libstl: add stl_format.h,c

src/libstl/stl_format.c

@@ -0,0 +1,52 @@
+#include "stl_format.h"
+
+#include "../endian.h"
+#include "../internal/byte_codec.h"
+#include "../internal/byte_swap.h"
+#include "stlb_triangle.h"
+
+#include <ctype.h>
+#include <string.h>
+
+#define _INTERNAL_FOUG_FIXED_BUFFER_SIZE  512
+
+foug_stl_format_t foug_stl_get_format(foug_stream_t *stream, size_t data_size)
+{
+  char fixed_buffer[_INTERNAL_FOUG_FIXED_BUFFER_SIZE];
+  size_t byte_read = 0;
+
+  if (stream == NULL || data_size == 0)
+    return FOUG_STL_UNKNOWN_FORMAT;
+
+  memset(fixed_buffer, 0, _INTERNAL_FOUG_FIXED_BUFFER_SIZE);
+  byte_read = foug_stream_read(stream, &fixed_buffer, 1, _INTERNAL_FOUG_FIXED_BUFFER_SIZE);
+
+  /* Binary STL ? */
+  if (byte_read >= (FOUG_STLB_HEADER_SIZE + 4)) {
+    /* Try with little-endian format */
+    uint32_t facet_count = foug_decode_uint32_le((const uint8_t*)fixed_buffer + 80);
+
+    if ((FOUG_STLB_HEADER_SIZE + 4 + facet_count*FOUG_STLB_TRIANGLE_RAWSIZE) == data_size)
+      return FOUG_STL_BINARY_LE_FORMAT;
+
+    /* Try with byte-reverted facet count */
+    facet_count = foug_uint32_bswap(facet_count);
+    if ((FOUG_STLB_HEADER_SIZE + 4 + facet_count*FOUG_STLB_TRIANGLE_RAWSIZE) == data_size)
+      return FOUG_STL_BINARY_BE_FORMAT;
+  }
+
+  /* ASCII STL ? */
+  {
+    size_t pos = 0;
+    while (isspace(fixed_buffer[pos]) && pos < _INTERNAL_FOUG_FIXED_BUFFER_SIZE)
+      ++pos;
+    if (pos == _INTERNAL_FOUG_FIXED_BUFFER_SIZE)
+      return FOUG_STL_ASCII_FORMAT;
+
+    if (strcmp(fixed_buffer + pos, "solid ") == 0)
+      return FOUG_STL_ASCII_FORMAT;
+  }
+
+  /* Fallback case */
+  return FOUG_STL_UNKNOWN_FORMAT;
+}

src/libstl/stl_format.h

@@ -0,0 +1,18 @@
+#ifndef FOUG_LIBSTL_FORMAT_H
+#define FOUG_LIBSTL_FORMAT_H
+
+#include "stl_global.h"
+#include "../stream.h"
+
+typedef enum
+{
+  FOUG_STL_ASCII_FORMAT,     /*!< STL ASCII (text) */
+  FOUG_STL_BINARY_LE_FORMAT, /*!< STL binary (little-endian) */
+  FOUG_STL_BINARY_BE_FORMAT, /*!< STL binary (big-endian) */
+  FOUG_STL_UNKNOWN_FORMAT
+} foug_stl_format_t;
+
+FOUG_DATAX_LIBSTL_EXPORT
+foug_stl_format_t foug_stl_get_format(foug_stream_t* stream, size_t data_size);
+
+#endif /* FOUG_LIBSTL_FORMAT_H */