From 374e1d3c3264593b1ebbdaaacbd0d8660470a7d9 Mon Sep 17 00:00:00 2001
From: bnnm <bananaman255@gmail.com>
Date: Thu, 26 Aug 2021 19:52:19 +0200
Subject: [PATCH] utils: chunk parsing helper

---
 src/libvgmstream.vcxproj         |  3 +++
 src/libvgmstream.vcxproj.filters |  9 +++++++
 src/meta/dmsg_segh.c             | 44 +-------------------------------
 src/util/chunks.c                | 35 +++++++++++++++++++++++++
 src/util/chunks.h                | 27 ++++++++++++++++++++
 5 files changed, 75 insertions(+), 43 deletions(-)
 create mode 100644 src/util/chunks.c
 create mode 100644 src/util/chunks.h

diff --git a/src/libvgmstream.vcxproj b/src/libvgmstream.vcxproj
index 7f89668a..1dfd82c5 100644
--- a/src/libvgmstream.vcxproj
+++ b/src/libvgmstream.vcxproj
@@ -168,6 +168,8 @@
     <ClInclude Include="coding\tac_decoder_lib_data.h" />
     <ClInclude Include="coding\tac_decoder_lib_ops.h" />
     <ClInclude Include="layout\layout.h" />
+    <ClInclude Include="util\chunks.h" />
+    <ClInclude Include="util\log.h" />
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="coding\at3plus_decoder.c" />
@@ -708,6 +710,7 @@
     <ClCompile Include="layout\blocked_xa.c" />
     <ClCompile Include="layout\blocked_xa_aiff.c" />
     <ClCompile Include="layout\blocked_xvas.c" />
+    <ClCompile Include="util\chunks.c" />
     <ClCompile Include="util\log.c" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
diff --git a/src/libvgmstream.vcxproj.filters b/src/libvgmstream.vcxproj.filters
index d3f751ef..179448be 100644
--- a/src/libvgmstream.vcxproj.filters
+++ b/src/libvgmstream.vcxproj.filters
@@ -302,6 +302,12 @@
     <ClInclude Include="meta\encrypted_bgm_streamfile.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="util\chunks.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="util\log.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="formats.c">
@@ -1918,6 +1924,9 @@
     <ClCompile Include="meta\sbk.c">
       <Filter>meta\Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="util\chunks.c">
+      <Filter>util\Source Files</Filter>
+    </ClCompile>
     <ClCompile Include="util\log.c">
       <Filter>util\Source Files</Filter>
     </ClCompile>
diff --git a/src/meta/dmsg_segh.c b/src/meta/dmsg_segh.c
index 900d7188..91142a9e 100644
--- a/src/meta/dmsg_segh.c
+++ b/src/meta/dmsg_segh.c
@@ -1,48 +1,6 @@
 #include "meta.h"
 #include "../coding/coding.h"
-
-typedef struct {
-    uint32_t type;
-    uint32_t size;
-    uint32_t offset;
-    off_t current;
-    off_t max;
-    int le_type;
-    int be_size;
-    int full_size;
-} chunk_t;
-
-static int next_chunk(chunk_t* chunk, STREAMFILE* sf) {
-    uint32_t (*read_u32type)(off_t,STREAMFILE*) = !chunk->le_type ? read_u32be : read_u32le;
-    uint32_t (*read_u32size)(off_t,STREAMFILE*) = chunk->be_size ? read_u32be : read_u32le;
-
-    if (chunk->max == 0)
-        chunk->max = get_streamfile_size(sf);
-
-    if (chunk->current >= chunk->max)
-        return 0;
-    /* can be used to signal "stop" */
-    if (chunk->current < 0)
-        return 0;
-
-    chunk->type = read_u32type(chunk->current + 0x00,sf);
-    chunk->size = read_u32size(chunk->current + 0x04,sf);
-
-    chunk->offset = chunk->current + 0x04 + 0x04;
-    chunk->current += chunk->full_size ? chunk->size : 0x08 + chunk->size;
-    //;VGM_LOG("CHUNK: %x, %x, %x\n", dc.offset, chunk->type, chunk->size);
-
-    /* read past data */
-    if (chunk->type == 0xFFFFFFFF || chunk->size == 0xFFFFFFFF)
-        return 0;
-
-    /* empty chunk with 0 size, seen in some formats (XVAG uses it as end marker, Wwise doesn't) */
-    if (chunk->type == 0 || chunk->size == 0)
-        return 0;
-
-    /* more chunks remain */
-    return 1;
-}
+#include "../util/chunks.h"
 
 enum { 
     CHUNK_RIFF = 0x52494646, /* "RIFF" */
diff --git a/src/util/chunks.c b/src/util/chunks.c
new file mode 100644
index 00000000..21486586
--- /dev/null
+++ b/src/util/chunks.c
@@ -0,0 +1,35 @@
+#include "chunks.h"
+//#include "log.h"
+
+
+int next_chunk(chunk_t* chunk, STREAMFILE* sf) {
+    uint32_t (*read_u32type)(off_t,STREAMFILE*) = !chunk->le_type ? read_u32be : read_u32le;
+    uint32_t (*read_u32size)(off_t,STREAMFILE*) = chunk->be_size ? read_u32be : read_u32le;
+
+    if (chunk->max == 0)
+        chunk->max = get_streamfile_size(sf);
+
+    if (chunk->current >= chunk->max)
+        return 0;
+    /* can be used to signal "stop" */
+    if (chunk->current < 0)
+        return 0;
+
+    chunk->type = read_u32type(chunk->current + 0x00,sf);
+    chunk->size = read_u32size(chunk->current + 0x04,sf);
+
+    chunk->offset = chunk->current + 0x04 + 0x04;
+    chunk->current += chunk->full_size ? chunk->size : 0x08 + chunk->size;
+    //;VGM_LOG("CHUNK: %x, %x, %x\n", dc.offset, chunk->type, chunk->size);
+
+    /* read past data */
+    if (chunk->type == 0xFFFFFFFF || chunk->size == 0xFFFFFFFF)
+        return 0;
+
+    /* empty chunk with 0 size, seen in some formats (XVAG uses it as end marker, Wwise doesn't) */
+    if (chunk->type == 0 || chunk->size == 0)
+        return 0;
+
+    /* more chunks remain */
+    return 1;
+}
diff --git a/src/util/chunks.h b/src/util/chunks.h
new file mode 100644
index 00000000..0df77cc5
--- /dev/null
+++ b/src/util/chunks.h
@@ -0,0 +1,27 @@
+#ifndef _UTIL_CHUNKS_H
+#define _UTIL_CHUNKS_H
+
+#include "../streamfile.h"
+
+typedef struct {
+    uint32_t type;      /* chunk id/fourcc */
+    uint32_t size;      /* chunk size */
+    uint32_t offset;    /* chunk offset (after type/size) */
+    off_t current;      /* start position, or next chunk after size (set to -1 to break) */
+    off_t max;          /* max offset, or filesize if not set */
+
+    int le_type;        /* read type as LE instead of more common BE */
+    int be_size;        /* read type as BE instead of more common LE */
+    int full_size;      /* chunk size includes type+size */
+} chunk_t;
+
+int next_chunk(chunk_t* chunk, STREAMFILE* sf);
+
+#if 0
+enum { 
+    CHUNK_RIFF = 0x52494646, /* "RIFF" */
+    CHUNK_LIST = 0x4C495354, /* "LIST" */
+};
+#endif
+
+#endif