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 #include <stdlib.h>
14 #include <string.h>
15
16 #if defined(_WIN32) || defined(__CYGWIN__)
17 # include <fcntl.h>
18 # include <io.h>
19 # define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
20 #else
21 # define SET_BINARY_MODE(file)
22 #endif
23
read_all(unsigned char * buf,size_t size)24 static int read_all(unsigned char *buf, size_t size) {
25 size_t total_read = 0;
26 while (total_read < size) {
27 size_t n_read = fread(buf + total_read, 1, size - total_read, stdin);
28 if (ferror(stdin)) {
29 perror("fread\n");
30 return 1;
31 }
32 if (n_read == 0) {
33 fprintf(stderr, "Premature EOF\n");
34 return 1;
35 }
36 total_read += n_read;
37 }
38 return 0;
39 }
40
write_all(unsigned char * buf,size_t size)41 static int write_all(unsigned char *buf, size_t size) {
42 size_t total_written = 0;
43 while (total_written < size) {
44 size_t n_written = fwrite(buf + total_written, 1, size - total_written, stdout);
45 if (ferror(stdout)) {
46 perror("fwrite\n");
47 return 1;
48 }
49 total_written += n_written;
50 }
51 return 0;
52 }
53
compress_chunk(PREFIX3 (stream)* strm,int level,int size,int last)54 static int compress_chunk(PREFIX3(stream) *strm, int level, int size, int last) {
55 int ret = 1;
56 int err = 0;
57 unsigned long compsize;
58 unsigned char *buf;
59
60 if (size <= 0) {
61 fprintf(stderr, "compress_chunk() invalid size %d\n", size);
62 goto done;
63 }
64 if (level < 0 || level > 9) {
65 fprintf(stderr, "compress_chunk() invalid level %d\n", level);
66 goto done;
67 }
68
69 compsize = 100 + 2 * PREFIX(deflateBound)(strm, size);
70 buf = malloc(size + compsize);
71 if (buf == NULL) {
72 fprintf(stderr, "Out of memory\n");
73 goto done;
74 }
75 if (read_all(buf, size) != 0) {
76 goto free_buf;
77 }
78
79 /* Provide only output buffer to deflateParams(). It might need some space to flush the leftovers from the last
80 * deflate(), but we don't want it to compress anything new. */
81 strm->next_in = NULL;
82 strm->avail_in = 0;
83 strm->next_out = buf + size;
84 strm->avail_out = compsize;
85 err = PREFIX(deflateParams)(strm, level, Z_DEFAULT_STRATEGY);
86 if (err != Z_OK) {
87 fprintf(stderr, "deflateParams() failed with code %d\n", err);
88 goto free_buf;
89 }
90
91 /* Provide input buffer to deflate(). */
92 strm->next_in = buf;
93 strm->avail_in = size;
94 err = PREFIX(deflate)(strm, last ? Z_FINISH : Z_SYNC_FLUSH);
95 if ((!last && err != Z_OK) || (last && err != Z_STREAM_END)) {
96 fprintf(stderr, "deflate() failed with code %d\n", err);
97 goto free_buf;
98 }
99 if (strm->avail_in != 0) {
100 fprintf(stderr, "deflate() did not consume %d bytes of input\n", strm->avail_in);
101 goto free_buf;
102 }
103 if (write_all(buf + size, compsize - strm->avail_out) != 0) {
104 goto free_buf;
105 }
106 ret = 0;
107
108 free_buf:
109 free(buf);
110 done:
111 return ret;
112 }
113
show_help(void)114 void show_help(void)
115 {
116 printf("Usage: switchlevels [-w bits] level1 size1 [level2 size2 ...]\n\n" \
117 " -w : window bits (8 to 15 for gzip, -8 to -15 for zlib)\n\n");
118 }
119
main(int argc,char ** argv)120 int main(int argc, char **argv) {
121 int ret = EXIT_FAILURE;
122 int err = 0;
123 int size = 0;
124 int level = Z_DEFAULT_COMPRESSION;
125 int level_arg = 1;
126 int window_bits = MAX_WBITS + 16;
127 PREFIX3(stream) strm;
128
129
130 if ((argc == 1) || (argc == 2 && strcmp(argv[1], "--help") == 0)) {
131 show_help();
132 return 0;
133 }
134
135 SET_BINARY_MODE(stdin);
136 SET_BINARY_MODE(stdout);
137
138 memset(&strm, 0, sizeof(strm));
139
140 for (int i = 1; i < argc - 1; i++) {
141 if (strcmp(argv[i], "-w") == 0 && i+1 < argc) {
142 window_bits = atoi(argv[++i]);
143 } else {
144 level_arg = i;
145 level = atoi(argv[i]);
146 break;
147 }
148 }
149
150 err = PREFIX(deflateInit2)(&strm, level, Z_DEFLATED, window_bits, 8, Z_DEFAULT_STRATEGY);
151 if (err != Z_OK) {
152 fprintf(stderr, "deflateInit() failed with code %d\n", err);
153 goto done;
154 }
155
156 for (int i = level_arg; i < argc - 1; i += 2) {
157 level = atoi(argv[i]);
158 size = atoi(argv[i + 1]);
159 if (compress_chunk(&strm, level, size, i + 2 >= argc - 1) != 0) {
160 goto deflate_end;
161 }
162 }
163 ret = EXIT_SUCCESS;
164
165 deflate_end:
166 PREFIX(deflateEnd)(&strm);
167 done:
168 return ret;
169 }
170