getline.c

   1 #ifndef CGPERF_GETLINE_C
   2 #define CGPERF_GETLINE_C
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #include <assert.h>
   7 #include "c_fixing.h"
   8 #include "getline.h"
   9 /*------------------------------------------------------------------------------------------------*/
  10 #include "namespace/getline.h"
  11 /*------------------------------------------------------------------------------------------------*/
  12 /*{{{ get_delim */
  13 static s32 get_delim(u8 **lineptr, u32 *n, s32 delimiter, FILE *stream)
  14 {
  15         return getstr(lineptr, n, stream, delimiter, 0);
  16 }/*}}}*/
  17 /*{{{ getstr */
  18 /* always add at least this many bytes when extending the buffer */
  19 #define MIN_CHUNK 64
  20 /* Reads up to (and including) a TERMINATOR from STREAM into *LINEPTR + OFFSET
  21    (and null-terminate it). *LINEPTR is a pointer returned from new [] (or
  22    NULL), pointing to *N characters of space.  It is realloc'd as
  23    necessary.  Returns the number of characters read (not including the
  24    null terminator), or -1 on error or immediate EOF.
  25    NOTE: There is another getstr() function declared in <curses.h>.  */
  26 static s32 getstr(u8 **lineptr, u32 *n, FILE *stream, u8 terminator,
  27                                                                 u32 offset)
  28 {
  29         u32 nchars_avail;       /* allocated but unused chars in *LINEPTR */
  30         u8 *read_pos;           /* Where we're reading into *LINEPTR. */
  31
  32         if (!lineptr || !n || !stream)
  33                 return -1;
  34         if (!*lineptr) {
  35                 *n = MIN_CHUNK;
  36                 *lineptr = calloc(*n, sizeof(u8));
  37         }
  38         nchars_avail = *n - offset;
  39         read_pos = *lineptr + offset;
  40         loop {
  41                 s32 c;
  42
  43                 c = getc(stream);
  44                 /*
  45                  * we always want at least one char left in the buffer, since we always (unless we
  46                  * get an error while reading the first char) NUL-terminate the line buffer
  47                  */
  48                 assert(*n - nchars_avail == (u32)(read_pos - *lineptr));
  49                 if (nchars_avail < 2) {
  50                         u8 *new_line;
  51
  52                         if (*n > MIN_CHUNK)
  53                                 *n *= 2;
  54                         else
  55                                 *n += MIN_CHUNK;
  56
  57                         nchars_avail = *n + *lineptr - read_pos;
  58                         new_line = calloc(*n, sizeof(u8));
  59                         if (*lineptr != 0) {
  60                                 memcpy(new_line, *lineptr, read_pos - *lineptr);
  61                                 free(*lineptr);
  62                         }
  63                         *lineptr = new_line;
  64                         read_pos = *n - nchars_avail + *lineptr;
  65                         assert(*n - nchars_avail == (u32)(read_pos - *lineptr));
  66                 }
  67                 if (c == EOF || ferror(stream)) {
  68                         /* return partial line, if any */
  69                         if (read_pos == *lineptr)
  70                                 return -1;
  71                         else
  72                                 break;
  73                 }
  74                 *read_pos++ = c;
  75                 nchars_avail--;
  76
  77                 if (c == terminator)
  78                         /* return the line */
  79                         break;
  80         }
  81         /* done - NUL terminate and return the number of chars read */
  82         *read_pos = '\0';
  83         return read_pos - (*lineptr + offset);
  84 }
  85 #undef MIN_CHUNK
  86 /*}}}*/
  87 /*------------------------------------------------------------------------------------------------*/
  88 #define EPILOG
  89 #include "namespace/getline.h"
  90 #undef EPILOG
  91 /*------------------------------------------------------------------------------------------------*/
  92 #endif
  93