I should not have merged the graph parser with the graph

framework. Split it.

Commited in SoC by Vitor Sessak on 2008-04-03 16:29:07

Originally committed as revision 13285 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavfilter/graphparser.c

@@ -0,0 +1,387 @@
+/*
+ * filter graph parser
+ * copyright (c) 2008 Vitor Sessak
+ * copyright (c) 2007 Bobby Bingham
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <ctype.h>
+#include <string.h>
+
+#include "avfilter.h"
+#include "avfiltergraph.h"
+
+/**
+ * For use in av_log
+ */
+static const char *log_name(void *p)
+{
+    return "Filter parser";
+}
+
+static const AVClass filter_parser_class = {
+    "Filter parser",
+    log_name
+};
+
+static const AVClass *log_ctx = &filter_parser_class;
+
+static int create_filter(AVFilterGraph *ctx, int index, char *name,
+                         char *args)
+{
+    AVFilterContext *filt;
+
+    AVFilter *filterdef;
+    char tmp[20];
+
+    snprintf(tmp, 20, "%d", index);
+    if(!(filterdef = avfilter_get_by_name(name)) ||
+       !(filt = avfilter_open(filterdef, tmp))) {
+        av_log(&log_ctx, AV_LOG_ERROR,
+               "error creating filter '%s'\n", name);
+        return -1;
+    }
+    avfilter_graph_add_filter(ctx, filt);
+    if(avfilter_init_filter(filt, args, NULL)) {
+        av_log(&log_ctx, AV_LOG_ERROR,
+               "error initializing filter '%s'\n", name);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int link_filter(AVFilterGraph *ctx, int src, int srcpad,
+                       int dst, int dstpad)
+{
+    AVFilterContext *filt, *filtb;
+
+    char tmp[20];
+
+    snprintf(tmp, 20, "%d", src);
+    if(!(filt = avfilter_graph_get_filter(ctx, tmp))) {
+        av_log(&log_ctx, AV_LOG_ERROR, "link source does not exist in graph\n");
+        return -1;
+    }
+    snprintf(tmp, 20, "%d", dst);
+    if(!(filtb = avfilter_graph_get_filter(ctx, tmp))) {
+        av_log(&log_ctx, AV_LOG_ERROR, "link destination does not exist in graph\n");
+        return -1;
+    }
+    if(avfilter_link(filt, srcpad, filtb, dstpad)) {
+        av_log(&log_ctx, AV_LOG_ERROR, "cannot create link between source and destination filters\n");
+        return -1;
+    }
+
+    return 0;
+}
+
+static void consume_whitespace(const char **buf)
+{
+    *buf += strspn(*buf, " \n\t");
+}
+
+/**
+ * Copy the first size bytes of input string to a null-terminated string,
+ * removing any control character. Ex: "aaa'bb'c\'c\\" -> "aaabbc'c\"
+ */
+static void copy_unquoted(char *out, const char *in, int size)
+{
+    int i;
+    for (i=0; i < size; i++) {
+        if (in[i] == '\'')
+            continue;
+        else if (in[i] == '\\') {
+            if (i+1 == size) {
+                *out = 0;
+                return;
+            }
+            i++;
+        }
+        *out++ = in[i];
+    }
+    *out=0;
+}
+
+/**
+ * Consumes a string from *buf.
+ * @return a copy of the consumed string, which should be free'd after use
+ */
+static char *consume_string(const char **buf)
+{
+    const char *start;
+    char *ret;
+    int size;
+
+    consume_whitespace(buf);
+
+    if (!(**buf))
+        return av_mallocz(1);
+
+    start = *buf;
+
+    while(1) {
+        *buf += strcspn(*buf, " ()=,'\\");
+        if (**buf == '\\')
+            *buf+=2;
+        else
+            break;
+    }
+
+    if (**buf == '\'') {
+        const char *p = *buf;
+        do {
+            p++;
+            p = strchr(p, '\'');
+        } while (p && p[-1] == '\\');
+        if (p)
+            *buf = p + 1;
+        else
+            *buf += strlen(*buf); // Move the pointer to the null end byte
+    }
+
+    size = *buf - start + 1;
+    ret = av_malloc(size);
+    copy_unquoted(ret, start, size-1);
+
+    return ret;
+}
+
+/**
+ * Parse "(linkname)"
+ * @arg name a pointer (that need to be free'd after use) to the name between
+ *           parenthesis
+ */
+static void parse_link_name(const char **buf, char **name)
+{
+    (*buf)++;
+
+    *name = consume_string(buf);
+
+    if (!*name[0])
+        goto fail;
+
+    if (*(*buf)++ != ')')
+        goto fail;
+
+    return;
+ fail:
+    av_freep(name);
+    av_log(&log_ctx, AV_LOG_ERROR, "Could not parse link name!\n");
+}
+
+/**
+ * Parse "filter=params"
+ * @arg name a pointer (that need to be free'd after use) to the name of the
+ *           filter
+ * @arg ars  a pointer (that need to be free'd after use) to the args of the
+ *           filter
+ */
+static int parse_filter(const char **buf, AVFilterGraph *graph, int index)
+{
+    char *name, *opts;
+    name = consume_string(buf);
+
+    if (**buf == '=') {
+        (*buf)++;
+        opts = consume_string(buf);
+    } else {
+        opts = NULL;
+    }
+
+    return create_filter(graph, index, name, opts);
+}
+
+enum LinkType {
+    LinkTypeIn,
+    LinkTypeOut,
+};
+
+/**
+ * A linked-list of the inputs/outputs of the filter chain.
+ */
+typedef struct AVFilterInOut {
+    enum LinkType type;
+    char *name;
+    int instance;
+    int pad_idx;
+
+    struct AVFilterInOut *next;
+} AVFilterInOut;
+
+static void free_inout(AVFilterInOut *head)
+{
+    while (head) {
+        AVFilterInOut *next;
+        next = head->next;
+        av_free(head);
+        head = next;
+    }
+}
+
+/**
+ * Parse "(a1)(link2) ... (etc)"
+ */
+static int parse_inouts(const char **buf, AVFilterInOut **inout, int firstpad,
+                        enum LinkType type, int instance)
+{
+    int pad = firstpad;
+    while (**buf == '(') {
+        AVFilterInOut *inoutn = av_malloc(sizeof(AVFilterInOut));
+        parse_link_name(buf, &inoutn->name);
+        inoutn->type = type;
+        inoutn->instance = instance;
+        inoutn->pad_idx = pad++;
+        inoutn->next = *inout;
+        *inout = inoutn;
+    }
+    return pad;
+}
+
+/**
+ * Parse a string describing a filter graph.
+ */
+int avfilter_graph_parse_chain(AVFilterGraph *graph, const char *filters, AVFilterContext *in, int inpad, AVFilterContext *out, int outpad)
+{
+    AVFilterInOut *inout=NULL;
+    AVFilterInOut  *head=NULL;
+
+    int index = 0;
+    char chr = 0;
+    int pad = 0;
+    int has_out = 0;
+
+    char tmp[20];
+    AVFilterContext *filt;
+
+    consume_whitespace(&filters);
+
+    do {
+        int oldpad = pad;
+
+        pad = parse_inouts(&filters, &inout, chr == ',', LinkTypeIn, index);
+
+        if (parse_filter(&filters, graph, index) < 0)
+            goto fail;
+
+        // If the first filter has an input and none was given, it is
+        // implicitly the input of the whole graph.
+        if (pad == 0 && graph->filters[graph->filter_count-1]->input_count == 1) {
+            snprintf(tmp, 20, "%d", index);
+            if(!(filt = avfilter_graph_get_filter(graph, tmp))) {
+                av_log(&log_ctx, AV_LOG_ERROR, "filter owning exported pad does not exist\n");
+                goto fail;
+            }
+            if(avfilter_link(in, inpad, filt, 0)) {
+                av_log(&log_ctx, AV_LOG_ERROR, "cannot create link between source and destination filters\n");
+                goto fail;
+            }
+        }
+
+        if(chr == ',') {
+            if (link_filter(graph, index-1, oldpad, index, 0) < 0)
+                goto fail;
+
+        }
+        pad = parse_inouts(&filters, &inout, 0, LinkTypeOut, index);
+        chr = *filters++;
+        index++;
+    } while (chr == ',' || chr == ';');
+
+    head = inout;
+    for (; inout != NULL; inout = inout->next) {
+        if (inout->instance == -1)
+            continue; // Already processed
+
+        if (!strcmp(inout->name, "in")) {
+            snprintf(tmp, 20, "%d", inout->instance);
+            if(!(filt = avfilter_graph_get_filter(graph, tmp))) {
+                av_log(&log_ctx, AV_LOG_ERROR, "filter owning exported pad does not exist\n");
+                goto fail;
+            }
+            if(avfilter_link(in, inpad, filt, inout->pad_idx)) {
+                av_log(&log_ctx, AV_LOG_ERROR, "cannot create link between source and destination filters\n");
+                goto fail;
+            }
+        } else if (!strcmp(inout->name, "out")) {
+            has_out = 1;
+            snprintf(tmp, 20, "%d", inout->instance);
+            if(!(filt = avfilter_graph_get_filter(graph, tmp))) {
+                av_log(&log_ctx, AV_LOG_ERROR, "filter owning exported pad does not exist\n");
+                goto fail;
+            }
+
+            if(avfilter_link(filt, inout->pad_idx, out, outpad)) {
+                av_log(&log_ctx, AV_LOG_ERROR, "cannot create link between source and destination filters\n");
+                goto fail;
+        }
+
+        } else {
+            AVFilterInOut *p, *src, *dst;
+            for (p = inout->next;
+                 p && strcmp(p->name,inout->name); p = p->next);
+
+            if (!p) {
+                av_log(&log_ctx, AV_LOG_ERROR, "Unmatched link: %s.\n",
+                       inout->name);
+                goto fail;
+            }
+
+            if (p->type == LinkTypeIn && inout->type == LinkTypeOut) {
+                src = inout;
+                dst = p;
+            } else if (p->type == LinkTypeOut && inout->type == LinkTypeIn) {
+                src = p;
+                dst = inout;
+            } else {
+                av_log(&log_ctx, AV_LOG_ERROR, "Two links named '%s' are either both input or both output\n",
+                       inout->name);
+                goto fail;
+            }
+
+            if (link_filter(graph, src->instance, src->pad_idx, dst->instance, dst->pad_idx) < 0)
+                goto fail;
+
+            src->instance = -1;
+            dst->instance = -1;
+        }
+    }
+
+    free_inout(head);
+
+    if (!has_out) {
+        snprintf(tmp, 20, "%d", index-1);
+        if(!(filt = avfilter_graph_get_filter(graph, tmp))) {
+            av_log(&log_ctx, AV_LOG_ERROR, "filter owning exported pad does not exist\n");
+            goto fail;
+        }
+
+        if(avfilter_link(filt, pad, out, outpad)) {
+            av_log(&log_ctx, AV_LOG_ERROR, "cannot create link between source and destination filters\n");
+            goto fail;
+        }
+
+    }
+
+    return 0;
+
+ fail:
+    free_inout(head);
+    avfilter_destroy_graph(graph);
+    return -1;
+}