Implemented a first attempt of a .wav decapitator (ticket 38)

libburn/libdax_audioxtr.c

@@ -0,0 +1,196 @@
+
+/* libdax_audioxtr 
+   Audio track data extraction facility of libdax and libburn.
+   Copyright (C) 2006 Thomas Schmitt <scdbackup@gmx.net>, provided under GPL
+*/
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+
+
+#include "libdax_msgs.h"
+extern struct libdax_msgs *libdax_messenger;
+
+
+/* Only this single source module is entitled to do this */
+#define LIBDAX_AUDIOXTR_H_INTERNAL 1
+
+/* All clients of the extraction facility must do this */
+#include "libdax_audioxtr.h"
+
+
+int libdax_audioxtr_new(struct libdax_audioxtr **xtr, char *path, int flag)
+{
+ int ret;
+ struct libdax_audioxtr *o;
+
+ o= *xtr= (struct libdax_audioxtr *)malloc(sizeof(struct libdax_audioxtr *));
+ if(o==NULL)
+   return(-1);
+ strncpy(o->path,path,LIBDAX_AUDIOXTR_STRLEN-1);
+ o->path[LIBDAX_AUDIOXTR_STRLEN]= 0;
+ o->fd= -1;
+ strcpy(o->fmt,"unidentified");
+ o->fmt_info[0]= 0;
+
+ o->wav_num_channels= 0;
+ o->wav_sample_rate= 0;
+ o->wav_bits_per_sample= 0;
+
+ ret= libdax_audioxtr_open(o,0);
+ if(ret<=0)
+   goto failure;
+
+ return(1);
+failure:
+ libdax_audioxtr_destroy(xtr,0);
+ return(-1);
+}
+
+
+int libdax_audioxtr_destroy(struct libdax_audioxtr **xtr, int flag)
+{
+ struct libdax_audioxtr *o;
+
+ o= *xtr;
+ if(o==NULL)
+   return(0);
+ if(o->fd>=0 && strcmp(o->path,"-")!=0)
+   close(o->fd);
+ free((char *) o);
+ *xtr= NULL;
+ return(1);
+}
+
+
+static int libdax_audioxtr_open(struct libdax_audioxtr *o, int flag)
+{
+ int ret;
+ char msg[LIBDAX_AUDIOXTR_STRLEN+80];
+ 
+ if(strcmp(o->path,"-")==0)
+   o->fd= 0;
+ else
+   o->fd= open(o->path, O_RDONLY);
+ if(o->fd<0) {
+   sprintf(msg,"Cannot open audio source file : %s",o->path);
+   libdax_msgs_submit(libdax_messenger,-1,0x00020200,
+                      LIBDAX_MSGS_SEV_SORRY, LIBDAX_MSGS_PRIO_HIGH,
+                      msg, errno, 0);
+   return(-1);
+ }
+ ret= libdax_audioxtr_identify(o,0);
+ if(ret<=0) {
+   sprintf(msg,"Audio source file has unsuitable format : %s",o->path);
+   libdax_msgs_submit(libdax_messenger,-1,0x00020201,
+                      LIBDAX_MSGS_SEV_SORRY, LIBDAX_MSGS_PRIO_HIGH,
+                      msg, 0, 0);
+   return(0);
+ }
+ ret= libdax_audioxtr_init_reading(o,0);
+ if(ret<=0) {
+   sprintf(msg,"Failed to prepare reading of audio data : %s",o->path);
+   libdax_msgs_submit(libdax_messenger,-1,0x00020202,
+                      LIBDAX_MSGS_SEV_SORRY, LIBDAX_MSGS_PRIO_HIGH,
+                      msg, 0, 0);
+   return(0);
+ }
+ return(1);
+}
+
+
+static int libdax_audioxtr_identify(struct libdax_audioxtr *o, int flag)
+{
+ int ret;
+ char buf[45];
+
+ /* currently this only works for MS WAVE files .wav */
+ /* info used: http://ccrma.stanford.edu/courses/422/projects/WaveFormat/ */
+
+ ret= read(o->fd, buf, 44);
+ if(ret<44)
+   return(0);
+ buf[44]= 0; /* as stopper for any string operations */
+
+ if(strncmp(buf,"RIFF",4)!=0)                                     /* ChunkID */
+   return(0);
+ if(strncmp(buf+8,"WAVE",4)!=0)                                    /* Format */ 
+   return(0);
+ if(strncmp(buf+12,"fmt ",4)!=0)                              /* Subchunk1ID */
+   return(0);
+ if(buf[16]!=16 || buf[17]!=0 || buf[18]!=0 || buf[19]!=0)  /* Subchunk1Size */
+   return(0);
+ if(buf[20]!=1 || buf[21]!=0)  /* AudioFormat must be 1 (Linear quantization) */
+   return(0);
+
+ strcpy(o->fmt,".wav");
+ o->wav_num_channels=  libdax_audioxtr_to_int(o,(unsigned char *) buf+22,2,0);
+ o->wav_sample_rate= libdax_audioxtr_to_int(o,(unsigned char *) buf+24,4,0);
+ o->wav_bits_per_sample= libdax_audioxtr_to_int(o,(unsigned char *)buf+34,2,0);
+ sprintf(o->fmt_info,
+         ".wav , num_channels=%d , sample_rate=%d , bits_per_sample=%d",
+         o->wav_num_channels,o->wav_sample_rate,o->wav_bits_per_sample);
+
+ return(1);
+}
+
+
+static unsigned libdax_audioxtr_to_int(struct libdax_audioxtr *o,
+                                      unsigned char *bytes, int len, int flag)
+{
+ unsigned int ret= 0;
+ int i;
+
+ for(i= len-1; i>=0; i--)
+   ret= ret*256+bytes[i];
+ return(ret);
+}
+
+
+static int libdax_audioxtr_init_reading(struct libdax_audioxtr *o, int flag)
+{
+ int ret;
+
+ /* currently this only works for MS WAVE files .wav */;
+ ret= lseek(o->fd,44,SEEK_SET);
+ if(ret==-1)
+   return(0);
+
+ return(1);
+}
+
+
+int libdax_audioxtr_get_id(struct libdax_audioxtr *o,
+                     char **fmt, char **fmt_info,
+                     int *num_channels, int *sample_rate, int *bits_per_sample,
+                     int flag)
+{
+ *fmt= o->fmt;
+ *fmt_info= o->fmt_info;
+ if(strcmp(o->fmt,".wav")==0) {
+   *num_channels= o->wav_num_channels;
+   *sample_rate= o->wav_sample_rate;
+   *bits_per_sample= o->wav_bits_per_sample;
+ } else
+   *num_channels= *sample_rate= *bits_per_sample= 0;
+ return(1);
+}
+
+
+int libdax_audioxtr_read(struct libdax_audioxtr *o,
+                         char buffer[], int buffer_size, int flag)
+{
+ int ret;
+
+ if(buffer_size<=0 || o->fd<0)
+   return(-2);
+ ret= read(o->fd,buffer,buffer_size);
+ return(ret);
+}
+