initHEADmain

1 files changed, 466 insertions, 0 deletions

diff --git a/src/graph.c b/src/graph.c
new file mode 100644
index 0000000..0e1a41e
--- /dev/null
+++ b/src/graph.c
@@ -0,0 +1,466 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <stdbool.h>
+
+#include <lua.h>
+#include <lauxlib.h>
+
+#include "melisma.h"
+#include "graph.h"
+#include "mem.h"
+
+#ifndef BUFFER_SIZE
+#define BUFFER_SIZE 4096
+#endif
+
+struct ml_channel
+{
+	ml_node        *node;
+	enum {IN,OUT}   dir;
+	ml_channel     *src;
+	ml_channel     *next;
+	size_t          buf;
+	int             refs;
+};
+
+struct ml_node
+{
+	ml_proc_fn   proc;
+	void        *userp;
+	ml_channel  *chans[2];
+	ml_node     *next;
+	bool         visited;
+	bool         cycle;
+	char        *label;
+};
+
+struct chunk
+{
+	char          *label;
+	ml_proc_fn     proc;
+	ml_proc_args   args;
+	struct chunk  *next;
+	float         *data[];
+};
+
+struct free_list
+{
+	size_t            buf;
+	struct free_list *next;
+};
+
+static ml_node          *root;
+static ml_node          *active;
+static ml_node          *active_tail;
+static struct free_list *free_list;
+static size_t            counter;
+static float            *buffers;
+static struct chunk     *graph;
+
+ml_node *ml_create_node(ml_proc_fn proc, void *userp)
+{
+	ml_node *node = scalloc(1,sizeof(*node));
+	node->proc = proc;
+	node->userp = userp;
+	return node;
+}
+
+void ml_label_node(ml_node *node, const char *fmt, ...)
+{
+	va_list ap_alloc,ap_print;
+
+	va_start(ap_alloc,fmt);
+	va_copy(ap_print,ap_alloc);
+
+	size_t len = 1 + vsnprintf(NULL,0,fmt,ap_alloc);
+	va_end(ap_alloc);
+
+	char *buf = smalloc(len);
+	vsnprintf(buf,len,fmt,ap_print);
+
+	node->label = buf;
+}
+
+void *ml_get_userp(ml_node *node)
+{
+	return node->userp;
+}
+
+ml_channel *add_channel(ml_node *node, int dir)
+{
+	ml_channel *chan = scalloc(1,sizeof(*chan));
+	chan->dir = dir;
+	chan->node = node;
+
+	if (node->chans[dir] == NULL)
+	{
+		node->chans[dir] = chan;
+	}
+	else
+	{
+		ml_channel *insert = node->chans[dir];
+		while (insert->next)
+		{
+			insert = insert->next;
+		}
+		insert->next = chan;
+	}
+
+	return chan;
+}
+
+ml_channel *ml_add_input(ml_node *node)
+{
+	return add_channel(node,IN);
+}
+
+ml_channel *ml_add_output(ml_node *node)
+{
+	return add_channel(node,OUT);
+}
+
+static ml_channel *get_channel(ml_node *node, size_t i, int dir)
+{
+	ml_channel *chan = node->chans[dir];
+
+	while (i > 0)
+	{
+		if (chan == NULL)
+		{
+			break;
+		}
+
+		i--;
+		chan = chan->next;
+	}
+
+	return chan;
+}
+
+ml_channel *ml_get_input(ml_node *node, size_t i)
+{
+	return get_channel(node,i,IN);
+}
+
+ml_channel *ml_get_output(ml_node *node, size_t i)
+{
+	return get_channel(node,i,OUT);
+}
+
+static size_t num_channels(ml_node *node, int dir)
+{
+	ml_channel *chan = node->chans[dir];
+	size_t n = 0;
+
+	while (chan != NULL)
+	{
+		n++;
+		chan = chan->next;
+	}
+
+	return n;
+}
+
+size_t ml_num_inputs(ml_node *node)
+{
+	return num_channels(node,IN);
+}
+
+size_t ml_num_outputs(ml_node *node)
+{
+	return num_channels(node,OUT);
+}
+
+void ml_connect(ml_channel *src, ml_channel *dst)
+{
+	assert(src->dir == OUT);
+	assert(dst->dir == IN);
+	src->refs++;
+	dst->src = src;
+}
+
+ml_node *ml_get_root_node(void)
+{
+	return root;
+}
+
+void init_graph(lua_State *s)
+{
+	root = ml_create_node(NULL,NULL);
+	ml_label_node(root,"root");
+
+	luaL_newmetatable(s,MELISMA_NODE_TYPENAME);
+	luaL_newmetatable(s,MELISMA_INPUT_CHANNEL_TYPENAME);
+	luaL_newmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+}
+
+static const char *topo_sort(ml_node *node)
+{
+	if (node->visited)
+	{
+		return NULL;
+	}
+
+	if (node->cycle)
+	{
+		return "cycle in audio graph detected";
+	}
+
+	node->visited = true;
+	node->cycle = true;
+
+	ml_channel *in = node->chans[IN];
+
+	while (in != NULL)
+	{
+		if (in->src == NULL)
+		{
+			return "disconnected input channel in audio graph detected";
+		}
+
+		const char *err = topo_sort(in->src->node);
+
+		if (err != NULL)
+		{
+			return err;
+		}
+
+		in = in->next;
+	}
+
+	if (active_tail)
+	{
+		active_tail->next = node;
+	}
+	else
+	{
+		active = node;
+	}
+
+	active_tail = node;
+	node->cycle = false;
+
+	return NULL;
+}
+
+static size_t alloc_buf(void)
+{
+	if (free_list)
+	{
+		struct free_list *head = free_list;
+		size_t buf = head->buf;
+		free_list = head->next;
+		free(head);
+		return buf;
+	}
+
+	return counter++;
+}
+
+static void free_buf(size_t buf)
+{
+	struct free_list *head = scalloc(1,sizeof(*head));
+	head->buf = buf;
+	head->next = free_list;
+	free_list = head;
+}
+
+static void assign_bufs()
+{
+	ml_node *node = active;
+
+	while (node)
+	{
+		ml_channel *in, *out;
+		in = node->chans[IN];
+		out = node->chans[OUT];
+
+		while (out)
+		{
+			out->buf = alloc_buf();
+			out = out->next;
+		}
+
+		while (in)
+		{
+			if (--in->src->refs == 0)
+			{
+				free_buf(in->src->buf);
+			}
+			in = in->next;
+		}
+
+		node = node->next;
+	}
+}
+
+static void make_chunks(void)
+{
+	struct chunk *chunk, *tail = NULL;
+	struct ml_node *node = active;
+
+	while (node)
+	{
+		size_t icnt = ml_num_inputs(node);
+		size_t ocnt = ml_num_outputs(node);
+		size_t nchans = icnt + ocnt;
+		size_t size = sizeof(*chunk) + sizeof(chunk->data[0]) * nchans;
+
+		chunk = scalloc(1,size);
+		chunk->label = node->label ? strdup(node->label) : NULL;
+		chunk->proc = node->proc;
+		chunk->args.userp = node->userp;
+		chunk->args.icnt = icnt;
+		chunk->args.ocnt = ocnt;
+		chunk->args.in = chunk->data;
+		chunk->args.out = chunk->data + icnt;
+
+		ml_channel *in, *out;
+		size_t i = 0;
+
+		in = node->chans[IN];
+
+		while (in != NULL)
+		{
+			chunk->data[i++] = &buffers[BUFFER_SIZE*in->src->buf];
+			in = in->next;
+		}
+
+		out = node->chans[OUT];
+
+		while (out != NULL)
+		{
+			chunk->data[i++] = &buffers[BUFFER_SIZE*out->buf];
+			out = out->next;
+		}
+
+		assert(i == nchans);
+
+		if (tail == NULL)
+		{
+			graph = chunk;
+		}
+		else
+		{
+			tail->next = chunk;
+		}
+
+		tail = chunk;
+		node = node->next;
+	}
+}
+
+const char *build_graph(void)
+{
+	const char *err = topo_sort(root);
+
+	if (err != NULL)
+	{
+		return err;
+	}
+
+	assign_bufs();
+
+	buffers = malloc(sizeof(*buffers)*BUFFER_SIZE*counter);
+
+	make_chunks();
+
+	return NULL;
+}
+
+static void proc_once(size_t n)
+{
+	struct chunk *c = graph;
+	while (c)
+	{
+		if (c->proc)
+		{
+			c->args.nframes = n;
+			c->proc(&c->args);
+		}
+
+		c = c->next;
+	}
+}
+
+void proc_graph(size_t n)
+{
+	while (n > 0)
+	{
+		size_t m = n > BUFFER_SIZE ? BUFFER_SIZE : n;
+		proc_once(m);
+		n -= m;
+	}
+}
+
+static void add_to_layout(lua_State *s, int layout, ml_node *node)
+{
+	int top = lua_absindex(s,lua_gettop(s));
+
+	lua_pushlightuserdata(s,node);
+	lua_gettable(s,layout);
+
+	if (!lua_isnil(s,-1))
+	{
+		return;
+	}
+
+	lua_newtable(s);
+	int tbl = lua_absindex(s,lua_gettop(s));
+
+	if (node->label)
+	{
+		lua_pushstring(s,node->label);
+		lua_setfield(s,tbl,"label");
+	}
+
+	lua_newtable(s);
+	int list = lua_absindex(s,lua_gettop(s));
+	ml_channel *in = node->chans[IN];
+	int i = 1;
+
+	while (in)
+	{
+		add_to_layout(s,layout,in->src->node);
+		lua_pushlightuserdata(s,in->src->node);
+		lua_rawseti(s,list,i++);
+		in = in->next;
+	}
+
+	lua_pushvalue(s,list);
+	lua_setfield(s,tbl,"inputs");
+
+	lua_pushlightuserdata(s,node);
+	lua_pushvalue(s,tbl);
+	lua_settable(s,layout);
+
+	lua_settop(s,top);
+}
+
+int l_graph_layout(lua_State *s)
+{
+	lua_newtable(s);
+	int layout = lua_absindex(s,lua_gettop(s));
+	add_to_layout(s,layout,root);
+	lua_pushvalue(s,layout);
+	return 1;
+}