audio: Add mpg123 bindings.

* chickadee/audio/mpg123.scm: New file.
* Makefile.am (SOURCES): Add it.
* configure.ac: Check for mpg123 library.

4 files changed, 243 insertions, 0 deletions

diff --git a/Makefile.am b/Makefile.am
index 54839f1..6183b03 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -55,6 +55,7 @@ SOURCES = 					\
   chickadee/math/grid.scm			\
   chickadee/math/easings.scm			\
   chickadee/math/path-finding.scm		\
+  chickadee/audio/mpg123.scm			\
   chickadee/audio/openal.scm			\
   chickadee/audio/vorbis.scm			\
   chickadee/audio/wav.scm			\
diff --git a/chickadee/audio/mpg123.scm b/chickadee/audio/mpg123.scm
new file mode 100644
index 0000000..20ff3ea
--- /dev/null
+++ b/chickadee/audio/mpg123.scm
@@ -0,0 +1,229 @@
+;;; Chickadee Game Toolkit
+;;; Copyright © 2019 David Thompson <dthompson2@worcester.edu>
+;;;
+;;; Chickadee is free software: you can redistribute it and/or modify
+;;; it under the terms of the GNU General Public License as published
+;;; by the Free Software Foundation, either version 3 of the License,
+;;; or (at your option) any later version.
+;;;
+;;; Chickadee is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;;; General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with this program.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; libmpg123 bindings.
+;;
+;;; Code:
+
+(define-module (chickadee audio mpg123)
+  #:use-module (chickadee config)
+  #:use-module (ice-9 format)
+  #:use-module (ice-9 match)
+  #:use-module (rnrs bytevectors)
+  #:use-module (srfi srfi-9)
+  #:use-module (srfi srfi-9 gnu)
+  #:use-module (system foreign)
+  #:export (mpg123-init
+            mpg123-exit
+            mpg123-open
+            mpg123-close
+            mpg123-format
+            mpg123-read
+            mpg123-time-seek
+            mpg123-length))
+
+
+;;;
+;;; Enums
+;;;
+
+(define MPG123_VERBOSE 0)
+(define MPG123_FLAGS 1)
+(define MPG123_ADD_FLAGS 2)
+(define MPG123_FORCE_RATE 3)
+(define MPG123_DOWN_SAMPLE 4)
+(define MPG123_RVA 5)
+(define MPG123_DOWNSPEED 6)
+(define MPG123_UPSPEED 7)
+(define MPG123_START_FRAME 8)
+(define MPG123_DECODE_FRAMES 9)
+(define MPG123_ICY_INTERVAL 10)
+(define MPG123_OUTSCALE 11)
+(define MPG123_TIMEOUT 12)
+(define MPG123_REMOVE_FLAGS 13)
+(define MPG123_RESYNC_LIMIT 14)
+(define MPG123_INDEX_SIZE 15)
+(define MPG123_PREFRAMES 16)
+(define MPG123_FEEDPOOL 17)
+(define MPG123_FEEDBUFFER 18)
+
+(define MPG123_ENC_8 #x00f)
+(define MPG123_ENC_16 #x040)
+(define MPG123_ENC_24 #x4000)
+(define MPG123_ENC_32 #x100)
+(define MPG123_ENC_SIGNED #x080)
+(define MPG123_ENC_FLOAT #xe00)
+(define MPG123_ENC_SIGNED_16 (logior MPG123_ENC_16 MPG123_ENC_SIGNED #x10))
+(define MPG123_ENC_UNSIGNED_16 (logior MPG123_ENC_16 #x20))
+(define MPG123_ENC_UNSIGNED_8 #x01)
+(define MPG123_ENC_SIGNED_8 (logior MPG123_ENC_SIGNED #x02))
+(define MPG123_ENC_ULAW_8 #x04)
+(define MPG123_ENC_ALAW_8 #x08)
+(define MPG123_ENC_SIGNED_32 (logior MPG123_ENC_32 MPG123_ENC_SIGNED #x1000))
+(define MPG123_ENC_UNSIGNED_32 (logior MPG123_ENC_32 #x2000))
+(define MPG123_ENC_SIGNED_24 (logior MPG123_ENC_24 MPG123_ENC_SIGNED #x1000))
+(define MPG123_ENC_UNSIGNED_24 (logior MPG123_ENC_24 #x2000))
+(define MPG123_ENC_FLOAT_32 #x200)
+(define MPG123_ENC_FLOAT_64 #x400)
+
+
+
+;;;
+;;; Low-level bindings
+;;;
+
+(define mpg123-func
+  (let ((lib (dynamic-link %libmpg123)))
+    (lambda (return-type function-name arg-types)
+      (pointer->procedure return-type
+                          (dynamic-func function-name lib)
+                          arg-types))))
+
+(define-syntax-rule (define-foreign name return-type func-name arg-types)
+  (define name
+    (mpg123-func return-type func-name arg-types)))
+
+(define off_t int)
+
+(define-foreign %mpg123-init
+  int "mpg123_init" '())
+
+(define-foreign mpg123-exit
+  void "mpg123_exit" '())
+
+(define-foreign mpg123-new
+  '* "mpg123_new" '(* *))
+
+(define-foreign mpg123-delete
+  void "mpg123_delete" '(*))
+
+(define-foreign mpg123-param
+  int "mpg123_param" (list '* int long double))
+
+(define-foreign mpg123-getparam
+  int "mpg123_getparam" (list '* int '* '*))
+
+(define-foreign mpg123-getformat
+  int "mpg123_getformat" '(* * * *))
+
+(define-foreign mpg123-plain-strerror
+  '* "mpg123_plain_strerror" (list int))
+
+(define-foreign mpg123-strerror
+  '* "mpg123_strerror" '(*))
+
+(define-foreign %mpg123-open
+  int "mpg123_open" '(* *))
+
+(define-foreign %mpg123-close
+  int "mpg123_close" '(*))
+
+(define-foreign %mpg123-read
+  int "mpg123_read" (list '* '* size_t '*))
+
+(define-foreign mpg123-timeframe
+  off_t "mpg123_timeframe" (list '* double))
+
+(define-foreign mpg123-seek-frame
+  off_t "mpg123_seek_frame" (list '* off_t int))
+
+(define-foreign %mpg123-length
+  off_t "mpg123_length" (list '*))
+
+
+;;;
+;;; Error Handling
+;;;
+
+(define (mpg123-check-error func error-id message . args)
+  (let* ((error-string (pointer->string (mpg123-plain-strerror error-id))))
+    (unless (zero? error-id)
+      (apply throw 'mpg123-error func (string-append message ": ~A")
+             (append args (list error-string))))))
+
+
+;;;
+;;; High-level bindings
+;;;
+
+(define (display-mpg123-handle handle port)
+  (display "#<mpg123-handle>" port))
+
+(define-wrapped-pointer-type <mpg123-handle> mpg123-handle?
+  wrap-mpg123-handle unwrap-mpg123-handle display-mpg123-handle)
+
+(define (mpg123-init)
+  (mpg123-check-error "mpg123-init" (%mpg123-init) "failed to initialize"))
+
+(define (mpg123-open file-name)
+  (let ((handle (or (mpg123-new %null-pointer %null-pointer)
+                    (error "failed to create mpg123 handle"))))
+    (%mpg123-open handle (string->pointer file-name))
+    (wrap-mpg123-handle handle)))
+
+(define (mpg123-close handle)
+  (let ((ptr (unwrap-mpg123-handle handle)))
+    (%mpg123-close ptr)
+    (mpg123-delete ptr)))
+
+(define (mpg123-format handle)
+  (let ((rate (make-bytevector (sizeof long)))
+        (channels (make-bytevector (sizeof int)))
+        (encoding (make-bytevector (sizeof int))))
+    (mpg123-check-error "mpg123-format"
+                        (mpg123-getformat (unwrap-mpg123-handle handle)
+                                          (bytevector->pointer rate)
+                                          (bytevector->pointer channels)
+                                          (bytevector->pointer encoding))
+                        "failed to get audio format info")
+    (let* ((encoding (bytevector-sint-ref encoding 0 (native-endianness)
+                                          (sizeof int)))
+           (bits-per-sample (cond
+                             ((= encoding MPG123_ENC_SIGNED_8)
+                              8)
+                             ((= encoding MPG123_ENC_SIGNED_16)
+                              16)
+                             ((= encoding MPG123_ENC_SIGNED_24)
+                              24)
+                             ((= encoding MPG123_ENC_SIGNED_32)
+                              32)
+                             (else
+                              (error "unsupported mp3 encoding" encoding)))))
+      (values (bytevector-sint-ref rate 0 (native-endianness) (sizeof long))
+              (bytevector-sint-ref channels 0 (native-endianness) (sizeof int))
+              bits-per-sample))))
+
+(define (mpg123-read handle buffer)
+  (let* ((bv (make-bytevector (sizeof size_t)))
+         (error-code (%mpg123-read (unwrap-mpg123-handle handle)
+                                   (bytevector->pointer buffer)
+                                   (bytevector-length buffer)
+                                   (bytevector->pointer bv))))
+    (when (> error-code 0)
+      (mpg123-check-error "mpg123-read" error-code "failed to read audio"))
+    (bytevector-sint-ref bv 0 (native-endianness) (sizeof size_t))))
+
+(define (mpg123-time-seek handle t)
+  (let ((offset (mpg123-timeframe (unwrap-mpg123-handle handle) t)))
+    (mpg123-check-error "mpg123-time-seek"
+                        (mpg123-seek-frame (unwrap-mpg123-handle handle) offset SEEK_SET)
+                        "failed to seek")))
+
+(define (mpg123-length handle)
+  (%mpg123-length (unwrap-mpg123-handle handle)))
diff --git a/chickadee/config.scm.in b/chickadee/config.scm.in
index ab88dbb..5a2a8f8 100644
--- a/chickadee/config.scm.in
+++ b/chickadee/config.scm.in
@@ -26,6 +26,7 @@
             %chickadee-version
             %libopenal
             %libvorbisfile
+            %libmpg123
             scope-datadir))
 
 (define %datadir
@@ -35,6 +36,8 @@
 
 (define %libopenal "@OPENAL_LIBDIR@/libopenal")
 (define %libvorbisfile "@VORBIS_LIBDIR@/libvorbisfile")
+(define %libmpg123 "@MPG123_LIBDIR@/libmpg123")
+
 (define (scope-datadir file)
   "Append the Chickadee data directory to FILE."
   (string-append %datadir "/" file))
diff --git a/configure.ac b/configure.ac
index 2bc4ad7..a28d1fe 100644
--- a/configure.ac
+++ b/configure.ac
@@ -43,4 +43,14 @@ AS_IF([test "VORBIS_LIBDIR" = "x"], [
 ])
 AC_SUBST([VORBIS_LIBDIR])
 
+PKG_CHECK_MODULES([mpg123], [libmpg123])
+PKG_CHECK_VAR([MPG123_LIBDIR], [libmpg123], [libdir])
+AC_MSG_CHECKING([mpg123 library path])
+AS_IF([test "MPG123_LIBDIR" = "x"], [
+  AC_MSG_FAILURE([Unable to identify mpg123 lib path.])
+], [
+  AC_MSG_RESULT([$MPG123_LIBDIR])
+])
+AC_SUBST([MPG123_LIBDIR])
+
 AC_OUTPUT