Add an extension to alter the block alignment for buffer unpack/pack ops

This is for unpacking (reading, e.g. alBufferData) and packing (writing, e.g.
alGetBufferSamplesSOFT) operations. The alignments are specified in sample
frames, with 0 meaning the default (65 for IMA4, 1 otherwise). IMA4 alignment
must be a multiple of 8, plus 1 (e.g. alignment = n*8 + 1), otherwise an error
will occur during (un)packing. Chenging the block alignment does not affect
already-loaded sample data, only future unpack/pack operations... so for
example, this is perfectly valid:

// Load mono IMA4 data with a block alignment of 1024 bytes, or 2041 sample
// frames.
alBufferi(buffer, AL_UNPACK_BLOCK_ALIGNMENT_SOFT, 2041);
alBufferData(buffer, AL_FORMAT_MONO_IMA4, data, data_len, srate);
alBufferi(buffer, AL_UNPACK_BLOCK_ALIGNMENT_SOFT, 0);

1 files changed, 5 insertions, 3 deletions

diff --git a/Alc/ALc.c b/Alc/ALc.c
index a7cb9e92..627724da 100644
--- a/Alc/ALc.c
+++ b/Alc/ALc.c
@@ -523,6 +523,8 @@ static const ALCenums enumeration[] = {
     DECL(AL_BYTE_LENGTH_SOFT),
     DECL(AL_SAMPLE_LENGTH_SOFT),
     DECL(AL_SEC_LENGTH_SOFT),
+    DECL(AL_UNPACK_BLOCK_ALIGNMENT_SOFT),
+    DECL(AL_PACK_BLOCK_ALIGNMENT_SOFT),
 
     DECL(AL_UNUSED),
     DECL(AL_PENDING),
@@ -706,9 +708,9 @@ static const ALchar alExtList[] =
     "AL_EXT_ALAW AL_EXT_DOUBLE AL_EXT_EXPONENT_DISTANCE AL_EXT_FLOAT32 "
     "AL_EXT_IMA4 AL_EXT_LINEAR_DISTANCE AL_EXT_MCFORMATS AL_EXT_MULAW "
     "AL_EXT_MULAW_MCFORMATS AL_EXT_OFFSET AL_EXT_source_distance_model "
-    "AL_LOKI_quadriphonic AL_SOFT_buffer_samples AL_SOFT_buffer_sub_data "
-    "AL_SOFT_deferred_updates AL_SOFT_direct_channels AL_SOFT_loop_points "
-    "AL_SOFT_source_latency";
+    "AL_LOKI_quadriphonic AL_SOFTX_block_alignment AL_SOFT_buffer_samples "
+    "AL_SOFT_buffer_sub_data AL_SOFT_deferred_updates AL_SOFT_direct_channels "
+    "AL_SOFT_loop_points AL_SOFT_source_latency";
 
 static volatile ALCenum LastNullDeviceError = ALC_NO_ERROR;