/* * 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 "graphparser.h"#include "avfilter.h"#include "avfiltergraph.h" static int link_filter(AVFilterContext *src, int srcpad,                       AVFilterContext *dst, int dstpad,                       AVClass *log_ctx){    if(avfilter_link(src, srcpad, dst, dstpad)) {        av_log(log_ctx, AV_LOG_ERROR,               "cannot create the link %s:%d -> %s:%d\n",               src->filter->name, srcpad, dst->filter->name, dstpad);        return -1;    }     return 0;} static int consume_whitespace(const char *buf){    return strspn(buf, " \n\t");} /** * 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){    char *out = av_malloc(strlen(*buf) + 1);    char *ret = out;     *buf += consume_whitespace(*buf);     do{        char c = *(*buf)++;        switch (c) {        case '\\':            *out++ = *(*buf)++;            break;        case '\'':            while(**buf && **buf != '\'')                *out++ = *(*buf)++;            if(**buf) (*buf)++;            break;        case 0:        case ']':        case '[':        case '=':        case ',':        case ';':        case ' ':        case '\n':            *out++ = 0;            break;        default:            *out++ = c;        }    } while(out[-1]);     (*buf)--;    *buf += consume_whitespace(*buf);     return ret;} /** * Parse "[linkname]" * @param name a pointer (that need to be free'd after use) to the name between *        parenthesis */static char *parse_link_name(const char **buf, AVClass *log_ctx){    const char *start = *buf;    char *name;    (*buf)++;     name = consume_string(buf);     if(!name[0]) {        av_log(log_ctx, AV_LOG_ERROR,               "Bad (empty?) label found in the following: \"%s\".\n", start);        goto fail;    }     if(*(*buf)++ != ']') {        av_log(log_ctx, AV_LOG_ERROR,               "Mismatched '[' found in the following: \"%s\".\n", start);    fail:        av_freep(&name);    }     return name;} static AVFilterContext *create_filter(AVFilterGraph *ctx, int index,                                      const char *filt_name, const char *args,                                      AVClass *log_ctx){    AVFilterContext *filt_ctx;     AVFilter *filt;    char inst_name[30];     snprintf(inst_name, sizeof(inst_name), "Parsed filter %d", index);     filt = avfilter_get_by_name(filt_name);     if(!filt) {        av_log(log_ctx, AV_LOG_ERROR,               "no such filter: '%s'\n", filt_name);        return NULL;    }     filt_ctx = avfilter_open(filt, inst_name);    if(!filt_ctx) {        av_log(log_ctx, AV_LOG_ERROR,               "error creating filter '%s'\n", filt_name);        return NULL;    }     if(avfilter_graph_add_filter(ctx, filt_ctx) < 0) {        avfilter_destroy(filt_ctx);        return NULL;    }     if(avfilter_init_filter(filt_ctx, args, NULL)) {        av_log(log_ctx, AV_LOG_ERROR,               "error initializing filter '%s' with args '%s'\n", filt_name, args);        return NULL;    }     return filt_ctx;} /** * Parse "filter=params" */static AVFilterContext *parse_filter(const char **buf, AVFilterGraph *graph,                                     int index, AVClass *log_ctx){    char *opts = NULL;    char *name = consume_string(buf);    AVFilterContext *ret;     if(**buf == '=') {        (*buf)++;        opts = consume_string(buf);    }     ret = create_filter(graph, index, name, opts, log_ctx);    av_free(name);    av_free(opts);    return ret;} static void free_inout(AVFilterInOut *head){    while(head) {        AVFilterInOut *next = head->next;        av_free(head->name);        av_free(head);        head = next;    }} static AVFilterInOut *extract_inout(const char *label, AVFilterInOut **links){    AVFilterInOut *ret;     while(*links && strcmp((*links)->name, label))        links = &((*links)->next);     ret = *links;     if(ret)        *links = ret->next;     return ret;} static void insert_inout(AVFilterInOut **inouts, AVFilterInOut *element){    element->next = *inouts;    *inouts = element;} static int link_filter_inouts(AVFilterContext *filter,                              AVFilterInOut **curr_inputs,                              AVFilterInOut **open_inputs, AVClass *log_ctx){    int pad = filter->input_count;     while(pad--) {        AVFilterInOut *p = *curr_inputs;        if(!p) {            av_log(log_ctx, AV_LOG_ERROR,                   "Not enough inputs specified for the \"%s\" filter.\n",                   filter->filter->name);            return -1;        }         *curr_inputs = (*curr_inputs)->next;         if(p->filter) {            if(link_filter(p->filter, p->pad_idx, filter, pad, log_ctx))                return -1;            av_free(p->name);            av_free(p);        } else {            p->filter = filter;            p->pad_idx = pad;            insert_inout(open_inputs, p);        }    }     if(*curr_inputs) {        av_log(log_ctx, AV_LOG_ERROR,               "Too many inputs specified for the \"%s\" filter.\n",               filter->filter->name);        return -1;    }     pad = filter->output_count;    while(pad--) {        AVFilterInOut *currlinkn = av_mallocz(sizeof(AVFilterInOut));        currlinkn->filter  = filter;        currlinkn->pad_idx = pad;        insert_inout(curr_inputs, currlinkn);    }     return 0;} static int parse_inputs(const char **buf, AVFilterInOut **curr_inputs,                        AVFilterInOut **open_outputs, AVClass *log_ctx){    int pad = 0;     while(**buf == '[') {        char *name = parse_link_name(buf, log_ctx);        AVFilterInOut *match;         if(!name)            return -1;         /* First check if the label is not in the open_outputs list */        match = extract_inout(name, open_outputs);         if(match) {            av_free(name);        } else {            /* Not in the list, so add it as an input */            match = av_mallocz(sizeof(AVFilterInOut));            match->name    = name;            match->pad_idx = pad;        }         insert_inout(curr_inputs, match);         *buf += consume_whitespace(*buf);        pad++;    }     return pad;} static int parse_outputs(const char **buf, AVFilterInOut **curr_inputs,                         AVFilterInOut **open_inputs,                         AVFilterInOut **open_outputs, AVClass *log_ctx){    int pad = 0;     while(**buf == '[') {        char *name = parse_link_name(buf, log_ctx);        AVFilterInOut *match;         AVFilterInOut *input = *curr_inputs;        *curr_inputs = (*curr_inputs)->next;         if(!name)            return -1;         /* First check if the label is not in the open_inputs list */        match = extract_inout(name, open_inputs);         if(match) {            if(link_filter(input->filter, input->pad_idx,                           match->filter, match->pad_idx, log_ctx) < 0)                return -1;            av_free(match->name);            av_free(name);            av_free(match);            av_free(input);        } else {            /* Not in the list, so add the first input as a open_output */            input->name = name;            insert_inout(open_outputs, input);        }        *buf += consume_whitespace(*buf);        pad++;    }     return pad;} int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,                         AVFilterInOut *open_inputs,                         AVFilterInOut *open_outputs, AVClass *log_ctx){    int index = 0;    char chr = 0;     AVFilterInOut *curr_inputs = NULL;     do {        AVFilterContext *filter;        filters += consume_whitespace(filters);         if(parse_inputs(&filters, &curr_inputs, &open_outputs, log_ctx) < 0)            goto fail;         filter = parse_filter(&filters, graph, index, log_ctx);         if(!filter)            goto fail;         if(filter->input_count == 1 && !curr_inputs && !index) {            /* First input can be omitted if it is "[in]" */            const char *tmp = "[in]";            if(parse_inputs(&tmp, &curr_inputs, &open_outputs, log_ctx) < 0)                goto fail;        }         if(link_filter_inouts(filter, &curr_inputs, &open_inputs, log_ctx) < 0)            goto fail;         if(parse_outputs(&filters, &curr_inputs, &open_inputs, &open_outputs,                         log_ctx) < 0)            goto fail;         filters += consume_whitespace(filters);        chr = *filters++;         if(chr == ';' && curr_inputs) {            av_log(log_ctx, AV_LOG_ERROR,                   "Could not find a output to link when parsing \"%s\"\n",                   filters - 1);            goto fail;        }        index++;    } while(chr == ',' || chr == ';');     if (chr) {        av_log(log_ctx, AV_LOG_ERROR,               "Unable to parse graph description substring: \"%s\"\n",               filters - 1);        goto fail;    }     if(open_inputs && !strcmp(open_inputs->name, "out") && curr_inputs) {        /* Last output can be omitted if it is "[out]" */        const char *tmp = "[out]";        if(parse_outputs(&tmp, &curr_inputs, &open_inputs,                         &open_outputs, log_ctx) < 0)            goto fail;    }     return 0;  fail:    avfilter_graph_destroy(graph);    free_inout(open_inputs);    free_inout(open_outputs);    free_inout(curr_inputs);    return -1;}