init commit

.gitignore

@@ -0,0 +1,2 @@
+build/
+*.o

src/Makefile

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+TARGET=xxd
+CC=gcc
+
+OBJ = main.o hex.o
+
+$(TARGET): $(OBJ)
+	mkdir -p ../build
+	$(CC) -Wall -g -o $(TARGET) $(OBJ) -g
+	mv $(TARGET) ../build/
+
+main.o: include/hex.h
+hex.o: include/hex.h
+
+.PHONY: clean
+clean:
+	rm -rf ../build $(OBJ)

src/hex.c

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+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdbool.h>
+
+#include "include/hex.h"
+
+void free_hex_chunk(hex_chunk_t* chunk)
+{
+	free(chunk->text);
+	free(chunk->hex);
+}
+
+void add_text_to_chunk(char* src, char** dst)
+{
+	*dst = malloc(sizeof(char) * (TEXT_LINE_LEN + 1));
+
+	strncpy(*dst, src, 16);
+	(*dst)[TEXT_LINE_LEN] = '\0';
+}
+
+void convert_text_to_hex(hex_chunk_t* chunk)
+{
+	int i, j;
+	chunk->hex = malloc(sizeof(char) * (HEX_LINE_LEN + 1));
+
+	for (i = 0, j = 0; i < HEX_LINE_LEN; i += 2, j += 1) {
+		if (chunk->text[j] == '\0')
+			snprintf(chunk->hex + i, 3, "  ");
+		else
+			snprintf(chunk->hex + i, 3, "%02x", chunk->text[j]);
+	}
+}
+
+// TODO: clean up the text formatting to not print it every time
+void display_hex_chunk(hex_chunk_t* chunk)
+{
+	int i, j;
+
+	printf("%08x: ", chunk->line * 16);
+	for (i = 0; i < HEX_LINE_LEN; i += 4) {
+		for (j = 0; j < 4; j += 2) {
+			if (((chunk->hex + i) + j)[0] == '0' && ((chunk->hex + i) + j)[1] == 'a')
+				printf("\x1b[33m");
+			else
+				printf("\x1b[32m");
+			printf("%2.2s", chunk->hex + i + j);
+		}
+		printf(" ");
+	}
+
+	for (i = 0; i < TEXT_LINE_LEN; i++) {
+		if (chunk->text[i] == '\n' || chunk->text[i] == EOF)
+			printf("\x1b[33m.");
+		else
+			printf("\x1b[32m%c", chunk->text[i]);
+	}
+	puts("\x1b[0m");
+}

src/include/hex.h

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+#ifndef HEX_H
+#define HEX_H
+
+#define TEXT_LINE_LEN 16
+#define HEX_LINE_LEN 32
+
+typedef struct {
+	int line;
+	char* text;
+	char* hex;
+} hex_chunk_t;
+
+void free_hex_chunk(hex_chunk_t* chunk);
+void add_text_to_chunk(char* src, char** dst);
+void convert_text_to_hex(hex_chunk_t* chunk);
+void display_hex_chunk(hex_chunk_t* chunk);
+
+#endif

src/main.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "include/hex.h"
+
+/**
+ * read_file_to_buf
+ *
+ * - const char* filename - Name of the file we're opening
+ * - char** buf - pointer to the buffer to hold the file in
+ *
+ *   read the file into a buffer to prevent unnecessary file ops
+ */
+void read_file_to_buf(const char* filename, char** buf)
+{
+	FILE* f;
+	int err, bufsize, newlen;
+
+	f = fopen(filename, "r");
+	if (f == NULL) {
+		perror("fopen");
+		exit(EXIT_FAILURE);
+	}
+
+	err = fseek(f, 0L, SEEK_END);
+	if (err != 0) {
+		perror("fseek");
+		fclose(f);
+		exit(EXIT_FAILURE); }
+
+	bufsize = ftell(f);
+	if (bufsize == -1) {
+		perror("ftell");
+		fclose(f);
+		exit(EXIT_FAILURE);
+	}
+
+	(*buf) = malloc(sizeof(char) * (bufsize + 1));
+	if (*buf == NULL) {
+		perror("malloc");
+		fclose(f);
+		exit(EXIT_FAILURE);
+	}
+
+	rewind(f); 
+
+	newlen = fread(*buf, sizeof(char), bufsize, f);
+	if (ferror(f) != 0) {
+		perror("fread");
+		fclose(f);
+		exit(EXIT_FAILURE);
+	} else {
+		(*buf)[newlen++] = '\0'; // just to be safe	
+	}
+
+	fclose(f);
+}
+
+int get_hex_lines(int len)
+{
+	int out;
+
+	out = len / 16;
+	if (len % 16 != 0)
+		out++;
+
+	return out;
+}
+
+int main(int argc, char* argv[])
+{
+	char* file_content;
+	int hex_lines, i;
+
+	if (argc != 2) {
+		fprintf(stderr, "Usage: %s [filename]\n", argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	read_file_to_buf(argv[1], &file_content);
+	hex_lines = get_hex_lines(strlen(file_content));
+
+	hex_chunk_t* lines = malloc(sizeof(hex_chunk_t) * hex_lines);
+
+	for (i = 0; i < hex_lines; i++) {
+		lines[i].line = i;
+	
+		add_text_to_chunk(file_content + (i * 16), &(lines[i].text));
+		convert_text_to_hex(&lines[i]);
+	}
+
+	for (i = 0; i < hex_lines; i++)
+		display_hex_chunk(&(lines[i]));
+
+
+		
+	free(file_content);	
+	for (i = 0; i < hex_lines; i++)
+		free_hex_chunk(&(lines[i]));
+	free(lines);
+
+
+	return 0;
+}