
-0xcc8844ff, 0xdd9955ff, 0xeeaa66ff, 0xffbb77ff,
-0xcc00ff, 0x11dd11ff, 0x22ee22ff, 0x33ff33ff,
-0x44cc00ff, 0x55dd11ff, 0x66ee22ff, 0x77ff33ff,
-0xcc44ff, 0x11dd55ff, 0x22ee66ff, 0x33ff77ff,
-0x44cc44ff, 0x55dd55ff, 0x66ee66ff, 0x77ff77ff,
-0x88cc00ff, 0x99dd11ff, 0xaaee22ff, 0xbbff33ff,
-0xcccc00ff, 0xdddd11ff, 0xeeee22ff, 0xffff33ff,
-0x88cc44ff, 0x99dd55ff, 0xaaee66ff, 0xbbff77ff,
-0xcccc44ff, 0xdddd55ff, 0xeeee66ff, 0xffff77ff,
-0x88ff, 0x111199ff, 0x2222aaff, 0x3333bbff,
-0x440088ff, 0x551199ff, 0x6622aaff, 0x7733bbff,
-0xccff, 0x1111ddff, 0x2222eeff, 0x3333ffff,
-0x4400ccff, 0x5511ddff, 0x6622eeff, 0x7733ffff,
-0x880088ff, 0x991199ff, 0xaa22aaff, 0xbb33bbff,
-0xcc0088ff, 0xdd1199ff, 0xee22aaff, 0xff33bbff,
-0x8800ccff, 0x9911ddff, 0xaa22eeff, 0xbb33ffff,
-0xcc00ccff, 0xdd11ddff, 0xee22eeff, 0xff33ffff,
-0x4488ff, 0x115599ff, 0x2266aaff, 0x3377bbff,
-0x444488ff, 0x555599ff, 0x6666aaff, 0x7777bbff,
-0x44ccff, 0x1155ddff, 0x2266eeff, 0x3377ffff,
-0x4444ccff, 0x5555ddff, 0x6666eeff, 0x7777ffff,
-0x884488ff, 0x995599ff, 0xaa66aaff, 0xbb77bbff,
-0xcc4488ff, 0xdd5599ff, 0xee66aaff, 0xff77bbff,
-0x8844ccff, 0x9955ddff, 0xaa66eeff, 0xbb77ffff,
-0xcc44ccff, 0xdd55ddff, 0xee66eeff, 0xff77ffff,
-0x8888ff, 0x119999ff, 0x22aaaaff, 0x33bbbbff,
-0x448888ff, 0x559999ff, 0x66aaaaff, 0x77bbbbff,
-0x88ccff, 0x1199ddff, 0x22aaeeff, 0x33bbffff,
-0x4488ccff, 0x5599ddff, 0x66aaeeff, 0x77bbffff,
-0x888888ff, 0x999999ff, 0xaaaaaaff, 0xbbbbbbff,
-0xcc8888ff, 0xdd9999ff, 0xeeaaaaff, 0xffbbbbff,
-0x8888ccff, 0x9999ddff, 0xaaaaeeff, 0xbbbbffff,
-0xcc88ccff, 0xdd99ddff, 0xeeaaeeff, 0xffbbffff,
-0xcc88ff, 0x11dd99ff, 0x22eeaaff, 0x33ffbbff,
-0x44cc88ff, 0x55dd99ff, 0x66eeaaff, 0x77ffbbff,
-0xccccff, 0x11ddddff, 0x22eeeeff, 0x33ffffff,
-0x44ccccff, 0x55ddddff, 0x66eeeeff, 0x77ffffff,
-0x88cc88ff, 0x99dd99ff, 0xaaeeaaff, 0xbbffbbff,
-0xcccc88ff, 0xdddd99ff, 0xeeeeaaff, 0xffffbbff,
-0x88ccccff, 0x99ddddff, 0xaaeeeeff, 0xbbffffff,
-0xccccccff, 0xddddddff, 0xeeeeeeff, 0xffffffff
-};
-
-static inline rosprite_error rosprite_read_word(reader reader, void* ctx, uint32_t* result);
-static rosprite_error rosprite_get_mode(uint32_t spriteMode, struct rosprite_mode* result);
-static uint32_t rosprite_palette_lookup(struct rosprite* sprite, uint32_t pixel);
-static inline uint32_t rosprite_cmyk_to_rgb(uint32_t cmyk);
-static uint32_t rosprite_next_mask_pixel(uint8_t* mask, struct rosprite_mask_state* mask_state);
-static rosprite_error rosprite_load_high_color(uint8_t* image_in, uint8_t* mask, struct rosprite* sprite, struct rosprite_header* header);
-static rosprite_error rosprite_load_low_color(uint8_t* image_in, uint8_t* mask, struct rosprite* sprite, struct rosprite_header* header);
-rosprite_error rosprite_load_sprite(reader reader, void* ctx, struct rosprite** result);
-static rosprite_error rosprite_init_mask_state(struct rosprite* sprite, struct rosprite_header* header, uint8_t* mask, struct rosprite_mask_state** result);
-static uint32_t rosprite_upscale_color(uint32_t pixel, struct rosprite_mode* mode, bool* has_alpha_pixel_data);
-static inline void rosprite_fix_alpha(uint32_t* image, unsigned long pixels);
-
-rosprite_error rosprite_load(reader reader, void* ctx, struct rosprite_area** result)
-{
-	struct rosprite_area* sprite_area = malloc(sizeof(struct rosprite_area));
-
-	ERRCHK(rosprite_read_word(reader, ctx, &(sprite_area->sprite_count)));
-
-	uint32_t firstSpriteOffset, firstFreeWordOffset;
-	ERRCHK(rosprite_read_word(reader, ctx, &firstSpriteOffset));
-	ERRCHK(rosprite_read_word(reader, ctx, &firstFreeWordOffset)); /* TODO: use this for some sanity checking? */
-	sprite_area->extension_size = 16 - firstSpriteOffset;
-
-	sprite_area->extension_words = NULL;
-	if (sprite_area->extension_size > 0) {
-		sprite_area->extension_words = malloc(sprite_area->extension_size);
-		int bytes_read = reader(sprite_area->extension_words, (size_t) (sprite_area->extension_size), ctx);
-		if (bytes_read < (signed long) sprite_area->extension_size) {
-			return ROSPRITE_EOF;
-		}
-	}
-
-	sprite_area->sprites = malloc(sizeof(struct rosprite*) * sprite_area->sprite_count); /* allocate array of pointers */
-	for (uint32_t i = 0; i < sprite_area->sprite_count; i++) {
-		struct rosprite* sprite;
-		ERRCHK(rosprite_load_sprite(reader, ctx, &sprite));
-		sprite_area->sprites[i] = sprite;
-	}
-
-	*result = sprite_area;
-
-	return ROSPRITE_OK;
-}
-
-void rosprite_destroy_sprite_area(struct rosprite_area* sprite_area)
-{
-	for (uint32_t i = 0; i < sprite_area->sprite_count; i++) {
-		struct rosprite* sprite = sprite_area->sprites[i];
-		if (sprite->has_palette) free(sprite->palette);
-		free(sprite->image);
-		free(sprite);
-	}
-
-	free(sprite_area->sprites);
-	if (sprite_area->extension_size > 0) free(sprite_area->extension_words);
-	free(sprite_area);
-}
-
-rosprite_error rosprite_load_palette(reader reader, void* ctx, struct rosprite_palette** result)
-{
-	/* TODO: currently assume palette has linear entries (2nd byte in is 00, 01, 02 etc) */
-	struct rosprite_palette* palette = malloc(sizeof(struct rosprite_palette));
-
-	palette->palette = malloc(sizeof(uint32_t) * 256); /* allocate 256 whether we need them all or not */
-
-	uint32_t c = 0;
-	uint8_t b[6];
-
-	unsigned int bytesRead = reader(b, 6, ctx);
-	assert(bytesRead % 6 == 0);
-	while (bytesRead == 6) {
-		assert(b[0] == 19); /* VDU 19 */
-
-		/* only process logical colours */
-		if (b[2] == 16) {
-			/*assert(c == b[1]);*/
-	
-			uint32_t entry = (b[3] << 24) | (b[4] << 16) | (b[5] << 8) | 0xff; /* last byte is alpha */
-			palette->palette[c] = entry;
-	
-			c++;
-			assert(c <= 256);
-		}
-
-		bytesRead = reader(b, 6, ctx);
-		assert(bytesRead % 6 == 0);
-	}
-
-	palette->size = c;
-
-	*result = palette;
-
-	return ROSPRITE_OK;
-}
-
-void rosprite_destroy_palette(struct rosprite_palette* palette)
-{
-	free(palette->palette);
-	free(palette);
-}
-
-rosprite_error rosprite_create_file_context(FILE* f, struct rosprite_file_context** result)
-{
-	struct rosprite_file_context* ctx = malloc(sizeof(struct rosprite_file_context));
-	if (!ctx) return ROSPRITE_NOMEM;
-	ctx->f = f;
-	*result = ctx;
-
-	return ROSPRITE_OK;
-}
-
-void rosprite_destroy_file_context(struct rosprite_file_context* ctx)
-{
-	free(ctx);
-}
-
-int rosprite_file_reader(uint8_t* buf, size_t count, void* ctx)
-{
-	return fread(buf, 1 /*size*/, count, ((struct rosprite_file_context*) ctx)->f);
-}
-
-rosprite_error rosprite_create_mem_context(uint8_t* p, unsigned long total_size, struct rosprite_mem_context** result)
-{
-	struct rosprite_mem_context* ctx = malloc(sizeof(struct rosprite_mem_context));
-	if (!ctx) return ROSPRITE_NOMEM;
- 
-	ctx->base = p;
-	ctx->offset = 0;
-	ctx->size = total_size;
-	*result = ctx;
- 
-	return ROSPRITE_OK;
-}
-
-void rosprite_destroy_mem_context(struct rosprite_mem_context* ctx)
-{
-	free(ctx);
-}
-
-int rosprite_mem_reader(uint8_t* buf, size_t count, void* ctx)
-{
-	struct rosprite_mem_context* memctx = (struct rosprite_mem_context*) ctx;
-	if (memctx->offset + count > memctx->size) {
-		return -1;
-	}
-
-	// if we're asked for more memory than the block contains, only copy as much as we can
-	size_t copy_size;
-	if ((memctx->offset + count) > memctx->size) {
-		copy_size = memctx->size - memctx->offset;
-	} else {
-		copy_size = count;
-	}
-	memcpy(buf, memctx->base + memctx->offset, count);
-	memctx->offset += count;
-	return copy_size;
-}
-
-/**
- * Load a single sprite.
- *
- * \param[out] result
- */
-rosprite_error rosprite_load_sprite(reader reader, void* ctx, struct rosprite** result)
-{
-	uint32_t nextSpriteOffset;
-	ERRCHK(rosprite_read_word(reader, ctx, &nextSpriteOffset));
-
-	struct rosprite* sprite = malloc(sizeof(struct rosprite));
-	struct rosprite_header* header = malloc(sizeof(struct rosprite_header));
-
-	reader(sprite->name, 12, ctx);
-	sprite->name[12] = '\0';
-
-	ERRCHK(rosprite_read_word(reader, ctx, &header->width_words)); /* file has width - 1 and height - 1 */
-	header->width_words += 1;
-	ERRCHK(rosprite_read_word(reader, ctx, &(sprite->height)));
-	sprite->height += 1;
-	ERRCHK(rosprite_read_word(reader, ctx, &(header->first_used_bit))); /* old format only (spriteType = 0) */
-	ERRCHK(rosprite_read_word(reader, ctx, &(header->last_used_bit)));
-
-	uint32_t imageOffset;
-	ERRCHK(rosprite_read_word(reader, ctx, &imageOffset));
-	assert(imageOffset >= 44); /* should never be smaller than the size of the header) */
-
-	uint32_t maskOffset, spriteModeWord;
-	ERRCHK(rosprite_read_word(reader, ctx, &maskOffset));
-	ERRCHK(rosprite_read_word(reader, ctx, &spriteModeWord));
-
-	ERRCHK(rosprite_get_mode(spriteModeWord, &(sprite->mode)));
-
-	/* TODO left-hand wastage */
-	
-	assert((header->last_used_bit + 1) % sprite->mode.colorbpp == 0);
-	/*assert(header->width_words % sprite->mode->colorbpp == 0);*/
-	sprite->width = (header->width_words * 32 - header->first_used_bit - (31 - header->last_used_bit)) / sprite->mode.colorbpp;
-
-	sprite->palettesize     = imageOffset - 44;
-	sprite->has_palette     = (sprite->palettesize > 0);
-
-	/* sprite has no mask if imageOffset == maskOffset */
-	if (imageOffset == maskOffset) {
-		sprite->has_mask   = false;
-		header->image_size = nextSpriteOffset - 44 - sprite->palettesize;
-		header->mask_size  = 0;
-	} else {
-		sprite->has_mask   = true;
-		header->image_size = maskOffset - imageOffset;
-		header->mask_size  = nextSpriteOffset - 44 - sprite->palettesize - header->image_size;
-	}
-	
-	if (sprite->has_palette) {
-		assert(sprite->palettesize % 8 == 0);
-		sprite->palette = malloc(sizeof(uint32_t) * sprite->palettesize);
-		uint32_t paletteEntries = sprite->palettesize / 8;
-
-		/* Each palette entry is two words big
-		 * The second word is a duplicate of the first
-		 * I think this is in case you ever wanted flashing colours
-		 * PRM1-730
-		 */
-		for (uint32_t j = 0; j < paletteEntries; j++) {
-			uint32_t word1, word2;
-			ERRCHK(rosprite_read_word(reader, ctx, &word1));
-			ERRCHK(rosprite_read_word(reader, ctx, &word2));
-			assert(word1 == word2); /* if they aren't equal, flashing colours are desired, which we don't support */
-			
-			/* swap rr and bb parts -- PRM1-731 */
-			uint32_t entry = ((word1 & 0xff000000) >> 16) | (word1 & 0x00ff0000) | ((word1 & 0x0000ff00) << 16) | 0xff;
-			sprite->palette[j] = entry;
-		}
-	}
-
-	uint8_t* image = malloc(header->image_size);
-	reader(image, header->image_size, ctx);
-
-	uint8_t* mask = NULL;
-	if (sprite->has_mask) {
-		mask = malloc(header->mask_size);
-		reader(mask, header->mask_size, ctx);
-	}
-
-	/* sanity check image_size */
-	assert((header->width_words) * 4 * (sprite->height) == header->image_size);
-	/* TODO: sanity check mask_size */
-	if (sprite->mode.colorbpp > 8) {
-		ERRCHK(rosprite_load_high_color(image, mask, sprite, header));
-	} else {
-		ERRCHK(rosprite_load_low_color(image, mask, sprite, header));
-	}
-
-	free(image);
-	free(mask);
-	free(header);
-
-	*result = sprite;
-
-	return ROSPRITE_OK;
-}
-
-/**
- * Determine the sprite_mode for the specified sprite_mode_word.
- *
- * \param[out] result
- */
-static rosprite_error rosprite_get_mode(uint32_t sprite_mode_word, struct rosprite_mode* result)
-{
-	struct rosprite_mode mode;
-
-	uint32_t spriteType = (sprite_mode_word & (15 << 27)) >> 27; /* preserve bits 27-30 only */
-
-	if (spriteType != 0) {
-		bool hasEightBitAlpha = sprite_mode_word >> 31; /* bit 31 */
-		/* new modes have 1bpp masks (PRM5a-111)
-		 * unless bit 31 is set (http://select.riscos.com/prm/graphics/sprites/alphachannel.html)
-		 */
-		mode.maskbpp = (hasEightBitAlpha ? 8 : 1);
-		mode.mask_width = mode.maskbpp;
-		mode.xdpi = (sprite_mode_word & (8191 << 14)) >> 14; /* preserve bits 14-26 only */
-		mode.ydpi = (sprite_mode_word & (8191 << 1)) >> 1; /* preserve bits 1-13 only */
-
-		mode.color_model = ROSPRITE_RGB;
-		switch (spriteType) {
-		case 1:
-			mode.colorbpp = 1; break;
-		case 2:
-			mode.colorbpp = 2; break;
-		case 3:
-			mode.colorbpp = 4; break;
-		case 4:
-			mode.colorbpp = 8; break;
-		case 5:
-			mode.colorbpp = 16; break;
-		case 6:
-			mode.colorbpp = 32; break;
-		case 7:
-			mode.colorbpp = 32;
-			mode.color_model = ROSPRITE_CMYK;
-			break;
-		case 8:
-			mode.colorbpp = 24; break;
-		default:
-			return ROSPRITE_BADMODE;
-		}
-	} else {
-		assert(sprite_mode_word < 256); /* don't think you can have modes over 255? */
-
-		mode = oldmodes[sprite_mode_word];
-	}
-
-	/* illegal mode check */
-	if ((mode.colorbpp == 0) || (mode.xdpi == 0) || (mode.ydpi == 0)) {
-		return ROSPRITE_BADMODE;
-	}
-
-	memcpy(result, &mode, sizeof(struct rosprite_mode));
-
-	return ROSPRITE_OK;
-}
-
-/**
- * Load a sprite image with 16 or more bpp.
- *
- * \param[out] sprite On exit, sprite.image will be populated
- */
-static rosprite_error rosprite_load_high_color(uint8_t* image_in, uint8_t* mask, struct rosprite* sprite, struct rosprite_header* header)
-{
-	struct rosprite_mask_state* mask_state = NULL;
-	if (sprite->has_mask) {
-		ERRCHK(rosprite_init_mask_state(sprite, header, mask, &mask_state));
-	}
-
-	sprite->image = malloc(sprite->width * sprite->height * 4); /* all image data is 32bpp going out */
-
-	uint32_t currentByteIndex = 0;
-	const uint32_t bpp = sprite->mode.colorbpp;
-	const uint32_t bytesPerPixel = bpp / 8;
-	const uint32_t row_max_bit = header->width_words * 32 - (31 - header->last_used_bit); /* Last used bit in row */
-
-	bool has_alpha_pixel_data = false;
-
-	/* Spec says that there must be no left-hand wastage */
-	assert(header->first_used_bit == 0);
-	
-	for (uint32_t y = 0; y < sprite->height; y++) {
-		uint32_t x_pixels = 0;
-		for (uint32_t x = 0; x < row_max_bit; x += bpp) {
-			uint32_t pixel = 0;
-			for (uint32_t j = 0; j < bytesPerPixel; j++) {
-				uint8_t b = image_in[currentByteIndex++];
-				pixel = pixel | (b << (j * 8));
-			}
-			
-			bool old_has_alpha = has_alpha_pixel_data;
-			pixel = rosprite_upscale_color(pixel, &(sprite->mode), &has_alpha_pixel_data);
-			if (old_has_alpha != has_alpha_pixel_data && (y > 0 || x_pixels > 0)) {
-				rosprite_fix_alpha(sprite->image, (y * sprite->width) + x_pixels - 1);
-			}
-			if (sprite->has_mask) {
-				uint8_t mask_pixel = rosprite_next_mask_pixel(mask, mask_state);
-				pixel = (pixel & 0xffffff00) | mask_pixel;
-			}
-			sprite->image[y*sprite->width + x_pixels] = pixel;
-			x_pixels++;
-		}
-
-		/* Ensure byte index is pointing at start of next row */
-		if (y + 1 < sprite->height) {
-			currentByteIndex = (currentByteIndex + 3) & ~3; /* Round up to next multiple of 4 */
-		}
-	}
-
-	if (sprite->has_mask) free(mask_state);
-	return ROSPRITE_OK;
-}
-
-/**
- * Iterate over the specified number of pixels, starting at the image pointer,
- * and set the alpha channel to 0x00.
- */
-static inline void rosprite_fix_alpha(uint32_t* image, unsigned long pixels)
-{
-	for (uint32_t i = 0; i <= pixels; i++) {
-		image[i] = image[i] & 0xffffff00;
-	}
-}
-
-/**
- * Load a sprite image with 8 or fewer bpp.
- *
- * \param[out] sprite On exit, sprite.image will be populated
- */
-static rosprite_error rosprite_load_low_color(uint8_t* image_in, uint8_t* mask, struct rosprite* sprite, struct rosprite_header* header)
-{
-	struct rosprite_mask_state* mask_state = NULL;
-	if (sprite->has_mask) {
-		ERRCHK(rosprite_init_mask_state(sprite, header, mask, &mask_state));
-	}
-
-	sprite->image = malloc(sprite->width * sprite->height * 4); /* all image data is 32bpp going out */
-
-	const uint32_t bpp = sprite->mode.colorbpp;
-	const uint32_t row_max_bit = header->width_words * 32 - (31 - header->last_used_bit); /* Last used bit in row */
-	const uint32_t bitmask = (1 << bpp) - 1; /* creates a mask of 1s that is bpp bits wide */
-
-	uint32_t current_byte_index = 0;
-	uint32_t currentword = BTUINT((image_in + current_byte_index));
-	current_byte_index += 4;
-	
-	for (uint32_t y = 0; y < sprite->height; y++) {
-		uint32_t x_pixels = 0;
-		for (uint32_t x = header->first_used_bit; x < row_max_bit ; x += bpp) {
-			const uint32_t offset_into_word = x % 32;
-
-			uint32_t pixel = (currentword & (bitmask << offset_into_word)) >> offset_into_word;
-			pixel = rosprite_palette_lookup(sprite, pixel); /* lookup returns 32bpp */
-			if (sprite->has_mask) {
-				uint8_t mask_pixel = rosprite_next_mask_pixel(mask, mask_state);
-				pixel = (pixel & 0xffffff00) | mask_pixel;
-			}
-			sprite->image[y*sprite->width + x_pixels] = pixel;
-			x_pixels++;
-
-			/* If we're not at the end of the row and we've processed all of this word, fetch the next one */
-			if (x + bpp < row_max_bit && offset_into_word + bpp == 32) {
-				currentword = BTUINT((image_in + current_byte_index));
-				current_byte_index += 4;
-			}
-		}
-
-		/* Advance to first word of next row */
-		if (y + 1 < sprite->height) {
-			currentword = BTUINT((image_in + current_byte_index));
-			current_byte_index += 4;
-		}
-	}
-
-	if (sprite->has_mask) free(mask_state);
-
-	return ROSPRITE_OK;
-}
-
-static uint32_t rosprite_palette_lookup(struct rosprite* sprite, uint32_t pixel)
-{
-	uint32_t translated_pixel;
-	 /* because we're dealing with 8bpp or less */
-	if (sprite->has_palette) {
-		assert(pixel <= sprite->palettesize); /* TODO: what to do if your color depth is bigger than palette? */
-		translated_pixel = sprite->palette[pixel];
-	} else {
-		switch (sprite->mode.colorbpp) {
-		case 8:
-			assert(pixel < 256);
-			translated_pixel = sprite_8bpp_palette[pixel];
-			break;
-		case 4:
-			assert(pixel < 16);
-			translated_pixel = sprite_4bpp_palette[pixel];
-			break;
-		case 2:
-			assert(pixel < 4);
-			translated_pixel = sprite_2bpp_palette[pixel];
-			break;
-		case 1:
-			assert(pixel < 2);
-			translated_pixel = sprite_1bpp_palette[pixel];
-			break;
-		default:
-			assert(false);
-		}
-	}
-	return translated_pixel;
-}
-
-static rosprite_error rosprite_init_mask_state(struct rosprite* sprite, struct rosprite_header* header, uint8_t* mask, struct rosprite_mask_state** result)
-{
-	struct rosprite_mask_state* mask_state = malloc(sizeof(struct rosprite_mask_state));
-	if (!mask_state) return ROSPRITE_NOMEM;
-
-	mask_state->x = header->first_used_bit;
-	mask_state->y = 0;
-	mask_state->first_used_bit = header->first_used_bit;
-	mask_state->row_max_bit = sprite->width * sprite->mode.mask_width;
-	mask_state->height = sprite->height;
-	mask_state->bpp = sprite->mode.mask_width;
-	mask_state->current_word = BTUINT(mask);
-	mask_state->current_byte_index = 4;
-
-	*result = mask_state;
-
-	return ROSPRITE_OK;
-}
-
-/**
- * Get the next mask byte.
- * A mask of 0xff denotes 100% opaque, 0x00 denotes 100% transparent.
- * 
- * \param[in,out] mask_state
- */
-static uint32_t rosprite_next_mask_pixel(uint8_t* mask, struct rosprite_mask_state* mask_state)
-{
-	/* a 1bpp mask (for new mode sprites), each row is word aligned (therefore potential righthand wastage */	
-	const uint32_t bitmask = (1 << mask_state->bpp) - 1;
-	const uint32_t offset_into_word = mask_state->x % 32;
-	uint32_t pixel = (mask_state->current_word & (bitmask << offset_into_word)) >> offset_into_word;
-
-	if (mask_state->x + mask_state->bpp < mask_state->row_max_bit && offset_into_word + mask_state->bpp == 32) {
-		mask_state->current_word = BTUINT((mask + mask_state->current_byte_index));
-		mask_state->current_byte_index += 4;
-	}
-
-	mask_state->x += mask_state->bpp;
-	if (mask_state->x >= mask_state->row_max_bit) {
-		mask_state->x = mask_state->first_used_bit;
-
-		if (mask_state->y + 1 < mask_state->height) {
-			mask_state->current_word = BTUINT((mask + mask_state->current_byte_index));
-			mask_state->current_byte_index += 4;
-		}
-
-		mask_state->y++;
-	}
-
-	/*
-	 * if the mask is 1bpp, make sure the whole byte is 0x00 or 0xff
-	 */
-	if (mask_state->bpp < 8) {
-		pixel = (pixel & 1) ? 0xff : 0x00;
-	}
-
-	return pixel;
-}
-
-/**
- * Upscale a 16, 24 or 32bpp sprite to the 0xRRGGBBAA representation.
- * Do not call this function with a sprite with less than 16bpp,
- * but use a palette lookup instead.
- */
-static uint32_t rosprite_upscale_color(uint32_t pixel, struct rosprite_mode* mode, bool* has_alpha_pixel_data)
-{
-	switch (mode->colorbpp) {
-	case 32:
-		if (mode->color_model == ROSPRITE_RGB) {
-			/* swap from 0xAABBGGRR to 0xRRGGBBAA */
-			pixel = BSWAP(pixel);
-		} else {
-			pixel = rosprite_cmyk_to_rgb(pixel);
-		}
-		break;
-	case 24:
-		/* reverse byte order */
-		pixel = BSWAP(pixel);
-		break;
-	case 16:
-		/* incoming format is b_00000000000000000bbbbbgggggrrrrr */
-		{
-			uint8_t red   = pixel & 31;
-			uint8_t green = (pixel & (31 << 5)) >> 5;
-			uint8_t blue  = (pixel & (31 << 10)) >> 10;
-
-			/* sanity check */
-			assert(red < 32);
-			assert(green < 32);
-			assert(blue < 32);
-
-			pixel =   (sprite_16bpp_translate[red] << 24)
-					| (sprite_16bpp_translate[green] << 16)
-					| (sprite_16bpp_translate[blue] << 8);
-		}
-		break;
-	case 8:
-	case 4:
-	case 2:
-	case 1:
-		assert(false); /* shouldn't need to call for <= 8bpp, since a palette lookup will return 32bpp */
-	default:
-		assert(false); /* unknown bpp */
-	}
-
-	uint8_t alpha = pixel & 0xff;
-	if (alpha == 0x00) {
-		if (!(*has_alpha_pixel_data)) {
-			pixel = pixel | 0xff;
-		}
-	} else {
-		*has_alpha_pixel_data = true;
-	}
-	return pixel;
-}
-
-static inline uint32_t rosprite_cmyk_to_rgb(uint32_t cmyk)
-{
-        uint8_t c = cmyk & 0xff;
-        uint8_t m = (cmyk & 0xff00) >> 8;
-        uint8_t y = (cmyk & 0xff0000) >> 16;
-        uint8_t k = cmyk >> 24;
- 
-        /* Convert to CMY colourspace */
-        uint8_t C = c + k;
-        uint8_t M = m + k;
-        uint8_t Y = y + k;
- 
-        /* And to RGB */
-        uint8_t r = 255 - C;
-        uint8_t g = 255 - M;
-        uint8_t b = 255 - Y;
- 
-        return r << 24 | g << 16 | b << 8;
-}
-
-static inline rosprite_error rosprite_read_word(reader reader, void* ctx, uint32_t* result)
-{
-	unsigned char b[4];
-	if (reader(b, 4, ctx) < 4) {
-		return ROSPRITE_EOF;
-	}
-	*result = BTUINT(b);
-	return ROSPRITE_OK;
-}