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input/trace32_ad: rephrase the header parse logic 

There were several issues with the previous implementation of the logic
which parses trace32 input files: A string comparison was inverted, and
compared a seven character literal to a five character copy of the input.
One more character was trimmed before CTRL-Z (the CP/M EOF), which often
is SPACE in input files, but might be excessive on other input files.

Replace a DIY character search while we are here. Use symbolic names for
special characters. Factor out a test and memory release, to simplify
error code paths in the remaining logic. Extend comments.
This commit is contained in:
Gerhard Sittig 2018-05-12 17:53:42 +02:00 committed by Uwe Hermann
parent 8c4bff1d25
commit 80430d4d20
1 changed files with 27 additions and 18 deletions
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45
src/input/trace32_ad.c
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@ -49,6 +49,10 @@
#define MAX_POD_COUNT 12
#define HEADER_SIZE 80
#define SPACE ' '
#define CTRLZ '\x1a'
#define TRACE32 "trace32"
#define TIMESTAMP_RESOLUTION ((double)0.000000000078125) /* 0.078125 ns */
/*
@ -198,7 +202,8 @@ static int process_header(GString *buf, struct context *inc)
{
char *format_name, *format_name_sig;
char *p;
int i, record_size, device_id;
int has_trace32;
int record_size, device_id;
/*
* 00-31 (0x00-1F) file format name
@ -227,33 +232,39 @@ static int process_header(GString *buf, struct context *inc)
* deal with unexpected or incorrect input data.
*/
/*
* Get up to the first 32 bytes of the file content. File format
* names end on SPACE or CTRL-Z (or NUL). Trim trailing SPACE
* before further processing.
*/
format_name = g_strndup(buf->str, 32);
p = strchr(format_name, CTRLZ);
if (p)
*p = '\0';
g_strchomp(format_name);
/* File format name ends on 0x20/0x1A, let's remove both. */
for (i = 1; i < 31; i++) {
if (format_name[i] == 0x1A) {
format_name[i - 1] = 0;
format_name[i] = 0;
}
}
g_strchomp(format_name); /* This is for additional padding spaces. */
/*
* File format names either start with the "trace32" literal,
* or with a digit and SPACE.
*/
format_name_sig = g_strndup(format_name, strlen(TRACE32));
has_trace32 = g_strcmp0(format_name_sig, TRACE32) == 0;
g_free(format_name_sig);
format_name_sig = g_strndup(format_name, 5);
/* Desired file formats either start with digit+space or "trace32". */
if (g_strcmp0(format_name_sig, "trace32")) {
if (has_trace32) {
/* Literal "trace32" leader, binary header follows. */
if (inc)
inc->format = AD_FORMAT_BINHDR;
} else if (g_ascii_isdigit(format_name[0]) && (format_name[1] == 0x20)) {
} else if (g_ascii_isdigit(format_name[0]) && (format_name[1] == SPACE)) {
/* Digit and SPACE leader, currently unsupported text header. */
if (inc)
inc->format = AD_FORMAT_TXTHDR;
g_free(format_name_sig);
g_free(format_name);
if (inc)
sr_err("This format isn't implemented yet, aborting.");
return SR_ERR;
} else {
g_free(format_name_sig);
/* Unknown kind of format name. Unsupported. */
g_free(format_name);
if (inc)
sr_err("Don't know this file format, aborting.");
@ -276,14 +287,12 @@ static int process_header(GString *buf, struct context *inc)
}
if (!device_id) {
g_free(format_name_sig);
g_free(format_name);
sr_err("Don't know how to handle this file with record size %d.",
record_size);
return SR_ERR;
}
g_free(format_name_sig);
g_free(format_name);
/* Stop processing the header if we just want to identify the file. */