[IE C Samples] Implement bmp reader (#8848)

* Implement bmp reader

* Use not os specific functions

* Fix code style

* Move `i` declaration from `for` loop

Co-authored-by: Vladimir Dudnik <vladimir.dudnik@intel.com>

Co-authored-by: Vladimir Dudnik <vladimir.dudnik@intel.com>

samples/c/common/opencv_c_wrapper/CMakeLists.txt

@@ -2,10 +2,10 @@
 # SPDX-License-Identifier: Apache-2.0
 #
 
-project(OpenCV_C_Wrapper)
+project(opencv_c_wrapper)
 set(TARGET_NAME opencv_c_wrapper)
 
-file(GLOB SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/*.cpp)
+file(GLOB SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/*.cpp ${CMAKE_CURRENT_SOURCE_DIR}/*.c)
 file(GLOB HEADERS ${CMAKE_CURRENT_SOURCE_DIR}/*.h)
 
 # create library

samples/c/common/opencv_c_wrapper/bmp_reader.c

@@ -0,0 +1,58 @@
+#include "bmp_reader.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int readBmpImage(const char* fileName, BitMap* image) {
+    FILE* input = fopen(fileName, "rb");
+
+    if (input == NULL) {
+        printf("[BMP] file %s is not opened\n", fileName);
+        return 1;
+    }
+
+    fread(&image->header.type, 2, 1, input);
+
+    if (image->header.type != 'M' * 256 + 'B') {
+        printf("[BMP] file is not bmp type\n");
+        return 2;
+    }
+
+    fread(&image->header.size, 4, 1, input);
+    fread(&image->header.reserved, 4, 1, input);
+    fread(&image->header.offset, 4, 1, input);
+
+    fread(&image->infoHeader, sizeof(BmpInfoHeader), 1, input);
+
+    image->width = image->infoHeader.width;
+    image->height = image->infoHeader.height;
+
+    if (image->infoHeader.bits != 24) {
+        printf("[BMP] 24bpp only supported. But input has: %d\n", image->infoHeader.bits);
+        return 3;
+    }
+
+    if (image->infoHeader.compression != 0) {
+        printf("[BMP] compression not supported\n");
+        return 4;
+    }
+
+    int padSize = image->width & 3;
+    char pad[3];
+    size_t size = image->width * image->height * 3;
+
+    image->data = malloc(sizeof(char) * size);
+
+    fseek(input, image->header.offset, 0);
+
+    // reading by rows in invert vertically
+    int i;
+    for (i = 0; i < image->height; i++) {
+        unsigned int storeAt = image->infoHeader.height < 0 ? i : (unsigned int)image->height - 1 - i;
+        fread(image->data + image->width * 3 * storeAt, image->width * 3, 1, input);
+        fread(pad, padSize, 1, input);
+    }
+
+    fclose(input);
+    return 0;
+}

samples/c/common/opencv_c_wrapper/bmp_reader.h

@@ -0,0 +1,29 @@
+#pragma once
+
+typedef struct BmpHeaderType {
+    unsigned short type; /* Magic identifier            */
+    unsigned int size;   /* File size in bytes          */
+    unsigned int reserved;
+    unsigned int offset; /* Offset to image data, bytes */
+} BmpHeader;
+
+typedef struct BmpInfoHeaderType {
+    unsigned int size;             /* Header size in bytes      */
+    int width, height;             /* Width and height of image */
+    unsigned short planes;         /* Number of colour planes   */
+    unsigned short bits;           /* Bits per pixel            */
+    unsigned int compression;      /* Compression type          */
+    unsigned int imagesize;        /* Image size in bytes       */
+    int xresolution, yresolution;  /* Pixels per meter          */
+    unsigned int ncolours;         /* Number of colours         */
+    unsigned int importantcolours; /* Important colours         */
+} BmpInfoHeader;
+
+typedef struct BitMapType {
+    BmpHeader header;
+    BmpInfoHeader infoHeader;
+    int width, height;
+    unsigned char* data;
+} BitMap;
+
+int readBmpImage(const char* fileName, BitMap* image);

samples/c/common/opencv_c_wrapper/opencv_c_wrapper.cpp

@@ -4,10 +4,24 @@
 
 #include "opencv_c_wrapper.h"
 
+extern "C" {
+#include "bmp_reader.h"
+}
+
 #ifndef USE_OPENCV
 
 int image_read(const char* img_path, c_mat_t* img) {
-    return -1;
+    BitMap bmp;
+    int retCode = readBmpImage(img_path, &bmp);
+
+    img->mat_data = bmp.data;
+    img->mat_data_size = bmp.width * bmp.height * 3;
+    img->mat_width = bmp.width;
+    img->mat_height = bmp.height;
+    img->mat_channels = 3;
+    img->mat_type = bmp.header.type;
+
+    return retCode;
 }
 int image_resize(const c_mat_t* src_img, c_mat_t* dst_img, const int width, const int height) {
     return -1;
@@ -16,7 +30,8 @@ int image_save(const char* img_path, c_mat_t* img) {
     return -1;
 }
 int image_free(c_mat_t* img) {
-    return -1;
+    delete img->mat_data;
+    return 0;
 }
 int image_add_rectangles(c_mat_t* img, rectangle_t rects[], int classes[], int num, int thickness) {
     return -1;