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author | Paul Eggert <eggert@cs.ucla.edu> | 2004-05-16 19:03:42 +0000 |
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committer | Paul Eggert <eggert@cs.ucla.edu> | 2004-05-16 19:03:42 +0000 |
commit | d175970f402a07706f7cf82b032be5037b2cebb5 (patch) | |
tree | 8d2b9ea7c042ab94770d0f07d66d99cb6d75ca09 /lib/getndelim2.c | |
parent | d6de223fa900d3d2ba3c44f3b0312bdce06653eb (diff) | |
download | gnulib-d175970f402a07706f7cf82b032be5037b2cebb5.tar.gz |
getline cleanup. This changes the getndelim2 API: both order of arguments,
and meaning of delim2 (now uses EOF, not 0, to indicate no delimiter).
Diffstat (limited to 'lib/getndelim2.c')
-rw-r--r-- | lib/getndelim2.c | 123 |
1 files changed, 76 insertions, 47 deletions
diff --git a/lib/getndelim2.c b/lib/getndelim2.c index 2b6dc11571..c3c0566be7 100644 --- a/lib/getndelim2.c +++ b/lib/getndelim2.c @@ -24,82 +24,106 @@ # include <config.h> #endif -/* Specification. */ #include "getndelim2.h" #include <stdlib.h> #include "unlocked-io.h" -/* Always add at least this many bytes when extending the buffer. */ +#include <limits.h> +#if HAVE_INTTYPES_H +# include <inttypes.h> +#endif +#if HAVE_STDINT_H +# include <stdint.h> +#endif +#ifndef PTRDIFF_MAX +# define PTRDIFF_MAX ((ptrdiff_t) (SIZE_MAX / 2)) +#endif +#ifndef SIZE_MAX +# define SIZE_MAX ((size_t) -1) +#endif +#ifndef SSIZE_MAX +# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2)) +#endif + +/* The maximum value that getndelim2 can return without suffering from + overflow problems, either internally (because of pointer + subtraction overflow) or due to the API (because of ssize_t). */ +#define GETNDELIM2_MAXIMUM (PTRDIFF_MAX < SSIZE_MAX ? PTRDIFF_MAX : SSIZE_MAX) + +/* Try to add at least this many bytes when extending the buffer. + MIN_CHUNK must be no greater than GETNDELIM2_MAXIMUM. */ #define MIN_CHUNK 64 ssize_t -getndelim2 (char **lineptr, size_t *linesize, size_t nmax, - FILE *stream, int delim1, int delim2, size_t offset) +getndelim2 (char **lineptr, size_t *linesize, size_t offset, size_t nmax, + int delim1, int delim2, FILE *stream) { - size_t nbytes_avail; /* Allocated but unused chars in *LINEPTR. */ + size_t nbytes_avail; /* Allocated but unused bytes in *LINEPTR. */ char *read_pos; /* Where we're reading into *LINEPTR. */ + ssize_t bytes_stored = -1; + char *ptr = *lineptr; + size_t size = *linesize; - if (!lineptr || !linesize || !nmax || !stream) - return -1; - - if (!*lineptr) + if (!ptr) { - size_t newlinesize = MIN_CHUNK; - - if (newlinesize > nmax) - newlinesize = nmax; - - *linesize = newlinesize; - *lineptr = malloc (*linesize); - if (!*lineptr) + size = nmax < MIN_CHUNK ? nmax : MIN_CHUNK; + ptr = malloc (size); + if (!ptr) return -1; } - if (*linesize < offset) - return -1; + if (size < offset) + goto done; - nbytes_avail = *linesize - offset; - read_pos = *lineptr + offset; + nbytes_avail = size - offset; + read_pos = ptr + offset; - if (nbytes_avail == 0 && *linesize >= nmax) - return -1; + if (nbytes_avail == 0 && nmax <= size) + goto done; for (;;) { - /* Here always *lineptr + *linesize == read_pos + nbytes_avail. */ + /* Here always ptr + size == read_pos + nbytes_avail. */ - register int c; + int c; - /* We always want at least one char left in the buffer, since we - always (unless we get an error while reading the first char) + /* We always want at least one byte left in the buffer, since we + always (unless we get an error while reading the first byte) NUL-terminate the line buffer. */ - if (nbytes_avail < 2 && *linesize < nmax) + if (nbytes_avail < 2 && size < nmax) { - size_t newlinesize = - (*linesize > MIN_CHUNK ? 2 * *linesize : *linesize + MIN_CHUNK); - char *p; - - if (! (*linesize < newlinesize && newlinesize <= nmax)) - newlinesize = nmax; - - *linesize = newlinesize; - nbytes_avail = *linesize + *lineptr - read_pos; - p = realloc (*lineptr, *linesize); - if (!p) - return -1; - *lineptr = p; - read_pos = *linesize - nbytes_avail + *lineptr; + size_t newsize = size < MIN_CHUNK ? size + MIN_CHUNK : 2 * size; + char *newptr; + + if (! (size < newsize && newsize <= nmax)) + newsize = nmax; + + if (GETNDELIM2_MAXIMUM < newsize - offset) + { + size_t newsizemax = offset + GETNDELIM2_MAXIMUM + 1; + if (size == newsizemax) + goto done; + newsize = newsizemax; + } + + nbytes_avail = newsize - (read_pos - ptr); + newptr = realloc (ptr, newsize); + if (!newptr) + goto done; + ptr = newptr; + size = newsize; + read_pos = size - nbytes_avail + ptr; } c = getc (stream); if (c == EOF) { /* Return partial line, if any. */ - if (read_pos == *lineptr) - return -1; + if (read_pos == ptr) + goto done; else break; } @@ -110,14 +134,19 @@ getndelim2 (char **lineptr, size_t *linesize, size_t nmax, nbytes_avail--; } - if (c == delim1 || (delim2 && c == delim2)) + if (c == delim1 || c == delim2) /* Return the line. */ break; } - /* Done - NUL terminate and return the number of chars read. + /* Done - NUL terminate and return the number of bytes read. At this point we know that nbytes_avail >= 1. */ *read_pos = '\0'; - return read_pos - (*lineptr + offset); + bytes_stored = read_pos - (ptr + offset); + + done: + *lineptr = ptr; + *linesize = size; + return bytes_stored; } |