[paraslash.git] / afh_common.c

/* Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */

/** \file afh_common.c Common audio format handler functions. */

#include <sys/mman.h> /* mmap */
#include <sys/types.h>
#include <regex.h>

#include "para.h"
#include "error.h"
#include "string.h"
#include "afh.h"

typedef void afh_init_func(struct audio_format_handler *);

/*
 * Declaration of the audio format handler init functions.
 *
 * These symbols are referenced in the afl array below.
 *
 * Most audio format handlers depend on an external library and are not
 * compiled in if the library is not installed. Hence it is well possible that
 * not all of these functions are defined. It does not hurt to declare them
 * anyway, and this avoids another set of ifdefs.
 */
extern afh_init_func mp3_afh_init, ogg_afh_init, aac_afh_init, wma_afh_init,
        spx_afh_init, flac_afh_init, opus_afh_init;

/** The list of all status items */
const char *status_item_list[] = {STATUS_ITEMS};

/**
 * The list of supported audio formats.
 *
 * We always define the full array of audio formats even if some audio formats
 * were not compiled in. This is because for each audio file the number of its
 * audio format is stored in the database. We don't want these numbers to become
 * stale just because the user installed a new version of paraslash that
 * supports a different set of audio formats.
 *
 * It can still be easily detected whether an audio format is compiled in by
 * checking if the init function pointer is not \p NULL.
 */
static struct audio_format_handler afl[] = {
        {
                .name = "mp3",
                .init = mp3_afh_init,
        },
        {
                .name = "ogg",
#if defined(HAVE_OGG) && defined(HAVE_VORBIS)
                .init = ogg_afh_init,
#endif
        },
        {
                .name = "aac",
#if defined(HAVE_FAAD)
                .init = aac_afh_init,
#endif
        },
        {
                .name = "wma",
                .init = wma_afh_init,
        },
        {
                .name = "spx",
#if defined(HAVE_OGG) && defined(HAVE_SPEEX)
                .init = spx_afh_init,
#endif
        },
        {
                .name = "flac",
#if defined(HAVE_OGG) && defined(HAVE_FLAC)
                .init = flac_afh_init,
#endif
        },
        {
                .name = "opus",
#if defined(HAVE_OGG) && defined(HAVE_OPUS)
                .init = opus_afh_init,
#endif
        },
        {
                .name = NULL,
        }
};

/**
 * Get the name of the given audio format.
 *
 * \param i The audio format number.
 *
 * \return This returns a pointer to statically allocated memory so it
 * must not be freed by the caller.
 */
const char *audio_format_name(int i)
{
        if (i < 0 || i >= ARRAY_SIZE(afl) - 1)
                return "???";
        return afl[i].name;
}

static inline int next_audio_format(int format)
{
        for (;;) {
                if (!afl[format].name)
                        return format;
                format++;
                if (afl[format].init)
                        return format;
        }
}

/** Iterate over each supported audio format. */
#define FOR_EACH_AUDIO_FORMAT(i) for (i = 0; afl[i].name; i = next_audio_format(i))

/**
 * Call the init function of each supported audio format handler.
 */
void afh_init(void)
{
        int i;

        PARA_NOTICE_LOG("supported audio formats: %s\n", AUDIO_FORMAT_HANDLERS);
        FOR_EACH_AUDIO_FORMAT(i) {
                PARA_INFO_LOG("initializing %s handler\n",
                        audio_format_name(i));
                afl[i].init(&afl[i]);
        }
}

/**
 * Tell whether an audio format handler provides chunk tables.
 *
 * Each audio format handler either provides a chunk table or supports dynamic
 * chunks.
 *
 * \param audio_format_id Offset in the afl array.
 *
 * \return True if dynamic chunks are supported, false if the audio format
 * handler provides chunk tables.
 */
bool afh_supports_dynamic_chunks(int audio_format_id)
{
        return afl[audio_format_id].get_chunk;
}

/**
 * Guess the audio format judging from filename.
 *
 * \param name The filename.
 *
 * \return This function returns \p -E_AUDIO_FORMAT if it has no idea what kind
 * of audio file this might be. Otherwise the (non-negative) number of the
 * audio format is returned.
 */
int guess_audio_format(const char *name)
{
        int i,j, len = strlen(name);

        FOR_EACH_AUDIO_FORMAT(i) {
                for (j = 0; afl[i].suffixes[j]; j++) {
                        const char *p = afl[i].suffixes[j];
                        int plen = strlen(p);
                        if (len < plen + 1)
                                continue;
                        if (name[len - plen - 1] != '.')
                                continue;
                        if (strcasecmp(name + len - plen, p))
                                continue;
//                      PARA_DEBUG_LOG("might be %s\n", audio_format_name(i));
                        return i;
                }
        }
        return -E_AUDIO_FORMAT;
}

static int get_file_info(int format, const char *path, char *data,
                size_t size, int fd, struct afh_info *afhi)
{
        int ret;
        const char *fmt = audio_format_name(format);

        memset(afhi, 0, sizeof(*afhi));
        ret = afl[format].get_file_info(data, size, fd, afhi);
        if (ret < 0) {
                PARA_WARNING_LOG("%s: %s format not detected: %s\n",
                        path, fmt, para_strerror(-ret));
                return ret;
        }
        PARA_NOTICE_LOG("%s: detected %s format\n", path, fmt);
        return format;
}

/**
 * Call get_file_info() to obtain an afhi structure.
 *
 * \param path The full path of the audio file.
 * \param data Pointer to the contents of the (mapped) file.
 * \param size The file size in bytes.
 * \param fd The open file descriptor.
 * \param afhi Result pointer.
 *
 * \return The number of the audio format on success, \p -E_AUDIO_FORMAT if no
 * compiled in audio format handler is able to handler the file.
 *
 * This function tries to find an audio format handler that can interpret the
 * file given by \a data and \a size.
 *
 * It first tries to determine the audio format from the filename given by \a
 * path. If this doesn't work, all other audio format handlers are tried until
 * one is found that can handle the file.
 */
int compute_afhi(const char *path, char *data, size_t size, int fd,
                struct afh_info *afhi)
{
        int ret, i, format;

        format = guess_audio_format(path);
        if (format >= 0) {
                ret = get_file_info(format, path, data, size, fd, afhi);
                if (ret >= 0)
                        goto success;
        }
        FOR_EACH_AUDIO_FORMAT(i) {
                if (i == format) /* we already tried this one to no avail */
                        continue;
                ret = get_file_info(i, path, data, size, fd, afhi);
                if (ret >= 0)
                        goto success;
        }
        return -E_AUDIO_FORMAT;
success:
        if (!afhi->techinfo)
                afhi->techinfo = para_strdup(NULL);
        if (!afhi->tags.artist)
                afhi->tags.artist = para_strdup(NULL);
        if (!afhi->tags.title)
                afhi->tags.title = para_strdup(NULL);
        if (!afhi->tags.year)
                afhi->tags.year = para_strdup(NULL);
        if (!afhi->tags.album)
                afhi->tags.album = para_strdup(NULL);
        if (!afhi->tags.comment)
                afhi->tags.comment = para_strdup(NULL);
        PARA_DEBUG_LOG("techinfo: %s\n", afhi->techinfo);
        PARA_DEBUG_LOG("artist: %s\n", afhi->tags.artist);
        PARA_DEBUG_LOG("title: %s\n", afhi->tags.title);
        PARA_DEBUG_LOG("year: %s\n", afhi->tags.year);
        PARA_DEBUG_LOG("album: %s\n", afhi->tags.album);
        PARA_DEBUG_LOG("comment: %s\n", afhi->tags.comment);
        return ret;
}

/**
 * Deallocate the contents of an afh_info structure.
 *
 * \param afhi The structure to clear.
 *
 * This only frees the memory the various pointer fields of \a afhi point to.
 * It does *not* free \a afhi itself.
 */
void clear_afhi(struct afh_info *afhi)
{
        if (!afhi)
                return;
        free(afhi->chunk_table);
        free(afhi->techinfo);
        free(afhi->tags.artist);
        free(afhi->tags.title);
        free(afhi->tags.year);
        free(afhi->tags.album);
        free(afhi->tags.comment);
}

static inline size_t get_chunk_len(long unsigned chunk_num,
                const struct afh_info *afhi)
{
        return afhi->chunk_table[chunk_num + 1] - afhi->chunk_table[chunk_num];
}

/**
 * Get one chunk of audio data.
 *
 * This implicitly calls the ->open method of the audio format handler at the
 * first call.
 *
 * \param chunk_num The number of the chunk to get.
 * \param afhi Describes the audio file.
 * \param audio_format_id Determines the afh.
 * \param map The memory mapped audio file.
 * \param mapsize Passed to the afh's ->open() method.
 * \param buf Result pointer.
 * \param len The length of the chunk in bytes.
 * \param afh_context Value/result, determines whether ->open() is called.
 *
 * Upon return, \a buf will point so memory inside \a map. The returned buffer
 * must therefore not be freed by the caller.
 *
 * \return Standard.
 */
__must_check int afh_get_chunk(long unsigned chunk_num, struct afh_info *afhi,
                uint8_t audio_format_id, const void *map, size_t mapsize,
                const char **buf, size_t *len, void **afh_context)
{
        struct audio_format_handler *afh = afl + audio_format_id;

        if (afh_supports_dynamic_chunks(audio_format_id)) {
                int ret;

                if (!*afh_context) {
                        ret = afh->open(map, mapsize, afh_context);
                        if (ret < 0)
                                return ret;
                }
                ret = afl[audio_format_id].get_chunk(chunk_num, *afh_context,
                        buf, len);
                if (ret < 0) {
                        afh->close(*afh_context);
                        *afh_context = NULL;
                }
                return ret;
        } else {
                size_t pos = afhi->chunk_table[chunk_num];
                *buf = map + pos;
                *len = get_chunk_len(chunk_num, afhi);
                return 0;
        }
}

/**
 * Deallocate resources allocated due to dynamic chunk handling.
 *
 * This function should be called if afh_get_chunk() was called at least once.
 * It is OK to call it even for audio formats which do not support dynamic
 * chunks, in which case the function does nothing.
 *
 * \param afh_context As returned from the ->open method of the afh.
 * \param audio_format_id Determines the afh.
 */
void afh_close(void *afh_context, uint8_t audio_format_id)
{
        struct audio_format_handler *afh = afl + audio_format_id;

        if (!afh_supports_dynamic_chunks(audio_format_id))
                return;
        if (!afh->close)
                return;
        if (!afh_context)
                return;
        afh->close(afh_context);
}

/**
 * Find a suitable start chunk.
 *
 * \param approx_chunk_num Upper bound for the chunk number to return.
 * \param afhi Needed for the chunk table.
 * \param audio_format_id Determines the afh.
 *
 * \return For audio format handlers which support dynamic chunks, the function
 * returns the given chunk number. Otherwise it returns the first non-empty
 * chunk <= \a approx_chunk_num.
 *
 * \sa \ref afh_get_chunk().
 */
int32_t afh_get_start_chunk(int32_t approx_chunk_num,
                const struct afh_info *afhi, uint8_t audio_format_id)
{
        int32_t k;

        if (afh_supports_dynamic_chunks(audio_format_id))
                return approx_chunk_num;

        for (k = PARA_MAX(0, approx_chunk_num); k >= 0; k--)
                if (get_chunk_len(k, afhi) > 0)
                        return k;
        return 0;
}

/**
 * Get the header of an audio file.
 *
 * \param afhi The audio file handler data describing the file.
 * \param audio_format_id Determines the audio format handler.
 * \param map The data of the audio file.
 * \param mapsize The amount of bytes of the mmapped audio file.
 * \param buf The length of the header is stored here.
 * \param len Points to a buffer containing the header on return.
 *
 * This function sets \a buf to \p NULL and \a len to zero if \a map or \a
 * afhi is \p NULL, or if the current audio format does not need special
 * header treatment.
 *
 * Otherwise, it is checked whether the audio format handler given by
 * \a audio_format_id defines a ->get_header() method. If it does, this
 * method is called to obtain the header. If ->get_header() is \p NULL,
 * a reference to the first chunk of the audio file is returned.
 *
 * Once the header is no longer needed, the caller must call \ref
 * afh_free_header() to free the resources allocated by this function.
 */
void afh_get_header(struct afh_info *afhi, uint8_t audio_format_id,
                void *map, size_t mapsize, char **buf, size_t *len)
{
        struct audio_format_handler *afh = afl + audio_format_id;

        if (!map || !afhi || !afhi->header_len) {
                *buf = NULL;
                *len = 0;
                return;
        }
        if (!afh->get_header) {
                *len = afhi->header_len;
                *buf = map;
                return;
        }
        afh->get_header(map, mapsize, buf, len);
}

/**
 * Deallocate any resources obtained from afh_get_header().
 *
 * \param header_buf Pointer obtained via afh_get_header().
 * \param audio_format_id Determines the audio format handler.
 */
void afh_free_header(char *header_buf, uint8_t audio_format_id)
{
        struct audio_format_handler *afh = afl + audio_format_id;

        if (afh->get_header)
                free(header_buf);
}

/**
 * Pretty-print the contents of a struct afh_info into a buffer.
 *
 * \param audio_format_num The audio format number.
 * \param afhi Pointer to the structure that contains the information.
 * \param result Pretty-printed ahfi is here after the call.
 *
 * The \a result buffer is dynamically allocated and should be freed by the
 * caller.
 *
 * \return The number of bytes. This function never fails.
 */
unsigned afh_get_afhi_txt(int audio_format_num, struct afh_info *afhi, char **result)
{
        return xasprintf(result, "%s: %dkbit/s\n" /* bitrate */
                "%s: %s\n" /* format */
                "%s: %dHz\n" /* frequency */
                "%s: %d\n" /* channels */
                "%s: %" PRIu32 "\n" /* seconds total */
                "%s: %lu: %lu\n" /* chunk time */
                "%s: %" PRIu32 "\n" /* num chunks */
                "%s: %" PRIu32 "\n" /* max chunk size */
                "%s: %s\n" /* techinfo */
                "%s: %s\n" /* artist */
                "%s: %s\n" /* title */
                "%s: %s\n" /* year */
                "%s: %s\n" /* album */
                "%s: %s\n", /* comment */
                status_item_list[SI_bitrate], afhi->bitrate,
                status_item_list[SI_format], audio_format_name(audio_format_num),
                status_item_list[SI_frequency], afhi->frequency,
                status_item_list[SI_channels], afhi->channels,
                status_item_list[SI_seconds_total], afhi->seconds_total,
                status_item_list[SI_chunk_time], (long unsigned)afhi->chunk_tv.tv_sec,
                        (long unsigned)afhi->chunk_tv.tv_usec,
                status_item_list[SI_num_chunks], afhi->chunks_total,
                status_item_list[SI_max_chunk_size], afhi->max_chunk_size,
                status_item_list[SI_techinfo], afhi->techinfo? afhi->techinfo : "",
                status_item_list[SI_artist], afhi->tags.artist? afhi->tags.artist : "",
                status_item_list[SI_title], afhi->tags.title? afhi->tags.title : "",
                status_item_list[SI_year], afhi->tags.year? afhi->tags.year : "",
                status_item_list[SI_album], afhi->tags.album? afhi->tags.album : "",
                status_item_list[SI_comment], afhi->tags.comment? afhi->tags.comment : ""
        );
}

/**
 * Determine the maximal chunk size by investigating the chunk table.
 *
 * \param afhi Value/result.
 *
 * This function iterates over the chunk table and sets ->max_chunk_size
 * accordingly. The function exists only for backward compatibility since as of
 * version 0.6.0, para_server stores the maximal chunk size in its database.
 * This function is only called if the database value is zero, indicating that
 * the file was added by an older server version.
 */
void set_max_chunk_size(struct afh_info *afhi)
{
        uint32_t n, max = 0, old = 0;

        for (n = 0; n <= afhi->chunks_total; n++) {
                uint32_t val = afhi->chunk_table[n];
                /*
                 * If the first chunk is the header, do not consider it for the
                 * calculation of the largest chunk size.
                 */
                if (n == 0 || (n == 1 && afhi->header_len > 0)) {
                        old = val;
                        continue;
                }
                max = PARA_MAX(max, val - old);
                old = val;
        }
        afhi->max_chunk_size = max;
}

/**
 * Create a copy of the given file with altered meta tags.
 *
 * \param audio_format_id Specifies the audio format.
 * \param map The (read-only) memory map of the input file.
 * \param mapsize The size of the input file in bytes.
 * \param tags The new tags.
 * \param output_fd Altered file is created using this file descriptor.
 * \param filename The name of the temporary output file.
 *
 * This calls the ->rewrite_tags method of the audio format handler associated
 * with \a audio_format_id to create a copy of the memory-mapped file given
 * by \a map and \a mapsize, but with altered tags according to \a tags. If
 * the audio format handler for \a audio_format_id lacks this optional method,
 * the function returns (the paraslash error code of) \p ENOTSUP.
 *
 * \return Standard.
 */
int afh_rewrite_tags(int audio_format_id, void *map, size_t mapsize,
                struct taginfo *tags, int output_fd, const char *filename)
{
        struct audio_format_handler *afh = afl + audio_format_id;

        if (!afh->rewrite_tags)
                return -ERRNO_TO_PARA_ERROR(ENOTSUP);
        return afh->rewrite_tags(map, mapsize, tags, output_fd, filename);
}