Add codecs to librbcodec.

Change-Id: Id7f4717d51ed02d67cb9f9cb3c0ada4a81843f97
Reviewed-on: http://gerrit.rockbox.org/137
Reviewed-by: Nils Wallménius <nils@rockbox.org>
Tested-by: Nils Wallménius <nils@rockbox.org>

lib/rbcodec/codecs/sgc.c

@@ -0,0 +1,123 @@
+
+/* Ripped off from Game_Music_Emu 0.5.2. http://www.slack.net/~ant/ */
+
+#include <codecs/lib/codeclib.h>
+#include "libgme/sgc_emu.h" 
+
+CODEC_HEADER
+
+/* Maximum number of bytes to process in one iteration */
+#define CHUNK_SIZE (1024*2)
+
+static int16_t samples[CHUNK_SIZE] IBSS_ATTR;
+static struct Sgc_Emu sgc_emu;
+
+/* Coleco Bios */
+/* Colecovision not supported yet
+static char coleco_bios[0x2000];
+*/
+
+/****************** rockbox interface ******************/
+
+static void set_codec_track(int t) {
+    Sgc_start_track(&sgc_emu, t); 
+
+    /* for REPEAT_ONE we disable track limits */
+    if (!ci->loop_track()) {
+        Track_set_fade(&sgc_emu, Track_get_length( &sgc_emu, t ), 4000);
+    }
+    ci->set_elapsed(t*1000); /* t is track no to display */
+}
+
+/* this is the codec entry point */
+enum codec_status codec_main(enum codec_entry_call_reason reason)
+{
+    if (reason == CODEC_LOAD) {
+        /* we only render 16 bits */
+        ci->configure(DSP_SET_SAMPLE_DEPTH, 16);
+
+        /* 44 Khz, Interleaved stereo */
+        ci->configure(DSP_SET_FREQUENCY, 44100);
+        ci->configure(DSP_SET_STEREO_MODE, STEREO_INTERLEAVED);
+
+        Sgc_init(&sgc_emu);
+        Sgc_set_sample_rate(&sgc_emu, 44100);
+
+        /* set coleco bios, should be named coleco_bios.rom */
+        /* Colecovision not supported yet
+        int fd = ci->open("/coleco_bios.rom", O_RDONLY);
+        if ( fd >= 0 ) {
+            ci->read(fd, coleco_bios, 0x2000);
+            ci->close(fd);
+            set_coleco_bios( &sgc_emu, coleco_bios );
+        }
+        */
+    }
+
+    return CODEC_OK;
+}
+
+/* this is called for each file to process */
+enum codec_status codec_run(void)
+{
+    blargg_err_t err;
+    uint8_t *buf;
+    size_t n;
+    intptr_t param;
+    int track = 0;
+
+    DEBUGF("SGC: next_track\n");
+    if (codec_init()) {
+        return CODEC_ERROR;
+    }
+
+    codec_set_replaygain(ci->id3);
+
+    /* Read the entire file */
+    DEBUGF("SGC: request file\n");
+    ci->seek_buffer(0);
+    buf = ci->request_buffer(&n, ci->filesize);
+    if (!buf || n < (size_t)ci->filesize) {
+        DEBUGF("SGC: file load failed\n");
+        return CODEC_ERROR;
+    }
+   
+    if ((err = Sgc_load_mem(&sgc_emu, buf, ci->filesize))) {
+        DEBUGF("SGC: Sgc_load_mem failed (%s)\n", err);
+        return CODEC_ERROR;
+    }
+
+    /* Update internal track count */
+    if (sgc_emu.m3u.size > 0)
+        sgc_emu.track_count = sgc_emu.m3u.size;
+
+next_track:
+    set_codec_track(track);
+
+    /* The main decoder loop */
+    while (1) {
+        enum codec_command_action action = ci->get_command(&param);
+
+        if (action == CODEC_ACTION_HALT)
+            break;
+
+        if (action == CODEC_ACTION_SEEK_TIME) {
+            track = param/1000;
+            ci->seek_complete();
+            if (track >= sgc_emu.track_count) break;
+            goto next_track;
+        }
+
+        /* Generate audio buffer */
+        err = Sgc_play(&sgc_emu, CHUNK_SIZE, samples);
+        if (err || Track_ended(&sgc_emu)) {
+            track++;
+            if (track >= sgc_emu.track_count) break;
+            goto next_track;
+        }
+
+        ci->pcmbuf_insert(samples, NULL, CHUNK_SIZE >> 1);
+    }
+
+    return CODEC_OK;
+}