1 /* Compresses a user-specified number of chunks from stdin into stdout as a single gzip stream.
2 * Each chunk is compressed with a user-specified level.
3 */
4
5 #include "zbuild.h"
6 #ifdef ZLIB_COMPAT
7 # include "zlib.h"
8 #else
9 # include "zlib-ng.h"
10 #endif
11
12 #include <stdio.h>
13
14 #if defined(_WIN32) || defined(__CYGWIN__)
15 # include <fcntl.h>
16 # include <io.h>
17 # define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
18 #else
19 # define SET_BINARY_MODE(file)
20 #endif
21
read_all(unsigned char * buf,size_t size)22 static int read_all(unsigned char *buf, size_t size) {
23 size_t total_read = 0;
24 while (total_read < size) {
25 size_t n_read = fread(buf + total_read, 1, size - total_read, stdin);
26 if (ferror(stdin)) {
27 perror("fread\n");
28 return 1;
29 }
30 if (n_read == 0) {
31 fprintf(stderr, "Premature EOF\n");
32 return 1;
33 }
34 total_read += n_read;
35 }
36 return 0;
37 }
38
write_all(unsigned char * buf,size_t size)39 static int write_all(unsigned char *buf, size_t size) {
40 size_t total_written = 0;
41 while (total_written < size) {
42 size_t n_written = fwrite(buf + total_written, 1, size - total_written, stdout);
43 if (ferror(stdout)) {
44 perror("fwrite\n");
45 return 1;
46 }
47 total_written += n_written;
48 }
49 return 0;
50 }
51
compress_chunk(PREFIX3 (stream)* strm,int level,int size,int last)52 static int compress_chunk(PREFIX3(stream) *strm, int level, int size, int last) {
53 int ret = 1;
54 int err = 0;
55 unsigned long compsize;
56 unsigned char *buf;
57
58 if (size <= 0) {
59 fprintf(stderr, "compress_chunk() invalid size %d\n", size);
60 goto done;
61 }
62 if (level < 0 || level > 9) {
63 fprintf(stderr, "compress_chunk() invalid level %d\n", level);
64 goto done;
65 }
66
67 compsize = PREFIX(deflateBound)(strm, size);
68 buf = malloc(size + compsize);
69 if (buf == NULL) {
70 fprintf(stderr, "Out of memory\n");
71 goto done;
72 }
73 if (read_all(buf, size) != 0) {
74 goto free_buf;
75 }
76
77 /* Provide only output buffer to deflateParams(). It might need some space to flush the leftovers from the last
78 * deflate(), but we don't want it to compress anything new. */
79 strm->next_in = NULL;
80 strm->avail_in = 0;
81 strm->next_out = buf + size;
82 strm->avail_out = compsize;
83 err = PREFIX(deflateParams)(strm, level, Z_DEFAULT_STRATEGY);
84 if (err != Z_OK) {
85 fprintf(stderr, "deflateParams() failed with code %d\n", err);
86 goto free_buf;
87 }
88
89 /* Provide input buffer to deflate(). */
90 strm->next_in = buf;
91 strm->avail_in = size;
92 err = PREFIX(deflate)(strm, last ? Z_FINISH : Z_SYNC_FLUSH);
93 if ((!last && err != Z_OK) || (last && err != Z_STREAM_END)) {
94 fprintf(stderr, "deflate() failed with code %d\n", err);
95 goto free_buf;
96 }
97 if (strm->avail_in != 0) {
98 fprintf(stderr, "deflate() did not consume %d bytes of input\n", strm->avail_in);
99 goto free_buf;
100 }
101 if (write_all(buf + size, compsize - strm->avail_out) != 0) {
102 goto free_buf;
103 }
104 ret = 0;
105
106 free_buf:
107 free(buf);
108 done:
109 return ret;
110 }
111
show_help(void)112 void show_help(void)
113 {
114 printf("Usage: switchlevels [-w bits] level1 size1 [level2 size2 ...]\n\n" \
115 " -w : window bits (8 to 15 for gzip, -8 to -15 for zlib)\n\n");
116 }
117
main(int argc,char ** argv)118 int main(int argc, char **argv) {
119 int ret = EXIT_FAILURE;
120 int err = 0;
121 int size = 0;
122 int level = Z_DEFAULT_COMPRESSION;
123 int level_arg = 1;
124 int window_bits = MAX_WBITS + 16;
125 PREFIX3(stream) strm;
126
127
128 if ((argc == 1) || (argc == 2 && strcmp(argv[1], "--help") == 0)) {
129 show_help();
130 return 0;
131 }
132
133 SET_BINARY_MODE(stdin);
134 SET_BINARY_MODE(stdout);
135
136 memset(&strm, 0, sizeof(strm));
137
138 for (int i = 1; i < argc - 1; i++) {
139 if (strcmp(argv[i], "-w") == 0 && i+1 < argc) {
140 window_bits = atoi(argv[++i]);
141 } else {
142 level_arg = i;
143 level = atoi(argv[i]);
144 break;
145 }
146 }
147
148 err = PREFIX(deflateInit2)(&strm, level, Z_DEFLATED, window_bits, 8, Z_DEFAULT_STRATEGY);
149 if (err != Z_OK) {
150 fprintf(stderr, "deflateInit() failed with code %d\n", err);
151 goto done;
152 }
153
154 for (int i = level_arg; i < argc - 1; i += 2) {
155 level = atoi(argv[i]);
156 size = atoi(argv[i + 1]);
157 if (compress_chunk(&strm, level, size, i + 2 >= argc - 1) != 0) {
158 goto deflate_end;
159 }
160 }
161 ret = EXIT_SUCCESS;
162
163 deflate_end:
164 PREFIX(deflateEnd)(&strm);
165 done:
166 return ret;
167 }
168