kopia lustrzana https://github.com/mikaelnousiainen/RS41ng
55 wiersze
1.6 KiB
C
55 wiersze
1.6 KiB
C
#include "utils.h"
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size_t str_replace(char *dest, size_t dest_len, char *orig, char *rep, char *with)
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{
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char *ins; // the next insert point
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char *tmp; // varies
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size_t len_rep; // length of rep (the string to remove)
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size_t len_with; // length of with (the string to replace rep with)
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size_t len_front; // distance between rep and end of last rep
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size_t count; // number of replacements
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// sanity checks and initialization
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if (!orig || !rep) {
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return 0;
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}
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len_rep = strlen(rep);
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if (len_rep == 0) {
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return 0; // empty rep causes infinite loop during count
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}
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if (!with) {
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with = "";
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}
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len_with = strlen(with);
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// count the number of replacements needed
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ins = orig;
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for (count = 0; (tmp = strstr(ins, rep)); ++count) {
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ins = tmp + len_rep;
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}
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size_t required_len = strlen(orig) + (len_with - len_rep) * count + 1;
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if (dest_len < required_len) {
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return 0;
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}
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tmp = dest;
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// first time through the loop, all the variable are set correctly
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// from here on,
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// tmp points to the end of the result string
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// ins points to the next occurrence of rep in orig
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// orig points to the remainder of orig after "end of rep"
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while (count--) {
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ins = strstr(orig, rep);
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len_front = ins - orig;
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tmp = strncpy(tmp, orig, len_front) + len_front;
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tmp = strcpy(tmp, with) + len_with;
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orig += len_front + len_rep; // move to next "end of rep"
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}
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strcpy(tmp, orig);
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return required_len - 1;
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}
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