114 lines
2.4 KiB
C
114 lines
2.4 KiB
C
/* cat.c -- provides a routine to output the contents of the named files in either a buffered or unbuffered fashion. */
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/* Accepts the following parameters: */
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/* -u: Output should be unbuffered. */
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/* Returns the following values: */
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/* 0: All files were printed successfully. */
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/* 1: One or more files could not be opened. */
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#include "common.h"
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/* If mode is set to zero, return a null pointer and print characters directly. Otherwise, return a pointer to a buffer containing */
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/* the contents of the file pointed to by fp. */
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char *cat(FILE *fp, const int mode)
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{
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char c;
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if(!mode)
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{
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int i, buflen;
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buflen = 4096;
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char *arr = malloc(4096);
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char *newarr = 0;
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for(i = 0; (c = fgetc(fp)) != EOF; i++)
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{
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if(i >= buflen)
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{
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buflen *= 2;
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newarr = malloc(buflen);
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strcpy(newarr, arr);
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free(arr);
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arr = newarr;
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}
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arr[i] = c;
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}
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arr[i] = '\0';
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return arr;
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}
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else
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{
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for(;(c = fgetc(fp)) != EOF;)
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{
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putchar(c);
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}
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}
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return NULL;
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}
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int main(int argc, char **argv)
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{
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char *buf, *newbuf, *tmpbuf;
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int i, upresence, fppresence;
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i = upresence = fppresence = 0;
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long unsigned int buflen;
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buflen = 4096;
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FILE *fp;
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fp = 0;
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buf = malloc(buflen);
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if((upresence = (getopt(argc, argv, ":u") == 'u')))
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{
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i++;
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}
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for(i++;argv[i] != NULL; i++)
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{
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if(!strcmp(argv[i], "-"))
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{
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fppresence++;
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newbuf = cat(stdin, upresence);
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}
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else if((fp = fopen(argv[i], "r")) != NULL)
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{
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fppresence++;
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newbuf = cat(fp, upresence);
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}
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else
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{
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fprintf(stderr, "%s: failed to open %s. Aborting.\n", argv[0], argv[i]);
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exit(1);
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}
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if(!upresence and (2 * (strlen(buf) + strlen(newbuf)) >= buflen))
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{
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/* Rewrite this bit to use realloc and/or memcpy? */
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tmpbuf = malloc(2 * (strlen(buf) + strlen(newbuf)));
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strcpy(tmpbuf, buf);
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free(buf);
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buf = tmpbuf;
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}
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if(!upresence)
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{
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strcat(buf, newbuf);
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}
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}
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if(!fppresence)
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{
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buf = cat(stdin, upresence);
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}
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if(!upresence)
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{
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printf("%s", buf);
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}
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exit(0);
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}
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