/* * 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]" * @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, AVClass *log_ctx){    const char *start = *buf;    (*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);    }} static AVFilterContext *create_filter(AVFilterGraph *ctx, int index,                                      const char *name, const char *args,                                      AVClass *log_ctx){    AVFilterContext *filt;     AVFilter *filterdef;    char inst_name[30];     snprintf(inst_name, sizeof(inst_name), "Parsed filter %d", index);     if(!(filterdef = avfilter_get_by_name(name))) {        av_log(log_ctx, AV_LOG_ERROR,               "no such filter: '%s'\n", name);        return NULL;    }     if(!(filt = avfilter_open(filterdef, inst_name))) {        av_log(log_ctx, AV_LOG_ERROR,               "error creating filter '%s'\n", name);        return NULL;    }     if(avfilter_graph_add_filter(ctx, filt) < 0)        return NULL;     if(avfilter_init_filter(filt, args, NULL)) {        av_log(log_ctx, AV_LOG_ERROR,               "error initializing filter '%s' with args '%s'\n", name, args);        return NULL;    }     return filt;} /** * 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 AVFilterContext *parse_filter(const char **buf, AVFilterGraph *graph,                                     int index, AVClass *log_ctx){    char *opts;    char *name = consume_string(buf);     if(**buf == '=') {        (*buf)++;        opts = consume_string(buf);    } else {        opts = NULL;    }     return create_filter(graph, index, name, opts, log_ctx);} static void free_inout(AVFilterInOut *head){    while(head) {        AVFilterInOut *next = head->next;        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 int link_filter_inouts(AVFilterContext *filter,                              AVFilterInOut **currInputs,                              AVFilterInOut **openLinks, AVClass *log_ctx){    int pad = 0;     pad = filter->input_count;    while(pad--) {        AVFilterInOut *p = *currInputs;        *currInputs = (*currInputs)->next;        if(!p) {            av_log(log_ctx, AV_LOG_ERROR,                   "Not enough inputs specified for the \"%s\" filter.\n",                   filter->name);            return -1;        }         if(p->filter) {            if(link_filter(p->filter, p->pad_idx, filter, pad, log_ctx))                return -1;            av_free(p);        } else {            p->filter = filter;            p->pad_idx = pad;            p->next = *openLinks;            *openLinks = p;        }    }      if(*currInputs) {        av_log(log_ctx, AV_LOG_ERROR,               "Too many inputs specified for the \"%s\" filter.\n",               filter->name);        return -1;    }     pad = filter->output_count;    while(pad--) {        AVFilterInOut *currlinkn = av_malloc(sizeof(AVFilterInOut));        currlinkn->name    = NULL;        currlinkn->type    = LinkTypeOut;        currlinkn->filter  = filter;        currlinkn->pad_idx = pad;        currlinkn->next    = *currInputs;        *currInputs = currlinkn;    }     return 0;} static int parse_inputs(const char **buf, AVFilterInOut **currInputs,                        AVFilterInOut **openLinks, AVClass *log_ctx){    int pad = 0;     while(**buf == '[') {        char *name;        AVFilterInOut *link_to_add;        AVFilterInOut *match;         parse_link_name(buf, &name, log_ctx);         if(!name)            return -1;         /* First check if the label is not in the openLinks list */        match = extract_inout(name, openLinks);         if(match) {            /* A label of a open link. Make it one of the inputs of the next               filter */            if(match->type != LinkTypeOut) {                av_log(log_ctx, AV_LOG_ERROR,                       "Label \"%s\" appears twice as input!\n", match->name);                return -1;            }             link_to_add = match;        } else {            /* Not in the list, so add it as an input */            link_to_add = av_malloc(sizeof(AVFilterInOut));             link_to_add->name    = name;            link_to_add->type    = LinkTypeIn;            link_to_add->filter  = NULL;            link_to_add->pad_idx = pad;        }        link_to_add->next = *currInputs;        *currInputs = link_to_add;        *buf += consume_whitespace(*buf);        pad++;    }     return pad;} static int parse_outputs(const char **buf, AVFilterInOut **currInputs,                         AVFilterInOut **openLinks, AVClass *log_ctx){    int pad = 0;     while(**buf == '[') {        char *name;        AVFilterInOut *match;         AVFilterInOut *input = *currInputs;        *currInputs = (*currInputs)->next;         parse_link_name(buf, &name, log_ctx);         if(!name)            return -1;         /* First check if the label is not in the openLinks list */        match = extract_inout(name, openLinks);         if(match) {            /* A label of a open link. Link it. */            if(match->type != LinkTypeIn) {                av_log(log_ctx, AV_LOG_ERROR,                       "Label \"%s\" appears twice as output!\n", match->name);                return -1;            }             if(link_filter(input->filter, input->pad_idx,                           match->filter, match->pad_idx, log_ctx) < 0)                return -1;            av_free(match);            av_free(input);        } else {            /* Not in the list, so add the first input as a openLink */            input->next = *openLinks;            input->type = LinkTypeOut;            input->name = name;            *openLinks = input;        }        *buf += consume_whitespace(*buf);        pad++;    }     return pad;} /** * Parse a string describing a filter graph. */int avfilter_parse_graph(AVFilterGraph *graph, const char *filters,                         AVFilterInOut *openLinks, AVClass *log_ctx){    int index = 0;    char chr = 0;    int pad = 0;     AVFilterInOut *currInputs = NULL;     do {        AVFilterContext *filter;        filters += consume_whitespace(filters);         pad = parse_inputs(&filters, &currInputs, &openLinks, log_ctx);         if(pad < 0)            goto fail;         if(!(filter = parse_filter(&filters, graph, index, log_ctx)))            goto fail;         if(filter->input_count == 1 && !currInputs && !index) {            // First input can be ommitted if it is "[in]"            const char *tmp = "[in]";            pad = parse_inputs(&tmp, &currInputs, &openLinks, log_ctx);            if(pad < 0)                goto fail;        }         if(link_filter_inouts(filter, &currInputs, &openLinks, log_ctx) < 0)            goto fail;         pad = parse_outputs(&filters, &currInputs, &openLinks, log_ctx);         if(pad < 0)            goto fail;         filters += consume_whitespace(filters);        chr = *filters++;         if(chr == ';' && currInputs) {            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(openLinks && !strcmp(openLinks->name, "out") && currInputs) {        // Last output can be ommitted if it is "[out]"        const char *tmp = "[out]";        if(parse_outputs(&tmp, &currInputs, &openLinks, log_ctx) < 0)            goto fail;    }     return 0;  fail:    avfilter_destroy_graph(graph);    free_inout(openLinks);    free_inout(currInputs);    return -1;}