Added C implementation

.gitignore

@@ -1,4 +1,4 @@
 result_image.ppm
 img.ppm
-test_img512x512.ppm
+test
-test
+test_c

README.txt

@@ -1,4 +1,4 @@
-RWPPM - a one-file drop-in C++ library for working with PPM image format.
+RWPPM - a one-file drop-in C and|or C++ library for working with PPM image format.
 
 
 --------------------------------------------------------------------------------------------
@@ -6,37 +6,15 @@ RWPPM - a one-file drop-in C++ library for working with PPM image format.
 
 How to use:
 Either:
-1) Copy src/pnm.cpp to your project, #include and you`re done ! No
+1) Copy src/rwppm.cpp if you're using C++ or src/rwppm.c if you're using C to your project, #include and you`re done ! No
 other dependencies needed.
 
 or
 
 2) Create a dynamic library and use it instead.
 
-
 --------------------------------------------------------------------------------------------
 
-
-Current version:
-v0.4
-
-Status:
-v0.4
-Remove '#' from comments when read
-
-v0.3
-Comments are now read correctly; remove all comments at once
-
-v0.2
-PPM comments writing/reading support
-
-v0.1
-PPM reading, writing
-
-
---------------------------------------------------------------------------------------------
-
-
 License:
 MIT Licese, you are free to do anything, just don`t forget
 to include the notice.

src/rwppm.c

@@ -0,0 +1,174 @@
+/*
+The MIT License (MIT)
+
+Copyright © 2022 Kasyanov Nikolay Alexeyevich (Unbewohnte <me@unbewohnte.xyz>)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+#ifndef RWPPM
+#define RWPPM
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+typedef struct rgb8 {
+    unsigned char r;
+    unsigned char g;
+    unsigned char b;
+} rgb8;
+
+// A very minimal ppm image
+typedef struct ppm_image {
+    unsigned int width;
+    unsigned int height;
+    rgb8* pixels;
+} ppm_image;
+
+// Read ppm image from file on the disk. Returns NULL if something went wrong
+ppm_image* read_ppm(const char* path) {
+    ppm_image* ppm;
+    FILE* file;
+    char magic_number[2];
+    int read_bytes;
+    int character;
+    unsigned int max_rgb_value;
+    rgb8* pixels;
+
+    // open file
+    file = fopen(path, "r");
+    if (file == NULL) {
+        return NULL;
+    }
+
+    // check if the magic number is in place
+    read_bytes = fread(magic_number, 1, 2, file);
+    if (read_bytes != 2 || magic_number[0] != 'P' || magic_number[1] != '6') {
+        return NULL;
+    }
+
+    // skip until width, height and color information
+    character = getc(file);
+    while (character == '#') {
+        while (getc(file) != '\n') {
+            character = getc(file);
+        }
+    }
+    ungetc(character, file);
+
+    ppm = (ppm_image*) malloc(sizeof(ppm_image));
+    if (!ppm) {
+        free(ppm);
+        return NULL;
+    }
+
+    // scan width, height, max color value
+    if (fscanf(file, "%d %d %d", &ppm->width, &ppm->height, &max_rgb_value) != 3) {
+        return NULL;
+    }
+
+    if (max_rgb_value > 255 || max_rgb_value == 0) {
+        // can't read that one !
+        return NULL;
+    }
+
+    // skip last newline before matrix of pixels
+    getc(file);
+
+    // read pixels
+    pixels = (rgb8*) malloc(sizeof(rgb8) * ppm->width * ppm->height);
+    if (!pixels) {
+        free(pixels);
+        return NULL;
+    }
+
+    read_bytes = fread(pixels, sizeof(rgb8) * ppm->width, ppm->height, file);
+    if (read_bytes != ppm->height) {
+        // here read_bytes is not actually bytes read, but
+        // rather rows read 
+        return NULL;
+    }
+    ppm->pixels = pixels;
+
+    // close file
+    fclose(file);
+
+    return ppm;
+}
+
+// Write ppm image to the disk. Returns 0 if everything is alright, 1 otherwise
+int write_ppm(const ppm_image* ppm, const char* path) {
+    FILE* file;
+    
+    file = fopen(path, "w");
+    if (!file) {
+        return 1;
+    }
+
+    fprintf(file, "P6\n");
+    fprintf(file, "%d %d %d\n", ppm->width, ppm->height, 255);
+    fwrite(ppm->pixels, sizeof(rgb8) * ppm->width , ppm->height, file);
+
+    fclose(file);
+
+    return 0;
+}
+
+// Put pixel with specified rgb8 color at x,y coordinates. Returns 0 if pixel has been replaced, 1 if 
+// coordinates are out of bounds
+int put_pixel_at(const unsigned int x, const unsigned int y, const rgb8 color, ppm_image* ppm) {
+    unsigned int index = ppm->width * y + x;
+    if (index >= ppm->width*ppm->height) {
+        // out of bounds !
+        return 1;
+    }
+
+    ppm->pixels[index] = color;
+
+    return 0;
+}
+
+// Get pixel color at specified coordinates. Returns a const pointer to that pixel color if 
+// it is present, NULL if coordinates are out of bounds
+const rgb8* get_pixel_at(const unsigned int x, const unsigned int y, ppm_image* ppm) {
+    unsigned int index = ppm->width * y + x;
+    if (index >= ppm->width*ppm->height) {
+        // out of bounds !
+        return NULL;
+    }
+
+    const rgb8* pixel_color = &ppm->pixels[index];
+
+    return pixel_color;
+}
+
+// Create a new ppm image with specified dimensions. All pixels are {0, 0, 0} (black) by default
+ppm_image* new_ppm_image(const unsigned int width, const unsigned int height) {
+    ppm_image* ppm;
+    rgb8* pixels;
+    const rgb8 default_pixel_color = {0, 0, 0};
+    
+    ppm = (ppm_image*) malloc(sizeof(ppm_image));
+    pixels = (rgb8*) malloc(sizeof(rgb8) * width * height);
+    
+    ppm->width = width;
+    ppm->height = height;
+
+
+    for (unsigned int y = 0; y < height; y++) {
+        for (unsigned int x = 0; x < width; x++) {
+            pixels[width * y + x] = default_pixel_color;
+        }
+    }
+    ppm->pixels = pixels;
+
+    return ppm;
+}
+
+#endif

src/rwppm.cpp

@@ -14,12 +14,6 @@ THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR I
 #ifndef RWPPM
 #define RWPPM
 
-/*
-RWPPM v0.4
-
-A drop-in library to work with PPM images
-*/
-
 #include <vector>
 #include <fstream>
 

tests/test.c

@@ -0,0 +1,35 @@
+#include "../src/rwppm.c"
+#include <stdio.h>
+#include <stdlib.h>
+
+int main() {
+    ppm_image* ppm = read_ppm("test_img512x512.ppm");
+    if (ppm == NULL) {
+        perror("could not read ppm image");
+        return 1;
+    }
+
+    if (write_ppm(ppm, "result_image.ppm") != 0) {
+        perror("could not write new ppm image");
+        return 1;
+    }
+
+    free(ppm);
+
+    ppm_image* new_ppm = new_ppm_image(200, 200);
+    for(int y = 0; y < 200; y++) {
+        for(int x = 0; x < 200; x++) {
+            rgb8 pixel = {10 + x, 20 + x, 50 + y};
+            put_pixel_at(x, y, pixel, new_ppm);
+        } 
+    }
+
+    if (write_ppm(new_ppm, "result_image.ppm") != 0) {
+        perror("could not write new ppm image");
+        return 1;
+    }
+
+    free(new_ppm);
+
+    return 0;
+}

tests/test.cpp

@@ -1,5 +1,5 @@
 #include <iostream>
-#include "../src/ppm.cpp"
+#include "../src/rwppm.cpp"
 
 
 void make_test_img() {