vgmstream/fb2k/foo_streamfile.cpp

#ifdef _MSC_VER
#define _CRT_SECURE_NO_DEPRECATE
#endif

#include <stdio.h>
#include <io.h>

#include <foobar2000.h>
#include <ATLHelpers/ATLHelpersLean.h>
#include <shared.h>

extern "C" {
#include "../src/vgmstream.h"
#include "../src/util.h"
}
#include "foo_vgmstream.h"

/* On EOF reads we can return length 0, or ignore and return the requested length + 0-set the buffer.
 * Some decoders don't check for EOF and may decode garbage if returned 0, as read_Nbit() funcs return -1.
 * Only matters for metas that get num_samples wrong (bigger than total data). */
#define STREAMFILE_IGNORE_EOF 0


/* a STREAMFILE that operates via foobar's file service using a buffer */
typedef struct _FOO_STREAMFILE {
    struct _STREAMFILE sf;
    abort_callback * p_abort;
    service_ptr_t<file> m_file;
    char * name;
    off_t offset;
    size_t validsize;
    uint8_t * buffer;
    size_t buffersize;
    size_t filesize;
}  FOO_STREAMFILE;

static STREAMFILE * open_foo_streamfile_buffer_by_file(service_ptr_t<file> m_file,const char * const filename, size_t buffersize, abort_callback * p_abort);
static STREAMFILE * open_foo_streamfile_buffer(const char * const filename, size_t buffersize, abort_callback * p_abort, t_filestats * stats);

static size_t read_the_rest_foo(uint8_t * dest, off_t offset, size_t length, FOO_STREAMFILE * streamfile) {
    size_t length_read_total=0;

    /* is the part of the requested length in the buffer? */
    if (offset >= streamfile->offset && offset < streamfile->offset + streamfile->validsize) {
        size_t length_read;
        off_t offset_into_buffer = offset - streamfile->offset;
        length_read = streamfile->validsize - offset_into_buffer;

        memcpy(dest,streamfile->buffer + offset_into_buffer,length_read);
        length_read_total += length_read;
        length -= length_read;
        offset += length_read;
        dest += length_read;
    }

    /* What would make more sense here is to read the whole request
     * at once into the dest buffer, as it must be large enough, and then
     * copy some part of that into our own buffer.
     * The destination buffer is supposed to be much smaller than the
     * STREAMFILE buffer, though. Maybe we should only ever return up
     * to the buffer size to avoid having to deal with things like this
     * which are outside of my intended use.
     */
    /* read the rest of the requested length */
    while (length > 0) {
        size_t length_to_read;
        size_t length_read;
        streamfile->validsize = 0; /* buffer is empty now */

        /* request outside file: ignore to avoid seek/read */
        if (offset > streamfile->filesize) {
            streamfile->offset = streamfile->filesize;

#if STREAMFILE_IGNORE_EOF
            memset(dest,0,length); /* dest is already shifted */
            return length_read_total + length; /* partially-read + 0-set buffer */
#else
            return length_read_total; /* partially-read buffer */
#endif
        }

        /* position to new offset */
        try {
            streamfile->m_file->seek(offset,*streamfile->p_abort);
            //if (streamfile->m_file->is_eof(*streamfile->p_abort)) /* allow edge case of offset=filesize */
            //   return length_read;
        } catch (...) {
            streamfile->offset = streamfile->filesize;
            return 0; /* fail miserably (fseek shouldn't fail and reach this) */
        }
        streamfile->offset = offset;

        /* decide how much must be read this time */
        if (length > streamfile->buffersize)
            length_to_read = streamfile->buffersize;
        else
            length_to_read = length;

        /* fill the buffer */
        try {
            length_read = streamfile->m_file->read(streamfile->buffer,streamfile->buffersize,*streamfile->p_abort);
        } catch(...) {
            return 0; /* fail miserably */
        }
        streamfile->validsize = length_read;


        /* if we can't get enough to satisfy the request (EOF) we give up */
        if (length_read < length_to_read) {
            memcpy(dest,streamfile->buffer,length_read);

#if STREAMFILE_IGNORE_EOF
            memset(dest+length_read,0,length-length_read);
            return length_read_total + length; /* partially-read + 0-set buffer */
#else
            return length_read_total + length_read; /* partially-read buffer */
#endif
        }

        /* use the new buffer */
        memcpy(dest,streamfile->buffer,length_to_read);
        length_read_total += length_to_read;
        length -= length_to_read;
        dest += length_to_read;
        offset += length_to_read;
    }

    return length_read_total;
}

static size_t read_foo(FOO_STREAMFILE *streamfile, uint8_t * dest, off_t offset, size_t length) {

    if (!streamfile || !dest || length<=0)
        return 0;

    /* request outside file: ignore to avoid seek/read in read_the_rest_foo() */
    if (offset > streamfile->filesize) {
        streamfile->offset = streamfile->filesize;

#if STREAMFILE_IGNORE_EOF
        memset(dest,0,length);
        return length; /* 0-set buffer */
#else
        return 0; /* nothing to read */
#endif
    }

    /* just copy if entire request is within the buffer */
    if (offset >= streamfile->offset && offset + length <= streamfile->offset + streamfile->validsize) {
        off_t offset_into_buffer = offset - streamfile->offset;
        memcpy(dest,streamfile->buffer + offset_into_buffer,length);
        return length;
    }

    /* request outside buffer: new fread */
    {
        return read_the_rest_foo(dest,offset,length,streamfile);
    }
}

STREAMFILE * open_foo_streamfile(const char * const filename, abort_callback * p_abort, t_filestats * stats) {
    return open_foo_streamfile_buffer(filename,STREAMFILE_DEFAULT_BUFFER_SIZE, p_abort, stats);
}

static STREAMFILE *open_foo(FOO_STREAMFILE *streamFile,const char * const filename,size_t buffersize) {
    service_ptr_t<file> m_file;

    STREAMFILE *newstreamFile;

    if (!filename)
        return NULL;

    // if same name, duplicate the file pointer we already have open
    if (!strcmp(streamFile->name,filename)) {
        m_file = streamFile->m_file;
        if (1) {
            newstreamFile = open_foo_streamfile_buffer_by_file(m_file,filename,buffersize,streamFile->p_abort);
            if (newstreamFile) {
                return newstreamFile;
            }
            // failure, close it and try the default path (which will probably fail a second time)
        }
    }
    // a normal open, open a new file

    return open_foo_streamfile_buffer(filename,buffersize,streamFile->p_abort,NULL);
}

static size_t get_size_foo(FOO_STREAMFILE * streamfile) {
    return streamfile->filesize;
}

static off_t get_offset_foo(FOO_STREAMFILE *streamFile) {
    return streamFile->offset;
}

static void close_foo(FOO_STREAMFILE * streamfile) {
    streamfile->m_file.release();
    free(streamfile->name);
    free(streamfile->buffer);
    free(streamfile);
}

static void get_name_foo(FOO_STREAMFILE *streamfile,char *buffer,size_t length) {
   /* Most crap only cares about the filename itself */
   size_t ourlen = strlen(streamfile->name);
   if (ourlen > length) {
      if (length) strcpy(buffer, streamfile->name + ourlen - length + 1);
   } else {
      strcpy(buffer, streamfile->name);
   }
}

static STREAMFILE * open_foo_streamfile_buffer_by_file(service_ptr_t<file> m_file,const char * const filename, size_t buffersize, abort_callback * p_abort) {
    uint8_t * buffer;
    FOO_STREAMFILE * streamfile;

    buffer = (uint8_t *) calloc(buffersize,1);
    if (!buffer) {
        return NULL;
    }

    streamfile = (FOO_STREAMFILE *) calloc(1,sizeof(FOO_STREAMFILE));
    if (!streamfile) {
        free(buffer);
        return NULL;
    }

    streamfile->sf.read = (size_t (__cdecl *)(_STREAMFILE *,uint8_t *,off_t,size_t)) read_foo;
    streamfile->sf.get_size = (size_t (__cdecl *)(_STREAMFILE *)) get_size_foo;
    streamfile->sf.get_offset = (off_t (__cdecl *)(_STREAMFILE *)) get_offset_foo;
    streamfile->sf.get_name = (void (__cdecl *)(_STREAMFILE *,char *,size_t)) get_name_foo;
    streamfile->sf.open = (_STREAMFILE *(__cdecl *)(_STREAMFILE *,const char *const ,size_t)) open_foo;
    streamfile->sf.close = (void (__cdecl *)(_STREAMFILE *)) close_foo;

    streamfile->m_file = m_file;

    streamfile->buffersize = buffersize;
    streamfile->buffer = buffer;
    streamfile->p_abort = p_abort;

    streamfile->name = strdup(filename);
    if (!streamfile->name) {
        free(streamfile);
        free(buffer);
        return NULL;
    }

    /* cache filesize */
    streamfile->filesize = streamfile->m_file->get_size(*streamfile->p_abort);

    return &streamfile->sf;
}

static STREAMFILE * open_foo_streamfile_buffer(const char * const filename, size_t buffersize, abort_callback * p_abort, t_filestats * stats) {
    STREAMFILE *streamFile;
    service_ptr_t<file> infile;

    if(!(filesystem::g_exists(filename, *p_abort)))
        return NULL;

    filesystem::g_open_read(infile,filename,*p_abort);
    if(stats) *stats = infile->get_stats(*p_abort);

    streamFile = open_foo_streamfile_buffer_by_file(infile,filename,buffersize,p_abort);
    if (!streamFile) {
        // fclose(infile);
    }

    return streamFile;
}