common: add SpiceBuffer - based on qemu-vnc Buffer

https://bugs.freedesktop.org/show_bug.cgi?id=34795

2 files changed, 70 insertions, 0 deletions

diff --git a/common/mem.c b/common/mem.c
index b0a7eb16..a9bd6cc2 100644
--- a/common/mem.c
+++ b/common/mem.c
@@ -237,3 +237,56 @@ void spice_chunks_linearize(SpiceChunks *chunks)
         chunks->chunk[0].len = chunks->data_size;
     }
 }
+
+void spice_buffer_reserve(SpiceBuffer *buffer, size_t len)
+{
+    if ((buffer->capacity - buffer->offset) < len) {
+        buffer->capacity += (len + 1024);
+        buffer->buffer = (uint8_t*)spice_realloc(buffer->buffer, buffer->capacity);
+    }
+}
+
+int spice_buffer_empty(SpiceBuffer *buffer)
+{
+    return buffer->offset == 0;
+}
+
+uint8_t *spice_buffer_end(SpiceBuffer *buffer)
+{
+    return buffer->buffer + buffer->offset;
+}
+
+void spice_buffer_reset(SpiceBuffer *buffer)
+{
+    buffer->offset = 0;
+}
+
+void spice_buffer_free(SpiceBuffer *buffer)
+{
+    free(buffer->buffer);
+    buffer->offset = 0;
+    buffer->capacity = 0;
+    buffer->buffer = NULL;
+}
+
+void spice_buffer_append(SpiceBuffer *buffer, const void *data, size_t len)
+{
+    spice_buffer_reserve(buffer, len);
+    memcpy(buffer->buffer + buffer->offset, data, len);
+    buffer->offset += len;
+}
+
+size_t spice_buffer_copy(SpiceBuffer *buffer, void *dest, size_t len)
+{
+    len = MIN(buffer->offset, len);
+    memcpy(dest, buffer->buffer, len);
+    return len;
+}
+
+size_t spice_buffer_remove(SpiceBuffer *buffer, size_t len)
+{
+    len = MIN(buffer->offset, len);
+    memmove(buffer->buffer, buffer->buffer + len, buffer->offset - len);
+    buffer->offset -= len;
+    return len;
+}
diff --git a/common/mem.h b/common/mem.h
index 5f0eb25e..797bba0a 100644
--- a/common/mem.h
+++ b/common/mem.h
@@ -39,6 +39,13 @@ typedef struct SpiceChunks {
     SpiceChunk   chunk[0];
 } SpiceChunks;
 
+typedef struct SpiceBuffer
+{
+    size_t capacity;
+    size_t offset;
+    uint8_t *buffer;
+} SpiceBuffer;
+
 char *spice_strdup(const char *str) SPICE_GNUC_MALLOC;
 char *spice_strndup(const char *str, size_t n_bytes) SPICE_GNUC_MALLOC;
 void *spice_memdup(const void *mem, size_t n_bytes) SPICE_GNUC_MALLOC;
@@ -103,4 +110,14 @@ size_t spice_strnlen(const char *str, size_t max_len);
 #define spice_new0(struct_type, n_structs) _SPICE_NEW(struct_type, n_structs, malloc0)
 #define spice_renew(struct_type, mem, n_structs) _SPICE_RENEW(struct_type, mem, n_structs, realloc)
 
+/* Buffer management */
+void spice_buffer_reserve(SpiceBuffer *buffer, size_t len);
+int spice_buffer_empty(SpiceBuffer *buffer);
+uint8_t *spice_buffer_end(SpiceBuffer *buffer);
+void spice_buffer_reset(SpiceBuffer *buffer);
+void spice_buffer_free(SpiceBuffer *buffer);
+void spice_buffer_append(SpiceBuffer *buffer, const void *data, size_t len);
+size_t spice_buffer_copy(SpiceBuffer *buffer, void *dest, size_t len);
+size_t spice_buffer_remove(SpiceBuffer *buffer, size_t len);
+
 #endif