/*
- * gunzip65 - a gunzip utility for 6502-based machines.
- *
- * Piotr Fusik <fox@scene.pl>
- *
- * This should be considered as a test of my zlib-compatible library
- * rather than a real application.
- * It's not user-friendly, fault-tolerant, whatever.
- * However, it really works for real GZIP files, provided they are small
- * enough to fit in buffer[] (after decompression!).
- */
+** gunzip65 - a gunzip utility for 6502-based machines.
+**
+** Piotr Fusik <fox@scene.pl>
+**
+** This should be considered as a test of my zlib-compatible library
+** rather than a real application.
+** It's not user-friendly, fault-tolerant, whatever.
+** However, it really works for real GZIP files, provided they are small
+** enough to fit in buffer[] (after decompression!).
+*/
#include <stdio.h>
#include <string.h>
#include <zlib.h>
+#ifdef __CC65__
+#include <stdlib.h>
+#include <cc65.h>
+#endif
+
#ifndef __CC65__
/*
- * Emulate inflatemem() if using original zlib.
- * As you can see, this program is quite portable.
- */
+** Emulate inflatemem() if using original zlib.
+** As you can see, this program is quite portable.
+*/
unsigned inflatemem(char* dest, const char* source)
{
- z_stream stream;
+ z_stream stream;
- stream.next_in = (Bytef*) source;
- stream.avail_in = 65535;
+ stream.next_in = (Bytef*) source;
+ stream.avail_in = 65535;
- stream.next_out = dest;
- stream.avail_out = 65535;
+ stream.next_out = dest;
+ stream.avail_out = 65535;
- stream.zalloc = (alloc_func) 0;
- stream.zfree = (free_func) 0;
+ stream.zalloc = (alloc_func) 0;
+ stream.zfree = (free_func) 0;
- inflateInit2(&stream, -MAX_WBITS);
- inflate(&stream, Z_FINISH);
- inflateEnd(&stream);
+ inflateInit2(&stream, -MAX_WBITS);
+ inflate(&stream, Z_FINISH);
+ inflateEnd(&stream);
- return stream.total_out;
+ return stream.total_out;
}
#endif /* __CC65__ */
/*
- * Structure of a GZIP file:
- *
- * 1. GZIP header:
- * Offset 0: Signature (2 bytes: 0x1f, 0x8b)
- * Offset 2: Compression method (1 byte: 8 == "deflate")
- * Offset 3: Flags (1 byte: see below)
- * Offset 4: File date and time (4 bytes)
- * Offset 8: Extra flags (1 byte)
- * Offset 9: Target OS (1 byte: DOS, Amiga, Unix, etc.)
- * if (flags & FEXTRA) { 2 bytes of length, then length bytes }
- * if (flags & FNAME) { ASCIIZ filename }
- * if (flags & FCOMMENT) { ASCIIZ comment }
- * if (flags & FHCRC) { 2 bytes of CRC }
- *
- * 2. Deflate compressed data.
- *
- * 3. GZIP trailer:
- * Offset 0: CRC-32 (4 bytes)
- * Offset 4: uncompressed file length (4 bytes)
- */
+** Structure of a GZIP file:
+**
+** 1. GZIP header:
+** Offset 0: Signature (2 bytes: 0x1f, 0x8b)
+** Offset 2: Compression method (1 byte: 8 == "deflate")
+** Offset 3: Flags (1 byte: see below)
+** Offset 4: File date and time (4 bytes)
+** Offset 8: Extra flags (1 byte)
+** Offset 9: Target OS (1 byte: DOS, Amiga, Unix, etc.)
+** if (flags & FEXTRA) { 2 bytes of length, then length bytes }
+** if (flags & FNAME) { ASCIIZ filename }
+** if (flags & FCOMMENT) { ASCIIZ comment }
+** if (flags & FHCRC) { 2 bytes of CRC }
+**
+** 2. Deflate compressed data.
+**
+** 3. GZIP trailer:
+** Offset 0: CRC-32 (4 bytes)
+** Offset 4: uncompressed file length (4 bytes)
+*/
/* Flags in the GZIP header. */
-#define FTEXT 1 /* Extra text */
-#define FHCRC 2 /* Header CRC */
-#define FEXTRA 4 /* Extra field */
-#define FNAME 8 /* File name */
-#define FCOMMENT 16 /* File comment */
+#define FTEXT 1 /* Extra text */
+#define FHCRC 2 /* Header CRC */
+#define FEXTRA 4 /* Extra field */
+#define FNAME 8 /* File name */
+#define FCOMMENT 16 /* File comment */
/*
- * We read whole GZIP file into this buffer.
- * Then we use this buffer for the decompressed data.
- */
+** We read whole GZIP file into this buffer.
+** Then we use this buffer for the decompressed data.
+*/
static unsigned char buffer[26000];
/*
- * Get a 16-bit little-endian unsigned number, using unsigned char* p.
- * On many machines this could be (*(unsigned short*) p),
- * but I really like portability. :-)
- */
+** Get a 16-bit little-endian unsigned number, using unsigned char* p.
+** On many machines this could be (*(unsigned short*) p),
+** but I really like portability. :-)
+*/
#define GET_WORD(p) (*(p) + ((unsigned) (p)[1] << 8))
/* Likewise, for a 32-bit number. */
#define GET_LONG(p) (GET_WORD(p) + ((unsigned long) GET_WORD(p + 2) << 16))
/*
- * Uncompress a GZIP file.
- * On entry, buffer[] should contain the whole GZIP file contents,
- * and the argument complen should be equal to the length of the GZIP file.
- * On return, buffer[] contains the uncompressed data, and the returned
- * value is the length of the uncompressed data.
- */
+** Uncompress a GZIP file.
+** On entry, buffer[] should contain the whole GZIP file contents,
+** and the argument complen should be equal to the length of the GZIP file.
+** On return, buffer[] contains the uncompressed data, and the returned
+** value is the length of the uncompressed data.
+*/
unsigned uncompress_buffer(unsigned complen)
{
- unsigned char* ptr;
- unsigned long crc;
- unsigned long unclen;
- void* ptr2;
- unsigned unclen2;
-
- /* check GZIP signature */
- if (buffer[0] != 0x1f || buffer[1] != 0x8b) {
- puts("Not GZIP format");
- return 0;
- }
-
- /* check compression method (it is always (?) "deflate") */
- if (buffer[2] != 8) {
- puts("Unsupported compression method");
- return 0;
- }
-
- /* get CRC from GZIP trailer */
- crc = GET_LONG(buffer + complen - 8);
-
- /* get uncompressed length from GZIP trailer */
- unclen = GET_LONG(buffer + complen - 4);
- if (unclen > sizeof(buffer)) {
- puts("Uncompressed size too big");
- return 0;
- }
-
- /* skip extra field, file name, comment and crc */
- ptr = buffer + 10;
- if (buffer[3] & FEXTRA)
- ptr = buffer + 12 + GET_WORD(buffer + 10);
- if (buffer[3] & FNAME)
- while (*ptr++ != 0);
- if (buffer[3] & FCOMMENT)
- while (*ptr++ != 0);
- if (buffer[3] & FHCRC)
- ptr += 2;
-
- /*
- * calculate length of raw "deflate" data
- * (without the GZIP header and 8-byte trailer)
- */
- complen -= (ptr - buffer) + 8;
-
- /*
- * We will move the compressed data to the end of buffer[].
- * Thus the compressed data and the decompressed data (written from
- * the beginning of buffer[]) may overlap, as long as the decompressed
- * data doesn't go further than unread compressed data.
- * ptr2 points to the beginning of compressed data at the end
- * of buffer[].
- */
- ptr2 = buffer + sizeof(buffer) - complen;
- /* move the compressed data to end of buffer[] */
- memmove(ptr2, ptr, complen);
-
- /* uncompress */
- puts("Inflating...");
- unclen2 = inflatemem(buffer, ptr2);
-
- /* verify uncompressed length */
- if (unclen2 != (unsigned) unclen) {
- puts("Uncompressed size does not match");
- return 0;
- }
-
- /* verify CRC */
- puts("Calculating CRC...");
- if (crc32(crc32(0L, Z_NULL, 0), buffer, unclen2) != crc) {
- puts("CRC mismatch");
- return 0;
- }
-
- /* return number of uncompressed bytes */
- return unclen2;
+ unsigned char* ptr;
+ unsigned long crc;
+ unsigned long unclen;
+ void* ptr2;
+ unsigned unclen2;
+
+ /* check GZIP signature */
+ if (buffer[0] != 0x1f || buffer[1] != 0x8b) {
+ puts("Not GZIP format");
+ return 0;
+ }
+
+ /* check compression method (it is always (?) "deflate") */
+ if (buffer[2] != 8) {
+ puts("Unsupported compression method");
+ return 0;
+ }
+
+ /* get CRC from GZIP trailer */
+ crc = GET_LONG(buffer + complen - 8);
+
+ /* get uncompressed length from GZIP trailer */
+ unclen = GET_LONG(buffer + complen - 4);
+ if (unclen > sizeof(buffer)) {
+ puts("Uncompressed size too big");
+ return 0;
+ }
+
+ /* skip extra field, file name, comment and crc */
+ ptr = buffer + 10;
+ if (buffer[3] & FEXTRA)
+ ptr = buffer + 12 + GET_WORD(buffer + 10);
+ if (buffer[3] & FNAME)
+ while (*ptr++ != 0);
+ if (buffer[3] & FCOMMENT)
+ while (*ptr++ != 0);
+ if (buffer[3] & FHCRC)
+ ptr += 2;
+
+ /*
+ ** calculate length of raw "deflate" data
+ ** (without the GZIP header and 8-byte trailer)
+ */
+ complen -= (ptr - buffer) + 8;
+
+ /*
+ ** We will move the compressed data to the end of buffer[].
+ ** Thus the compressed data and the decompressed data (written from
+ ** the beginning of buffer[]) may overlap, as long as the decompressed
+ ** data doesn't go further than unread compressed data.
+ ** ptr2 points to the beginning of compressed data at the end
+ ** of buffer[].
+ */
+ ptr2 = buffer + sizeof(buffer) - complen;
+ /* move the compressed data to end of buffer[] */
+ memmove(ptr2, ptr, complen);
+
+ /* uncompress */
+ puts("Inflating...");
+ unclen2 = inflatemem(buffer, ptr2);
+
+ /* verify uncompressed length */
+ if (unclen2 != (unsigned) unclen) {
+ puts("Uncompressed size does not match");
+ return 0;
+ }
+
+ /* verify CRC */
+ puts("Calculating CRC...");
+ if (crc32(crc32(0L, Z_NULL, 0), buffer, unclen2) != crc) {
+ puts("CRC mismatch");
+ return 0;
+ }
+
+ /* return number of uncompressed bytes */
+ return unclen2;
}
/*
- * Get a filename from standard input.
- */
+** Get a filename from standard input.
+*/
char* get_fname(void)
{
- static char filename[100];
- unsigned len;
- fgets(filename, sizeof(filename), stdin);
- len = strlen(filename);
- if (len >= 1 && filename[len - 1] == '\n')
- filename[len - 1] = '\0';
- return filename;
+ static char filename[100];
+ unsigned len;
+ fgets(filename, sizeof(filename), stdin);
+ len = strlen(filename);
+ if (len >= 1 && filename[len - 1] == '\n')
+ filename[len - 1] = '\0';
+ return filename;
}
int main(void)
{
- FILE* fp;
- unsigned length;
-
- /* read GZIP file */
- puts("GZIP file name:");
- fp = fopen(get_fname(), "rb");
- if (!fp) {
- puts("Can't open GZIP file");
- return 1;
- }
- length = fread(buffer, 1, sizeof(buffer), fp);
- fclose(fp);
- if (length == sizeof(buffer)) {
- puts("File is too long");
- return 1;
- }
-
- /* decompress */
- length = uncompress_buffer(length);
- if (length == 0)
- return 1;
-
- /* write uncompressed file */
- puts("Uncompressed file name:");
- fp = fopen(get_fname(), "wb");
- if (!fp) {
- puts("Can't create output file");
- return 1;
- }
- if (fwrite(buffer, 1, length, fp) != length) {
- puts("Error while writing output file");
- return 1;
- }
- fclose(fp);
-
- puts("Ok.");
- return 0;
+ FILE* fp;
+ unsigned length;
+
+#ifdef __CC65__
+ /* allow user to read exit messages */
+ if (doesclrscrafterexit()) {
+ atexit((void (*)) getchar);
+ }
+#endif /* __CC65__ */
+
+ /* read GZIP file */
+ puts("GZIP file name:");
+ fp = fopen(get_fname(), "rb");
+ if (!fp) {
+ puts("Can't open GZIP file");
+ return 1;
+ }
+ length = fread(buffer, 1, sizeof(buffer), fp);
+ fclose(fp);
+ if (length == sizeof(buffer)) {
+ puts("File is too long");
+ return 1;
+ }
+
+ /* decompress */
+ length = uncompress_buffer(length);
+ if (length == 0)
+ return 1;
+
+ /* write uncompressed file */
+ puts("Uncompressed file name:");
+ fp = fopen(get_fname(), "wb");
+ if (!fp) {
+ puts("Can't create output file");
+ return 1;
+ }
+ if (fwrite(buffer, 1, length, fp) != length) {
+ puts("Error while writing output file");
+ return 1;
+ }
+ fclose(fp);
+
+ puts("Ok.");
+ return 0;
}
projects / cc65 / blobdiff