From a24e8116cca13337153f217bf595dd3ff63cffcb Mon Sep 17 00:00:00 2001
From: DeaDDooMER <deaddoomer@deadsoftware.ru>
Date: Wed, 7 Apr 2021 16:41:52 +0300
Subject: [PATCH] streams: new method: getlen

---
 src/common/files.c   | 17 +++++++++++++++++
 src/common/streams.c |  4 ++++
 src/common/streams.h |  7 +++++--
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/common/files.c b/src/common/files.c
index 792df2d..8961c03 100644
--- a/src/common/files.c
+++ b/src/common/files.c
@@ -22,6 +22,21 @@ static void FILE_Stream_SetPos (Stream *r, long pos) {
   assert(res == 0); // fail
 }
 
+static long FILE_Stream_GetLen (Stream *r) {
+  FILE_Stream *rd = (FILE_Stream*)r;
+  assert(rd != NULL);
+  assert(rd->fp != NULL);
+  long pos = ftell(rd->fp);
+  assert(pos != -1); // fail get cur pos
+  int res = fseek(rd->fp, 0, SEEK_END);
+  assert(res == 0); // fail jump to end
+  long len = ftell(rd->fp);
+  res = fseek(rd->fp, pos, SEEK_SET);
+  assert(res == 0); // fail return
+  assert(len != -1); // fail get length
+  return len;
+}
+
 static void FILE_Stream_Read (Stream *r, void *data, size_t size, size_t n) {
   FILE_Stream *rd = (FILE_Stream*)r;
   assert(rd != NULL);
@@ -43,6 +58,7 @@ void FILE_Assign (FILE_Stream *r, FILE *fp) {
   assert(fp != NULL);
   r->base.getpos = FILE_Stream_GetPos;
   r->base.setpos = FILE_Stream_SetPos;
+  r->base.getlen = FILE_Stream_GetLen;
   r->base.read   = FILE_Stream_Read;
   r->base.write  = FILE_Stream_Write;
   r->fp = fp;
@@ -65,6 +81,7 @@ void FILE_Close (FILE_Stream *r) {
   }
   r->base.getpos = NULL;
   r->base.setpos = NULL;
+  r->base.getlen = NULL;
   r->base.read   = NULL;
   r->base.write  = NULL;
   r->fp = NULL;
diff --git a/src/common/streams.c b/src/common/streams.c
index 76edaab..685ace1 100644
--- a/src/common/streams.c
+++ b/src/common/streams.c
@@ -12,6 +12,10 @@ void stream_setpos (Stream *s, long pos) {
   s->setpos(s, pos);
 }
 
+long stream_getlen (Stream *s) {
+  return s->getlen(s);
+}
+
 void stream_read (void *data, size_t size, size_t n, Stream *r) {
   r->read(r, data, size, n);
 }
diff --git a/src/common/streams.h b/src/common/streams.h
index e40427f..e0a9dd8 100644
--- a/src/common/streams.h
+++ b/src/common/streams.h
@@ -7,8 +7,9 @@
 typedef struct Stream Stream;
 
 struct Stream {
-  long (*getpos)(Stream *r);
-  void (*setpos)(Stream *r, long pos);
+  long (*getpos)(Stream *rw);
+  void (*setpos)(Stream *rw, long pos);
+  long (*getlen)(Stream *rw);
   void (*read)(Stream *r, void *data, size_t size, size_t n);
   void (*write)(Stream *w, const void *data, size_t size, size_t n);
 };
@@ -16,6 +17,8 @@ struct Stream {
 long stream_getpos (Stream *s);
 void stream_setpos (Stream *s, long pos);
 
+long stream_getlen (Stream *s);
+
 void stream_read (void *data, size_t size, size_t n, Stream *r);
 int8_t stream_read8 (Stream *r);
 int16_t stream_read16 (Stream *r);
-- 
2.29.2