WAV hands-off reading.

Hands-off readering code built into tracklength plugin.

diff --git a/lib/hreader.c b/lib/hreader.c
index 597337519e8d6e647be0be54f0e184fe38bb08db..9bcc808d9203041a68dab85db73ff180ced1dc3c 100644 (file)
--- a/lib/hreader.c
+++ b/lib/hreader.c
@@ -23,6 +23,8 @@
 #include <string.h>
 #include <fcntl.h>
 
 #include <string.h>
 #include <fcntl.h>
 

+static int hreader_fill(struct hreader *h, off_t offset);
+

 void hreader_init(const char *path, struct hreader *h) {
   memset(h, 0, sizeof *h);
   h->path = xstrdup(path);
 void hreader_init(const char *path, struct hreader *h) {
   memset(h, 0, sizeof *h);
   h->path = xstrdup(path);


@@ -31,43 +33,51 @@ void hreader_init(const char *path, struct hreader *h) {
 }
 
 int hreader_read(struct hreader *h, void *buffer, size_t n) {
 }
 
 int hreader_read(struct hreader *h, void *buffer, size_t n) {

-  if(h->consumed == h->bytes) {
-    int r;
+  int r = hreader_pread(h, buffer, n, h->read_offset);
+  if(r > 0)
+    h->read_offset += r;
+  return r;
+}

 
 

-    if((r = hreader_fill(h)) <= 0)
-      return r;
+int hreader_pread(struct hreader *h, void *buffer, size_t n, off_t offset) {
+  size_t bytes_read = 0;
+
+  while(bytes_read < n) {
+    // If the desired byte range is outside the file, fetch new contents
+    if(offset < h->buf_offset || offset >= h->buf_offset + (off_t)h->bytes) {
+      int r = hreader_fill(h, offset);
+      if(r < 0)
+        return -1;                      /* disaster! */
+      else if(r == 0)
+        break;                          /* end of file */
+    }
+    // Figure out how much we can read this time round
+    size_t left = h->bytes - (offset - h->buf_offset);
+    // Truncate the read if we don't want that much
+    if(left > (n - bytes_read))
+      left = n - bytes_read;
+    memcpy((char *)buffer + bytes_read,
+           h->buffer + (offset - h->buf_offset),
+           left);
+    offset += left;
+    bytes_read += left;

   }
   }

-  if(n > h->bytes - h->consumed)
-    n = h->bytes - h->consumed;
-  memcpy(buffer, h->buffer + h->consumed, n);
-  h->consumed += n;
-  return n;
+  return bytes_read;

 }
 
 }
 

-int hreader_fill(struct hreader *h) {
-  if(h->consumed < h->bytes)
-    return h->bytes - h->consumed;
-  h->bytes = h->consumed = 0;
+static int hreader_fill(struct hreader *h, off_t offset) {

   int fd = open(h->path, O_RDONLY);
   if(fd < 0)
     return -1;
   int fd = open(h->path, O_RDONLY);
   if(fd < 0)
     return -1;

-  if(lseek(fd, h->offset, SEEK_SET) < 0) {
-    close(fd);
-    return -1;
-  }
-  int n = read(fd, h->buffer, h->bufsize);
+  int n = pread(fd, h->buffer, h->bufsize, offset);

   close(fd);
   if(n < 0)
     return -1;
   close(fd);
   if(n < 0)
     return -1;

+  h->buf_offset = offset;

   h->bytes = n;
   h->bytes = n;

-  h->offset += n;

   return n;
 }
 
   return n;
 }
 

-void hreader_consume(struct hreader *h, size_t n) {
-  h->consumed += n;
-}
-

 /*
 Local Variables:
 c-basic-offset:2
 /*
 Local Variables:
 c-basic-offset:2

diff --git a/lib/hreader.h b/lib/hreader.h
index 1eadc5574b5610d699d683dce851d9b62baabcce..8ef3a4079e4229662f674267d6a5168c3e2e5da9 100644 (file)
--- a/lib/hreader.h
+++ b/lib/hreader.h
@@ -29,11 +29,11 @@
  */
 struct hreader {
   const char *path;            /* file to read */
  */
 struct hreader {
   const char *path;            /* file to read */

-  off_t offset;                        /* how far we've read so far */
+  off_t read_offset;            /* for next hreader_read() */
+  off_t buf_offset;             /* offset of start of buffer */

   char *buffer;                        /* input buffer */
   size_t bufsize;              /* buffer size */
   size_t bytes;                        /* size of last read */
   char *buffer;                        /* input buffer */
   size_t bufsize;              /* buffer size */
   size_t bytes;                        /* size of last read */

-  size_t consumed;             /* bytes consumed by caller from last read */

 };
 
 /** @brief Initialize a hands-off reader
 };
 
 /** @brief Initialize a hands-off reader


@@ -50,20 +50,14 @@ void hreader_init(const char *path, struct hreader *h);
  */
 int hreader_read(struct hreader *h, void *buffer, size_t n);
 
  */
 int hreader_read(struct hreader *h, void *buffer, size_t n);
 

-/** @brief Read more bytes
- * @param h Reader to update
- * @return Bytes available to read
- *
- * If not all bytes were consumed so far then just returns the number
- * of bytes left to consume.
- */
-int hreader_fill(struct hreader *h);
-
-/** @brief Consume some bytes
- * @param h Reader to update
- * @param n Bytes to consume
+/** @brief Read some bytes at a given offset
+ * @param h Reader to read from
+ * @param offset Offset to read at
+ * @param buffer Where to store bytes
+ * @param n Maximum bytes to read
+ * @return Bytes read, or 0 at EOF, or -1 on error

  */
  */

-void hreader_consume(struct hreader *h, size_t n);
+int hreader_pread(struct hreader *h, void *buffer, size_t n, off_t offset);

 
 #endif /* HREADER_H */
 
 
 #endif /* HREADER_H */
 

diff --git a/lib/wav.c b/lib/wav.c
index 455bb729275ea66bcfae8efb4080aff735fc132d..8b2d640a044bee70fabcea46085b542727872b8a 100644 (file)
--- a/lib/wav.c
+++ b/lib/wav.c
@@ -128,9 +128,8 @@ int wav_init(struct wavfile *f, const char *path) {
   off_t where;
   
   memset(f, 0, sizeof *f);
   off_t where;
   
   memset(f, 0, sizeof *f);

-  f->fd = -1;

   f->data = -1;
   f->data = -1;

-  if((f->fd = open(path, O_RDONLY)) < 0) goto error_errno;
+  hreader_init(path, f->input);

   /* Read the file header
    *
    *  offset  size  meaning
   /* Read the file header
    *
    *  offset  size  meaning


@@ -138,7 +137,7 @@ int wav_init(struct wavfile *f, const char *path) {
    *  04      4     length of rest of file
    *  08      4     'WAVE'
    * */
    *  04      4     length of rest of file
    *  08      4     'WAVE'
    * */

-  if((n = pread(f->fd, header, 12, 0)) < 0) goto error_errno;
+  if((n = hreader_pread(f->input, header, 12, 0)) < 0) goto error_errno;

   else if(n < 12) goto einval;
   if(strncmp(header, "RIFF", 4) || strncmp(header + 8, "WAVE", 4))
     goto einval;
   else if(n < 12) goto einval;
   if(strncmp(header, "RIFF", 4) || strncmp(header + 8, "WAVE", 4))
     goto einval;


@@ -151,7 +150,7 @@ int wav_init(struct wavfile *f, const char *path) {
      *  00      4     chunk ID
      *  04      4     length of rest of chunk
      */
      *  00      4     chunk ID
      *  04      4     length of rest of chunk
      */

-    if((n = pread(f->fd, header, 8, where)) < 0) goto error_errno;
+    if((n = hreader_pread(f->input, header, 8, where)) < 0) goto error_errno;

     else if(n < 8) goto einval;
     if(!strncmp(header,"fmt ", 4)) {
       /* This is the format chunk
     else if(n < 8) goto einval;
     if(!strncmp(header,"fmt ", 4)) {
       /* This is the format chunk


@@ -168,7 +167,8 @@ int wav_init(struct wavfile *f, const char *path) {
        *  18      ?     extra undocumented rubbish
        */
       if(get32(header + 4) < 16) goto einval;
        *  18      ?     extra undocumented rubbish
        */
       if(get32(header + 4) < 16) goto einval;

-      if((n = pread(f->fd, header + 8, 16, where + 8)) < 0) goto error_errno;
+      if((n = hreader_pread(f->input, header + 8, 16, where + 8)) < 0)
+        goto error_errno;

       else if(n < 16) goto einval;
       f->channels = get16(header + 0x0A);
       f->rate = get32(header + 0x0C);
       else if(n < 16) goto einval;
       f->channels = get16(header + 0x0A);
       f->rate = get32(header + 0x0C);


@@ -196,14 +196,7 @@ error:
 }
 
 /** @brief Close a WAV file */
 }
 
 /** @brief Close a WAV file */

-void wav_destroy(struct wavfile *f) {
-  if(f) {
-    const int save_errno = errno;
-
-    if(f->fd >= 0)
-      close(f->fd);
-    errno = save_errno;
-  }
+void wav_destroy(struct wavfile attribute((unused)) *f) {

 }
 
 /** @brief Visit all the data in a WAV file
 }
 
 /** @brief Visit all the data in a WAV file


@@ -227,7 +220,7 @@ int wav_data(struct wavfile *f,
     size_t want = (off_t)sizeof buffer > left ? (size_t)left : sizeof buffer;
 
     want -= want % bytes_per_frame;
     size_t want = (off_t)sizeof buffer > left ? (size_t)left : sizeof buffer;
 
     want -= want % bytes_per_frame;

-    if((n = pread(f->fd, buffer, want, where)) < 0) return errno;
+    if((n = hreader_pread(f->input, buffer, want, where)) < 0) return errno;

     if((size_t)n < want) return EINVAL;
     if((err = callback(f, buffer, n, u))) return err;
     where += n;
     if((size_t)n < want) return EINVAL;
     if((err = callback(f, buffer, n, u))) return err;
     where += n;

diff --git a/lib/wav.h b/lib/wav.h
index d2de912b280ff9b16d8d4d9a96784bbe7ce25311..3c9c477bc5a2975559891126bd010cdb7a6b153c 100644 (file)
--- a/lib/wav.h
+++ b/lib/wav.h
@@ -22,10 +22,12 @@
 #ifndef WAV_H
 #define WAV_H
 
 #ifndef WAV_H
 #define WAV_H
 

+#include "hreader.h"
+

 /** @brief WAV file access structure */
 struct wavfile {
 /** @brief WAV file access structure */
 struct wavfile {

-  /** @brief File descriptor onto file */
-  int fd;
+  /** @brief File read handle */
+  struct hreader input[1];

 
   /** @brief File length */
   off_t length;
 
   /** @brief File length */
   off_t length;

diff --git a/plugins/Makefile.am b/plugins/Makefile.am
index 7852152a2a81f30d09fafac385ea89dcda784828..410f5ae1cfdf83b3107dfb0466d2210ca0a2f345 100644 (file)
--- a/plugins/Makefile.am
+++ b/plugins/Makefile.am
@@ -23,7 +23,7 @@ AM_CPPFLAGS=-I${top_srcdir}/lib
 notify_la_SOURCES=notify.c
 notify_la_LDFLAGS=-module
 
 notify_la_SOURCES=notify.c
 notify_la_LDFLAGS=-module
 

-disorder_tracklength_la_SOURCES=tracklength.c mad.c madshim.h ../lib/wav.h ../lib/wav.c
+disorder_tracklength_la_SOURCES=tracklength.c mad.c madshim.h ../lib/wav.h ../lib/wav.c ../lib/hreader.h ../lib/hreader.c

 disorder_tracklength_la_LDFLAGS=-module
 disorder_tracklength_la_LIBADD=$(LIBVORBISFILE) $(LIBMAD) $(LIBFLAC) -lm
 
 disorder_tracklength_la_LDFLAGS=-module
 disorder_tracklength_la_LIBADD=$(LIBVORBISFILE) $(LIBMAD) $(LIBFLAC) -lm