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Diffstat (limited to 'reference/C/PROBLEMS/hexdump1.c')
| -rw-r--r-- | reference/C/PROBLEMS/hexdump1.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/reference/C/PROBLEMS/hexdump1.c b/reference/C/PROBLEMS/hexdump1.c new file mode 100644 index 0000000..0c808c5 --- /dev/null +++ b/reference/C/PROBLEMS/hexdump1.c @@ -0,0 +1,187 @@ +/************************************************************************ + * + * Purpose: To display a file in (mainframe) dump format as shown below. + * + * 20 2A 20 68 65 78 5F 63 68 61 72 28 63 68 61 72 * hex_char(char + * 20 2A 70 6F 73 69 74 69 6F 6E 2C 20 63 68 61 72 *position, char + * 20 63 29 0A 20 20 20 7B 0A 20 20 20 73 70 72 69 c). {. spri + * 6E 74 66 28 70 6F 73 69 74 69 6F 6E 2C 20 22 25 ntf(position, "% + * 30 32 58 20 22 2C 20 63 29 3B 20 0A 0A 09 09 09 02X ", c); ..... + * + * Syntax: hexdump filename + * + * Method: The program fills a variable (line) with the data, when + * the variable is full - it is sent to STDOUT. + * Unprintable charcters are converted to '.' in the ASCII + * display on the right. + * + * Bugs: If the last line of the dump is full, the program will + * follow it with a blank line. Not exactly a serious bug + * but you are welcome to fix it. + * + * To do: o Highlight '0A' (end of line) - seems like a good idea. + * o Get it to read directories. + * o Remove the directory info from argv[0] (if present). + * o Add a column showing the byte offset. + * + * Author: M J Leslie + * + * Rev Date Comments + * --- --------- -------- + * 1.0 08-Feb-94 Inital Release. + * + * 1.1 12-May-95 Original only worked for the hex range 00-7F + * This version supports 00-FF. + * Thanks to Emmanuel Guyot for the fix. + * + ************************************************************************/ + +#include <stdio.h> + +#define HEX_OFFSET 1 +#define ASCII_OFFSET 51 +#define NUM_CHARS 16 + +/************************************************************************/ + +void hexdump (char* prog_name, char * filename); + + /* Clear the display line. */ +void clear_line (char *line, int size); + + /* Put a character (in hex format + * into the display line. */ +char * hex_char (char *position, int c); + + /* Put a character (in ASCII format + * into the display line. */ +char * ascii_char (char *position, int c); + +/************************************************************************/ + +main(int argc, char * argv[]) + { + char *prog_name="hexdump"; + + if (argc != 2) + { + printf("\n\t%s syntax:\n\n", argv[0]); + printf("\t\t%s filename\n\n", argv[0]); + exit(0); + } + + hexdump( argv[0], argv[1]); + } + +/************************************************************************ + * + * The program proper. + * + ************************************************************************/ + +void hexdump(char* prog_name, char * filename) + { + int c=' '; /* Character read from the file */ + + char * hex_offset; /* Position of the next character + * in Hex */ + + char * ascii_offset; /* Position of the next character + * in ASCII. */ + + FILE *ptr; /* Pointer to the file. */ + + char line[81]; /* O/P line. */ + + /* Open the file */ + ptr = fopen(filename,"r"); + if ( ferror(ptr) ) + { + printf("\n\t%s: Unable to open %s\n\n", prog_name, filename); + exit(0); + } + /* little heading. */ + printf("\n\tHex dump of %s\n\n", filename); + + /* Read one character at a time, + * checking for the End of File. + * EOF is defined in <stdio.h> */ + while (c != EOF ) + { + /* Prepare the variables. */ + clear_line(line, sizeof line); + hex_offset = line+HEX_OFFSET; + ascii_offset = line+ASCII_OFFSET; + + while ( ascii_offset < line+ASCII_OFFSET+NUM_CHARS + &&(c = fgetc(ptr)) != EOF ) + { + /* Build the hex part of + * the line. */ + hex_offset = hex_char(hex_offset, c); + + /* Build the Ascii part of + * the line. */ + ascii_offset = ascii_char(ascii_offset, c); + + } + /* Display the current line */ + printf("%s\n", line); + } + + fclose(ptr); /* Close the file. */ + } + +/************************************************************************ + * + * Clear the display line. + * + ************************************************************************/ + +void clear_line(char *line, int size) + { + int count; + + for (count=0; count < size; line[count]=' ', count++); + } + +/************************************************************************ + * + * Put a character into the display line and return the location + * of the next character. + * + ************************************************************************/ +char * ascii_char(char *position, int c) + { + /* If the character is NOT printable + * replace it with a '.' */ + if (!isprint(c)) c='.'; + + sprintf(position, "%c", c); /* Put the character to the line + * so it can be displayed later */ + + /* Return the position of the next + * ASCII character. */ + return(++position); + } + +/************************************************************************ + * + * Put the hex value of a character into the display line and + * return the location of the next hex character. + * + ************************************************************************/ +char * hex_char(char *position, int c) + { + int offset=3; + /* Format and place the character into + * the display line. + * (unsigned char) required for correct + * O/P. */ + + sprintf(position, "%02X ", (unsigned char) c); + + *(position+offset)=' '; /* Remove the '/0' created by 'sprint' */ + + return (position+offset); + } |