/* * filter graph parser * Copyright (c) 2008 Vitor Sessak * Copyright (c) 2007 Bobby Bingham * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; 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 "libavutil/avstring.h"#include "avfilter.h"#include "avfiltergraph.h" #define WHITESPACES " \n\t" /** * Link two filters together. * * @see avfilter_link() */static int link_filter(AVFilterContext *src, int srcpad,                       AVFilterContext *dst, int dstpad,                       void *log_ctx){    int ret;    if ((ret = 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 ret;    }     return 0;} /** * Parse the name of a link, which has the format "[linkname]". * * @return a pointer (that need to be freed after use) to the name * between parenthesis */static char *parse_link_name(const char **buf, void *log_ctx){    const char *start = *buf;    char *name;    (*buf)++;     name = av_get_token(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;} /** * Create an instance of a filter, initialize and insert it in the * filtergraph in *ctx. * * @param filt_ctx put here a filter context in case of successful creation and configuration, NULL otherwise. * @param ctx the filtergraph context * @param index an index which is supposed to be unique for each filter instance added to the filtergraph * @param filt_name the name of the filter to create * @param args the arguments provided to the filter during its initialization * @param log_ctx the log context to use * @return 0 in case of success, a negative AVERROR code otherwise */static int create_filter(AVFilterContext **filt_ctx, AVFilterGraph *ctx, int index,                         const char *filt_name, const char *args, void *log_ctx){    AVFilter *filt;    char inst_name[30];    char tmp_args[256];    int ret;     snprintf(inst_name, sizeof(inst_name), "Parsed filter %d %s", index, filt_name);     filt = avfilter_get_by_name(filt_name);     if (!filt) {        av_log(log_ctx, AV_LOG_ERROR,               "No such filter: '%s'\n", filt_name);        return AVERROR(EINVAL);    }     ret = avfilter_open(filt_ctx, filt, inst_name);    if (!*filt_ctx) {        av_log(log_ctx, AV_LOG_ERROR,               "Error creating filter '%s'\n", filt_name);        return ret;    }     if ((ret = avfilter_graph_add_filter(ctx, *filt_ctx)) < 0) {        avfilter_free(*filt_ctx);        return ret;    }     if (!strcmp(filt_name, "scale") && args && !strstr(args, "flags")) {        snprintf(tmp_args, sizeof(tmp_args), "%s:%s",                 args, ctx->scale_sws_opts);        args = tmp_args;    }     if ((ret = avfilter_init_filter(*filt_ctx, args, NULL)) < 0) {        av_log(log_ctx, AV_LOG_ERROR,               "Error initializing filter '%s' with args '%s'\n", filt_name, args);        return ret;    }     return 0;} /** * Parse a string of the form FILTER_NAME[=PARAMS], and create a * corresponding filter instance which is added to graph with * create_filter(). * * @param filt_ctx Pointer that is set to the created and configured filter *                 context on success, set to NULL on failure. * @param filt_ctx put here a pointer to the created filter context on * success, NULL otherwise * @param buf pointer to the buffer to parse, *buf will be updated to * point to the char next after the parsed string * @param index an index which is assigned to the created filter * instance, and which is supposed to be unique for each filter * instance added to the filtergraph * @return 0 in case of success, a negative AVERROR code otherwise */static int parse_filter(AVFilterContext **filt_ctx, const char **buf, AVFilterGraph *graph,                        int index, void *log_ctx){    char *opts = NULL;    char *name = av_get_token(buf, "=,;[\n");    int ret;     if (**buf == '=') {        (*buf)++;        opts = av_get_token(buf, "[],;\n");    }     ret = create_filter(filt_ctx, 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 *filt_ctx,                              AVFilterInOut **curr_inputs,                              AVFilterInOut **open_inputs, void *log_ctx){    int pad = filt_ctx->input_count, ret;     while (pad--) {        AVFilterInOut *p = *curr_inputs;        if (!p) {            av_log(log_ctx, AV_LOG_ERROR,                   "Not enough inputs specified for the \"%s\" filter.\n",                   filt_ctx->filter->name);            return AVERROR(EINVAL);        }         *curr_inputs = (*curr_inputs)->next;         if (p->filter_ctx) {            if ((ret = link_filter(p->filter_ctx, p->pad_idx, filt_ctx, pad, log_ctx)) < 0)                return ret;            av_free(p->name);            av_free(p);        } else {            p->filter_ctx = filt_ctx;            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",               filt_ctx->filter->name);        return AVERROR(EINVAL);    }     pad = filt_ctx->output_count;    while (pad--) {        AVFilterInOut *currlinkn = av_mallocz(sizeof(AVFilterInOut));        if (!currlinkn)            return AVERROR(ENOMEM);        currlinkn->filter_ctx  = filt_ctx;        currlinkn->pad_idx = pad;        insert_inout(curr_inputs, currlinkn);    }     return 0;} static int parse_inputs(const char **buf, AVFilterInOut **curr_inputs,                        AVFilterInOut **open_outputs, void *log_ctx){    int pad = 0;     while (**buf == '[') {        char *name = parse_link_name(buf, log_ctx);        AVFilterInOut *match;         if (!name)            return AVERROR(EINVAL);         /* 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 */            if (!(match = av_mallocz(sizeof(AVFilterInOut))))                return AVERROR(ENOMEM);            match->name    = name;            match->pad_idx = pad;        }         insert_inout(curr_inputs, match);         *buf += strspn(*buf, WHITESPACES);        pad++;    }     return pad;} static int parse_outputs(const char **buf, AVFilterInOut **curr_inputs,                         AVFilterInOut **open_inputs,                         AVFilterInOut **open_outputs, void *log_ctx){    int ret, pad = 0;     while (**buf == '[') {        char *name = parse_link_name(buf, log_ctx);        AVFilterInOut *match;         AVFilterInOut *input = *curr_inputs;        if (!input) {            av_log(log_ctx, AV_LOG_ERROR,                   "No output pad can be associated to link label '%s'.\n",                   name);            return AVERROR(EINVAL);        }        *curr_inputs = (*curr_inputs)->next;         if (!name)            return AVERROR(EINVAL);         /* First check if the label is not in the open_inputs list */        match = extract_inout(name, open_inputs);         if (match) {            if ((ret = link_filter(input->filter_ctx, input->pad_idx,                                   match->filter_ctx, match->pad_idx, log_ctx)) < 0)                return ret;            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 += strspn(*buf, WHITESPACES);        pad++;    }     return pad;} int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,                         AVFilterInOut *open_inputs,                         AVFilterInOut *open_outputs, AVClass *log_ctx){    int index = 0, ret;    char chr = 0;     AVFilterInOut *curr_inputs = NULL;     do {        AVFilterContext *filter;        const char *filterchain = filters;        filters += strspn(filters, WHITESPACES);         if ((ret = parse_inputs(&filters, &curr_inputs, &open_outputs, log_ctx)) < 0)            goto fail;         if ((ret = parse_filter(&filter, &filters, graph, index, log_ctx)) < 0)            goto fail;         if (filter->input_count == 1 && !curr_inputs && !index) {            /* First input can be omitted if it is "[in]" */            const char *tmp = "[in]";            if ((ret = parse_inputs(&tmp, &curr_inputs, &open_outputs, log_ctx)) < 0)                goto fail;        }         if ((ret = link_filter_inouts(filter, &curr_inputs, &open_inputs, log_ctx)) < 0)            goto fail;         if ((ret = parse_outputs(&filters, &curr_inputs, &open_inputs, &open_outputs,                                 log_ctx)) < 0)            goto fail;         filters += strspn(filters, WHITESPACES);        chr = *filters++;         if (chr == ';' && curr_inputs) {            av_log(log_ctx, AV_LOG_ERROR,                   "Invalid filterchain containing an unlabelled output pad: \"%s\"\n",                   filterchain);            ret = AVERROR(EINVAL);            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);        ret = AVERROR(EINVAL);        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 ((ret = parse_outputs(&tmp, &curr_inputs, &open_inputs, &open_outputs,                                 log_ctx)) < 0)            goto fail;    }     return 0;  fail:    for (; graph->filter_count > 0; graph->filter_count--)        avfilter_free(graph->filters[graph->filter_count - 1]);    av_freep(&graph->filters);    free_inout(open_inputs);    free_inout(open_outputs);    free_inout(curr_inputs);    return ret;}