Screenshot numbering

src/gba/gba-thread.c

@@ -504,7 +504,7 @@ struct GBAThread* GBAThreadGetContext(void) {
 void GBAThreadTakeScreenshot(struct GBAThread* threadContext) {
 	unsigned stride;
 	void* pixels = 0;
-	struct VFile* vf = VDirOptionalOpenFile(threadContext->stateDir, threadContext->gba->activeFile, "screenshot", ".png", O_CREAT | O_TRUNC | O_WRONLY);
+	struct VFile* vf = VDirOptionalOpenIncrementFile(threadContext->stateDir, threadContext->gba->activeFile, "screenshot", "-", ".png", O_CREAT | O_TRUNC | O_WRONLY);
 	threadContext->gba->video.renderer->getPixels(threadContext->gba->video.renderer, &stride, &pixels);
 	png_structp png = PNGWriteOpen(vf);
 	png_infop info = PNGWriteHeader(png, VIDEO_HORIZONTAL_PIXELS, VIDEO_VERTICAL_PIXELS);

src/util/vfs.c

@@ -211,6 +211,105 @@ struct VFile* VDirOptionalOpenFile(struct VDir* dir, const char* realPath, const
 	return vf;
 }
 
+struct VFile* VDirOptionalOpenIncrementFile(struct VDir* dir, const char* realPath, const char* prefix, const char* infix, const char* suffix, int mode) {
+	char path[PATH_MAX];
+	path[PATH_MAX - 1] = '\0';
+	char realPrefix[PATH_MAX];
+	realPrefix[PATH_MAX - 1] = '\0';
+	if (!dir) {
+		if (!realPath) {
+			return 0;
+		}
+		const char* separatorPoint = strrchr(realPath, '/');
+		const char* dotPoint;
+		size_t len;
+		if (!separatorPoint) {
+			strcpy(path, "./");
+			separatorPoint = realPath;
+			dotPoint = strrchr(realPath, '.');
+		} else {
+			path[0] = '\0';
+			dotPoint = strrchr(separatorPoint, '.');
+
+			if (separatorPoint - realPath + 1 >= PATH_MAX - 1) {
+				return 0;
+			}
+
+			len = separatorPoint - realPath;
+			strncat(path, realPath, len);
+			path[len] = '\0';
+			++separatorPoint;
+		}
+
+		if (dotPoint - realPath + 1 >= PATH_MAX - 1) {
+			return 0;
+		}
+
+		if (dotPoint >= separatorPoint) {
+			len = dotPoint - separatorPoint;
+		} else {
+			len = PATH_MAX - 1;
+		}
+
+		strncpy(realPrefix, separatorPoint, len);
+		realPrefix[len] = '\0';
+
+		prefix = realPrefix;
+		dir = VDirOpen(path);
+	}
+	if (!dir) {
+		// This shouldn't be possible
+		return 0;
+	}
+	dir->rewind(dir);
+	struct VDirEntry* dirent;
+	size_t prefixLen = strlen(prefix);
+	size_t infixLen = strlen(infix);
+	unsigned next = 0;
+	while ((dirent = dir->listNext(dir))) {
+		const char* filename = dirent->name(dirent);
+		char* dotPoint = strrchr(filename, '.');
+		size_t len = strlen(filename);
+		if (dotPoint) {
+			len = (dotPoint - filename);
+		}
+		const char* separator = 0;
+		const char* nextSeparator = filename;
+		size_t strstrlen = len;
+		while ((nextSeparator = strnstr(nextSeparator, infix, strstrlen))) {
+			strstrlen -= nextSeparator - separator - 1;
+			separator = nextSeparator;
+			++nextSeparator;
+		}
+		if (!separator) {
+			continue;
+		}
+		len = separator - filename;
+		if (len != prefixLen) {
+			continue;
+		}
+		if (strncmp(filename, prefix, prefixLen) == 0) {
+			int nlen;
+			separator += infixLen;
+			snprintf(path, PATH_MAX - 1, "%%u%s%%n", suffix);
+			unsigned increment;
+			if (sscanf(separator, path, &increment, &nlen) < 1) {
+				continue;
+			}
+			len = strlen(separator);
+			if (nlen < (ssize_t) len) {
+				continue;
+			}
+			if (next <= increment) {
+				next = increment + 1;
+			}
+		}
+	}
+	snprintf(path, PATH_MAX - 1, "%s%s%u%s", prefix, infix, next, suffix);
+	path[PATH_MAX - 1] = '\0';
+	return dir->openFile(dir, path, mode);
+}
+
 bool _vdClose(struct VDir* vd) {
 	struct VDirDE* vdde = (struct VDirDE*) vd;
 	if (closedir(vdde->de) < 0) {

src/util/vfs.h

@@ -40,5 +40,6 @@ struct VDir* VDirOpenZip(const char* path, int flags);
 #endif
 
 struct VFile* VDirOptionalOpenFile(struct VDir* dir, const char* realPath, const char* prefix, const char* suffix, int mode);
+struct VFile* VDirOptionalOpenIncrementFile(struct VDir* dir, const char* realPath, const char* prefix, const char* infix, const char* suffix, int mode);
 
 #endif