Buffer-based streams.

Liviu Nicoara · Liviu Nicoara · commit b57633ba2a61 · 2015-09-12T13:55:19.000-04:00
diff --git a/src/lib/openjp2/openjpeg.c b/src/lib/openjp2/openjpeg.c
@@ -86,6 +86,129 @@ OPJ_BOOL OPJ_CALLCONV opj_set_error_handler(opj_codec_t * p_codec,
 	return OPJ_TRUE;
 }
 
+/* ---------------------------------------------------------------------- */
+/* Buffer-based */
+
+static OPJ_SIZE_T
+opj_read_from_buffer (void* pdst, OPJ_SIZE_T len, opj_buffer_info_t* psrc)
+{
+    OPJ_SIZE_T n = psrc->buf + psrc->len - psrc->cur;
+
+    if (n) {
+        if (n > len)
+            n = len;
+
+        memcpy (pdst, psrc->cur, n);
+        psrc->cur += n;
+    }
+    else
+        n = (OPJ_SIZE_T)-1;
+
+    return n;
+}
+
+static OPJ_SIZE_T
+opj_write_to_buffer (void* p_buffer, OPJ_SIZE_T p_nb_bytes,
+                     opj_buffer_info_t* p_source_buffer)
+{
+    void* pbuf = p_source_buffer->buf;
+    void* pcur = p_source_buffer->cur;
+
+    OPJ_SIZE_T len = p_source_buffer->len;
+
+    if (0 == len)
+        len = 1;
+
+    OPJ_SIZE_T dist = pcur - pbuf, n = len - dist;
+    assert (dist <= len);
+
+    while (n < p_nb_bytes) {
+        len *= 2;
+        n = len - dist;
+    }
+
+    if (len != p_source_buffer->len) {
+        pbuf = opj_malloc (len);
+
+        if (0 == pbuf)
+            return (OPJ_SIZE_T)-1;
+
+        if (p_source_buffer->buf) {
+            memcpy (pbuf, p_source_buffer->buf, dist);
+            opj_free (p_source_buffer->buf);
+        }
+
+        p_source_buffer->buf = pbuf;
+        p_source_buffer->cur = pbuf + dist;
+        p_source_buffer->len = len;
+    }
+
+    memcpy (p_source_buffer->cur, p_buffer, p_nb_bytes);
+    p_source_buffer->cur += p_nb_bytes;
+
+    return p_nb_bytes;
+}
+
+static OPJ_SIZE_T
+opj_skip_from_buffer (OPJ_SIZE_T len, opj_buffer_info_t* psrc)
+{
+    OPJ_SIZE_T n = psrc->buf + psrc->len - psrc->cur;
+
+    if (n) {
+        if (n > len)
+            n = len;
+
+        psrc->cur += len;
+    }
+    else
+        n = (OPJ_SIZE_T)-1;
+
+    return n;
+}
+
+static OPJ_BOOL
+opj_seek_from_buffer (OPJ_SIZE_T len, opj_buffer_info_t* psrc)
+{
+    OPJ_SIZE_T n = psrc->len;
+
+    if (n > len)
+        n = len;
+
+    psrc->cur = psrc->buf + n;
+
+    return OPJ_TRUE;
+}
+
+opj_stream_t* OPJ_CALLCONV
+opj_stream_create_buffer_stream (opj_buffer_info_t* psrc, OPJ_BOOL input)
+{
+    if (!psrc)
+        return 0;
+
+    opj_stream_t* ps = opj_stream_default_create (input);
+
+    if (0 == ps)
+        return 0;
+
+    opj_stream_set_user_data        (ps, psrc, 0);
+    opj_stream_set_user_data_length (ps, psrc->len);
+
+    if (input)
+        opj_stream_set_read_function (
+            ps, (opj_stream_read_fn)opj_read_from_buffer);
+    else
+        opj_stream_set_write_function(
+            ps,(opj_stream_write_fn) opj_write_to_buffer);
+
+    opj_stream_set_skip_function (
+        ps, (opj_stream_skip_fn)opj_skip_from_buffer);
+
+    opj_stream_set_seek_function (
+        ps, (opj_stream_seek_fn)opj_seek_from_buffer);
+
+    return ps;
+}
+
 /* ---------------------------------------------------------------------- */
 
 static OPJ_SIZE_T opj_read_from_file (void * p_buffer, OPJ_SIZE_T p_nb_bytes, FILE * p_file)
diff --git a/src/lib/openjp2/openjpeg.h b/src/lib/openjp2/openjpeg.h
@@ -567,6 +567,11 @@ typedef struct opj_dparameters {
 
 } opj_dparameters_t;
 
+typedef struct opj_buffer_info {
+    OPJ_BYTE* buf;
+    OPJ_BYTE* cur;
+    OPJ_SIZE_T len;
+} opj_buffer_info_t;
 
 /**
  * JPEG2000 codec V2.
@@ -1180,8 +1185,12 @@ OPJ_API opj_stream_t* OPJ_CALLCONV opj_stream_create_default_file_stream (const
 OPJ_API opj_stream_t* OPJ_CALLCONV opj_stream_create_file_stream (const char *fname,
                                                                      OPJ_SIZE_T p_buffer_size,
                                                                      OPJ_BOOL p_is_read_stream);
- 
-/* 
+
+
+OPJ_API opj_stream_t* OPJ_CALLCONV
+opj_stream_create_buffer_stream (opj_buffer_info_t*, OPJ_BOOL);
+
+/*
 ==========================================================
    event manager functions definitions
 ==========================================================
