blocxx
SafeCStringIO.cpp
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32
33
37
38#include "blocxx/BLOCXX_config.h"
41 /* to get OverflowException and RESULT_TRUNCATED */
42#include "blocxx/String.hpp"
45#include <cstdio>
46
47namespace BLOCXX_NAMESPACE
48{
49namespace SafeCString
50{
51
52char * fgets_trunc(char * dst, std::size_t dstsize, FILE * fp)
53{
54 char * res = std::fgets(dst, dstsize, fp);
55 if (!res)
56 {
57 if (feof(fp))
58 {
59 return 0;
60 }
61 BLOCXX_THROW(blocxx::IOException, "read error");
62 }
63 return res;
64}
65
66char * fgets_check(char * dst, std::size_t dstsize, FILE * fp)
67{
68 std::size_t const end = dstsize - 1;
69 char savechar = dst[end];
70 dst[end] = ' '; // anything but '\0'
71 char * res = std::fgets(dst, dstsize, fp);
72 char endchar = dst[end];
73 dst[end] = savechar;
74 if (res)
75 {
76 if (endchar == '\0' && (end == 0 || dst[end - 1] != '\n'))
77 {
78 // No newline at end. Either the input line was truncated, or
79 // we read the last line of the file and it had no newline.
80 // We test for EOF to distinguish the two cases. Since the EOF
81 // marker doesn't get set until we actually try to read past EOF,
82 // we first peek one character ahead.
83 std::ungetc(std::fgetc(fp), fp);
84 if (!feof(fp))
85 {
87 OverflowException, "fgets overflow", RESULT_TRUNCATED);
88 }
89 }
90 return res;
91 }
92 else
93 {
94 if (feof(fp))
95 {
96 return 0;
97 }
98 BLOCXX_THROW(blocxx::IOException, "read error");
99 }
100}
101
102String fget_string(FILE * fp, std::size_t const max_chars)
103{
104 // This could perhaps be made more efficient by reading directly into a
105 // custom resizable character array.
106 std::size_t const BUFSIZE = 8 * 1024;
107 StringBuffer sb;
108 char buf[BUFSIZE];
109 while (!sb.endsWith('\n') && sb.length() <= max_chars &&
110 fgets_trunc(buf, fp))
111 {
112 sb.append(buf);
113 }
114 if (sb.length() > max_chars)
115 {
116 BLOCXX_THROW(StringConversionException, "input line too long");
117 }
118 return sb.releaseString();
119}
120
121} // namespace SafeCString
122} // namespace BLOCXX_NAMESPACE
#define BLOCXX_THROW(exType, msg)
Throw an exception using FILE and LINE.
#define BLOCXX_THROW_ERR(exType, msg, err)
Throw an exception using FILE and LINE.
StringBuffer & append(char c)
This String class is an abstract data type that represents as NULL terminated string of characters.
Definition String.hpp:67
char * fgets_trunc(char *dst, std::size_t dstsize, FILE *fp)
String fget_string(FILE *fp, std::size_t const max_chars)
char * fgets_check(char *dst, std::size_t dstsize, FILE *fp)
int const RESULT_TRUNCATED
Error codes for use with OverflowException class.
Taken from RFC 1321.